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1993
Interspecific and intraspecific ariabilityv in placoid scale morphology in relation to body form variability in squaliformes
Christopher R. Tabit College of William and Mary - Virginia Institute of Marine Science
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Recommended Citation Tabit, Christopher R., "Interspecific and intraspecific ariabilityv in placoid scale morphology in relation to body form variability in squaliformes" (1993). Dissertations, Theses, and Masters Projects. Paper 1539616872. https://dx.doi.org/doi:10.25773/v5-3hhf-db24
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Interspecific and intraspecific variability in placoid scale morphology in relation to body form variability in squaliformes
Tabit, Christopher Rob, Ph.D.
The College of William and Mary, 1993
U-M-I 300 N. Zeeb Rd. Ann Arbor, MI 48106
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with with permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. INTERSPECIFIC AND INTRASPECIFIC VARIABILITY IN PLACOID
SCALE MORPHOLOGY IN RELATION TO BODY FORM VARIABILITY
IN SQUALIFORMES
A Dissertation
Presented to
The Faculty of the School of Marine Science
The College of William and Mary in Virginia
In Partial Fulfillment
Of the Requirements for the Degree of
Doctorate of Philosophy
By
Christopher R. Tabit
1993
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPROVAL SHEET
This dissertation is submitted in partial fulfillment of the requirements for the degree of
Doctor of Philosophy
\ o J 2 ^ r - isVopher R. Tabit
Approved, October 1, 1993
n A. Commi t Chairman / Advisor
Davi'cTA. 'Evans - k i t JL Evon P. Ruzecki
William G. Raschi Bucknell University Lewisburg, Pennsylvania
Geowge Burgess UmMersrty of Flori Gainesville, Florida
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS ...... iv
LIST OF FIGURES ...... v
LIST OF PLATES ...... x
ABSTRACT ...... xi
INTRODUCTION ...... 1
HISTORICAL REVIEW ...... 5
METHODS...... 27
RESULTS ...... 36
Body Shape Variability ...... 36
Placoid Scale Variability ...... 78
DISCUSSION ...... 146
Body Shape Variability ...... 146
Placoid Scale Variability ...... 189
APPENDICES...... 208
LITERATURE CITED ...... 260
VITAE ...... 267
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGEMENTS
This section is generally thought to be the only portion written under no outside influence. However, few people take into consideration the time at which this section is finally written. It is the night before this dissertation is due at the libraries for binding, the printer beside me is whirling away at the final copies, and the last thing on my mind is the people that influenced this research over the past years. However, I will endeavor to at least mention the major players. First, I would like to express by gratitude to Dr. John Musick. Jack gave me the latitude and freedom to research a project of my own design and conception, and I am truly grateful. My committee members, William Raschi, Evon Ruzecki, David Evans and George Burgess all deserve thanks for their input, patience and fortitude in reviewing this manuscript. There is no way I would have gotten to this point without the students, staff and faculty of Jefferson Hall. They may not always be politically correct, but you can count on them to be there when all is said and done. Obvious to any Jeffersonian, special thanks go to Gloria Rowe for keeping me in line, up to date and when possible, out of trouble. One cannot mention Jefferson Hall without noting the Bubbas and the Brazilian contingency. Finally, I would like to extend my special thanks to Heidi Banford. For the past seven years she has stood along side me during the good times and bad. Heidi has taught me a lot about myself and the world we live in. I could not have done it without her. Now, after almost eight years here, it has come time to move on. In parting, I reminded of a line from Hunter S. Thompson;
’When the going gets weird, the weird turn pro.’
iv
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF FIGURE,S
Figure Page
1. The placoid s c a le ...... 7
2. The forces acting on a swimming shark ...... 17
3. Nine species of Squaliformes examined ...... 30
4. Morphometric m easurem ents ...... 31
5. Placoid scale sampling locations ...... 33
6. The relationship of body shape morphometry to standard length in Centrophorus granulosus ...... 38
7. Mean and 95% confidence intervals for the fin aspect ratios of Centrophorus granulosus ...... 40
8. The relationship of surface area to standard length in Centrophorus granulosus ...... 42
9. The relationship of body shape morphometry to standard length in Centroscymnus coelolepis...... 44
10. Mean and 95% confidence intervals for the fin aspect ratios of Centroscymnus coelolepis...... 45
11. The relationship of surface area to standard length in Centroscymnus coelolepis...... 46
12. The relationship of body shape morphometry to standard length in Dalatias lich a ...... 49
13. Mean and 95% confidence intervals for the fin aspect ratios of Dalatias lich a ...... 50
14. The relationship of surface area to standard length in Dalatias lich a ...... 51
v
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 15. The relationship of body shape morphometry to standard length in Deania calcea...... 54
16. Mean and 95% confidence intervals for the fin aspect ratios of Deania calcea...... 55
17. The relationship of surface area to standard length in Deania calcea ...... 57
18. The relationship of body shape morphometry to standard length in Etmopterus princeps ...... 59
19. Mean and 95% confidence intervals for the fin aspect ratios of Etmopterus princeps ...... 61
20. The relationship of surface area to standard length in Etmopterus princeps ...... 62
21. The relationship of body shape morphometry to standard length in Isistius brasiliensis ...... 64
22. Mean and 95% confidence intervals for the fin aspect ratios of Isistius brasiliensis ...... 66
23. The relationship of surface area to standard length in Isistius brasiliensis ...... 67
24. The relationship of body shape morphometry to standard length in Oxynotus centrina ...... 69
25. Mean and 95% confidence intervals for the fin aspect ratios of Oxynotus centrina ...... 70
26. The relationship of surface area to standard length in Oxynotus centrina ...... 72
27. The relationship of body shape morphometry to standard length in Squalus acanthias ...... 75
28. Mean and 95% confidence intervals for the fin aspect ratios of Squalus acanthias ...... 76
vi
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 29. The relationship of surface area to standard length in Squalus acanthias ...... 77
30. Mean placoid scale morphometric measurements, by location, for Centrophorus granulosus females ...... 81
31. Mean placoid scale morphometric measurements, by location, for Centrophorus granulosus m ales...... 83
32. Spatial distribution of placoid scale morphology by sex in Centrophorus granulosus ...... 85
33. Mean placoid scale morphometric measurements, by location, for Centroscymnus coelolepis fem ales...... 89
34. Mean placoid scale morphometric measurements, by location, for Centroscymnus coelolepis males ...... 90
35. Spatial distribution of placoid scale morphology by sex in Centroscymnus coelolepis...... 93
36. Mean placoid scale morphometric measurements, by location, for Dalatias licha males ...... 97
37. Mean placoid scale morphometric measurements, by location, for Dalatias licha females ...... 99
38. Spatial distribution of placoid scale morphology by sex in Dalatias licha...... 101
39. Mean placoid scale morphometric measurements, by location, for Deania calcea males ...... 105
40. Mean placoid scale morphometric measurements, by location, for Deania calcea fe m a le s...... 107
41. Spatial distribution of placoid scale morphology by sex in Deania calcea...... 109
42. Mean placoid scale morphometric measurements, by location, for Echinorhinus cookei...... 112
vii
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 43. Spatial distribution of placoid scale morphology by sex in Echinorhinus cookei...... 114
44. Mean placoid scale morphometric measurements, by location, for Etmopterus princeps fem ales...... 117
45. Mean placoid scale morphometric measurements, by location, for Etmopterus princeps m a le s ...... 119
46. Spatial distribution of placoid scale morphology by sex in Etmopterus princeps ...... 121
47. Mean placoid scale morphometric measurements, by location, for Isistius brasiliensis fem ales...... 125
48. Mean placoid scale morphometric measurements, by location, for Isistius brasiliensis m a le s ...... 126
49. Spatial distribution of placoid scale morphology by sex in Isistius brasiliensis ...... 129
50. Mean placoid scale morphometric measurements, by location, for Oxynotus centrina m a le s...... 133
51. Mean placoid scale morphometric measurements, by location, for Oxynotus centrina females ...... 134
52. Spatial distribution of placoid scale morphology by sex in Oxyntous centrina ...... 136
53. Mean placoid scale morphometric measurements, by location, for Squalus acanthias females ...... 140
54. Mean placoid scale morphometric measurements, by location, for Squalus acanthias m a le s...... 142
55. Spatial distribution of placoid scale morphology by sex in Squalus acanthias ...... 144
56. The relationship of body surface area to standard length in eight species of Squaliformes ...... 148
viii
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 57. The relationship of measured body surface area vs calculated surface area for nine species of Squaliformes ...... 149
58. The relationship of measured surface area vs calculated surface area for squaloid and galeoid sharks ...... 151
59. The comparative relationship of body girth and standard length for nine species of Squaliformes ...... 154
60. Duncan’s Multiple Range Test for the mean distance measurements as a ratio of standard length for nine species of Squaliformes ...... 155
61. Plot of body girths vs distance from snout as a ratio of S L ...... 156
62. Duncan’s Multiple Range Test for the mean fineness ratio of nine species of Squaliformes ...... 160
63. The relationship of body surface area to standard length by species based on an optimal fineness ratio of 4 .5 ...... 162
64. The frequency distribution of the relative fin position in nine species of Squaliformes ...... 164
65. Duncan’s Multiple Range Test for the distance measurements; POB, PD1, PD2, PP1 and PP2 as a percentage of standard length ...... 165
66. Duncan’s Multiple Range Test for; (a) the mean inter-dorsal distance and (b) the pectoral - pelvic fin distance ...... 167
67. Duncan’s Multiple Range Test for the mean fin aspect ratio ...... 171
68. Duncan’s Multiple Range Test for the mean caudal fin angle ...... 173
69. Means and 95% confidence intervals for fin surface area by species . .. 175
70. Drag coefficient vs Reynold’s number for nine species of Squaliformes 179
71. Total drag vs Reynold’s number for nine species of Squaliformes 180
ix
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF PLATES Plate Page
I. Placoid scales from Centrophorus granulosus...... 79
II. Placoid scales from Centroscymnus coelolepis ...... 87
III. Placoid scales from Dalatias licha ...... 95
IV. Placoid scales from Deania calcea ...... 103
V. Placoid scales from Echinorhinus cookei ...... 110
VI. Placoid scales from Etmopterus princeps ...... 115
VII. Placoid scales from Isistius brasiliensis ...... 123
VIII. Placoid scales from Oxynotus centrina...... 131
IX. Placoid scales from Squalus acanthias...... 139
x
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT
An ontogenetic series of nine species; Centrophorus granulosus, Centroscymnus coelolepis, Dalatias licha, Deania calcea, Echinorhinus cookei, Isistius brasiliensis, Oxynotus centrina and Squalus acanthias were studied to determine swimming capabilities, boundary-layer flow conditions and placoid scale functional morphologies. Body morphometric variables included the girth and the distance from snout to the orbitals, origin of the median and paired fins, and the caudal peduncle, body and fin surface area, fin aspect ratios and caudal fin angles. Placoid scales were sampled from sixteen regions across the body. Morphometric variables included the number of scales per area of integument, scale crown width, length and area, and scale weight. Body shape morphometry coupled with published natural histories suggest a majority of the species examined are probably capable of moderate to fast swimming speeds. There was a correlation between low fin aspect ratios and near neutral buoyancy among the species examined suggesting functions other than dynamic lift for the paired fins. Likewise, there was a trend for these fins to be reduced in size suggesting decreased drag. Freed from functioning in generating lift, the pectoral fins probably provide a high degree of vertical directional control. Larger fins with relatively high aspect ratios were correlated with negatively buoyant species suggesting a role in providing dynamic lift. These sharks were more typical in body form of coastal pelagic or benthic sharks of the order Carcharinidae. The squaloid sharks have been recognized to possess the most morphologically diverse placoid scales. Among the nine species examined, three general crown morphologies were distinguished; traditional plate-like crowns, spike or thorn-like crowns and concave trapezoidal crowns. Ontogenetic, sexual dimorphic, and spatial variability within a specimen was observed in all species and interspecific variability was observed in the trends of placoid scale variability. Placoid scale functional morphologies are hypothesisied from intraspecific and interspecific variability, body shape morphologies and natural histories.
XI
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. INTERSPECIFIC AND INTRASPECIFIC VARIABILITY IN PLACOID SCALE MORPHOLOGY IN RELATION TO BODY FORM VARIABILITY IN SQUALIFORMES
xii
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INTRODUCTION
Swimming, like all forms of locomotion, is the result of momentum transfer
from an animal to the environment. Momentum transfer from the water to the
animal and the animal’s inertia act as forces resisting motion. Hence, in order to
understand the role of swimming in the biology of vertebrates, a knowledge of how
the animal interacts with its environment is essential. Performance measures
(magnitude of the forces determining speed, linear accelerations and turning rate)
place restrictions on behavior and therefore the range of hydrodynamic environments
that a vertebrate is physically competent to occupy (Webb, 1986; Daniel & Webb
1987). Energy costs associated with these forces are met by consumed metabolic
energy and consequently affect functional features such as the diet breadth. Efficient
locomotion allows an animal to allocate more energy resources to growth and/or
reproduction (Werner, 1986; Ware, 1984).
The pertinent force components for aquatic vertebrates are; friction and
pressure drag, lift, acceleration reaction and ground reaction (Webb, 1988). An
acceleration reaction results from changes in the kinetic energy of water affected by
an accelerating or decelerating body. The acceleration reaction is calculated as
additional inertial mass (added mass) that when added to the inertia of a body
accelerating in water conserves momentum according to Newtonian law.
Ground reaction or contact involves the force between an animal and the
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bottom and can be resolved into two orthogonal force components (Daniel & Webb,
1987). Frictional force, parallel to the ground, results from molecular attractions
between an object and the bottom, resisting slippage. Normal to the bottom is an
elastic force resulting from the molecular distortion of a body pushing directly
against the ground. The magnitude depends on the animal’s excess weight in water,
which is always small (Lighthill, 1979; Alexander, 1983; Blake, 1983). Ground
reaction falls off rapidly with distance, and is almost negligible when a propulsor is
more than one span length from the surface.
Lift arises from asymmetries in the flow originating from the water viscosity
and is usually induced by orienting a body or appendage at a small angle to the
flow. The asymmetry generates a pressure difference across the body nearly normal
to the incident flow (Hoerner, 1975; Vogel, 1981).
Viscous drag (friction) always contributes to the total force acting on an
animal. Small, slow swimming animals with small accelerations have viscous forces
that are significant and inertial, and density related force components that can be
neglected (Vogel, 1981; Daniel & Webb 1987). Large, fast animals have large
velocity gradients and viscous forces restricted to a small region close to the body
defined as the boundary layer. Viscous effects in the boundary layer cause it to
separate, distorting the flow outside the boundary layer, resulting in asymmetry of
the flow which is the basis of pressure drag. (Hoerner, 1965: Schlichting, 1968).
Pressure or form drag is potentially the largest drag component when flow
separation occurs. Some pressure drag occurs when the flow remains attached, but,
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once flow separation occurs this form drag component increase tremendously
(Bushnell and Moore, 1991).
Skin friction drag and drag due to lift are generally of the same order but
significantly smaller than the form drag associated with flow separation. Skin
friction drag results from the no-slip boundary condition and can either be laminar
or turbulent.
Drag forces therefore can be reduced either through the maintenance of
laminar flow or by avoiding flow separation. As laminar flow is more easily
separated, it may be advantageous to intentionally trip the boundary layer from
laminar to turbulent flow, thereby eliminating the large pressure drag associated with
separated flow (Bushnell and Moore, 1991).
The role of placoid scales as mechanisms for the reduction of drag has been
documented for only fast swimming galeoids (Raschi & Elsom, 1986; Bechart,
Hoppe and Reif, 1985). Placoid scales of deep sea squaloids may function as a
protective mechanism against predation, abrasion and external parasites (Reif, 1982).
This speculation is based on little known natural histories and observations and
inadequately account for the large amount of intraspecific and interspecific diversity
present in the placoid scale morphology of this group.
This research, describes the spatial and ontogenetic changes in placoid scale
morphology, both interspecific and intraspecific, in light of ontogenetic and
interspecific variability in body shape within the order Squaliformes. Theoretical
hydrodynamics and published natural histories were incorporated to facilitate a better
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understanding of swimming behaviors. Subsequently, scale functions are proposed,
scale variability limits defined and the taxonomic value of scales reevaluated. To
this end, the following hypothesis was proposed.
Ho: The observed diversity in placoid scale morphology within the suborder
Squaloidei is random.
Hi: The diversity present in the placoid scale morphology with the suborder
Squaloidei is not random.
The following questions were proposed to test the validity of the null hypothesis and
to evaluate the intraspecific variability in placoid scale morphology.
1. Is there site specific ontogenetic variation in placoid scale morphology?
2. Is there site specific sexual variation in placoid scale morphology?
3. Is there spatial variation in placoid scale morphology within and between
the sexes?
The intraspecific variation in body shape was evaluated via the following questions:
4. Is there ontogenetic variation in body shape within and between the sexes?
5. What are the hydrodynamic implications of this variation?
The intraspecific relationship between scale morphology and body form variability
was evaluated via the following questions:
6. Is there a relationship between site specific ontogenetic scale morphology
variation and ontogenetic variation in body shape?
7. What are the hydrodynamic implications of such a relationship?
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. HISTORICAL REVIEW
Introduction
Intraspecific and interspecific variability in elasmobranch shagreen has been
observed for over 100 years. Garman (1885) described the dermal denticles or
placoid scales of Chlamvdoselachus anguineus (Garm.) and noted spatial and
interspecific irregularities in size and shape with scales from Heptranchias
pectorosus, H. cinereus. and H. maculatus. Radcliffe (1916, 1917) recommended
that for identification purposes a three inch square piece of shagreen from the middle
of the side below the first dorsal fin should be collected in addition to the standard
field notes and jaws. Radcliffe further noted that in most species the form and
sculpturing of the dermal denticles from a specific body region appeared to vary
little, if any, with age, but in some species there were differences. Applegate (1967)
noted that dorsal lateral trunk scales exhibit greater species specific morphologies
than do scales from other regions of the body, where similarities exist among
nonrelated species. Applegate concluded that when describing sharks, denticles from
more than one area should be examined and that the erection of species based on
individual scales to be meaningless until the limits of denticle variation have been
defined. Historically, however, scale descriptions have generally been limited to
dorsal lateral trunk scales.
More recent research has focused on the functional morphology of placoid
5
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. scales (Raschi & Musick, 1984; Raschi & Elsom, 1986; Reif, 1982; Reif &
Dinkelacker, 1982), and although ontogenetic and spatial differences exist (Radcliffe,
1916; Sakamoto, 1930; Saylest & Hershkowitz, 1937; Norman, 1947; Applegate,
1967; Zayets, 1973; Grover, 1974 & Reif,1985), descriptions have generally been
limited to the dorsal lateral denticles (Comgagno, 1988; etc.). Proposed functions
based on scale descriptions, shark ecology and theoretical hydrodynamics include
drag reduction (Burdak, 1973; Zayets, 1973; Pershin, Chernyshov, Kozlov, Koval
Zayets, 1976; Bechert, Hoppe & Reif, 1985; Bechert, Bartenwerfer, Hoppe Y Reif,
1986; Raschi & Musick, 1984; Raschi & Elson, 1986), protection and defense (Reif,
1978, 1979, 1982 and 1985; Tabit, 1986; Tabit & Raschi, 1992). Grover (1974)
reported that the placoid scales of the juvenile swell shark, Cephaloscvllium
ventriosum, function as a mechanical aid to the sharks movements during hatching.
To date, however, the relationship between observed interspecific, intraspecific and
ontogenetic scale variability and ontogenetic and interspecific variability in body
form and hence swimming mechanics have been neglected.
Placoid Scales. Morphology and Developement
The placoid scale is unique to the Selachians and consists of three primary
units; basal plate, pedicle and crown (Applegate, 1967) (Fig. 1). The basal plate lies
beneath the integument and is attached to the corium via connective tissue. Usually
four lobed or at least rectangular in shape (Daniel, 1928), it may be two or three
lobed, stellate or rounded (Applegate, 1967). The pedicle connects the basal plate
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Figure 1. The placoid scale: (a) basal plate, (b) neck, and (c) crown.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. my&
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. below the integument with the scale crown above. That portion of the crown not
underlaid by the pedicle is termed the blade (Applegate, 1967). Three general scale
crown types are recognized to be widespread among modern sharks; lanceolate
crowns with a single blade, tricuspid crowns, and those with five or more blades or
keels (Applegate, 1967).
Development of placoid scales is from the dermal and epidermal cells of
the integument (Applegate, 1967). Epidermal cells differentiate into elongated
rectangular cells called ameloblasts that deposit enamel, whereas the dermal cells
differentiate into ondontoblasts, which lay down dentine. The dentine comprises at
least three varieties, an outer pallial layer, an inner tubercular dentine, and within the
basal plate a massive nontublar dentine called hyladentine (Applegate, 1967).
The first indication of a scale is the formation of a dermal papilla in the
upper layer of the corium (Daniel, 1928). As the papilla grows upward it raises the
basal layer of the epidermis making a cap or the ameloblast. These cells form a
layer of enamel over the tip of the papilla. The ondontoblasts of the dermal papilla
lying most superficially are the first to lay down dentine which covers the tip and
sides of the papilla. Deeper ondontoblasts send out processes about which dentine is
deposited, thus creating the dentinal canals into which the protoplasmic processes of
the deeper lying ondontoblasts will later enter as the formation of dentine continues
(Daniel, 1928). The production of dentine from outward in, and the thickening and
final crowding of the core of the papilla has led to the conclusion that denticles do
not grow (Holmgren, 1942). Hence, it is through replacement that the denticle size
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and shape is altered with increasing size in sharks (Radcliffe, 1916; Ford, 1921;
Garrick, 1960; Applegate, 1967; Reif, 1985).
The crowns of placoid scales characteristic of modern sharks vary from
spike or spine like structures lacking any true blade to complex features with a
honeycomb microstructure and exhibiting longitudinal ridges on the exposed surface
(Raschi & Elsom, 1986; Reif, 1985; Reif & Dinkelacker, 1982). Spatial distribution
ranges from densely packed overlapping arrangements to sparsely distributed,
nonoverlapping patterns leaving a large percentage of the integument exposed
(Raschi & Elsom, 1986; Tabit, 1985; Raschi & Tabit, 1992). Scale descriptions
have been limited to those scales present on the dorsolateral surface just anterior to
the first dorsal fin. These dorsolateral scales tend to show greater interspecific
variation than scales from the pectoral fins or snout which tend to be similar among
nonrelated species.
Placoid Scales. Functions
Proposed functions for dermal denticles include drag reduction,
mechanically aiding in hatching and the protection from abrasion, parasites,
epibionts and predators. Grover (1974) reported that the juveniles of
Cephaloscvllium ventriosum posses two longitudinal dorsolateral rows of denticles,
designated juvenile denticles, that interact with the edge of the egg case opening and
increase the efficiency of the sharks movement in hatching. These specialized
denticles are found on the juveniles of a variety of oviparous sharks and chimaeroids
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and disappear from the young soon after hatching (Grover, 1974). Reif (1978, 1979,
1982, 1982, & 1985) proposed protection from abrasion on rocky substrate,
parasites, epibionts and predation, hydrodynamics and providing space for
photophores as additional functions of placoid scales. Although Reif (1982) did not
describe a generalized scale type, he proposed that from a generalized scale type,
adaptations radiated outward along four major lines: 1) spike like scales and mucus
for defense; 2) knob like scales for abrasion resistance and strength: 3) grooved
scale crowns for drag reduction and 4) scales with concaved facets which never
erupt through the epidermis for the placement of photophores. Consequently,
observed scale morphologies represent a mosaic of one or more of these functions to
varying degrees.
Various hydrodynamic aspects of placoid scales have been investigated.
Pershin et al (1976) noted that the scaley integument of slow and fast swimming
sharks differ significantly in the density and size of the placoid scales and keels.
They observed that the scales of the Black Sea spiny dogfish are large and relatively
far apart while those of the fast mako shark are smaller, tighter packed, often
touching one another and form precise diagonal rows. The heights of the keels
decrease proportionately with swimming speed and despite a wide variety of scale
types, a relative decrease in the size of the scales with increasing Reynolds number
is characteristic. Pershin et al (1976) further concluded that a hyperbolic
relationship exists between the relative maximum swimming speed (Urn = Um/gL)
and the relative length of the scales (1/1), where Um is the maximum swimming
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speed, g is the acceleration due to gravity, L is SL and 1 is scale crown length. For
slow, fresh water fishes, 1/1 ranged from 10-45 with Um = 1. In contrast, for small
fast marine fishes, 1/1 ranged from 2-8 and Um ranged from 1.5 - 3.0. Pershin et al
(1976) concluded that the scales’ protrusions heights satisfies the demands of
boundary layer theory for both teleost fishes and sharks. Reif (1978, 1982) while
looking at the scales from fast swimming sharks (maximum speed - 20m / sec)
concluded that the hydrodynamic function of the ridges cannot satisfactorily be
explained from classic boundary layer theory. With boundary layer flow being
either laminar or turbulent, and turbulent boundary layers having a very thin laminar
sublayer close to the wall, roughness elements having heights smaller that the
thickness of the laminar sublayer are not expected to influence the flow. Element
heights larger than the thickness of the sublayer will result in additional flow
resistance. Reif and Dinklebacker (1982) estimated for fast swimming sharks, that
flow was turbulent along almost the entire length of the body, and the heights of the
ridges are larger than the thickness of the laminar sublayer, leading to an increase in
flow resistance. Kline et al. (1967) proposed that the turbulent boundary layer does
not consist of a random arrangement of eddies but is somewhat structured within the
laminar sublayer into fluid streaks that alternate locally between high velocity streaks
and low velocity streaks. Reif and Kinklebacker (1982) determined that the scale
ridge spacings were somewhat smaller than the streak spacing and hypothesized that
the ridges influence the flow field close to the body such that the streaky structures
have smaller spacings than observed in turbulent boundary flow. This leads to a
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reduction in turbulent mixing and hence a reduction in flow resistance. Raschi and
Musick (1985) in conjunction with NASA (Walsh, 1982) have shown that the lateral
scale crown ridging present on the dorsal lateral trunk scales of galeoid sharks
exhibit appropriate heights and spacings to promote drag reduction by as much as
15%.
Locomotion
During the Fourth Century B.C., Aristotle (History of Animals) noted
that all creatures capable of motion move with four points of motion. In the case of
fishes, this meant either four fins, four bends in their body or a combination of two
fins and two bends. Today, we understand fish locomotion as a series of waves.
Contractions of the lateral muscles on alternating sides of the body, starting with the
myotomes behind the head and proceeding to the last myotomes of the tail, cause
the lateral displacement of the body and fins and in turn, cause forward motion by
the reaction with water (Wardle & Videler, 1980). Webb (1984) defined four
functional categories to embrace the range of locomotory diversity of aquatic
vertebrates; body caudal fin (BCF) periodic propulsion, body caudal fin (BCF)
transient propulsion, median and paired fin (MPF) propulsion, and nonswimmers.
Body caudal fin periodic propulsion is characterized by cyclically repeating
kinematic patterns using the body and caudal fin for activities sustained for a second
to several weeks. This includes such activities as constant speed cruising, prolonged
and sprint swimming, and two phase locomotory patterns. Body caudal fin transient
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propulsion is characterized by brief, noncyclic kinematics utilized in fast starts and
power turns. Median paired fin propulsion, undulation or oscillation of the median
or paired fins, produces low speed, highly maneuverable motion. Optimal
morphologies for each of these categories, defined as those maximizing thrust while
minimizing drag, are mutually exclusive.
Optimal morphological features for BCF periodic propulsion includes a
high aspect ratio lunate tail, narrow caudal peduncle, relatively stiff, streamlined
anterior body with a large anterior depth to mass ratio and possible endothermy.
Body caudal fin transient propulsion optimizes a large body depth and area,
especially caudally, flexible body and a large muscle mass relative to body mass.
Median and paired fin propulsion optimizes a lateral insertion of pectoral fins,
anterior ventro-lateral insertion of the pelvic fins, extended anal and dorsal fins and
a deep laterally flattened body. The optimal body form for occassional and
nonswimmers is more dependent upon where and how they make their living than
on swimming mechanics.
Although less morphologically specialized than teleosts that exhibit
carangiform swimming (BCF periodic propulsion), some sharks represent a different
level and type of specialization for sustained periodic propulsion (Webb 1984).
Retaining a more flexible body and exploiting the interaction between the sidewash
from an anterior median fin and the next posterior median fin or caudal fin, sharks
effectively increase thrust and can be considered specialized cruisers (Webb 1984).
This specialized case of BCF periodic propulsion is referred to as carchariniform
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swimming after sharks of the genus Carcharhinus that are representive of this form
of lococmotion (Webb, 1984).
Elasmobranchs, having no swim bladder and tending to be denser than
their surroundings, need to exert force against gravity when swimming to maintain
their position in the water column. This upward force or lift is generally thought to
be produced by a positive angle of attack of the pectoral fins and by the effective
action of the heterocercal tail. That the pectoral fins provide lift has been
demonstrated by Harris (1936, 1938) for Mustelus, while the lift produced by the
heterocercal tail had been questioned for many years (Grove & Newell, 1936;
Affleck, 1950; Alexander, 1964).
Caudal Fin
Sharks possess a heterocercal caudal fin, regarded as being an extremely
primitive character in which the notochordal axis is upturned into the upper or
epicaudal lobe (Thomson, 1976). Following the conventions of Thomson (1976) the
angle of upward flexure of the notochordal axis is termed the heterocercal angle.
The notochordal mass includes the main axis of the body containing the notochord,
muscles and internal skeleton. From this mass extends the epicaudal lobe, the
subterminal lobe and the hypochordal lobe. The angle from the base of the caudal
to the tip of the ventral lobe is the hypochordal angle and the angle of elevation is
from the center of gravity and the center of effort of the ventral and dorsal lobes.
The constituent lobes’ proportions vary among species and the heterocercal angle
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can range from 0 to greater than 45°. A well developed epicaudal lobe is only
present in the squalomorph euselachians (Thomson, 1976).
The hemal processes of the vertebrae are elongated, project downward
and back, and provide a stiff base to the enlarged lower, hypochordal lobe. Longer
rays grasp the extended hemal processes and further stiffen the hypochordal lobe.
The anterior hemal process of the fin base may bear detached radial elements. The
neural processes, which are shorter than the hemal, posses an outer row of more
numerous radials which in turn support a tightly packed row of ceratotrichia or fin
rays occupying the long, low ridge which is the epichordal fin lobe (Lindsey, 1978).
The myomeres, extending out along the posterior section of the vertebral column and
retaining their zigzag pattern, are capable of resisting vertebral column bending.
Within the hypochordal lobe, numerous stratified muscle bundles run diagonally
down and forward from the skin covering the ventral edge of the myotomes and
inserting into the hemal processes (Lindsey, 1978).
Prior to Grove’s & Newell’s (1936) description of the motion resulting
from six different types of caudal fin models, there was general speculation as to the
effective action of the heterocercal tail. A heterocercal tail with an epicaudal lobe
smaller than the hypochordal produces an upward and forward propulsion of the
model, whereas, lobes of equal size produce only a forward motion. Caudal fin
models with the notochordal axis bent downward and with equal lobes or with a
larger hypochordal lobe also propelled the model upward and forward while caudal
fin models with straight notochordal axis and symmetrical lobes resulted again in
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only a forward component of motion. Grove and Newell (1936) concluded that the
effective action of the caudal fin lies in the relative sizes of the epicaudal and
hypochordal lobes. Mechanically, the vertical force component acting on each lobe
will be proportional to the size of the respective lobe. When the lower lobe is larger
than the upper, the resulting vertical force component causes the tail to rise. Caudal
fins with equal sized lobes have vertical force components that cancel, eliminating
any vertical component.
Affleck (1950), repeating and extending the Grove & Newell (1936)
experiments, concluded that the relative size of the epicaudal and hypochordal lobes,
caudal fin flexibility and the exact direction of the terminal vertebral axis are
responsible for the precise action of the caudal fin. Confirming the generally
accepted view, Affleck (1950) concluded that the caudal and pectoral fins produce
lift which combined with a buoyancy force acting slightly anterior to the center of
gravity supports the weight of the fish.
Alexander (1965), experimenting with the caudal fins taken from
Scyliorhinus canicula and Galeorhinus galeus, refined the experimental approach of
Grove and Newell (1936) and Affleck (1950) so that the forces generated by the
caudal fins could be measured. Assuming a horizontally swimming shark at
equilibrium subject to the vertical forces (Fig. 2), with the center of buoyancy
anterior to the center of gravity, balancing the vertical forces gives;
A + B + C = W.
where W represents the weight of the fish in air, A the upthrust due to the weight of
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Figure 2. The forces acting on a swimming shark; (A) the upthrust due to the
weight of water displaced, (B) lift due to the pectoral fins, (C) lift due to the caudal
fin, and (W) the weight of the fish in air.
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water it displaces, B the lift due to the pectoral fins and C the lift due to the
heterocercal tail.
Balancing the moments about the center of gravity yields;
Aa + Bb = Cc,
where a, b, and c are the distances from the center of gravity to the lines of action
of A, B, and C. Substituting values obtained from Magnan (1929) for a, b, and c,
the center of gravity and buoyancy into the above equations, Alexander (1965)
estimated the lift produced by the heterocercal tail to be approximately proportional
to the 1.4 power of the transverse speed of the fin. Furthermore, the hypochordal
lobe, acting passively, provides more lift than required for equilibrium at all speeds
greater than 0.5 body lengths per second and maybe adjusted to the required value
by means of the radial muscles of the hypochordal lobe.
Simons (1970) repeated the experiments of Alexander using a more
refined apparatus. Me proposed that the epibatic effect of the thrust of the caudal fin
varied inversely with the size of the hypochordal lobe. Removing different portions
of the hypochordal, Simons showed that the ventral hypochordal lobe reduced rather
than enhanced the epibatic effect and concluded that the hypobatic effect of the
ventral lobe offset the epibatic effect of the dorsal lobe. Thomson (1976) notes that
with the tails Simons used, the ventral lobe was not in the expected trailing position.
Thomson observed that the ventral hypochordal lobe assumes a leading position
during each stroke.
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Paired and Median Fins
The internal support of the dorsal and anal fins of elasmobranchs is a flat
median mosaic of cartilaginous plates called radials (Lindsey, 1978). These radials
are joined by ligaments and the outer of the two or three radials extend into the flat
fin base and sometimes almost to the fin margin. Tightly packed ceratotrichia
greatly outnumber and grasp the underlying radials. A single muscle on either side
of each radial originates from the outer margin of the myotomes and inserts via a
broad tendon into the bases of all the adjacent ceratotrachia. Contractions of the
radial muscles can bend the fin from side to side, but neither forward or aft, nor can
they alter the area of the fin.
The base of the pectoral fin is generally comprised of two cartilaginous
plates, the mesopterygium and metapterygium, which articulate with the pectoral
girdle (Lindsey, 1978). A row of triserial radial rods are continuous with the distal
margin of the pterygia. The pattern of segmentation and fusion of the pterygia and
radials forms a tightly knit mosaic that is rigid proximally and somewhat flexible
distally. The outer web is supported by closely spaced ceratotrachia, completely
covered by skin and muscle.
The muscles associated with the pectoral fin include a superficial
abductor and a deep and superficial adductor (Lindsey, 1978). Each originates from
the girdle and inserts on the fin supports. A tongue from the lateral musculature
recurves ventrally to insert into the lower fin base. The pectoral fins, although more
mobile than the dorsal fins, are less mobile than most teleost pectoral fins. The
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articulation with the pectoral girdle allows the fin to swing forward and aft in its
own plane. The leading edge turns downward slightly as it swings forward, altering
the amount of lift provided by the fins. The low horizontal position of these fins
allows them to act as hydroplanes, counteracting the negative buoyancy and pitch of
the caudal fin.
The components of force acting on a rigid body can be measured with
respect to three primary axis shown in (Harris, 1936). The X axis is along the
direction of flow, the Y axis horizontal and the Z axis is vertical. Turning about
these three axis is known as rolling, pitching and yawing, respectively. The pectoral
and pelvic fins modify the pitching force while the median fins adjust the yawing
moment and play a part as a keel in reducing the tendency to roll (Harris, 1936).
The yawing moments for a shark model, without any fins present, is
positively sloped, implying instability (Harris, 1936). Small deviations along the
long axis of the model from the plane of the X axis produce a large turning moment
that tends to further increase the deflection. The addition of the second dorsal,
caudal and anal fins increases the lateral drag forces and adjusts the slope of the
yawing moments to steeply negative, indicative of strong directional stability. The
addition of the first dorsal fin increases the lateral drag by approximately 50% and
completely changes the moment curve. Negatively sloped at high angles of attack
(a= 10°) the yawing moment is almost negligible over the whole range of
intermediate angles. The further addition of pectoral fins increases the magnitude of
the restoring force by about 30% for attack angles above 10°, however, contrary to
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the increase in stability provided by swept-backed aeroplane wings, below this limit,
no noticeable difference in the moment curve is observed.
The equilibrium of the pitching forces differs from that for yawing
forces. The body is not symmetrical about the horizontal plane with a strongly
curved dorsal surface and flattened underside and although the lift to drag ratio is
only 1.5 (Harris, 1936), the model exhibits small lifting properties, even at zero
attack angles. The vertical forces acting upon a ridged body are controlled by the
placement of the pectoral fins and to a lesser extent the pelvic fins (Harris, 1936).
Attached at 8° angle of incidence, the pectoral fins and their relatively large area
increases the lifting force by a factor of ten. The new position for zero lift is at an
attack angle of -7°, determined by the negative lift of the body and the small positive
lift of the fins. The presence of the pelvic fins increases the slope of the lift curve
by about 7% and decreases the slope of the pitching moment curve by about 10%.
Hydrodynamics
All animals swimming through a fluid encounter a force acting in the
opposite direction of movement resisting its motion. This force is termed drag and
the magnitude of this resistance is directly proportional to the square of the moving
animals speed relative to the surrounding water (Daily & Harleman, 1966).
Total Drag = D = CD p AV02/2
where CD is a dimensionless form coefficient, p is the density of the fluid, V0 is the
swimming velocity and A is the area on a plane normal V0. Owing to Jthe viscosity
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of water, a boundary layer is formed around any moving body in which the moving
body has imparted additional velocity, ie. the boundary layer moves with the moving
body, forming what is termed added mass (Daily & Harleman, 1966). The speed of
the water within the boundary layer is inversely proportional to the distance of that
point from the moving body’s surface. The flow velocity curve in the boundary
layer thus decreases from a maximum at the surface of the moving body to ambient
velocity in the outer stream where the fluid can be considered to be flowing without
friction. The thickness of the boundary layer is expressed as a velocity thickness
and is considered to be the distance from the surface of the body to which the
boundary layer is attached to a distance such that the velocity in the boundary layer
differs by 1% from free stream velocity (Blake, 1983).
Two states of the boundary layer are distinguished; laminar flow in
which the adjacent layers of the fluid move relative to each other, forming smooth
streamlines without macroscopic mixing, and turbulent flow in which macroscopic
mixing both laterally and in the direction of the flow result in fluid particles having
irregular, near random, fluctuating motions and erratic paths (Blake, 1983).
Turbulence is the mode that occurs when viscous shear forces are secondary to
inertial forces in establishing the flow field. The turbulent boundary layer
immediately adjacent to the surface of the moving body retains a very thin laminar
sublayer amounting to about 1% of the total boundary layer thickness. It is the
boundary layer, flowing along the moving body to its posterior tip that creates the
characteristic hydrodynamic wake behind the body.
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The boundary layer, for the case of streamlined bodies, is relatively thin
on the anterior portion and thickens posteriorly. Owing to this thinness, the flow
remains laminar to a certain distance after which the increase in boundary layer
thickness causes a transition to turbulent flow. Turbulent flow, in turn, causes the
boundary layer thickness to increase at a greater rate then laminar flow (Hoerner,
1965).
Osborne Reynolds in 1883 demonstrated these two modes of flow and
presented a parameter (Re) as a criterion for use in determining which mode should
exist (Hoerner, 1965). The Reynold’s number is defined as the ratio
inertial force / mass
frictional force / mass
and is estimated
Re = lV/v
where 1 is the length or width of the stream or of the moving body (animal’s
absolute length), V is the velocity of the stream or the speed of the moving object
(the velocity of the animal relative to the surrounding water) and v is the kinematic
viscosity of the water. A low Reynolds number implies that the viscous forces
dominate the flow, while a high Reynolds number indicates that the inertial forces
dominate the flow.
A critical Reynolds number is defined as the Re where the transition
from laminar to turbulent flow occurs (Hoerner, 1965). This critical value varies
from 9.0 x 104 to 3.0 x 106, with the transition occurring most often at Re values
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around 5.0 x 10s. This transition of the boundary layer from laminar to turbulent
occurs according to the intensity of the initial turbulence in the flow, the shape of
the body and the nature of its surface. The laminar state of the boundary layer is
generally more advantageous energywise than the turbulent state and prevention of
transition to the turbulent state is desired to preserve a lower total drag (Blake,
1983).
Adverse pressure gradients normal to the body surface cause the
boundary layer to separate. For laminar boundary layer flow, the point of separation
is a function of body shape only, while for turbulent boundary layer flow the point
of separation can not be predicted by available theoretical methods (Hoerner, 1965).
Separation of the boundary layer results in a differential between the positive
pressures on the leading end and negative pressures on the trailing side that represent
the pressure drag.
Drag
Gero (1952) considered the total drag as the sum of the drag from the
surface area of the fish, the physical configuration of the fish, and the induced drag
of the tail associated with its oscillatory motion and expressed as:
CDT = Cf + CDF + CDi
where Cr is a skin friction coefficient, CDF is a form drag coefficient, and CDi is an
induced drag coefficient.
The frictional drag coefficient, Cf, is a function of the surface condition
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of the fish and velocity of the water relative to the body of the fish. The areas of
the body on which this coefficient is based have relatively small oscillatory motions
so that the values for this coefficient are assumed to be the same as for a rigid body
(Gero, 1952). The value of Cf is a function of the Reynolds number which in turn
reflects the velocity of the fish, basic linear dimensions of the body and the
kinematic viscosity of the fluid. Turbulent and laminar flow produce two different
frictional drag coefficient curves and are calculated as:
Cf = 4.55/(logI0 Re)2'58 (Turbulent)
Cf = 1.328/(Re)0 5 (Laminar)
For the transition zone form laminar to turbulent flow, neither the
laminar nor turbulent coefficient is applicable.
The form drag coefficient, CDF does not lend itself to exact equations.
Errors exist in the transformation of Cf based on a flat plate to a body of three
dimensions (Gero, 1952) so a residual drag coefficient is used to include the Cf
conversion error and the CDF form drag of the body.
C-Dres = ACf + CDF.
The wave making resistance which can increase the residual drag to
many times its normal must also be taken into account on the drag of a swimming
body and can be expressed as a function of the Froude number, V0/(gl)°'5. The drag
contributed by the caudal fin is of an induced nature in the form of turbulence in the
wake of the fish. It is a function of lift, CL, or thrust coefficient and the aspect ratio
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. (A.R.) of the caudal fin. For any given CL, as the aspect ratio of the caudal fin
increases the associated induced drag decreases (Gero, 1952).
The swept back aspect of the caudal fin results in a reduction in the
velocity of flow across a section normal to the leading edge and a decrease in the
slope of the lift curve (Gero, 1952). Gero further concluded that this reduction in
velocity results in an increase in the local pressure which could delay the onset of
cavitation. Furthermore, the effective angle of attack for a swept-backed caudal fin
is increased and V0 decreased so that the induced drag is smaller than for unswept
surfaces.
The flexible action of the tail may further reduce drag by developing a
favorable pressure gradient permitting a large area of laminar flow to exist. Gero
(1952) proposed that the energy stored in the boundary layer and eventually lost in
the vortices set up by the trailing edges may be reduced by the flexible trailing edge
of the caudal fin presenting a large radius corner around which the fluid can flow.
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The order Squaliformes, although limited to three families, is a highly
diverse group in terms of body shape and hence natural histories. Nine species were
selected to encompass all three families and represent a cross-section of body shapes
and sizes (Fig. 3). Morphometric measurements were selected to evaluate
differences in swimming capabilities based on swimming kinematic models and
theories.
Preserved and fresh specimens of Centrophorus granulosus,
Centroscymnus coelolepis, Dalatias licha, Deania calcea, Echinorhinus cookei,
Etmopterus princeps, Isistius brasiliensis, Oxynotus centrina and Squalus acanthias
were obtained from the Virginia Institute of Marine Science (VIMS), the Florida
Museum of Natural History (UF) and the United States Natural History Museum
(USNM) (Appendix 1). Every attempt was made to sample an ontogenetic series for
each sex within a species. Optimally, this was considered to include at least five
specimens, of each sex, and encompassing the entire known size range as reported in
the literature. Unfortunately, for certain species, notably E. cookei and O. centrina,
the number of specimens sampled is limited at this time.
Morphometric measurements were taken to the nearest millimeter with a
meter stick. Most measurements follow Compagno (1984) and are described as
follows (Fig. 4):
27
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1. Total Length (TLT Tip of the snout to the posterior tip of the terminal lobe of the caudal fin.
2. Standard Length fSLT Tip of the snout to the precaudal notch. Defined as the precaudal length by Compagno (1984).
3. Pre-Orbital Length (POET): Tip of snout to the anterior margin of the orbit.
4. Pre-First Dorsal Length (PD1): Tip of snout to the origin of the first dorsal fin.
5. Pre-Second Dorsal Length (PD2): Tip of snout to the origin of the second dorsal fin.
6. Pre-Pectoral Length (TPIT Tip of snout to the origin of the pectoral fins.
7. Pre-pelvic Length (PP2): Tip of snout to the origin of the pelvic fins.
8. Girth at Orbitals fG-OBh Maximum girth at orbitals.
9. Girth at First Dorsal Fin (G-Dl): Maximum girth at the first dorsal fin orgin.
10. Girth at Second Dorsal Fin (G-D2): Maximum girth at the second dorsal fin orgin.
11. Girth at Pectoral Fins (G-Pl): Maximum girth at the pectoral fin origin.
12. Girth at the Pelvic Fin Origin: Maximum girth at the pelvic fin origin.
13. First Dorsal Fin Length (D1L): Fin origin to free rear tip.
14. First Dorsal Fin Height (PUT): Fin base to apex.
15. Second Dorsal Fin Length (D2L): Fin origin to free rear tip.
16. Second Dorsal Fin Height (D2FD: Fin base to apex.
17. Pectoral Fin Length (P1LT Fin origin to free rear tip.
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18. Pectoral Fin Height ('P1H): Fin base to apex.
19. Pelvic Fin Length (T2L): Fin origin to free rear tip.
20. Pelvic Fin Height (P2H): Fin base to apex.
21. Caudal Fin Dorsal Margin (CDM1: Upper caudal fin origin to posterior tip.
22. Caudal Fin Ventral Margin (CVMl: Lower caudal fin origin to ventral tip.
23. Caudal Fin Span (CDSl: Posterior tip to ventral tip.
25. Hypochordal Angle (HYP)
26. Heterocercal Angle CHET)
Fin aspect ratios, an index of the lift to drag ratio of the fin, was calculated as
the ratio of fin height to fin length. Fineness ratio, an index to minimum surface
area to maximum volume was calculated as the ratio of SL to maximum diamter.
Maximum diameter was calculated from maximum girth which was taken to be at
the G-Dl. However, where maximum girth was not at G-Dl, maximum girth was
measured and the distance from snout noted.
Body and fin surface areas were measured using polyethylene plastic and
follow the general procedures outlined by Musick et al (1990). The head, from
snout to the first gill opening, was divided into a dorsal and ventral half, covered
with a sheet of clear polyethylene plastic and etched with a scalpel creating a pattern
of the two surfaces. In similiar fashion, the body was divided along a vertical
longitudinal plane and a template was cut for one side. Likewise, by outlining the
fins on plastic, a template for each fin was cut. Templates were than washed of
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Figure 3. Nine species of Squaliformes examined from top to bottom; E. cookei,
C. granulosus, C. coelolepis, D. licha, D. calcea, E. princeps, I. brasiliensis and S.
acanthias.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ReproducedReproduced with permission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 31
Figure 4. Morphometric measurements following Compagno, 1984. See text for
explanation.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. - 1 H
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extraneous fluids, dried and weighed to the nearest 0.01 grams on a Fisher Scientific
top loading electronic balance. Four samples (10cm X 10cm) of the polyethyelene
plastic were weighed and their mean (cm2/gm) used to calculate area from weight.
Templates were cut in body sections because large templates were difficult to handle
and increased error. Body surface area (BSA) was than calculated as the sum of the
body template. Median fin surface area was calculated as twice the template area
and paired fin surface area as four time the template area. Total surface area (TSA)
was than calculated as the product of the BSA and the fin surface areas.
Placoid scales were sampled from 70 specimens representing nine species
(Appendix 1). Skin samples were removed from 16 locations across the body (Fig.
5); six head, eight body and two caudal locations. Scale morphometry was
quantified by measuring the scale density, the crown surface area, crown width and
crown length with the aide of a dissecting microscope and the computer enhanced
Biosonics Optical Pattern Recognition System (ref).
Skin samples, ranging in size from 25mm2 to 100mm2, were removed from
the right side of the specimen with a scalpel, marked on the anterior edge for
orientation, labeled for location and archived. Scale density was measured as the
total number of scales per a given area of integument, and then adjusted for the skin
shrinkage (8%) that normally occurs upon removal of the sample from the specimen
(Raschi and Elsom, 1986). Scale surface area was measured as the maximum
projected area of the crown surface and did not take into account contours, ridging
or other crown ornamentation. Crown length was measured as the maximum
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Figure 5. Placoid scale sampling locations.
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<0
CM CO
in
to
co
CM
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longitudinal medial distance and the width as the maximum distance between lateral
point. The percentage of the integument covered by scales (PC) was calculated as
the product of scale crown area and scale density.
Individual scales were isolated by dissolving the integument in household
strength chlorine bleach for one to three days. Scales were then rinsed in distilled
water and allowed to air dry. Whenever possible, scales were weighed in lots of one
hundred on a Fisher Scientific analytical balance to the nearest 0.0001 gm. Scale
weights were then divided by the number of scales weighed and reported as an
average single scale weight.
Body Shape Analysis
Intraspecific sexual dimorphism in body shape was analyzed by
comparing the regression equations for each morphometric measurement on SL, by
sex, for homogeneity of slopes and equality of means using Analysis of Covariance
(ANCOVA) and Analysis of variance (ANOVA). All measurements were log
transformed to eliminate any .allometry that might be present.
The sexes were combined and analyzed for allometry by regressing the
ratio of the morphometric measurement to SL on SL. Positive allometry was
defined as a regression slope greater than and statistically (a = 0.01) different from
zero. Likewise, negative allometry was defined as a slope less than and significantly
(a = 0.01) different from zero.
Interspecific variability in body shape was analyzed using ANCOVA for
the homogeneity of slopes and ANOVA for the equality of means.
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Placoid Scale Morphologic Analysis
Univariate descriptive statistics (mean, range and standard deviation)
were calculated for each placoid scale morphometric character, by species and sex,
and are presented in Appendix 1. Placoid scale morphometric parameters were
regressed on SL, by location and sex, for each species to determine whether an
ontogenetic relationship existed and are presented in Appendix 5.
Analysis of covariance (ANCOVA) was used to examine sexual
dimorphic variability in the regression lines of each character by location (Sokal and
Rohlf). The general linear models program (PROC GLM) in the SAS Statistical
package, was used to perform the ANCOVA procedure. Where slopes were
determined to be homogeneous (a = 0.01), analysis of variance (ANOVA) was used
to examine the homogeneity of means. The SAS, PROC GLM procedure was used
to compute the ANOVA.
Placoid scales within a species and sex were examined for similarity
among locations using cluster analysis and multivariate statistics. The specimen
specific, mean scale parameters; width, length, area, PC and weight, by location
were subjected to clustering into five arbitrary categories by sex. The frequency
distribution for each sample location within the five clusters was used to construct a
spatial distribution pattern of similar scales.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. RESULTS
BODY MORPHOLOGY
The physical parameters of body shape define the mechanical limits or
boundaries of swimming performance and hence define the behavioral constraints on
aquatic vertebrates. Consequently, when little is known concerning the swimming
capabilities or behavior of an organism, body shape may be used to define the limits
of swimming capabilities. Therefore, the objective of this research was to gain
insight into the relative swimming capabilities of the dogfish sharks, Squaliformes,
by quantifing the variability in body shape.
Centrophorus granulosus
Fifteen specimens of C. granulosus ranging in size from neonates
(343mm TL) to adults (1690mm TL) were examined. The morphometric
measurements of eight females and seven males are summarized in Appendix 1.
The size range sampled represents the known size range (300 - >1500mm TL) and
included mature and immature specimens for both males and females as reported by
Compagno (1984).
Linear regression computed for eleven body characters on SL, by sex,
are summarized in Appendix II. The high R2 values suggest a conservative
36
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 37
relationship exists within each sex. Analysis of covariance resulted in no significant
difference (a = 0.01) between either the slopes or the means, between the sexes, for
six of the seven characters. The slope for the regression of girth at PP1 was
significantly different between males and females. Apparently, females increase
girth at the pectoral fins at a faster rate (0.95SL) than males (0.88SL).
Regression of the eleven characters, as percentages of SL, on SL suggest
an allometric relationship for five of the characters (App. III). Regression slopes
were statistically (a = 0.01) less than zero for the POB, PP1 and PD1 distances and
the girth at the caudal peduncle and greater then zero for the PP2 distance. Slopes
ranging from 0.0033 - 0.0070 translate into a 2 - 5%, or a 25-65mm, change across
the sampled size range. This implies that the head and anterior region grow more
stout with size and the posterior region grows narrower. Statistically, the pectoral
fins shift from 0.13SL to 0.075SL and the first dorsal fin from 0.40SL to 0.32SL.
The pelvic fins shift posteriorly from 0.70SL to 0.77SL. The second-dorsal fin
insertion was constant with size and averaged 0.82SL. The inter-dorsal and the
pectoral to pelvic distances both averaged 0.44SL.
Increases in SL accounted for 95 - 99.9% of the observed morphometric
variability (App. IV). The girth at eyes exhibited the greatest variability and the PP2
distance the least. Distance measurements, POB, PD1, PD2, PP1, and PP2,
increased at comparable rates as shown by ANCOVA (a = 0.01). Multiple range
test for comparison of means suggest three groups, PP1, and PD1, PP2 and PD2, and
POB (Fig. 6). Girths were determined to increase at statistically different
(ANCOVA, a =0.01) rates (Fig. 6). The caudal region increased at the slowest
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 38
Figure 6. The relationship of body shape morphometry to standard length in
Centrophorus granulosus; (a) distance measurements: (1) POB, (2) PD1, (3) PD2,
(4) PP1, (5) PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3)
second dorsal fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. H1UI9 AC108 901
30NV1SIQ 901
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 39
rate (0.13mm / mmSL). The girth at eyes and D2 increased at equal rates of
0.27mm / mmSL and the girths at pectorals and D1 increased at the fastest rate (
0.48-0.54mm / mmSL). Generally, the body region, between the pectoral and the
pelvic fins, increased at the fastest rate followed by the head and then the caudal
region. This confirms the earlier notion that the body grows blunt forward and
slender aft with size.
Fineness ratio and fin aspect ratios are summarized in Appendix 1.
Fineness ratio averaged 1.94 with only 16% of the observed variation explained by
increases in SL. Fin aspect ratios did not exhibit any significant relationship with
SL. Increases in size accounted for 27 - 56% of the observed variability in aspect
ratios. The caudal fin had the highest aspect ratio (2.44) and the first dorsal fin the
lowest (0.54) (Fig. 7). The second dorsal, pectoral and pelvic fin aspect ratios were
not significantly different.
The variability in heterocercal and hypocaudal angles was not correlated
with changes in SL. The heterocercal angle averaged 29° and increases in SL
accounted for only 12% of the observed variability. The hypocaudal angle averaged
36.73° and SL accounted for 59% of the variability.
Fin surface areas regressed on SL were significant for all fins (Fig. 8).
Increases in SL accounted for 72 - 97% of the observed variability. ANCOVA
indicated a significant difference among the regression slopes (a = 0.01). The first
and second dorsal fins were determined to have homogenous slopes and means. The
pectoral and pelvic fins also had homogenous slopes but their means were
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 40
Figure 7. Mean and 95% confidence intervals for the fin aspect ratios of
Centrophorus granulosus.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced
FIN Q Q CM CL CL CM o u (C 13 m CO LO CO CM \i c LO d LO LO
ASPECT RATIO 41
significantly different. The caudal fin surface area increased at the fastest rate and
the median fins at the slowest rate.
Body surface area and total surface area regressed on SL yielded a
significant relationship (Fig. 8). Body surface area increase at a rate of 67.61cm2 /
cmSL. Total surface area increased at a rate of 85.87 cm2 / cmSL.
Centroscymnus coelolepis
Thirteen specimens of C. coelolepis ranging in size from 511 - 1050mm
TL were measured. The morphometric measurements for six females and seven
males are summarized in. Appendix 1. The sampled size range represents
approximately 90% of their known size range and included mature and immature
specimens from both sexes.
Linear regression for the eleven body characters on SL, by sex, and
analysis of covariance results are summarized in Appendix II. In all cases the
regressions were significant with high R2 values indicative of a conservative
relationship. With the exception of the slope for girth at the pectorals, all slopes and
means were determined to be homogenous between the sexes (Ancova, a=0.01).
Increases in girth at the pectorals for females (0.951 mm girth / mm SL) was
statistically (a = 0.01) greater than for males (0.628 mm girth / mm SL).
Regression of the eleven characters, as a percentage of SL, on SL were
not significant, suggesting a linear relationship for all characters and SL (App. III.).
The pectoral fin inserted at a mean of 0.28SL and the first-dorsal fin at 0.46SL. The
second-dorsal fin position averaged 0.86SL and the pelvic fins 0.73SL.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 42
Figure 8. The relationship of surface area to standard length in Centrophorus
granulosus: (a) fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4)
pelvic, (5) and (6) caudal; and (b) surface area; (1) BSA, and (2) TSA.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
2.05
1.95 1.85 1.75 1.65 1.55
1.45
1.35 in CO vauv aovduns ocn LOG SL LOG SL LOG
CO If)
co m in r * in 1.35 1.45 1.55 1.65 1.75 1.85 1.95 2.05 oi t-' o vauv aovddns got
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 43
The inter-dorsal distance averaged 0.39SL and the pectoral to pelvic distance
averaged 0.50SL.
Increases in SL accounted for 49 - 99% of the observed variability (App.
IV.). The pre-orbital distance exhibited the greatest variability with SL and the pre-
first dorsal the least. The distance measurements, POB, PD1, PD2, PP1, and PP2
increased with SL at statistically different rates (a = 0.01, Fig. 9). The pre-second
dorsal and pre-pelvic distances increased at the fastest rates and the slopes were
determined to be homogeneous. The pre-first dorsal and pre-orbital distances
increased at the slowest rate. Increases in girth with SL were also determined to be
significantly different (a = 0.01). Girth at the first dorsal increased at the greatest
rate and the girth at the caudal peduncle the slowest rate (Fig. 9).
Body fineness ratio and fin aspect ratios are summarized in Appendix 1.
No significant relationship was found between fineness ratio or fin aspect ratios and
SL (App. IV). Increase in SL accounted for only 9 - 54% of the observed
variability in aspect ratios. The caudal fin and the pectoral fins had the highest
aspect ratios and the first dorsal fin the lowest (Fig. 10). Fineness ratio averaged
1.73 with increases in size accounting for 31% of the observed variability.
Fin surface area exhibited a significant relationship with SL (Fig. 11).
Increases in SL accounted for 91 - 98% of the observed variability. Analysis of
covariance indicated significant differences among the regression slopes. The first
and second dorsal increased at the slowest rates (0.75 & 0.69 mm2 /mm SL,
respectively) and the slopes were determined to be homogeneous. The caudal fin
and the pectoral fins increased size at the fastest rate ( 5.55 & 4.65mm2 / mmSL,
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 44
Figure 9. The relationship of body shape morphometry to standard length in
Centroscymnus coelolepis; (a) distance measurements: (1) POB, (2) PD1, (3) PD2,
(4) PP1, (5) PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3)
second dorsal fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. c°pyright Figure 10. Mean and 95% confidence intervals for the fin aspect ratios of
Centroscymnus coelolepis.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CM
in ASPECT ASPECT RATIO
in o
o CM ■o n ro
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 46
Figure 11. The relationship of surface area to standard length in Centroscymnus
coelolepis: (a) fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4)
pelvic, (5) and (6) caudal; and (b) surface area; (1) BSA, and (2) TSA.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 00
CO CD - ^ O
co
.Q in * n 1------1------»------1------«------1------■------r N i n CO r - CJ> N co co co co c\i o i V3UV 30V3ynS 001
00
LO CD CO
in co in in in c\i o V3UV 30VddnS 001
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 47
respectively) and the slopes were also determined to be homogenous.
Body surface area and total surface area exhibited a positive relationship
with SL (Fig. 11). Body surface area increased at a rate of 4.69mm2 / mmSL while
total surface area increased at a rate of 6.24mm2 / mmSL.
Dalatias licha
Ten specimens of D. licha were measured for morphologic variability.
The morphometric measurements for 7 males and 3 females are summarized in
Appendix 1. TL ranged from 355 to 1135mm and included mature and immature
individuals for both sexes (Compagno, 1984). Sixty percent of their reported size
range (300 - 1600mm TL) was sampled.
Linear regression computed for five distance measurements and six girth
measurements on SL, by sex, are summarized in Appendix II. A highly
conservative relationship was apparent by the high R2 values. Analysis of
covariance detected no significant difference (a = 0.01) between either the slopes or
the means between the sexes and suggested a lack of sexual dimorphism in shape.
The eleven characters, as percentages of SL, were regressed on SL (App.
III.). With the exception of the girth at POB, all slopes were determined not to be
significantly different from zero (ANOVA, a = 0.01). The girth at POB, as a
percent of SL, decreased with increases in SL suggesting a negative allometric
relationship. The -0.015 regression slope would result in the POB girth decreasing
from 0.33SL to 0.24SL over the sampled size range.
Increases in SL accounted for 93 - 99.8% of the observed variability in
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 48
the eleven body shape characters (App. IV.). Analysis of covariance for the distance
measurements, POB, PD1, PD2, PP1, and PP2, indicated that the pectoral fins
inserted at 0.27SL and the pelvic fins at 0.72SL (Fig. 12). The pectoral to pelvic
distance averaged 0.44SL. The median fins inserted at 0.44SL and 0.80SL and the
inter-dorsal distance was 0.37SL. The snout to orbital distance averaged 0.06SL.
Analysis of covarance for the regression of girths on SL resulted in the slopes at
PD1 and PP1 and the girths at POB and PD2 to be homogeneous (a = 0.01, Fig.
12). PP1 and PD1 girths increased at the fastest rate (0.44 - 0.49mm / mmSL)
followed by the girth at PP2 (0.36mm / mmSL). The girth at POB and PD2
increased at 23-25mm / mmSL. The caudal peduncle increased at the slowest rate
of 0.13mm / mmSL.
Fineness ratio and fin aspect ratios are summarized in Appendix 1.
Fineness ratio averaged 1.99 and only 20% of the variation was explained by
increased SL (App. IV.). Fin aspect ratios exhibited no significant relationship with
SL. Increases in SL accounted for 12% (Pl-AR) to 63% (Dl-AR) of the observed
variability. The caudal fin had the highest aspect ratio (2.29) followed by the
pectoral fins (Fig. 13). The first and second dorsal fins had the smallest aspect
ratios.
The caudal fin heterocercal and hypocaudal angles regressed on SL were
significant (a = 0.05, App. IV) . SI accounted for 65 - 72% of the variability. The
heterocercal angle decreased with size and the hypocaudal angle increased.
Fin surface area regressed on SL was significant for all fins (Fig. 14),
with 94 - 98% of the observed variability was explained by increases in SL.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 49
Figure 12. The relationship of body shape morphometry to standard length in
Dalatias licha\ (a) distance measurements: (1) POB, (2) PD1, (3) PD2, (4) PP1, (5)
PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3) second dorsal
fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 'Pe, 'on 0fthi C°PVr:
Utylthi out PerO)is ■s/an 50
Figure 13. Mean and 95% confidence intervals for the fin aspect ratios of Dalatias
licha.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced
FIN CM o TD TO =3 CO CM c\i LO o o to LO
ASPECT RATIO 51
Figure 14. The relationship of surface area to standard length in Dalatias licha: (a)
fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4) pelvic, (5) and
(6) caudal; and (b) surface area; (1) BSA, and (2) TSA.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. coo^rcvjcoooio'cj- co co co co* oi oj c\i vauv aovduns ooi
CO
10 LOG LOG SL in in
in
coin in mco c\i t -1 d vauvaovdans ooi
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 52
Analysis of covariance indicated a difference in the rate of increase in surface area
among the fins. The caudal fin increased at the fastest rate (6.45mm2 / mmSL) and
the first and second dorsal fins the slowest (0.99 - 1.25mm2 / mmSL).
Body surface area and total surface area increased significantly (a =
0.01) with SL (Fig. 14). BSA increased at a rate of 3.80cm2 / cmSL. Total surface
area increased at a rate of 5.42cm2 / cmSL. Increases in SL accounted for 98 - 99%
of the observed variability.
Deania calcea
Fifteen specimens, (10 males, 5 females) ranging in TL from 195 to
1046mm, accounting for 100% of the reported size range (Compagno, 1984) were
sampled. Morphometric measurements are summarized in Appendix 1. The size
range sampled included mature and immature specimens for both sexes and a
prenatal male.
Linear regression for the eleven body characters on SL, by sex, are
summarized in Appendix II. Analysis of covariance determined there was no
significant (a = 0.01) difference between the sexes except for the girths at POB and
PPL Females tended to increase anterior girths at a faster rate than males.
The eleven body shape measurements, expressed as a percentage of SL,
regressed on SL were significantly different (a = 0.01) from zero for 5 of the 11
characters (App. III). A negative allometric relationship existed for POB, PP1 and
for the girths POB, PP2 and CP. Over the sampled size range, this resulted in the
orbitals shifting anteriorly from 0.18SL to 0.14SL, and the pectoral fins from
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 53
0.36SL to 0.29SL. The insertion of the first and second-dorsal fins and the pelvic
fins remained constant at an average of 0.47SL, 0.79SL and 0.78SL, respectively.
The inter-dorsal and pelvic to pectoral distances averaged 0.44SL and 0.46SL,
respectively. The girths at the POB, PP1 and CP decreased over the range sampled
from 0.35SL to 0.20SL, 0.44SL to 0.33SL, and 0.13SL to 0.10SL, respectively.
This, in general, would result in a more slender anterior and posterior region with
increased size.
Increases in SL accounted for 74 to 99% of the observed variability in
body shape (App. IV). The girth at the second dorsal exhibited the greatest
variability with SL while the pre-pectoral distance the least. The PP1 and PD1
distance increased with SL at equal rates (ANCOVA, a = 0.01, Fig. 15). Likewise
PP1 and PP2 distances increased at equal rates. Girths increased at significantly (a
= 0.01) different rates (Fig. 15). Generally, the caudal and head region increased at
a slower rate (0.10 to 0.19 mm / mmSL) and the body at a faster rate (0.26 to
0.35mm /mmSL).
Fineness ratio and fin aspect ratios are summarized in Appendix 1.
Fineness ratio and fin aspect ratios exhibited no significant relationship with SL.
Fineness ratio averaged 2.62 and only 46% of the observed variability could be
explained by SL. SL accounted for ? to ?% of the variability in aspect ratios. The
caudal fin exhibited the highest aspect ratio (2.29) followed by the pectoral fins
(1.56) (Fig. 16). The first dorsal fin exhibited the lowest aspect ratio (0.24).
The heterocercal and hypocaudal angles of the caudal fin exhibited no
significant relationship with SL. The heterocercal angle averaged 25°. The
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 54
Figure 15. The relationship of body shape morphometry to standard length in
Deania calcea\ (a) distance measurements: (1) POB, (2) PD1, (3) PD2, (4) PP1, (5)
PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3) second dorsal
fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CM CO'
CD
CM CO M- CM CO CD CM CM CM H id 19 AQOS 901 o> CM h- CM CO CM LOG SL LOG SL LOG M* CM 05 aoNvisia 9oi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 55 Figure 16. Mean and 95% confidence intervals for the fin aspect ratios of Deania calcea. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced FIN TJ o TO 3 o in cm to ASPECT RATIO 56 hypocaudal angle averaged 45°. SL accounted for ? of the observed variability. Fin surface area regressed on SL accounted for 92% - 96% of the observed variation (Fig. 17). Analysis of covariance suggested that the caudal and pectoral fins increased surface area with increased SL at equal rates. The first dorsal, second dorsal and pelvic fins growth rates were homogeneous. Body surface area and total surface area increased with increased SL (Fig. 17). Increases in SI accounted for 94-96% of the observed variability. Body surface area increased at a rate of 3.12cm2 / cmSL and total surface area at a rate of 4.43cm2 / cmSL. Echinorhinus cookei Two males and one female, ranging in TL from 135 to 1050mm, were measured and are summarized in Appendix 1. The 135mm and the 240mm specimens represented prenatals and the 1050mm a small juvenile. This species is recorded to reach at least 4820mm TL. The small sample size and limited size range limited the descriptive statistical analyses. Regression results are reported in Appendix III and IV for reference purposes only and should not be considered definite for the species. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 57 Figure 17. The relationship of surface area to standard length in Deania colcea: (a) fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4) pelvic, (5) and (6) caudal; and (b) surface area; (1) BSA, and (2) TSA. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CO m CD - O eg co in in V3UV 30VdUnS 001 ooin in co in in in co in CO CM in in co T“ o T" V3yv3ovddnsooi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 58 Etmopterus princeps Thirteen specimens, 5 males and 8 females, of E. princeps were examined. TL ranged from 405 to 637mm and represented about 85% of their known size range and probably included mature and immature specimens for both sexes (Compagno, 1984). Linear regressions computed for the eleven body characters on SL, by sex, are summarized in Appendix II. The R2 values indicate that female morphometries had a stronger relationship with SL than their male counterparts. Analysis of covariance suggested that there was no significant (a = 0.01) difference between the sexes. Linear regression for the eleven characters, as a percentage of SL, on SL, were not significantly different from zero, suggesting no linear relationship (App. III). The insertion of the second-dorsal and the pelvic fins averaged 0.80SL while the first-dorsal and pectoral fins averaged 0.54SL and 0.35SL respectively. The inter-dorsal distance averaged 0.45SL and the pectoral to pelvic distance 0.36SL. The orbitals averaged 0.10SL. Increases in SL accounted for 51 - 98% of the observed variability (App. IV). Linear regression was not significant for the variability in the girths at second dorsal and the pelvic fins. Analysis of covariance suggested that the pre-pectoral and pre-dorsal distances increased at comparable rates as well as the pre-second dorsal and pre-pelvic distances (Fig. 18). There were no statistically (a = 0.01) significant differences between the slopes of girths regressed on SL (Fig. 18). Fineness ratio and fin aspect ratios, summarized in Appendix 1, exhibited Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 59 Figure 18. The relationship of body shape morphometry to standard length in Etmopterus princeps', (a) distance measurements: (1) POB, (2) PD1, (3) PD2, (4) PP1, (5) PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3) second dorsal fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. <0 *o °^OOg OO7 V<0 o‘ COp^8/,( °Wner FUrther reProa. Uction ProfHbitea ^ithout Porm,''ssion 60 no dependency on SL (App. IV). Fineness ratio averaged 2.07 and only 25% of the variability was explained by SL. Increases in SL accounted for 7-35% of the variability in fin aspect ratios. The caudal fin had the highest aspect ratio followed by the pectoral fins (Fig. 19). The mean aspect ratios for the dorsal and pelvic fins were not significantly different. The caudal fin heterocercal and hypocaudal angles showed no dependency upon SL (App. IV). The heterocercal angle averaged 29.2° and the hypochordal angle averaged 14.6°. SL accounted for 29 - 35% of the variability. Fin surface areas regressed on SL were not significant (a = 0.01, Fig. 20). SL accounted for only 23-48% of the variability. The caudal fin was the largest followed by the pectoral and pelvic fins. The first dorsal was the smallest. Body surface area and total surface area were significantly regressed on SL (Fig. 20). BSA increased at a rate of 18.8cm2 / cmSL. Total surface area increased at a rate of 21.2 cm2/cm SL. Isistius brasiliensis Fourteen specimens ranging in TL from 169 - 443 mm were examined. This represented approximately 88% of their known size range of a maximum of 500mm and included mature and immature individuals for both sexes. The morphometric measurements are summarized in Appendix 1. Linear regression for the eleven body characters on SL, by sex, are Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 19. Mean and 95% confidence intervals for the fin aspect ratios of Etmopterus princeps. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced FIN Q Q CM CL Q. CM O ~o ro D (0 co CM \i c LO ASPECT RATIO 62 Figure 20. The relationship of surface area to standard length in Etmopterus princeps: (a) fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4) pelvic, (5) and (6) caudal; and (b) surface area; (1) BSA, and (2) TSA. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. T— CO o vauv aovduns son LOG SL LOG SL LOG CO LO CO O) vauvaovdunsooi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 63 summarized in Appendix II. Analysis of covariance indicated that only the slope for girth at the pectoral fins were sexually dimorphic. Males increased at a faster rate than females. Linear regression of the morphometric characters, as ratios of SL, on SL was significant (a = 0.01) for only the pre-orbital girth (App. III). The ratio of pre orbital girth to SL decreased at a rate of 0.02% per millimeter increase in SL. This would result in a decrease of 5.48% over the size ranged examined. Consequently the head region was narrower in adults than juveniles. Fin placement remained constant with size. The first and second-dorsal averaged 0.68SL and 0.80SL, while the pectoral and pelvic fins averaged 0.27SL and 0.71 SL, respectively. The orbitals averaged 0.06SL. The inter-dorsal and pectoral to pelvic distances averaged 0.14SL and 0.48SL, respectively. The results of regressing the morphometric characters on SL are summarized in Appendix IV. Analysis of covariance for the homogeneity of slopes resulted in significant difference among the distances and among the girths (Fig. 21). The slope and the means for the pre-first dorsal and pre-pectoral fin distance were homogeneous. Generally, the girths at the pectoral, first dorsal and pelvic fins increased at a significantly greater rate than the girths at the orbitals and second dorsal fin, resulting in a more robust shape with size. The slopes for the regression of fineness ratio and fin aspect ratios on SL were not statistically different from zero, with the exception of the caudal fin (App. IV). The caudal fin increased A.R. at a rate of 0.0065/mm SL. However, SL only Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 64 Figure 21. The relationship of body shape morphometry to standard length in Isistius brasiliensis; (a) distance measurements: (1) POB, (2) PD1, (3) PD2, (4) PP1, (5) PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3) second dorsal fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. b r ig h t 65 accounted for 67% of the variability. The caudal fin and the pectoral fin had the highest mean A.R. of 2.88 and 2.28 respectively (Fig. 22). The first and second dorsal and the pelvic fins had equally low A.R’s. The fineness ratio averaged 2.74 with 41% of the variability explained by SL. The slopes of the caudal fin heterocercal and hypocaudal angles regressed on SL were not significant (a = 0.01, App. IV). The heteroceral angle averaged 10.9° and the hypochordal angle 30.9°. Standard length accounted for 14% and 16% of the observed variability. The slopes for the regression of fin surface areas on SI were significant for all fins (Fig. 23). Analysis of covariance indicated homogeneous slopes among the first dorsal and second dorsal fins and the pectoral and pelvic fins. The caudal fin increased at the greatest rate followed by the pectoral and pelvic fins. The dorsal fins grew at the slowest rate. Body surface area and total surface area increased significantly with increased SL (Fig. 23). The BSA increased at 15.39cm2 / cmSL and SL accounted for 94% of the variability. The TSA increased at 18.55cm2 / cmSL and SL accounted for 95% of the observed variability. Oxynotus centrina Four specimens, 3 females and 1 male, were examined. The TL ranged from 354 to 550mm, representing only about one third of its reported size range of 1500mm TL. Thought to mature around 500mm, only the single male could be Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 66 Figure 22. Mean and 95% confidence intervals for the fin aspect ratios of Isistius brasiliensis. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced FIN O ro 3 c\i LO 10 o ASPECT RATIO 67 Figure 23. The relationship of surface area to standard length in Isistius brasiliensis: (a) fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4) pelvic, (5) and (6) caudal; and (b) surface area; (1) BSA, and (2) TSA. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CM N CO 0 5 vaav iovdans 001 in in in LOG SL LOG SL LOG co coin co co CD o vaav aovaans 001 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 68 considered to be mature. The small sample size precluded any analysis of sexual dimorphorism. The slopes for the linear regression of the eleven morphometric characters, as percentages of SL, on SL were not significantly diffferent from zero (App. III). The position of the orbitals averaged 0.1 OSL. The pectoral and first- dorsal fin insertions averaged 0.34SL and 0.36SL, respectively. The second dorsal averaged 0.65SL and the pelvic fins 0.87SL. The inter-dorsal and the pectoral to pelvic distances averaged 0.49SL. Only five of the eleven characters regressed on SL were significant (App. IV) However, SL did account for 66 - 99.9% of the variability. Lack of significance might be related to the small sample size and size range available for analysis. The analysis of covariance suggested that the regression slopes for pre orbital, first dorsal and pectoral distances on SI were not significantly different (a = 0.01, Fig. 24). Increases in girth, at all locations, with SI were determined not to be significantly different (ANCOVA, a = 0.01, Fig. 24). However, the girth at the caudal peduncle increased the least and the girth at the second dorsal the greatest with SL. Fineness ratio and fin aspect ratios exhibited no significant relationship with SL (App. IV). The fineness ratio averaged 1.25 with SL accounting for approximately 38% of the variability. The pectoral fins exhibited the highest aspect ratio followed by the first and second dorsal fins( Fig. 25). The pelvic fins exhibited the lowest aspect ratio. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 69 Figure 24. The relationship of body shape morphometry to standard length in Oxynotus centrincr, (a) distance measurements: (1) POB, (2) PD1, (3) PD2, (4) PP1, (5) PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3) second dorsal fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CO C4 m co oj Hid 10 AQ0 9 0 01 LOG SL LOG SL LOG aoNvisia ooi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 70 Figure 25. Mean and 95% confidence intervals for the fin aspect ratios of Oxynotus centrina. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CO ASPECT ASPECT RATIO CM v - CM v CM (0 Q Q CL CL U 13 Z ro L i. O Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 71 The slopes for the heterocercal and hypocaudal angle of the caudal peduncle regressed on SL were not statistically significant (a = 0.01; App. IV). The heterocercal angle averaged 22.8° and 78% of the variability explained by SL. The hypocaudal angle averaged 32.8° and SL accounted for 5% of the variability. Fin surface areas exhibited no significant relationship with SL (a = 0.01, Fig. 26). The caudal and pectoral fins were the largest and the pectoral fins the smallest. Body surface area and total surface area exhibited a significant relationship with SL (Fig. 26). Body surface area increased at 38cm2 / cmSL with over 99% of the variability explained by increase in SL. Total surface area increased at 48.4cm2 / cmSL and 98% of the variability explained. Squalus acanthias Eleven specimens ranging in TL from 624 to 1095mm were examined. Although representing only the middle of their known size range of 220 - 1240mm TL, both mature and immature specimens for both sexes were included. Morphometric measurements are summarized in Appendix 1. Linear regression for eleven body measurements on SL, by sex, are summarized in Appendix II. Analysis of covariance for the homogeneity of slopes and analysis of variance for equality of means indicated that there were no differences between the sexes (a = 0.01). The regression of the eleven body characters, as ratios of SL, on SL were not significant for all but one character (App. III). The ratio of the pre-orbital distance to SL decreased at a statistically significant (a = 0.01) rate of 0.04 per mm SL. This resulted in a decrease of 4% in head girth in relation to SL over the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 72 Figure 26. The relationship of surface area to standard length in Oxynotus centrina: (a) fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4) pelvic, (5) and (6) caudal; and (b) surface area; (1) BSA, and (2) TSA. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. co T“ o> h- co CO eg c\i vauv aovduns ooi .to CO LOG SL LOG SL LOG 00 CO CM CO vauvaovdans ooi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 73 reported size range. Consequently, adults present a slightly sleeker profile than do juveniles. The pectoral and first-dorsal fin average insertion was 0.26SL and 0.41 SL, respectively. The second-dorsal and pelvic fins averaged 0.80SL and 0.62SL. The inter-dorsal distance averaged 0.38SL and the pectoral to pelvic distance 0.41SL. Linear regression for the body characters on SL were statistically significant at a = 0.01 for ten of the eleven characters (App. IV). However, the girth at POB was significant at the a = 0.05 level. The slopes among the distance measurements and among the girth measurements were determined to be heterogenous (ANCOVA, a = 0.01, Fig. 27). The slopes for the regressions of the girths at the first dorsal and the pectorals were determined to be homogeneous. There was a general trend for the mid-section, between the pectoral and pelvic fins, to increase girth at the fastest rate. Likewise, the anterior and posterior girths increased at homogeneously slower rates. This resulted in an increase in robustness with increased size. Fineness ratio and fin aspect ratios did not exhibit a significant relationship with SL (App. IV). Fineness ratio averaged 2.47 with 35% of the variability explained by SL. The caudal and pectoral fins averaged the highest A.R. at 2.58 and 2.16 respectively (Fig. 28). The dorsal fins averaged the smallest. SL accounted for 1 - 38% of the variability in AR. The caudal fin heterocercal and hypocaudal angles regressed on SL (a = 0.01, App. IV) were not statistically significant. The heterocercal angle averaged 32° and the hypocaudal angle averaged 38°. SL accounted for 42% and 50% of the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 74 observed variability. Fin surface area exhibited a high dependency on SL (Fig. 29). SL explained 94% to 98% of the variability. Analysis of covariance indicated a significant difference among the slopes. The pectoral fins surface area increased at the greatest rate and the second dorsal fin the least. Body surface area and total surface area were also dependant on SL (Fig. 29). SL accounted for 96-97% of the observed variability. BSA increased at 49.59cm2 / cmSL and TSA increased at 66.16cm2 / cmSL. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 75 Figure 27. The relationship of body shape morphometry to standard length in Squalus acanthias; (a) distance measurements: (1) POB, (2) PD1, (3) PD2, (4) PP1, (5) PP2; and (b) girth measurement at: (1) orbital, (2) first dorsal fin, (3) second dorsal fin, (4) pectoral fin, (5) pelvic fin, and (6) caudal peduncle. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. , 0 ^ S07 a to 0 3 Oi ight °^ner. Furth,e r reProatuotion Pr°hibitl ea *ith,out Porrrit'ISsior, 76 Figure 28. Mean and 95% confidence intervals for the fin aspect ratios of Squalus acanthias. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced FIN CNJ O TJ co 3 o o in CO c\i in ASPECT RATIO 77 Figure 29. The relationship of surface area to standard length in Squalus acanthias: (a) fin surface area: (1) first dorsal, (2) second dorsal, (3) pectoral, (4) pelvic, (5) and ( 6) caudal; and (b) surface area; (1) BSA, and (2) TSA. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. “1 ------1------1------i------co r-; cr> r^. in co' co’ c\i co co vauv aovduns son c o \ « LOG SL LOG co CM o V3HV aovdans ooi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 78 PLACOID SCALE MORPHOLOGY Although the placoid scales of squaloid sharks exhibit a high degree of intraspecific and interspecific variability in morphology, little effort has been made to describe this diversity. Therefore, the objective of this section was to describe spatial and sexual dimorphic variability in placoid scale morphology within the dogfish, Squaliformes. Centrophorus granulosus The placoid scales exhibited a high degree of ontogenetic and spatial variability in general morphology (Pl.I) With the exception of the anterior head (HI, H2) scales, adult specimens exhibited scales that were generally lanceolate in shape. The dorsal snout scales (HI) were blunt or less tapered in profile. The ventral snout (H2) scales were more knob-like, lacking any tapered crown. All scales, to some extent, exhibited scale crown or margin ridging. In the juveniles, the placoid scales were generally more spike-like with narrow bases. Linear regression of the placoid scale morphometries on SL by sex are presented in Appendix V. Analysis of covariance for the homogeneity of slopes for the regression of each scale character on SL indicated larger variability in the head and caudal scales than body scales between the sexes. Within each sex, ANCOVA indicated that the slopes were statistically different among the sampled locations for Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 79 Plate I. Placoid scales from Centrophorus granulosus. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. m Sm m Reproduced w«d permission o, «de copyripd, owner, .udder reproduce p r o v e d w«doUt permission. 80 width, length and area in females and the scale density in males (App. VI.). Where slopes were determined to be homogeneous, ANOVA determined the means were significantly different for PC in females and the width, length and area in males. A plot of mean scale width versus mean scale length in females illustrated a positive correlation (Fig. 30a). Head scales (HI, H2, H4, H5 and H 6) were the shortest and narrowest with the anterior gill region (H4) scales being the smallest. The body scales (Bl, B4, B5, B 6, B7 and B 8 ) and the dorsal head region (H3) scales were relatively wide and long. Scales in the B2 - B3 region were transitional between the previous two areas. Caudal fin scales (C2) where the longest and widest followed by the caudal peduncle (Cl) scales. The percentage of integument covered by scales exhibited a weak correlation with scale crown area in females (Fig. 30b). Anterior gill scales (H4) were the smallest and covered the least amount of integument followed by the head scales (HI, H2, H5 and H 6). A second group of relatively large scales but covering a similar percentage of the integument consisted of those from the body regions; Bl, B5, B6, B7 and B 8 , and the dorsal head region, H3. The scales from the B2 and B3 regiosn were transitional in size between the above two groups. The anterior lateral scales (B2) covered a relatively greater percentage of the integument. The scales posterior to the first dorsal fin (B4) although similar in size to the other body scales, also covered a relatively large percentage of the integument. The caudal peduncle scales (Cl) were the largest and covered the greatest percentage of the integument. There was a general trend for scale weight to reflect scale size in females Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 81 Figure 30. Mean placoid scale morphometric measurements, by location, for Centrophorus granulosus females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Y = 0.082 + 1.075X r = 0.871 0.2 0 2 5 0 3 0.350 4 0.45 05 0 55 0.0 CROWN WIDTH (mm) 0 9 0 6 o ).7 qLU: 8! O)6 0LU >5 1 Y = 0.188 + 1.682X LU OdO r = 0.611 UJ >4 CL H2 0 3 0.2 . 050 7 0.91.1 1.3 15 1.710 2.1 2 3 2 5 2.70.5 2.0 CROWN AREA (mm1) 120 100 80 oX 60 Y = 12.7 + 313.65X r s 0.61 < o(/> 40 20 0 L— 005 0 07 0 00 0 11 013 015 017 0.10 021 023 0.25 0.27 CROWN AREA (mm3) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 82 (Fig. 30c). The relative smallness of the head scales was reflected in low scale weights. Within the head region, the anterior gill scales (H4) were the lightest. Although scales from the HI, H2, H5 and H 6 regions were similar in size, HI and H6 scales were much heavier, with the H6 region scales having weights comparable to scales twice their size. The transitional scales (B2, B3) were relatively moderate in both weights and size. The larger size of the body scales was reflected in higher weights. Again, however, there was a broad spectrum of scale weights. The scales from the B4 and B7 areas were lighter than their size would suggest while FI3 region scales had weights comparable to scales half their size. The caudal region (Cl, C2) scales exhibited more typical weight to area ratios. The placoid scales from males exhibit a conservative width length relationship (Fig. 31a). The head scales (H4 and H5) were the shortest and narrowest. The scales from the H2, B3 and B4 regions had scales of comparable length to the first group but were relatively longer. The body scales (Bl, B3, B4, B5, B7 and B 8 ), the head scales (H2, H3 and H6) and the caudal fin (C2) scales were generally similar in widths and lengths. The caudal peduncle (Cl) scales were the longest and the lateral body (B2) scales were the widest. The relationship between PC and area was fairly conservative (Fig. 31b), with the exception of the lateral body (B2) scales. Although relatively large in size, the B2 region scales covered the least percentage of integument. The body scales (Bl, B3, B4, B5 and B 6) generally exhibited similar size to PC relationships and covered lower percentages of integument than the head scales (H 6, HI and H3) of Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 83 Figure 31. Mean placoid scale morphometric measurements, by location, for Centrophorus granulosus males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0.8 Y = 0.28776 + 1.215X r = 0.80 0 0 E hI 0 Z J.4 o OC£ 02 0 02 025 03 0350.4 0.45 0.5 055 00 0 65 0.7 CROWN WIDTH (mm) 12 Y = 0.288 + 1.215X i r = 0.81 o a:uj LU > 0o ) 8 LU 0 1 ).0 LU oX LU Q. 0.4 0 2 L - 0 0 5 0.1 0 15 02 0 25 0 3 0 35 0 4 5 0 5 0.5504 0 6 CROWN AREA (mm5* 500 •0.003 + 942.6X r = 0.84 400 300 i- ox 200 100 0 e------0036 0 066 0 136 0.1QG 0 236 0 280 0 330 0.386 0 436 0486 0 530 0 586 AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 84 comparable size. The ventral snout (H2), caudal fin (C2) and the posterior body (B7 and B 8 ) had similar PC to area relationships. Although the caudal peduncle exhibited the largest scales, the PC value was similar to the caudal fin scales. With the exception of the lateral body (B2) scales, a conservative relationship existed between scale area and scale weight in males (Fig. 31c). The head scales (HI, H2, H4, H6 and H 6) were the smallest and lightest. The body scales were moderate in both size and weight, relative to both the head and caudal peduncle regions. Caudal fin scales (C2) were most similar to the body scales. Cluster analysis and MANOVA, resulted in five statistically significant (a = 0.01) clusters in both males and females. In females, 95% of the scales fell into four clusters and the frequency distribution within the five clusters ranged from two to seventeen scales per cluster. In males, 98% of the scales examined fell into four clusters and the frequency distribution within the five clusters ranged from one to twenty-six. Three general regions of similar scales were defined in both sexes (Fig. 32). Distribution patterns were generally similar in males and females in that dorsal head scales were similar to the posterior body, and the anterior body and the caudal areas constituted two distinct regions. The anterior head scales were characterized as moderate in width, length, area weight and in the percentage of the integument covered. In females, this anterior head region extended from the snout along the dorsal head surface. In males, this region was restricted to the dorsal head surface. The anterior body region was characterized by scales relatively small in width, length, area, weight and Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 32. Spatial distribution of placoid scale morphology by sex in Centrophon granulosus; regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. (N ir Wm Reproduced with permission ofthe copyright owner. Further reproduction prohibited without permission. 86 PC. In females, these scales extended from the gill region posteriorly to the dorso lateral trunk region anterior to the second dorsal region. In males, this scale type was restricted posteriorly to the mid-trunk region and extended anteriorly into the ventral head region. Posterior to this region, scales were characterized as moderate in size and being similar to the dorsal head scales. The caudal peduncle and fin scales were similar and characterized by relatively large widths, lengths, areas, weights and PC. Centroscymnus coelolepis The placoid scales exhibited spatial and ontogenetic morphologic variability in a true plate-like crowns, atop a neck or pedicle (PI. II). Generally, the scales were characterized as tear drop to tricuspid in shape. To some degree, all scales exhibited a central depression or dimple in the crown surface. In the head (HI, H2) and juvenile scales, this depression was exaggerated to form a central groove and two longitudinal ridges. In adults, this depression was restricted to a central dimple on an otherwise smooth crown. Ontogenetic and spatial variability in scale distribution also was observed. The snout scales (HI, H2), in juveniles were densely packed, overlapping to some degree and leaving little integument exposed. Throughout the rest of the body, a relatively large amount of the integument was exposed. In adults, scale size and density interacted to leave virtually no integument exposed. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 87 Plate II. Placoid scales from Centroscymnus coelolepis. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with with permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 88 Linear regression of the placoid scale morphometries on SL, by sex, are presented in Appendix V. Analysis of covariance for the homogeneity of slopes between the sexes indicated high variability at most locations. Furthermore, ANCOVA for the homogeneity of slopes between locations within sex were statistically different (App. VI.). Although differences existed between male and female scales, both exhibited conservative relationships between scale width and length and between size and weight (Fig. 33 a,b and Fig. 34 a,b). Furthermore, both sexes generally exhibited no increase in PC with increased scale size (Fig. 33c and Fig. 34c) . In both males and females, there was a generl trend for the scales on the head to be the shortest and narrowest and the body scales (B2, B5, B 6 and B7) to be the widest and longest. This general trend was reflected in the weight to area relationship in both males and females. Female scale width - length relationship defined four generally similar regions. The anterior head (HI, H2) scales were narrow and short. The posterior head and caudal fin (H3, H4, H5, C2) were wider and longer. The dorsal region (H 6, Bl, B3, B4, B8 , Cl) were relatively wide and long and the ventral body (B3, B5, B 6, B7) were the widest and longest. This general pattern of variability in scale widths and lengths also was present in males with a few exceptions. The dorsal region extended further into the head region (H3) and excluded the anterior lateral B2 region. The ventral body region extended further dorsally to include the B2 region. Females exhibited greater diversity in PC than males. In females, the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 89 Figure 33. Mean placoid scale morphometric measurements, by location, for Centroscymnus coelolepis females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2 Y = 0 + 1.37X r = 0.97 t.5 E E HO X ow z 1 LU _J 0.5 0 0.7 08 00 1 1.1 1.2 1.3 1.4 CROWN WIDTH (mm) 200 Y *= 0.86 + 0.187X r = 0.24 til O 100 0 3 0 4 0 50 8 0.7 0.8 00 1 1.1 1.2 1.3 1.4 15 CROWN AREA (mm1) 1,400 1.200 1.000 ^ 000 Y = 256 = 936.3X r = 0.91 0 35 045 055 0 65 0 75 0 85 0 05 1 05 1.15 1 25 1.35 1.45 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 90 Figure 34. Mean placoid scale morphometric measurements, by location, for Centroscymnus coelolepis males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.5 2 1.5 Y = -0.736 + 1.57X r = 0.95 1 0 5 0 1 1.1 1.2 13 1.4 15 1.0 1.7 1.8 1.8 SCALE WIDTH (mm) > 100 Y = 106.2 + 8.28X r = 0.38 0 60 8 1 12 1.4 1 6 18 2 22 2.4 2.6 SCALE AREA (mm1) 1.200 •4.206 + 364.07X r = 0.89 3o> K- oX lli 00 0 8 1 1 2 1 4 1 6 18 2 22 2 4 2 6 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 91 caudal region (Cl, C2) exhibited the highest PC. Localized differences were observed in the head and the body regions. There was a dorsal ventral trend in the head region to increase PC. The scales in the body regions, B3 - B7, B4 - B 8 , and B2 - B6, corresponding to the belly, and the dorsal posterior and lateral sections, respectively, were similar in size and PC. In males, similarities in size and PC existed within the anterior head (HI, H2), the caudal fin and ventral posterior head (C2, H4, H5) , the dorsal region (H3, H 6, Bl, B4, B8 , Cl) and the ventral body region (B2, B3, B5, B 6, B7). Although four very loosely associated regions could be defined by the scale weight to area relationship, differences existed between males and females. The anterior head region (HI, H2), in females, exhibited the smallest and lightest scales and the ventral body (B3, B5, B 6, B7) region the largest and heaviest scales. In males, this ventral region extended to include the lateral B2 region. The dorsal region (H3, H 6, Bl, B4, B8 and C2) exhibited relatively large heavy scales and the posterior head and caudal fin regions relatively small light scales. In males, these regions were less defined. Small, light weight scales were characteristic among the posterior head (H3, H4, H5) and caudal fin scales (C2). The relatively heavy, large scales of the dorsal region were restricted to the B2, B4, B 8 , and Cl region with an intermediate region existing in the B 6, Bl region. Cluster analysis and MANOVA resulted in the five clusters being significantly different (a = 0.01). In females, four clusters accounted for 94% of the scales examined and the frequency distribution within the five clusters ranged from Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 92 four to twenty-eight. In males, four clusters accounted for 93% of the scales examined and the frequency distribution within the five clusters ranged from three to fifteen. Five regions of similarity were distinguished in both sexes and there was a general overall trend for scale size and weight to increase in a posterior direction (Fig. 35). In females, the anterior and lateral head scales were relatively small in width and length and small to moderate in overall size. They were characteristically light weight and covered a relatively small percentage of the integument. A transitional region was apparent in the dorsal and ventral head and the anterior shoulder region. Scales here exhibited mixed characteristics of the regions immediately anterior and posterior. Posterior of the shoulder through the caudal peduncle, the scales were characterized as relatively large in width, length and area, relatively heavy in weight and covered a moderate percentage of the integument. The belly scales in this region were among the largest and heaviest observed and could be considered a seperate region. The caudal fin scales were a mosaic of small and moderate scales that covered a relatively high percentage of integument. The trend in scale variability in males was similar to females although different regional boundaries were defined. The anterior and ventral head scales were characteristically short and narrow, small in size and relatively light weight. The anterior body region was characterized by scales moderate in width, length, area and weight. The body scales, anterior to the pelvic and second dorsal fins, were among the largest in width, length Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 93 Figure 35. Spatial distribution of placoid scale morphology by sex in Centroscymnus coelolepis', regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. VO Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 94 and area and heaviest in scale weight. The caudal region scales were characterized as moderate in size and weight. The scales of the caudal fin were relatively small and light weight. The percentage of the integument covered by scales in this region was high, greater than 100%, suggesting that the scale crowns overlap. Dalatias licha The general shape of placoid scales varied from lanceolate or triangular shaped crowns to spike-like, rhomboidal shaped crowns (PI. III). The snout scales (HI, H2), were generally more rhomboidal, plate-like crowns than other scales. The majority of scales exhibited a square or diamond shaped base with a medial longitudinal ridge arising from the anterior corner and terminating into a point. This apex flared outward to the two lateral corners creating a leading face comprised of a lateral ridge on either side of a dominate medial ridge. Scale spacing appeared regular and left a relatively large percentage of the integument exposed. Linear regression of the scale morphometric parameters on SL, by sex, are presented in Appendix V. Analysis of covariance indicated very little variability between the sexes for the slopes of the regression equations . The greatest variability was observed in the scale density and PC. Little variability was observed in the scale dimensions between males and females. Analysis of covariance for the homogeneity of slopes between sample sites by sex indicated a significant difference in width, length and density in females and length, density and PC in males (App. VI 31). Analysis of variance resulted in significant differences in means for Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 95 Plate III. Placoid scales from Dalatias licha. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with with permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 96 scale area in females and width and area in males. There was a weak, positive correlation between scale width and length and no clear patterns of distribution were evident in males (Fig. 36a). The caudal fin scales (C2) were the narrowest and shortest and the ventral snout scales (FI2) were the widest and longest. The anterior body (B7, B 8 ) and caudal peduncle (Cl) region scales were relatively narrow and short. The scales anterior to the gills (H4) while narrow, were uncharacteristically long. The ventral and lateral posterior head scales were relatively short but wide. The anterior and ventral body (Bl, B2, B3, B5) as well as the dorsal head region (HI) exhibited proportionally wide and long scales. The percentage of the integument covered by scales and scale area exhibited a positive association and again, no clear pattern in variability was observed in males (Fig. 36b). The ventral snout region (H2) exhibited the largest scales and covered the greatest percentage of the integument. Although the caudal fin scales were the smallest, they covered a relatively moderate percentage of the integument. The dorsal head scales (HI, H3) exhibited relatively large scales that covered a large percentage of the integument. With the exception of the ventral snout region (H2), a conservative relationship existed between scale weight and scale size in males (Fig. 36c). Ventral snout scales were the largest and relatively heavy while the dorsal snout (HI) scales were relatively light and small. Overall, there was a general trend to decrease size and weight from snout to tail. Exceptions included the HI, H4, B4 and B5 region Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 97 Figure 36. Mean placoid scale morphometric measurements, by location, for Dalatias licha males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1.2 02 0 I------0.4 0.45 05 0.55 0.6 0 65 0.7 0.75 0.6 065 CROWN WIDTH (mm) in Y = 5.12 + 11.81X r = 0.08 CD 40 a. 0.1 0.15 02 5 0 3 0.4 0.45 0 5 0 5 502 CROWN AREA (mmJ) 122 + 167.9X r = 0.57 co 0 50 1 0 15 02 0 25 0 3 035 04 0 45 0 50 CROWN AREA (mmJ) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 98 scales. The scales in the head region (HI, H4) were of similar weights but differed in size. The scales in the B5 region were larger and heavier than the majority of the head scales while the B4 scales were smaller and lighter than scales in close proximity. Scales from females exhibited greater diversity in scale widths than lengths and only a weak correlation existed between lengths and widths (Fig. 37a). Similar to males, scales in the ventral snout region were the widest and longest and the caudal fin scales were the shortest and narrowest. Again, no clear pattern of distribution was evident. Generally, head scales (HI, H3, H4, H5) were relatively narrow and short and the body region (Bl, B2, B3, B4, B6, B7) scales were wide and long. The percentage of the integument covered by the scales exhibited no relationship with scale area (Fig. 37b). The ventral head (H2) scales were relatively large and covered a large percentage of the integument. In general, there was a trend for the body scales to cover less percentage of the integument than either the head or caudal scales. The relationship between scale weight and area was very conservative with the exception of the ventral head (H2) scales (Fig. 37c). In the most general of terms, there was a trend for ventral scales to be heavier than dorsal scales. Dorsal head scales were lighter although similar in size to their ventral counter parts. Within the body region, this trend also existed between scales in the Bl, B2, B3 region as well as the B4 - B6 and B5 - B7 regions. In the posterior body region Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 99 Figure 37. Mean placoid scale morphometric measurements, by location, for Dalatias licha females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced PERCENTAGE COVERED SCALE WEIGHT (ug) CROWN LENGTH (mm) 100 120 100 0.8 0.7 00 o.o 1.1 100 70 00 00 0 >— 60 10 40 20 BO 20 1 0 4 0.45 0.5 0 6 0 65 0 6 0 0.5 0.45 4 0 0.15 0 0 1 Y = 0.308 + 0.6882X 0.66 = 0.6882X + r 0.308 = Y 15 0 02 02 0.25 RW IT (mm) WIDTH CROWN 5 5 0 503 0 25 0 CROWN AREA (mm5) AREA CROWN CROWN AREA (mm5) AREA CROWN 0.3 Y = 58.9 + 132.8X 132.8X + 58.9 = Y = 0.70 = r H4 l C 0 35 0 4 0 0 4 0 0.7 Y = 0.291 + 188.9X 188.9X + 0.291 = Y = 0.87 = r .5 50.5 0.45035 5 0 5 4 0 0.75 0 6 100 (B8), scales were considerably smaller and lighter than the B7 region. Cluster analysis and MANOVA resulted in a statistically significant (a = 0.01) difference among the five clusters. In females, four clusters accounted for 97% of the scales examined and the frequency distribution among the five cluster ranged from one to thirteen. In males, four clusters accounted for only 86% of the scales examined and the frequency distribution among the five clusters ranged from nine to twenty scales. There was a general trend to increase scale size and weight and decrease PC from the snout to the shoulder. The trend was then reversed from the shoulder to the caudal peduncle region. In both sexes, the caudal fin scales were the smallest and lightest and covered a moderate to high percentage of the integument. The ventral snout scales were the largest, heaviest and covered the greatest percentage of the integument. Females exhibited a distribution pattern of five to six scale types across the body (Fig. 38). The dorsal head region had relatively small and light-weight scales that covered a relatively high percentage of the integument. The lateral and ventral regions were characterized by scales that were moderate in size, weight and PC. The shoulder region scales were among the largest and heaviest but covered a relatively small percentage of the integument. Posterior body scales were generally smaller in size, light weight and covered a moderate percentage of the integument. The distribution pattern of scale types in males was difficult to ascertain because each sampling location often fell into three or four different clusters. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 101 Figure 38. Spatial distribution of placoid scale morphology by sex in Dalatias licha\ regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. VO VO M Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 102 Including the snout and caudal fin as seperate distinct regions, five regions of similarity were defined (Fig. 38). The anterior body scales were characteristically large and heavy. The posterior body region generally exhibited small, light weight scales. The head scales exhibited large variability, with the snout scale being the largest and the dorsal and ventral scales the lightest. Deania calcea Two distinctly different scale morphologies were observed (PI IV). The placoid scales present on the head and body regions were strongly trident shaped with three prongs or spikes. The spikes appeared to vary, ontogenetically and spatially, in their relative positioning and angles. In the caudal region, placoid scales exhibited a more lanceolate shape with lateral ridges present. Linear regression of the scale morphometric parameters on SL, by sex, are presented in Appendix V. Analysis of covariance for the homogeneity of slopes indicated a high degree of variability between the sexes for all characters at all locations. Within each sex, ANCOVA indicated a statistical difference between slopes among the sample sites for all characters in males (App. VI.). The slopes were determined to be homogeneous for area and PC in females but ANOVA indicated their means were not (a = 0.01). The scales from male specimens exhibited less variability in scale length than scale width (Fig. 39a). The caudal region (Cl, C2) and the snout region (HI, H2) exhibited the narrowest scales. The caudal scales were longer than the snout Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Plate IV. Placoid scales from Deania calcea. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ------·----- .. ---···· Reproduced with with permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 104 scales. The belly scales (B3, B5) exhibited the widest and longest scales. There was a general trend for the dorsal scales to be narrower than the ventral scales. No relationship was apparent between the scale size and PC in males (Fig. 39b). The caudal fin (C2) and caudal peduncle (Cl) scales, although similar in size and not the largest, covered the largest percentage of the integument, respectively. Within the head scales, the snout region (HI, H2) exhibited small scales that covered a relatively large percentage of the integument. There appeared to be an inverse relationship between scale size and PC from ventral to dorsal regions. Among body scales, there was a general trend for the dorsal regions to have smaller scales covering a lower percentage of the integument than the ventral regions. Scale weights generally reflected differences in scale size (Fig. 39c). The head region (HI, H2, H4) scales were the smallest and among the lightest. The anterior belly region (B3) exhibited the largest and heaviest scales. The anterior dorsal region (H3, H6, Bl), although different in size, covered similar and relatively high PC values. The scales of the Bl region were considerably smaller than either H3 or H6. In females, scale width and length exhibited a strong positive correlation (Fig. 40a). Head scales tended to be narrower and shorter than body scales. The caudal region (Cl, C2) scales were longer than their width suggested. The belly region (B3, B5) exhibited the widest and longest scales. There was a general trend for the dorsal scales to be smaller in width and length than their corresponding Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 105 Figure 39. Mean placoid scale morphometric measurements, by location, for Deania calcea males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1 Y = 0.216 + 0.714X OB r = 0.80 E E P 6 0 H5 Z lli _» .4 o oo: 02 0 0 3 0 3 5 0.4 0 4 5 0.5 0.55 OS 0.65 0.7 CROWN WIDTH (mm) 60 50 Y = 32.9 + 27.86X 40 30 20 10 — 0 05 0 0 0 0 07 OOS 0 0 9 0.1 0.110.12 0.13 0.14 0.15 0.10 CROWN AREA (mm1' -32.3 + 789.78X r = 0.92 0 05 0 06 0 07 0 05 0 09 0 1 0 11 0.12 0 13 0 14 0 15 0.16 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 106 ventral scales. Little variability was observed in PC either by location or scale size with the exception of the caudal fin (C2) scales (Fig. 40b). The C2 region scales were the largest and covered over 100% of the integument. The dorsal head region (HI, H3, H4) exhibited the smallest scales but covered a similar percentage of integument as the largest scales of the ventral region (B3, B5). Placoid scale weight showed a liberal relationship with scale size (Fig. 40c). The snout region (HI, H2) followed by the anterior gill region (H4) exhibited the smallest and lightest scales. The belly region (B3, B5) scales were relatively large and heavy. The caudal fin scales, although the largest, were relatively light. In the anterior head region, there was a trend for the dorsal scales (H3, H6) to be larger and heavier than ventral head scales. Across the body, there was a trend for the ventral regions to exhibit larger and heavier scales than their dorsal counterparts. Furthermore, there was a trend for the mid-body (B3, B4, B5, B6) scales to be larger and somewhat heavier than either the anterior body (Bl, B2) and head or the posterior body (B7, B8, Cl) scales. Cluster analysis and MANOVA resulted in a statistical (a = 0.01) difference among the five clusters. In females, four clusters accounted for 93% of the scales examined and the frequency distribution for the five clusters ranged from four to twenty-four. In males, four clusters accounted for 84% of the scales examined and the frequency distribution for the five clusters ranged from twelve to twenty. In both sexes, there was a broad trend for the head scales to be the smallest Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 107 Figure 40. Mean placoid scale morphometric measurements, by location, for Deania calcea females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Y = 0.166 + 0.822X 00 r * 0.82 00 E £ ).7 fO z )0 UJ o 0 5 oa: 0 4 0.3 0.2 *— 0.350.4 045 0 5 0.55 0 0 0.65 0.7 0.75 00 0 0 5 CROWN WIDTH (mm) 120 100 Y = 11.36 + 192.8X Q r = 0.61 o:UJ 00 UJ > o o 60 UJ oa: 40 6 3 65 20 0 — 0 0 5 0 07 0 0 9 0.11 0.13 0 1 5 0.17 0.10 0 21 0 2 3 0.25 0 27 0 20 CROWN AREA (mm1) Y = 32.17 + 206.35X r = 0.51 005 0 070 00 0 11 0 13 015 0.17 0 10 0 21 023 0 2 5 0.27 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 108 and the body or trunk scales to be the largest and heaviest. In females, only three distinct regions of scale patterns were observed (Fig. 41). The snout and lateral head scales were small and light weight. The body scales were the largest and heaviest. The caudal region scales were long, narrow, relatively small and moderate in weight. The percentage of the integument covered by scales varied little across the body. In males, the distribution of scale type varied from females in the posterior head region. The posterior head scales were relatively long, wide, heavy and covered a small percentage of the integument. The body scales were of moderate size, weight and PC. The caudal region scales were characteristically long, moderate in size, light weight and covered a high percentage of the integument. Echinorhinus cookei The placoid scales present on the single specimen examined were multi ridged thorn or spike like crowned and lacking any true neck or pedicle (PI. V). A central apex or point radiated outward in a multi-ridge spoke like fashion to a circular base. Spatial distribution appeared random and left a large percentage of the integument exposed. Placoid scales where sampled from only one juvenile male. Consequently, any scale descriptions and distribution patterns should be interpreted with cution. Furthermore, no sexual dimorphic variability was examined. There was a positive correlation between scale width and length Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 109 Figure 41. Spatial distribution of placoid scale morphology by sex in Deania calcea; regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0+ Reproduced withwith permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. Plate V. Placoid scales from Echinorhinus cookei. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ~ ‘ - - y -' . \ ‘ ' "- - -■■■'’ •;■■■■' ' ‘. ' • • . " . i V ' ’’.' - r ' : „■ •■ * ,/.“ **’. . •Jv - v > ' V . ‘.? > . :~";y ‘ ■ ■■"■ - 1 - ’•-: •-■■"'■£' i- ■• •■■■'-■• ''.'.^W - -.;,v 1 -• - W lm lm •W. *»V^ •' - -w- v";?-v *?-YV •'ul'*' j-*' i^fl‘‘v::**^*A V'v ...... ^Jc**--£< .*;?-. i. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. I l l (Fig. 42a). The dorsal region (Bl) exhibited the longest and widest scales. The mid - ventral region (B5) exhibited the shortest and narrowest scales. In the head and anterior body regions, there was a tendency for the dorsal region scales to be longer and wider than their ventral counterparts (HI - H2, Bl - B2 - B3, and B4 - B6 - B5).There was no apparent trend anterior to posterior. The relationship between PC and crown area was generally weak (Fig. 42b). The Bl region exhibited the largest scales and covered the greatest percentage of integument. The ventral (B5) region had the smallest scales covering the least percentage of integument. Although not the largest scales, the caudal region (Cl, C2) exhibited relatively high PC. The head scales, although variable in area, had higher PC values than most body regions. There was a general trend for the posterior body scales to be smaller and they had lower PC values than anterior scales. There was a moderate association for scale weight to increase with scale size (Fig. 42c). The Bl region scales were the heaviest and largest while the H2 scales where the lightest and the B5 scales were the smallest. There was a definite trend to decrease size and weight dorso-ventrally. Furthermore, this trend to decrease size and weight was also evident in an anterior posterior direction through mid-trunk. Cluster analysis and MANOVA resulted in a statistically significant (a = 0.01) difference among the five clusters. For the one male, four clusters accounted for 93% of the scales examined and the frequency distribution for the five clusters Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 112 Figure 42. Mean placoid scale morphometric measurements, by location, for Echinorhinus cooker, (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2 5 2 e Y = 0.20 + 0.598X 6. r = 0.77 f 1'5 2!G UJ _J 1 o O£T 0 5 0 0.2 0 4 0.0 00 1 12 1.41.0 1.8 2 22 CROWN WIDTH (mm) 70 25.66 + 9.928X 0.65 GO o 50 UJ a: oS- & UJ 30 ao: aUJ 20 10 0 •— 0 0 5 0.55 1.05 1.55 2 05 2.55 305 3 55 CROWN AREA (mm1) 160 140 120 100 t- 16.66 + 30.15X oX 0.79 § 60 UJ 60 40 20 0 01 00 1.1 10 2 1 2 6 3 1 3 6 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 113 ranged from one to five. Four relatively distinct scale types were defined across the body (Fig. 43). The pre-first dorsal fin region exhibited the largest and heaviest scales covering the greatest percentage of the integument. The anterior region was divided dorso-laterally in two. The anterior dorsal scales were relatively wide and moderately long, large in overall size and of moderate weight. The scales covered a relatively high percentage of the integument in this region. The anterior ventral region was characterized by small to moderate sized scales of medium width and length. They were generally light weight and covered a variable percentage of the integument. The posterior region was divided laterally into a posterior body region and a caudal region. The posterior region scales were characteristically short, narrow and moderate to small in size. The percentage of the integument covered was relatively low and the scale weights ranged from moderate to high. The caudal region scales were characteristically short, moderate in width and weight and covered a large percentage of the integument. Etmopterus princeps The placoid scales were spike-like in form and generally very similar to those scales found on D. licha (PI. VI). A square or diamond shaped base had a ridge rising from each corner and converged into an apex in the center. Scale distributions left a relatively large percentage of the integument exposed. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 114 Figure 43. Spatial distribution of placoid scale morphology by sex in Echinorhinus cookei; regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. t?A VI . Reproduced with with permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. Plate VI. Placoid scales from Etmopterus princeps. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ReproducedReproduced with with permission permission of ofthe the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 116 Linear regression of the scale morphometric parameters, by sex, on SL are presented in Appendix V. Analysis of variance and covariance indicated significant differences in scale morphometries between the sexes. With the exception of scale density in males, regression slopes were heterogeneous among sample location within sex (App. VI.). The regression slopes and means for the scale density on SL in males were not statistically different. There was a weak, positive correlation between scale width and length in females (Fig. 44a). The dorsal head region (H3) exhibited the widest scales and the caudal fin the longest scales. The anterior gill (H4) scales where the narrowest and shortest. Head scales tended to be shorter and narrower than either the body or caudal scales. The anterior dorsal region (HI, H3, Bl) exhibited the widest scales. The caudal and the posterior body region (C2, Cl, B8, B6) was characterized by relatively long scales. PC values exhibited a moderate correlation with scale size in females (Fig. 44b). The lateral head region (H4, H6) exhibited the smallest scales covering a relatively small percentage of integument. The body scales (B3, B4) were the largest scales and the anterior head scales (H2, HI) covered the highest percentage of integument. In general, anterior body scales were larger and covered slightly more of the integument than posterior body scales. Within females, there was a weak association between scale weight and crown area (Fig. 44c). Head scales (H4, H6) exhibited the smallest and lightest scales. Body scales (B3, B4) were the largest and B6 scales the heaviest. Head Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 117 Figure 44. Mean placoid scale morphometric measurements, by location, for Etmopterus princeps females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0 0 0.7 Y = 0.374 + 0.493X r = 0.34 0.0 0S « 0.5 0 4 0 3 I------0.25 0 27 0.29 0 31 0 33 0 35 0.37 0.39 0 41 0.43 0.45 0 47 0 4 9 0 51 0.53 0 55 CROWN WIDTH (mm) Y = 2.08 + 164.90X r = 0.63 LU LU10 5 0 055 0 OS 0.005 0 07 0 075 0.00 0 065 0 09 0 0950.1 0.105 0.11 CROWN AREA (mm1) Y = 22.99 + 133.41X r = 0.33 I 40 LU 35 0 055 0 0 0 0 005 0 07 0 075 0 0 0 0 085 0 09 0 095 1 0 105 0110 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 118 (HI, H2, H3), body (Bl, B2) and caudal (Cl, C2) scales, although relatively large, were characterized as relatively light weight. There was a weak correlation between scale width and scale length in males (Fig. 45a). The Bl scales exhibited uncharacteristically large widths and lengths. The caudal region (Cl, C2) exhibited relatively long scales and the H3 scales were relatively wide. The head region, in general, displayed relatively short scales. The anterior head region (HI, H2, H3) were generally wider and longer than the posterior region (H4, H5, H6). No clear trend was evident for the body region, although a general trend to decrease scale width posteriorly was present. A moderately positive association existed between scale area and PC in males (Fig. 45b). The snout region (HI, H2) had the highest PC values and the posterior ventral head (H5) the lowest. The anterior gill region (H4) scales were the smallest and the dorsal head (H3) scales the largest. No clear trends in scale area and PC distribution was evident. There was a weak positive relationship between scale weight and area in males (Fig. 45c). Although head scales varied greatly in size, their scale weights were comparable. There was a general trend for the anterior scales (HI, H2, H3) to be larger and slightly heavier than the posterior and ventral head region. Within the body region their was a tendency for dorsal scales to be smaller and lighter than the ventral scales. The caudal region (Cl, C2) exhibited relatively large, light scales. Cluster analysis and MANOVA resulted in a statistically significant (a = 0.01) difference among the five clusters. In females, four clusters accounted for Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 119 Figure 45. Mean placoid scale morphometric measurements, by location, for Etmopterus princeps males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced SCALE WEIGHT (ug) PERCENT COVERED CROWN LENGTH (mm) 35 15 20 25 30 02 0.4 0 0 6 0 25 10 12 20 10 15 05 3 3 0 4 .4 00 0 5 00 005 7 .7 0.08 0.075 07 0 065 0 0.00 055 0 05 0 0.045 04 0 035 0 03 0 025 0 0 025 0 03 0 035 0 04 0 045 0 05 0 055 0 06 0 065 0 07 0 075 0 08 0 075 0 07 0 065 0 06 0 055 0 05 0 045 0 04 0 035 0 03 0 025 0 0 0 5 i 0.2 I. 1 ------Y = 4.50 + 215.66X 215.66X + 4.50 = Y = 0.59 = r = 0.38 = r Y = 16.0 + 124.51X 124.51X + 16.0 = Y 5 2 0 0 3 0 35 0 4 0 45 0 4 0 35 0 3 0 ...... RW IT (mm) WIDTH CROWN CROWN AREA (mm1) AREA CROWN CROWN AREA (mm1) AREA CROWN 07 r = = r = Y OS 0.91 02 .0 + 1.206X + 0.104 00 0 65 0 120 93% of the scales examined and the frequency distribution among the five clusters ranged from four to nineteen. In males, four clusters accounted for 98% of the scales examined and the frequency distribution for the five clusters ranged from one to nineteen. A general trend for scales to decrease width and increase length from the dorsal head region posteriorly to the caudal region was exhibited. In females, four regions of similar scale types were defined (Fig. 46). The anterior head or snout, dorsally to the first dorsal fin exhibited scales that were relatively wide and short. Overall, these scales were large and light weight. The percentage of the integument covered in this region was variable. The ventral head region comprised a distinct region characterized by relatively short and narrow scales. These scales were relatively small, light weight and covered a small percentage of the integument. The posterior region was characterized by long scales of moderate width, generally heavy and variable in area and PC. The lateral and ventral midsection was highly variable in scale morphology and probably represent a transition between the anterior and posterior region. In males, the dorsal anterior region was restricted to the head area and was characterized by scales that were generally short and wide and overall relatively large and covered a high percentage of the integument. Scale weight in this region was moderate. The ventral head to the dorsal midsection defined a region characterized by short narrow scales. Overall, these scales were small to moderate in size, covered a variable percentage of the integument and were highly variable in weight. The ventral and anterior body and caudal region scales were long and of Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 121 Figure 46. Spatial distribution of placoid scale morphology by sex in Etmopterus princeps; regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 122 moderate width. Generally, they were moderate in size and moderate to heavy in weight. The belly scales were highly variable and could not be generalized. Isistius brasiliensis The placoid scales present were of a unique trapezoidal shape (PI. VII). A large square base, often touching adjacent scales, tapered to a smaller square concaved crown. Little ontogenetic or spatial variability in this general morphology was observed. Linear regression of the scale morphometric parameters on SL, by sex, are presented in Appendix V. Analysis of covariance resulted in little to no difference in the regression slopes for the head scales in males and females. Body and caudal fin scales exhibited large diversity in slopes between males and females. ANOVA, testing the homogeneity of means indicated a larger diversity in ventral head scales than dorsal head scales between the sexes. Lateral head scales anterior to the gills were homogeneous between the sexes. ANCOVA, for the homogeneity of slopes among locations within each sex exhibited differences among almost all parameters (App. VI). There was a strong correlation between scale width and length among females (Fig. 47a). Ventral body scales(B3, B5, B7) exhibited the longest and widest dimensions. The anterior head region (HI, H2) were characterized by having the shortest and narrowest scales. In the posterior head region, the ventral (H5) and the dorsal (H3) scales were narrower and shorter than the anterior gill (H4) scales. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Plate VII. Placoid scales from Isistius brasiliensis. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced withwith permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 124 With a few exceptions, there was a positive correlation between PC values and scale area (Fig. 47b). Dorsal snout (HI) scales were the smallest and covered the smallest percentage of integument. Caudal fin (C2) scales, although not the largest, covered the highest percentage of integument. Ventral body scales (B3, B5, B7) were generally the largest and covered a relatively high percentage of integument. With the exception of H4 scales, head scales were consistently smaller than body or caudal scales. Within the body region, dorsal scales were smaller and covered less integument than ventral scales. No relationship was apparent between scale weight and scale area in females (Fig. 47c). Furthermore, no wholesale generalizations were apparent in the scale size - weight pattern of distribution. Within the head region, snout scales (HI, H2) were different in size but exhibited similar weights. The anterior gill region (H4) were the lightest although they were of moderate size. Dorsal head (H3) scales were smaller and heavier than H4 scales, but larger and lighter than the snout and lateral head (HI, H2, H6) scales. Ventral scales (H5, H3, B5) were all relatively heavy but variability in size. There was a good correlation between scale width and length in males (Fig. 48a). HI and B8 scales were both narrowest and shortest and B3 and B5 scales were the longest and widest. There was a general trend to increase scale length and width from dorsal to ventral regions. The percentage of integument covered by scales and scale areas, in males, exhibited a positive correlation (Fig. 48b). The caudal fin scales were the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 125 Figure 47. Mean placoid scale morphometric measurements, by location, for Isistius brasiliensis females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0 20 Y = 0.072 + 0.757X r = 0.93 0 5 - E E. C£D O oo: 0 1 0 0.10 0 2 0.21 0 22 0 2 3 0 2 4 0 2 5 0 20 CROWN WIDTH (mm) Y = 29.9 + 1147.9X r = 0.73 LU 50 0 014 0 016 0 018 002 0 022 0 024 0.020 0 0 3 CROWN AREA (mmJ) Y = 2.82 + 14.82X r = 0.12 iu 2.5 0 0 1 4 0010 0 018 0 02 0 022 0 024 0 026 0 028 0 03 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 126 Figure 48. Mean placoid scale morphometric measurements, by location, for Isistius brasiliensis males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced SCALE WEIGHT (ug) PERCENT COVERED 0 CROV^J LENGTH (mm) 5 2 0.3 . 1 1— 1.5 100 22 24 60 0 1— 40 50 70 60 7 1 0 0 00 4 5 5 7 1 0 0 2 3 Y = 7.1 + 2310.5X 0.81 = 2310.5X r + 7.1 = Y Y = 0.086 = 0.718X 0.718X = 0.086 = Y = 0.84 = r Y = 1.9 + 46.93X 46.93X + 1.9 = Y = 0.27 = r 0010 0010 021 0 021 0 0021 0 0 2 3 0.025 0 0 2 7 0 0 2 9 0 031 0 9 2 0 0 7 2 0 0 0.025 3 2 0 0 0021 022 CROWN WIDTH (mm) WIDTH CROWN RW RA (mm3) AREA CROWN (mm1) AREA CROWN 0 023 0 027 0 023 0 0 23 0 0 25 0 M3 0 029 0 0 2 6 0 270.2 0 6 2 0 24 0 0 031 0 127 largest and had the highest PC values. The pre-second dorsal (B8) scales were the smallest and covered the smallest percentage of integument. Generally, the caudal region (Cl, C2) covered the greatest percentage of the integument. There was a tendency for the ventral anterior region (H2, H4, H5, H6, B2) to be relatively large and cover a relatively high percentage of integument. The anterior dorsal region (HI, H6, Bl) with the exception of the H3 region, exhibited relatively small scales covering a small percentage of the integument. The mid-body region (B4, B6, B7) and the H3 region had intermediate sized scales covering an intermediate percentage of integument. No relationship was apparent between scale weight and area in males (Fig. 48c). The caudal region (C2, Cl) exhibited the heaviest scales. The anterior gill (H4) scales the lightest. The ventral scales (H5, B3, B5, B7), the lateral posterior head scales (H6) and the pre-second dorsal (B8) scales were characteristically heavy although they were very different in size. The head (HI, H2, H3) and the anterior body (Bl, B2) scales were relatively light although represented a diverse size range. Cluster analysis and MANOVA resulted in a statistical difference among the five clusters. In females, four clusters accounted for 86% of the scales examined and the frequency distribution among the five clusters ranged from nine to eighteen. In males, four clusters accounted for 90% of the scales examined and the frequency distribution for the five clusters ranged from six to eighteen. Four regions of similar scale types were defined for females and males (Fig. 49). Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 128 In females, the head region defined a region of similar scales that were characterized as short, narrow and generally small in size. These scales were moderate to heavy in weight and covered a low percentage of the integument. The dorsal and ventral body region anteriorly to the gill region was characterized by scales of moderate width and length and moderate to large in overall size. These scales covered a moderate to high percentage of the integument and were moderate in weight. The ventral body region defined a third region characterized by relatively wide and long scales. Generally large in size, these scales covered a modest percentage of the integument and were relatively heavy with a tendency to increase weight in a posterior direction. The caudal peduncle and fin scales were characteristically smaller in width, length and area than either the dorsal and ventral body scales. The percentage of the integument covered in the caudal fin region was higher than any other region. The caudal peduncle PC values were moderate. In males, four different scale type were recognized. The head region was split into a dorsal and ventral region. The dorsal head region was combined with the dorsal surface posteriorly to the caudal peduncle and was characterized by short and narrow scales. Overall, these scales were small, covered a small percentage of the integument and were moderate in weight. The ventral head, extending into the anterior lateral body was characterized by scales moderate in width and length. Scale size and PC were generally moderate while the weight was relatively low. The belly or ventral body region was characterized by long, wide scales generally large in size. The scale weight and PC was considered moderate. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 49. Spatial distribution of placoid scale morphology by sex in Isistius brasiliensis\ regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. . I n CN C ) rs (N c n i : Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 130 The caudal region scales were moderate in width and length although relatively large and heavy. The percentage of the integument covered in this region was generally high. Oxynotus centrina The placoid scales were lanceolate or spike-like in general morphology (PI. VIII). Similar to D. licha and E. princeps, the scale base was square and the apex radiated outward to two lateral corners and an anterior oriented corner. The transition from anterior to lateral corners was concave, creating a medial ridge and two minor lateral troughs. Scale spacing was regular and allowed a large percentage of the integument exposed. The sample size of one female and two males precluded any analysis of sexual dimorphism in placoid scale morphology. However, analysis of covariance for the homogeneity of slopes indicated significant differences for all parameters among sample locations. A general correlation between scale width and length was observed in males (Fig. 50a). The caudal fin scales were the narrowest and the dorsal head (HI) scales the widest. Anterior gill scales (H4) were the shortest and the posterior head (H3) the longest. A general trend to decrease scale width and length was observed between anterior and posterior regions (HI, H3, H6, Bl, B4, B6, B8). Dorso- ventrally, head scales decreased in width and length (HI, FI2, H3, H5) and decreased in width in the body regions (Bl, B2, B3, B4, B5, B6) and increased in length and Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Plate VIII. Placoid scales from Oxynotus centrina. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 132 width from B8 to B7. No correlation was present between PC values and area in males (Fig. 50b). The caudal fin (C2) scales were among the smallest but covered the highest percentage of the integument. The ventral (H2, H5, B3, B5, B6, B7) and the caudal peduncle (Cl) regions covered a greater percentage of the integument than the dorsal region with the exception of H3. The anterior gill region covered the smallest percentage of the integument with the smallest scales. Scale weight was generally related to scale size in males (Fig. 50c). Dorsal anterior scales (HI, H3, H6, Bl) were the heaviest. The ventral region (H2, B2, B3, B5, B6, B7) and the caudal fin (C2) region were among the lightest. Scale lengths and widths exhibited a positive correlation among females (Fig. 51a). The pre-pelvic region (B7) exhibited the shortest and narrowest scales and the dorsal head (H3) region the widest and longest. Among the body scales, there was a tendency to increase scale width and length in a posterior direction along the dorsal surface (Bl, B4, B8) and to decrease width along the ventral surface (B3, B5, B6, B7). Within this region, there was a decrease in width and length from dorsal to ventral regions. The percentage of the integument covered by scales exhibited a positive correlation with scale size in females (Fig. 51b). The B7 and B6 region scales were the smallest and covered the least percentage of integument. The B8 region scales were the largest and the caudal fin scales covered the most integument. Within the head, the dorsal snout (HI) exhibited the smallest scales with the lowest PC values Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 133 Figure 50. Mean placoid scale morphometric measurements, by location, for Oxynotus centrinci males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced SCALE WEIGHT (ug) PERCENT COVERED CROWN LENGTH (mm) 0.0 400 10 15 20 25 30 35 34 3.5 3.0 3.7 3.8 200 500 100 0 008 0 08 0 1 0.5 0 0 7 .1 1 0 5 7 .9 3 5 .7 9 031 29 0 0.27 25 0 23 0 1 2 0 0.19 17 0 15 0 13 0 0.11 9 0 0 07 0 [ ------0.55 = .0 + .4X 0.80 0.849X = + r 0.005 = Y 0.80 -101.5 + 1476.1X 1476.1X + -101.5 0 1 0 00 .2 .4 .8 . 0 2 8 .8 0.3 0.28 28 0 4 2 0 22 0 0.2 0.18 0 1 0 0.14 0.12 5 6 0 RW IT (mm) WIDTH CROWN CROWN AREA (mm1) AREA CROWN CROWN AREA (mmJ) AREA CROWN .50808509 0 5 8 0 0.8 0.75 7 0 H5 Y = 16.55 + 15.87X 0.17 15.87X = + r 16.55 = Y 0 05 0 134 Figure 51. Mean placoid scale morphometric measurements, by location, for Oxynotus centrina females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced SCALE WEIGHT (ug) PERCENT COVERED CROWN LENGTH (mm) 0.7 0.8 . L- L 0.2 3 0 D.4 200 250 20 30 40 10 150 100 0 035 0 ' '— 0 50 0 35 0 0.035 0'— Y = 4.45 + 137.45X 137.45X + 4.45 = Y = 0.70 = r 0.055 0 075 0 0.055 .5 7 5 1 1 0 075 0 0.055 . + 696.15X + 5.2 0.57 5 5 0 5 0 5 4 0 CROWN AREA (mm1) AREA CROWN (mm) WIDTH CROWN 0.005 RW AE (mm1) AREA CROWN H5 .1 .3 0.155 0.135 0.115 00 6 0.750.4 7 0 65 0 = 0.83 = r 00 + 0.967X + ■0.03 .5 175 0 0.155 0.175 135 and the ventral snout (H2) had the largest scales and the highest PC value. Along the dorsal surface there was a tendency to decrease scale size and PC from anterior head (H3) to the first dorsal fin (Bl, B4) before increasing again to the second dorsal fin (B8) region. Along the ventral surface, there was a trend to increase size and PC posteriorly from H3 and B3 to the mid region (B5) and then decrease again to B7. Scale weights exhibited little correlation with scale size in females (Fig. 51c). Scales from the pre-pelvic fin (B7) region were the lightest and those from the dorsal head (H3) region the heaviest. There was a general trend for scale weights to decrease from dorsal to ventral surfaces. Furthermore, along the dorsal and ventral regions, there was a trend to decrease scale weight in a posterior direction. Scale size exhibited no apparent pattern in variation. Cluster analysis and MANOVA resulted in a statistically significant (a = 0.01) difference among the five clusters. In females, four clusters accounted for 94% of the scales examined and the frequency distribution for the five clusters ranged from one to five. In males, four clusters accounted for 97% of the scales examined and the frequency distribution for the five clusters ranged from one to eleven. Five regions of similar scales were defined for the female specimen and four regions for the males (Fig. 52). In the females, the dorsal lateral head region was characterized by scales small to moderate in width and length. They were generally moderate in overall size, weight and PC. The ventral head scales were longer, wider and large than the dorsal head Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 136 Figure 52. Spatial distribution of placoid scale morphology by sex in Oxyntous centrina; regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0+ Reproduced with with permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 137 scales. The scale weights were moderate and the PC values variable. The dorsal body scales were characterized as being the longest, widest and the largest. They were generally the heaviest and covered the greatest percentage of the integument. The ventral body scales were characteristically smaller in width and length. Moderate in overall size, they covered a relatively high percentage of the integument and were among the lightest in weight. The posterior and lateral body region scales were the smallest in width, length and size. They covered the smallest percentage of the integument and were among the lightest in weight. In males, four regions of similar scales were defined as the dorsal head and body, ventral and lateral head, lateral and ventral body and the caudal fin. The dorsal head and body scales were characterized as long, wide and generally large in size. They covered the least percentage of the integument and were the heaviest in weight. The ventral and lateral head scales were characterized as narrow, short and small. These scales were among the lightest and covered a moderate percentage of the integument. The ventral body region was characterized by scales of moderate size, width and length. These scales were moderate in weight and covered a high percentage of the integument. The caudal fin scales were similar, in general, to the scales of the ventral body in size and weight. However, they were considerably narrower and covered the largest percentage of the integument. Squalns acanthias The placoid scales varied from spike-like or pyramid shaped to Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 138 lanceolate and bicuspidate shaped (PI. IX). The head (HI, H2, H3) and caudal (Cl, C2) scales had rhomboidal shaped plate-like crowns. Anterior head and body scales exhibited a more cuspid posterior or trailing margin. In most all cases, a medial, bisected longitudinal ridge was present. In the head, the spatial arrangement of scales completely covered the integument. Elsewhere, scale spacing left a small portion of the integument exposed. Linear regression of the scale crown morphometries on SI, by sex, are presented in Appendix V. Analysis of variance and covariance indicated no statistical difference between male and female dorsal snout scales, posterior ventral body scales and the caudal peduncle scales. The largest differences between the sexes tended to be in the dorso-lateral posterior head region and the anterior ventral body. Statistical differences were exhibited among the sample locations, by sex, for all the parameters Appendix VI. Scale widths and lengths showed little correlation in females (Fig. 53a). The head scales (HI, H2) were the widest and relatively longest. Body scales (B2) were the narrowest and shortest. Generally, the lateral scales were among the shortest and relatively narrow. From the dorsal snout (HI) to the first dorsal fin (B4) there was a decrease in scale width and length before an increase to the second dorsal (B8). There was a strong positive correlation between the scale area and PC in females (Fig. 53b). The ventral head (H2) had the largest scales that covered the highest percentage of the integument. The lateral head (H6) scales were the smallest Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 139 Plate IX. Placoid scales from Squalus acanthias. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced withwith permissionpermission of of the the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 140 Figure 53. Mean placoid scale morphometric measurements, by location, for Squalus acanthias females; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Y = 0.305 + 398x r = 0.57 X 0.45 0 25 0 27 0 29 0 31 0 33 0.35 0.37 0.39 0 41 0.43 0.45 0 47 CROWN WIDTH (mm) 105 o LUq: £ 85 o 0111 1 65 Y = 8.40 + 572.27X LU ccO r a 0.94 LU CL 45 25 I------0 035 0 045 0 055 0 065 0.075 0.085 0 095 0.105 0.115 0.125 0.135 0.145 CROWN AREA (mm1) 40 Y = 1.12 + 192.92X r b 0.94 30 O §>0 LU _ l < (/)o 10 0 I------0035 0 045 0 055 0 005 0 075 0 065 0 095 0.105 0.115 0.125 0.135 0 145 CROWN AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 141 and covered the least amount of integument. Within the head scales there was a tendency to decrease size in a posterior direction. The smallest scales were observed in the anterior lateral region (B4, H6) and the dorsal region (Bl). In the shoulder region, the dorsal scales were larger than the ventral scales. Posterior to the shoulder, this trend was reversed. Within the head, there was a decrease in PC values in a posterior direction. PC values decreased from dorsal to ventral surfaces in the shoulder region. This trend was reversed posterior to the shoulder. There was a strong correlation between scale area and weight in females (Fig. 53c). The head (HI, H2) scales were the largest and heaviest scales observed. The anterior lateral scales were the smallest and weighed the least. There was a general trend for scale weight to decrease posteriorly within the head. Furthermore, there was a tendency for ventral scales to weigh more then the corresponding dorsal scales. There was a moderate association between scale width and length in males (Fig. 54a). The head scales (HI, H2, H3) were the widest and longest. The anterior body scales (Bl, B3) and the dorso-lateral scales (H6) were the shortest and narrowest. Within the head region, scales decreased widths and lengths in both a posterior direction and dorso-ventrally. The lateral head scales (H4, H6) were the narrowest and shortest. There was a general trend for scale widths and lengths to increase in a posterior direction. The scale area and PC values were highly correlated in males (Fig. 54b). The head scales (HI, H2) were the largest and covered the greatest amount of Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 142 Figure 54. Mean placoid scale morphometric measurements, by location, for Squalus acanthias males; (a) crown width vs crown length, (b) percentage of integument covered by scale crowns (PC) vs crown area, (c) scale weight vs crown area. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 042 Y = 0.232 + 0.447X r = 0.77 0.4 0.38 h - 0.38 .34 U 0 32 .0 2 ,H 4 0.3 0.28 ' — 0 17 0.10 0 21 0.23 0 25 0.27 0.20 0.31 0 3 3 0 35 0 3 7 0 3 9 0 41 CROWN WIDTH (mm) Y = 5.75 + 777.37 r = 0.94 > 60 Q. 0 0 1 5 0 025 0 0 3 5 0 045 0.055 0 005 0 0 7 5 0 085 CROWN AREA (mmJ) Y = 1.62 + 218.54X r = 0.83 X 20 BW"»B4BB 0 0 1 6 0 028 0 0 4 0 0 050 0 0 7 6 SCALE AREA (mm1) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 143 integument. Overall, there was a trend for the head and caudal scales to be larger and cover higher percentages than body scales. In the shoulder region (Bl, B2, B3, B4, B5, B6) there was a general trend to increase size and PC in a dorso-ventral direction. In the posterior body region (B7, B8) this trend was reversed. Scale weights exhibited a positive correlation with scale size in males (Fig. 54c). Ventral head (H2) scales were extraordinarily heavy for their size. The anterior head scales (HI, H2, H3) were the heaviest scales. There was a general decrease in scale weight from the snout to the shoulder region and an increase in weight from the shoulder to the caudal region. Cluster analysis and MANOVA resulted in a statistically significant (a = 0.01) difference among the five clusters in both males and females. In females, four clusters accounted for 90% of the scales examined and the frequency distribution of the five clusters ranged from eight to twenty-two. In males, four clusters accounted for 97% of the scales examined and the frequency distribution for the five clusters ranged from two to twenty-three. Five scale types were defined across the body in both sexes (Fig. 55). In males, an anterior head region was defined as exhibiting scales that were relatively long, wide and overall large in size. These scales covered a moderate to large percentage of the integument and were among the heaviest. The ventral posterior scales were characterized as moderate in width, relatively short in length. These scales were generally moderate in size and PC and light in weight. The body scales were generally the smallest in width, length and area. These scales Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 144 Figure 55. Spatial distribution of placoid scale morphology by sex in Squalus acanthias', regions of similar scale morphologies denoted by similar shading patterns. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0+ Reproduced with with permission permission of ofthe the copyright copyright owner. owner. Further Further reproduction reproduction prohibited prohibited without without permission. permission. 145 covered the least percentage of the integument and were the lightest in weight. The adjacent belly or ventral body scales were wider, longer and larger than the body scales. They were also heavier and covered a greater percentage of the integument. The scales from the caudal region were relatively long and moderate in width. These scales were second to only the dorsal head region in overall size, weight, and the percentage of the integument covered. In females, the head region was divided into two regions similar in characteristics to their male counterparts. The body region was divided into a ventral, posterior region and an anterior, dorsal region with the scales in proximity of the first dorsal fin similar to the ventral scales. The anterior dorsal and lateral region was characterized by small, light weight scales that covered a small percentage of the integument. The posterior and ventral body scales were relatively moderate in width, length and weight and moderate to small in area. The percentage of the integument they covered was small. The caudal region, as in males, was characterized by relatively long and moderately wide scales. Moderate in area, these scales covered a generally high percentage of the integument and were among the heaviest. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. DISCUSSION BODY MORPHOLOGY Body Shape and Surface Area Body morphology and surface area are integral factors in determining the swimming mechanics and performance in fishes. Whether best adapted for undulatory or oscillatory propulsion, cruising, accelerating or maneuvering, swimming performance is constrained by body morphology. Sharks, generally considered to be fusiform in shape, are well adapted for cruising (Webb, 1988). The functional morphology of galeoid sharks has been often studied and body shape in this group is considered to be very conservative (Thomas and Simanek, 1977; Musick et al, 1990). Squaloids, on the other hand, appear to be more diverse in body and fin morphology. Many are known to be neutrally bouyant (Corner et al, 1968; Deprez et al, 1990) and are considered by some to be poor swimmers that ’hover and wait’ for their prey (Reif, 1985, Compagno, 1984). Conversely, Sedberry and Musick (1977) reported that two neutrally bouyant squaloids, Centroscymnus coelolepis and Centroscyllium fabricci, were the most active swimming bathyal fishes observed during submersible dives. In fishes, differences in body shape maybe reflected in the differences in relative body surface area (BSA) among species. For squaloids, the regression of 146 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 147 the body surface area on SL, by species, is presented in Fig. 56. Although analysis of covariance for the homogeneity of slopes for the BSA regressions revealed no statistically significant (a = 0.01) differences between species, their means were different (ANOVA, a = 0.01), reflecting differences in body shape. Musick et al (1990) showed that for galeoid sharks, BSA was related to the relationship of girth to SL. The interspecific model for predicting BSA for squaloids, following Musick etal (1990) was: BSA/SL = A + B (GIRTH/SL) was not significant. Therefor the dependency upon GIRTH/SL was ignored. The best estimate of BSA was the mean value of BSA/SL X GIRTH; 0.76, yielding a final result of: BSA = 0.76 (GIRTH X SL) Plotting the measured BSA against predicted BSA (Fig. 57) illustrate the fit of the model. The slope of the line was not statistically different (a = 0.01) from one. The relationship between GIRTH, SL and BSA for squaloids was compared with the galeoid BSA results of Musick etal (1990): BSA = 0.71 (GIRTH X SL). The mean value of BSA / (SL X GIRTH) for squaloids and galeoids was determined not to be statistically (a = 0.01) different. Therefore, the two data sets were merged and the mean BSA / (SL X GIRTH) of 0.75 gave a final result: BSA = 0.75 (GIRTH X SL). The plot of the combined data against predicted BSA (Fig. 58) illustrates the fit of this model. The regression line was not significantly different from one. Thus, the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 148 Figure 56. The relationship of body surface area to standard length in eight species of squaloids; (1) C. granulosus, (2) C. coelolepis, (3) D. licha, (4) D. calcea, (6) E. princeps, (7) I. brasiliensis, (8) O. centrina and (9) S. acanthias. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced LOG SURFACE AREA 3.5 H 3.5 3H . 12 . 14 . 16 . 18 . 2 2.1 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 O SLLOG 149 Figure 57. The relationship of measured body surface area vs. calculated surface area for nine species of squaloids. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced CALCULATED SURFACE AREA (1000 cm2) - 4 0 ESRD UFC AE 10 cm2) (1000 AREA SURFACE MEASURED 2 4 6 8 150 model BSA = 0.75 (GIRTH X SL), is a good predictor of BSA for a large range of distantly related shark species with diverse body shapes. The appearance of a greater spread for the squaloid surface areas around the regression line indicated a greater diversity in squaloid body shape than galeoid body shape. However, the ability of this model to predict BSA reaffirms the basic conservative nature of body shape in elasmobranchs (Thomson and Simanek, (1977); Musick etal, 1990). The physical forces of aquatic locomotion, lift, drag, acceleration and gravity must be balanced and therefor place restrictions upon the body shape of swimming vertebrates. Likewise, the body shape defines the boundaries of swimming behavior and consequently the range of hydrodynamic environments a vertebrate is physically competent to occupy (Webb, 1986; Daniels and Webb, 1987) Webb (1988) defined the shape factors that maximize thrust and reduce drag and energy waste for four different modes of propulsion. Furthermore, Webb (1988) predicted the optimal body morphologies for five swimming behavior patterns; cruising and sprinting, cruising, acceleration, station holding and low speed maneuvering and concluded that optimal forms tended to be mutually exclusive, providing a framework relating form and function in an ecological context. Unfortunately, the consideration of elasmobranchs in the model was limited to lamnids, and they were characterized with tuna and ichthyosaurs in the general group of thunniform animals. This group is negatively bouyant and dynamic lift is necessary to keep these animals from sinking to the bottom. Squaloids, on the other hand, are a diverse group with densities ranging from negative bouyaney to near Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 151 Figure 58. The relationship of measured surface area vs. calculated surface area for squaloid and galeoid sharks. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced CALCULATED SURFACE AREA (cm2) 100000 10000 1000 100 10 ESRD UFC AREA(cm2) SURFACE MEASURED 100 1000 GALEOID + SQUALOID0 10000 152 neutral and positive bouyancy. Many squaloids achieve neutral bouyancy, through reduced body density by concentrating the low density lipid squalene in an oversized liver. Neutral bouyancy, frees the pectoral fins and ventral body from the constraints of providing dynamic lift. Therefore, squaloid body shape design is the result of a diverse set of selection pressures different from other elasmobranchs. Even in benthic sharks, where swimming capabilities are limited, large pectoral fins are required to obtain the necessary lift to rise off the bottom. Consequently, a large diversity in body and fin shape is observed in the squaloids. Although Webb’s (1988) model, predicting the optimal morphologies for various swimming behaviors, does not implicitly account for neutrally bouyant elasmobranchs, it is useful in assessing function for a diversity of morphologies. Furthermore, although Webb (1988) conceded that the numerical solutions to his model are probably only good within an order of magnitude, the qualitative definitions of swimming mechanisms is useful for comparative study. With this in mind, comparative morphologies were examined in squaloids to postulate swimming behaviors, in light of Webb’s (1988) model and information on natural histories and feeding habits. Body girths at six locations across the body were examined to define body morphology. Rates of increase of girth with SL for each of the locations was examined for homogeneity among the nine species. Analysis of covariance (a = 0.01) indicated a significant difference among slopes for the regression of girth on Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 153 SL at the pectoral fins, first dorsal fin and the caudal peduncle (Fig. 59). Although the regression slopes for the girth at the orbitals, second dorsal and pelvic fins were not significantly different, the means were (ANOVA, a = 0.01. Fig. 59). Oxynoytus centrina exhibited the greatest slopes for the regression of PD1 and PP2 girths on SL followed by C. granulosus. Deania calcea and I. brasiliensis generally had the slowest increase in girth with SL at PD1 and PP1. In S. acanthias girth increased at the caudal peduncle the slowest while E. cookei had the fastest increase. The mean girths, as ratios of SL, exhibited significant differences at all locations among the species (ANCOVA, a = 0.01, Fig. 60 & 61). Isistius brasiliensis, S. acanthias and D. calcea, exhibited relatively slender body forms. Maximum girths ranged from 0.37SL to 0.41 SL and the distance from snout to maximum girth was 0.34SL and 0.35SL for I. brasiliensis and D. calcea and 0.41SL for S. acanthias. Oxynotus centrina presented the most robust body form with a maximum girth of 0.65SL at 0.24SL from the snout. Echinorhinus cookei exhibited a relatively slender anterior region and a moderately robust posterior region with a maximum girth of 0.53SL at 0.61 SL distance from snout. The remaining four species, C. granulosus, C. coelolepis, D. licha and E. princeps were generally intermediate in profile. Maximum girths ranged from 0.48SL to 0.58SL and their distance from the snout ranged from 0.38SL to 0.44SL. Webb (1984a) associated differences in body form with different swimming modes. A thick cadual peduncle and generally slender or narrow body form is optimal for acceleration, and Webb (1984a) offered the pike as an example Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 154 Figure 59. The comparative relationship of body girth and standard length for nine species of squaloids; (1) C. granulosus,(2) C. coelolepis, (3) D. licha, (4) D. calcea, (5) E. cookei, (6) E. princeps, (7) I. brasiliensis, (8) O. centrina and (9) S. acanthias: (a) girth at pectoral fin origin, (b) girth at first dorsal fin origin, and (c) girth at caudal peduncle. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. n co cm , 100 100 200 300 400 500 600 700 800 900 1,000 200 Hi - j 100, 100 100 200 300 400 500 600 700 800 900 1,000 100 500 600 200 E E Z 4 0 0 LL < cc Q 300 QC Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 155 Figure 60. Duncan’s Multiple Range Test for the mean distance measurements as a ratio of standard length for nine species of squaloids. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0.15 0.14 0.13 0.22 0.21 coelolepis granulosus 0.15 acanthias 0.11 O. centrinaE.cookeiC. 0.19 D. licha 0.18 C. E. princeps brasiliensis1. 0.12 D. calceaS. 0.11 O. O. centrina E. princeps 0.58C. granulosus 0.27D. calcea 0.27 D. licha C. coelolepis 0.25 0.23 0.24 E. cookei brasiliensis1. 0.21 S. acanthias Caudal Peduncle Girth / SL Pre-Second Dorsal Girth / SL | 0.50 0.48 centrina 0.65 calcea 0.37 coelolepis 0.58 licha . granulosus 0.52 acanthias 0.41 cookei 0.34 princeps centrina 0.45 \ o. c. c. D. E. S. D. E. brasiliensis1. 0.29 0. C. granulosus E. 0.40 cookei E. princeps C. coelolepis 0.39 0.37 D. licha 0.37 0.35 S. acanthias D. calcea 0.31 brasiliensis1. 0.27 0.31 Pre-Pelvic Girth / SL Pre-First Dorsal Girth / SL I centrina 0.64 C. C. granulosus 0.48 E. E. cookei 0.53 C. C. coelolepis 0.51 D. licha E. princeps brasiliensis1. 0.48 0.45 S. 0.39 acanthias 0.38 0. D. D. calcea 0.37 E. E. cookei 0. centrina C. coelolepis 0.44 0.41 0.36 E. E. princeps C. granulosus 0.32 0.29D. licha D. calcea S. acanthias 0.26 brasiliensis1. 0.25 0.25 0.73 Pre-Orbital Girth / SL Pre-Pectoral Girth / SL Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 61. Girth maesurements plotted against distance from snout as a ratio standard length. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. DIAMETER/SL 0.25 (8) O. centrina (1) C. granulosus (2) C. coelolepis (3) D. licha (5) E. cookei 0.2 8 (6) E. princeps 0.15 0.1 0.05 (4) D. calcea (7) I. brasiliensis (9) S. acanthias 0 I______L _L 0 0.2 0.4 0.6 0.8 1.2 DISTANCE/SL Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 157 of a fish specialized for accelerating in quick strikes at prey. Echinorhinus cookei exhibits a similiar body profile, long and flexible, relatively slender with a thick caudal peduncle. The relatively narrow caudal peduncle of I. brasiliensis, S. acanthias and D. calcea combined with a slender fusiform shape suggest a body form designed for constant cruising (Webb, 1984b). Oxynotus centrina, with a robust anterior body and slender posterior body is probably not reflective of strong selection for an efficient swimming mode. Very triangular in body cross-section, with an almost flat ventral surface, this body form is probably best adapted for a lifestyle on or near the bottom (Chao and Musick, 1977). The remainder of the species, all bathyal in habit, exhibited a generally thick, fusiform shape typical of epi-pelagic elasmobranchs. However, the body musculature in all bathyal species was much more flacid than in their epi-pelagic counterparts. To facilitate the reduction of body density in the deepsea species, integument thickness and muscle mass has probably been reduced. The integument of elasmobrachs serves as one of two anchoring structures for the swimming muscles. The tension of the muscles along with the overall underlying muscle mass and integument thickness gives the body it’s rigidity. With the exception of the coastal forms, like S. acanthias, most squaloids are relatively flacid or jelly-like, especially in the lateral and ventral regions. Consequently, although the body girths might suggest a fusiform shape, the true shape in water might be laterally flattened, providing for a more ovate cross-section. The placement of the shoulder or maximum girth effects the boundary Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 158 layer flow conditions. Laminar boundary flow is generally predicted anterior of the point of maximum girth and turbulent flow posterior. Under laminar flow boundary layer separation is generally predicted to occur at the point of maximum girth. Under laminar flow conditions, an increase in pressure drag is associated with this separation. Under turbulent flow conditions, boundary layer separation is delayed and occurs much further back on the body where it produces lower pressure drag. Consequently, under laminar flow conditions, the positioning of maximum girth should be shifted posteriorly to reduce the region of separation to as small as possible, as seen in E. cookei. Webb’s (1988), optimal morphologies model for teleost and negatively bouyant elasmobranchs predicts that the ratio of the distance from snout to maximum girth to standard length (LH/L) to be 0.5 to 0.7 for optimal sprinting, 0.3 to 0.5 for cruising or low speed maneuvering, 0.3-0.4 for accelerating and 0.2 to 0.3 for station holding. For a majority of the squaloid species examined, this suggests an optimal shape for cruising or low speed maneuvering. Low speed maneuvering and station holding further optimizes a streamlined gibbous body shape. Oxynotus centrina with a humpbacked anterior dorsal profile and a low LH/L exhibited characteristics probably optimal for low speed maneuvering and station holding. Fineness ratio (F.R.), or the ratio of SL to maximum diameter is an index of maximum volume to minimum surface area and provides insight into the magnitude of drag (Webb; 1975). For the bodies of fish, an optimal fineness ratio is calculated as 4.5. At fineness ratios less than 4.5 frictional drag is decreased but Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 159 pressure drag is increased. Conversely, body forms with F.R. values greater than 4.5 experience a decreased pressure drag but increased frictional drag. A 10% increase in drag is associated with a change in F.R. from an optimal value of 4.5 to either 3 or 7. Fineness ratios for the nine species examined, ranged from 4.6 to 8.0 (Fig. 62). Duncan’s multiple range test for the equality of means resulted in a statistical difference (a = 0.01). Deania calcea, S. acanthias and I. brasiliensis had the highest fineness ratios, ranging from 7.5 - 8.0, and would experience the highest frictional drag and lowest pressure drag. Oxynotus centrina had the lowest fineness ratio (4.6) within the ranged optimal balance between pressure drag and frictional drag. In between, fineness ratios ranged from 5.4 for C. coelolepis to 6.5 for E. princeps. Fineness ratios provide an index into optimal swimming modes. Optimal values for fineness ratios as predicted by Webb (1988) are 4 to 5 for sprinting and cruising as characteristized by the tuna, greater than 4 for acceleration as exhibited by the esocids and cottids, 12 to 14 for station holding ability characteristic of flatfish and rays and 1-2 for the low speed maneuvering typical of the chaetodontiform fishes. Webb’s (1988) generalizations based on fineness ratios may offer insight into the swimming behavior of fishes such as squaloids. Oxynotus centrina had the lowest F.R. (4.6) and this suggests an optimal fusiform body shape for reducing drag. However, the maximum girth in this species is shifted anteriorly, and is formed by a dorsal hump that is the apex of a triangular cross-sectional shape. A relatively large pressures drag is probably associated with this body shape, Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 160 Figure 62. Duncan’s Multiple Range Test for the mean fineness ratio of nine species of squaloids. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Fineness Ratios Duncan's Multiple Range Test D. calcea 7.98 S. acanthias 7.66 1. brasiliensis 7.56 E. princeps 6.51 D. licha 6.32 C. granulosus 6.11 E. cookei 5.95 C. coelolepis 5.42 0. centrina 4.62 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 161 suggesting a predominately turbulent, separated flow environment. Deania calcea, I. brasiliensis, and S. acanthias with F.R. values greater than 7.5 suggest a body shape designed to optimize sprinting or cruising. Etmopterus princeps, D. licha, and C. granulosus F.R. values suggest a body form better designed for cruising. Echinorhinus cookei and C. coelolepis with F.R. values between 5 and 6 probably exhibit slow cruising accompanied by fast starts or lunges. The body surface area was evaluated in light of the F.R to gain insight into the boundary layer flow environment. The optimal BSA predicted from a F.R. of 4.5 is plotted as a line in Fig. 63. Fineness ratios greater than the optimal would be expected to exhibit decreased surface areas and be associated with flow environment that would minimize frictional drag. Fineness ratios less than optimal should be associated with increased surface areas and flow regimes that would minimize pressure drag. Centrophorus granulosus, C. coelolepis, D. licha, E. cookei and E. princeps exhibited optimal BSA for their SL, based on a F.R value of 4.5 (Fig. 63), suggesting an increase in volume at the expense of increased surface area. The volume increase might be required to increase bouyancy in these sharks. Isistius brasiliensis, D. calcea and S. acanthias had the highest fineness ratios and exhibited reduced BSA (Fig. 63) suggesting attached laminar boundary layer flow conditions. The BSA for O. centrina, with a F.R. of 4.6, was consistently greater than would be predicted (Fig. 63), sugessting an increase in volume. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 162 Figure 63. The relationship of body surface area to standard length by species based on an optimal fineness ratio of 4.5. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. T 1000 * * D. calcea x S. acanthias x o. centrina + brasiliensis I. — OPTIMAL F.R. LOG STANDARD LENGTH STANDARD LOG + - - - - 100 10 100 1000 10000 100000-1 O SRAE AREA SURFACE LOG T E. cookei * * C. granulosus * E. princeps * D. licha x + C. coelolepis — Optim al F.R. LOG STANDARD LENGTH STANDARD LOG - - 1 0 1 0 0 0 0 < LU tn < hi < cc tn o LL 3 a o Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 163 Fin Size, Shape and Placement Fin size, shape and placement play an integral part in lift, drag, control ability and stability (Harris, 1936), and optimal morphologies are defined by Webb (1988) for various swimming behaviors. In addition to body shape, the variability in fin size, shape, flexibility, and placement, both anterior-posteriorly and dorso- ventrally, and their relative spacing to one another will define another set of limits of swimming performance. To compare interspecific fin position, ANOVA for the mean distance measurements (POB, PD1, PD2, PP1 and PP2) as a ratio of SL, was employed to remove differences in size. Although individual fin placement is generally limited to a small region of the body, (Fig. 64), supporting the conclusions of Thomson and Simanek (1977), statistically significant differences (a = 0.01) were observed among the species (Fig. 65). Analysis of variance indicated that among the nine species, the orbital and first dorsal fin positions exhibited the highest variability (Fig. 65) while the pectoral fin placement was the most conservative. The orgin of the paired fins was among the most conservative character among the species (Fig. 65). Two statistically significant groups were distinguished for the insertion of the pectoral fins (Fig 65). Echinorhinus cookei exhibited the most posteriorly inserted fins at 0.60SL. The remainder of the species were not significantly different and ranged from 0.24SL for I. brasiliensis to 0.30SL for D. calcea. The orgin of the pelvic fins generally comprised three separate groups. The greatest distance aft was observed in O. centrina, D. calcea and C. coelolepis Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 164 Figure 64. The frequency distribution of the relative fin position in nine species of squaloids. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Pelvic S S Pectoral 1^1 1^1 Second Second Dorsal EH EH PERCENT STANDARD LENGTH First First Dorsal 0 0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 165 Figure 65. Duncan’s Multiple Range Test for the distance measurements; POB, PD1, PD2, PP1 and PP2 as a percentage of standard length. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0.90 i 0.84 0.82 0.81 0.80 0.80 0.79 0.78 0.73 E. E. cookei I. brasiliensis C. coelolepis C. granulosus E. princeps D. lichahias S.acanthias D. calcea O. centrina 0.77 0.75 0.73 0.73 0.66 Pre-Second Dorsal Distance / SL C. coelolepisE. cookei 0.77 O. centrina D. calcea 0.79 E. princeps D. licha brasiliensis1. C. granulosus 0.73 S. acanthias 0.72 I Pre-Pelvic Distance / SL 0.70 0.44 0.43 0.42 0.79 i 0.41 0.38 0.35 0.24 E. E. cookei I. brasiliensis E. princeps C. coelolepis D. D. licha S. acanthias C. granulosus D. calcea O. centrina Pre-First Dorsal Distance / SL 0.61 0.31 0.28 0.26 0.24 0.24 0.15 0.14 0.10 0.10 0.09 0.09 0.06 E. cookei D. licha 0.29 D. D. calcea C. granulosus E. princepsO. centrinaC. 0.28 coelolepis S. 0.27 acanthias 1. 1. basiliensis Pre-Pectoral Distance / SL D. D. calcea E. E. cookei C. granulosus C. coelolepis 0.11 E. E. princeps O. centrina S. acanthias D. licha brasiliensis1. 0.05 Pre-Orbital Distance / SL Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 166 (0.77-0.79SL) and the pelvic fins of S. acanthias originated most anteriorly at 0.665L. The mean distance between the pectoral and pelvic fins was moree conservative (Fig. 66). Although O. centrina and E. cookei exhibited the greatest and the least pectoral to pelvic distance, respectively, little variability was exhibited among the species. The paired fins provide lift and an associated drag force as well as stability to yawing. A slight change in the angle of incidence, for pectoral fins positioned well anterior to the center of gravity, will produce large vertical turning forces (Harris, 1936). Likewise, the farther aft the pelvic fins insert, the greater their stabilizing ability. Webb’s model (1988) predicts the placement of the paired fins to be medial to optimize cruising and sprinting, anterior and ventro-lateral for low speed maneuvering, and variable for optimal accelerators and station holders for teolest and selected elasmobranchs. However, elasmobranchs, probably because many are obligatory ram ventilators, may not have had all of these evoltionary options in body forms. The origin of the first and second dorsal fins exhibited the greatest diversity (Fig. 65). The most anterior placement of the first dorsal fin was 0.24SL observed for O. centrina followed by D. calcea (0.35SL) and C. granulosus (0.38SL). The most posterior first dorsal fin orgin was for E. cookei (0.73SL) and 1. brasiliensis (0.70SL). Oxynotus centrina also exhibited the most anterior orgin of the second dorsal fin (0.73SL) followed by D. calcea (0.79SL). Again, E. cookei and I. brasiliensis exhibited the most posterior orgin with 0.90 and 0.84SL Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 167 Figure 66. Duncan’s Multiple Range Test for; (a) the mean inter-dorsal distance and (b) the pectoral - pelvic fin distance. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0.44 0.50 0.48 0.41 0.45 0.51 0.14 I 0.46 0.44 centrina coelolepis calcea granulosus acanthias C. C. S. E. cookei 0 . C. D. E. princeps 1. brasiliensis1. D. licha Pectoral - Pelvic Distance / SL 0.49 I 0.44 0.43 0.39 0.38 0.37 0.36 0.14 0.12 Distance / SL centrina 0 . C. granulosus S. S. acanthias D. licha E. princeps brasiliensis1. D. calcea C. coelolepis E. cookei Inter-Dorsal Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 168 respectively for the second dorsal fin. The mean distance between the first and second dorsal fin ranged from 0.11- 0.49SL. Analysis of variance indicated four discrete groups (Fig. 66). Oxynotus centrina exhibited the greatest distance between the median fins. E. cookei and I. brasiliensis exhibited the smallest distance. The median fins provide stability to pitching in the horizontal plane created in part by the transverse motion of the caudal fin, and act as a keel to control roll. A large first dorsal fin positioned well forward on the body, as exhibited by O, centrina, increases horizontal directional control. First and second- dorsal fins, placed well aft, characteristic of E. cookei and I. brasiliensis, might contribute to the thrust produced by the caudal fin. The posterior placement of the second dorsal fin of D. licha, D. calcea and E. princeps might be similiarly explained. The relatively large, anterior median fin placed over the center of mass, characteristic of S. acanthias and C. granulosus, is predited by Webb (1988) to minimize recoil in cruise and sprint swimming modes. The posterior position of the first dorsal fin of D. calcea probably allows for an increase in the transverse motion of the head region. Besides horizontal directional control or increased thrust, it has been noted that interdorsal or dorsal caudal fin spacing, that produces a 90° phase shift in the fin wake, can enhance the thrust of the second fin. This requires that the second fin be as large or larger than the first to be able to interact with the wake (Webb, 1984; Webb and Keyes, 1982). Webb and Keyes (1982) calculated that the distance between the first dorsal fin and the caudal fin required to produce a 90° shift in the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 169 wake for three sharks; leopard, bonnethead and blacktip, to range between 0.47SL to 0.50SL. Oxynotus centrina, C. granulosus and D. calcea exhibited interdorsal distances that might promote this interaction. Likewise, the position of the first dorsal fin in relation to the caudal fin of S. acanthias also suggested the possibility of an interaction that increases thrust. Analysis of variance for the orbital placement (POB) indicated four to five somewhat discrete groups (Fig. 65). The eye was most posterior in D. calcea at 0.15SL followed by E. cookei at 0.14SL. The most anterior orbitals were in I. brasiliensis at 0.05SL and D. licha at 0.06SL. The positioning of the orbitals, and consequently the length of the snout are probably a reflection of feeding behavior in some species. Isistius brasiliensis and D. licha have been reported to exhibit a ’cookie cutter’ feeding behavior, taking chunks or plugs of flesh from large, pelagic bony fishes and cetaceans (Compagno, 1984; Musick, per. com.). Their tooth morphology, terminal mouth and the forward position of the orbitals would be optimal for such a feeding behavior. Reported to feed on shrimp, hatchetfish and scaly dragonfish (Compagno, 1984), the elongated rostral region of D. calcea might function to increase the sensitivity of the ampullary system to mesopelagic prey close to the bottom. Fin aspect ratio is an index of hydrodynamic performance. The higher the aspect ratio, the greater the lift to drag ratio. The aspect ratios for all fins exhibited significant differences among the species (Fig. 67). With the exception of the caudal fin, O. centrina exhibited the highest fin aspect ratios for each fin. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 170 The first dorsal, pectoral and pelvic fins of S. acanthias also had relatively high aspect ratios. The relatively high aspect ratio pectoral fins suggest these two species probably gain dynamic lift from theses fins. Deania calcea, C. coelolepis and I. brasiliensis had relatively low paired fin aspect ratios as would be expected of species that concentrate squalene and are neutrally bouyant and do not require dynamic lift from their fins. The mechanical significance of the heterocercal tail in sharks, in which the notochordal axis is upturned resulting in an asymmetrical tail, has been the subject of much debate over the years; Breder (1926), Gray (1933), Grove & Newell (1936), Affleck (1950), Aleev (1963), Alexander (1965), Simons (1970) and Thomson (1971 & 1976) and Thomson and Simanek (1977) to name but a few. For purposes of disscussion, Thomson and Simanek’s (1977) proposed action of the caudal fin in sharks will be presented. The forces acting on the caudal fin can be separated into two components; A forward (F) component directed downward (Affleck, 1950) and a transverse (T) component producing an upward thrust from the rotation of the caudal fin along its longitudinal axis (Thomson & Simanek, 1977). According to Thomson and Simanek, the ratio of F:T changes with changes in the lateral speed of the tail and the angle of inclination. Although, the ratio of F:T does not change with changes in heterocercal angle, the vertical component of force produced by the caudal fin will be a direct function of the heterocercal angle (downward) and angle of rotation (upward). Accordingly, they predicted that the theoretical maximum Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 171 Figure 67. Duncan’s Multiple Range Test for the mean fin aspect ratio. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1.56 1.46 1.18 1.15 1.48 1.75 1.69 3.10 2.16 Pectoral Pectoral Fin centrina O. O. S. acanthias C. coelolepis C. C. granulosus 1. brasiliensis1. D. calcea E. cookei D. licha E. E. princeps 2.19 2.26 2.28 2.29 2.74 2.58 2.44 2.36 2.80 Caudal Fin centrina coelolepis licha granulosus cookei acanthias princeps C. C. 0. C. S. S. 1. brasiliensis1. £. £. D. calcea D. D. 1.65 1.10 0.81 0.75 0.68 0.62 0.67 0.54 0.44 centrina O. O. C. granulosus C. C. coelolepis S. acanthias brasiliensis1. E. E. cookei D. licha E. princeps D. calcea Second Dorsal Fin 1.02 1.04 0.77 0.77 0.73 0.67 0.61 0.61 0.52 Pelvic Pelvic Fin centrina O. O. S. acanthias C. C. granulosus C. coelolepis E. E. princeps D. calcea brasiliensis1. D. D. licha 0.98 0.61 E. cookei 0.60 0.59 0.58 0.52 0.33 0.24 4.59 centrina princeps First First Dorsal Fin 0. C. granulosus C. coelolepis S. acanthias D. D. licha E. cookei £. brasiliensis1. D. calcea Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 172 heterocercal angle for a fully balanced thrust from the dorsal caudal fin lobe will not exceed 33°. At angles greater than 33°, a ventral hypochordal lobe is necessary and would be useful for heterocercal angles ranging from 24° to 33° because it would reduce the angle of rotation needed for balance. They further suggested that the greater the heterocercal angle, the greater the versatility in producing moments of thrust around the center of balance and hence the greater the turning ability in the vertical plane. Total tail angle, the sum of the heterocercal and hypochordal angle is hypothesized to be proportional to the maximum obtainable speed and high angles are correlated with a forward position of the dorsal fin and a posterior position of the pelvic fins. Lower heterocercal angles, accompanied by a reduction in the ventral caudal lobe, are correlated with a relatively posterior position of the first- dorsal fin and anterior position of the pelvic fins. The mean heterocercal angles for the nine species examined here ranged from 14.64° to 29.00° (Fig. 68), confirming Thomson and Simanek (1977) predictions that heteroceral angles should be less than 33°. The hypochordal angles of 26.50° to 37.38° provided total tail angles of 46.50° to 65.73°. A weak correlation was observed between total tail angle and the position of the first-dorsal and no correlation was evident between low heteroceral angles and the relative position of the pectoral or pelvic fins suggesting tail angle is conservative within the squaloids. Interspecific variability in fin size was analyzed by regressing the fin surface area on SL for each species. ANCOVA (a = 0.01) for the regression of the first dorsal fin and the pectoral fins on SL indicated no significant differences Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 173 Figure 68. Duncan’s Multiple Range Test for the mean caudal fin angle. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 37.30 36.73 37.38 33.29 32.75 31.00 31.62 29.57 26.50 c o e lo le p is C. C. C. granulosus S. acanthias O. centrina D. lich a 1. 1. brasiliensis D. c a lc e a E. c o o k e i E. princeps Hypochordal Hypochordal Angle 18.85 18.73 14.69 14.64 29.00 23.90 22.93 22.75 20.00 g r a n u lo s u s Heterocercal Angle C. C. 0. centrina C. coelolepis D. lich a D. c a lc e a S. acanthias E. c o o k e i E. princeps 1. brasiliensis Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 174 among the 9 species. The means, however, were significantly different. The growth rate for the caudal, second-dorsal and pelvic fins were significantly different among the nine species. The pelvic fins had the highest growth rates among the fins for five species, the second dorsal for two species and the pectorals for one species. Assuming the size of the fin is proportional to its importance in the swimming kinematics (Thomson and Simanek, 1977), the relative fin surface area (Fig. 69) revealed a general pattern among the species. Four species, D. licha, E. cookei, E. princeps and S. acanthias exhibited small median fins, medium sized paired fins and large caudal fins. Furthermore, there seemed to be a linear relationship between the relative size of the first-dorsal, pectoral and caudal fins as well as the second-dorsal, pelvic, and caudal fins within these species, suggesting similar functions among the species. However, fin position among these species does not confirm this conclusion. For D. calcea the relative size of the pectorals is equal to that of the caudal fin and for S. acanthias, the high aspect ratio, pectoral fins were relatively larger than the caudal fin. Hydrodynamics All animals moving through a fluid encounter a force acting in the opposite direction of movement and resisting its motion. This force, termed drag, and the magnitude of the resistance is directly proportional to the square of the swimming speed (U) and is defined as the sum of frictional, pressure, and induced drag. Induced drag occurs because of the movement of the swimming animal and as Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 175 Figure 69. Means and 95% confidence intervals for fin surface area by species. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. D1 D2 P1 C.g P2 CAUDAL D1 D2 C.c PI P2 CAUDAL D1 D2 D.l P1 P2 CAUDAL D1 D2 D.c P1 P2 CAUDAL D1 D2 E.c PI P2 CAUDAL D1 D2 E.p P1 P2 CAUDAL D1 D2 l.b P1 P2 CAUDAL D1 D2 O.c P1 P2 CAUDAL D1 S.a D2 P1 P2 CAUDAL -0.05 0.05 0.1 0.15 0.2 MEAN FIN SA/TOTAL SA Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 176 there is no way to measure it, theoretical drag is defined .as the hydrodynamic resistance of an equivalent rigid body with the same dimensions as the fish to which it is compared moving at the same velocity in the same fluid (Webb. 1975). Therefore, we can estimate theoretical drag as the product: Dt = 0.5 CD p SU2, where CD is a dimensionless force coefficient, p the density of the fluid, S the surface area and U2 the swimming velocity. The surface area can be expressed as either the maximum cross-sectional surface area of a plane normal to the flow, or the wetted surface area. The frontal area is often used when viscous drag is important and wetted area where pressure drag is more important (Alexander, 1990). At low Reynolds numbers, details of shape and orientation have little influence on drag so the frontal area is an adequate scale factor (Alexander, 1990). However, most macroscopic swimming animals operate at intermediate Reynolds numbers and with the relationship between the drag coefficient and Re being dependent upon the geometry of the object and the nature of the flow (Hoerner, 1965), one cannot be sure whether viscous or pressure drag is most important (Alexander, 1990). Following the recommendation of Alexander (1990), that typical swimming animals are elongated in the direction of swimming and that streamlining and orientation are important to boundary layer separation and wake size, wetted area is preferable and will be used herein. Swimming capabilities are generally divided into three categories; sustained, prolonged and burst swimming (Hoar and Randall, 1978). Sustained or Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 177 voluntary swimming involves speeds that can be maintained indefinitely and can be estimated as a function of SL (Weihs, 1977) as: Us = 0.503 SL0'43. Prolonged swimming involves speeds that can be maintained for a couple of hours with effort. Burst swimming speed achieved with maximum effort for about 30 seconds is estimated from Wardle’s (1975) equation: UB = (A SL) / 2T, where A is the stride length, estimated as 80% SL and T is the muscle contraction time, estimated here as 0.8. Reynolds number is a dimensionless index of the relative importance of inertial forces to viscous forces and is calculated as: Re = SL U / v, where v is the kinematic viscosity of water. When Re is less than 1, viscous forces dominate and when greater than 106, inertial forces dominate. At Re values between 102 to 105, intermediate forces dominate. A coefficient of frictional drag (Cf) is than defined as a function of the Reynolds number and the nature of the fluid. For each of the flow conditions, laminar, turbulent or transitional, a separate Cf is defined: Cflamln„ = 1.33 Re0'5 Cf,„„sitional = (0.074 Re0'2) - (1700 Re1) C W „ , = 0.074 Re0'2. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 178 Finally, the total drag coefficient is defined as a function of the coefficient of frictional drag, maximum diameter of the object (D), and the SL: CD = Cf [1+1.5(D/SL)‘ 5 + 7(D/SL)3]. Extrapolating theoretical drag calculations to a swimming fish assumes that the swimming drag is equal to that of the body stretched straight and making no lateral movements, the flow pattern is streamlined with boundary layer flow conditions dictated by Reynolds number and the secondary flow patterns produced by propulsive movements are neglected. Drag coefficients and total drag plotted against Reynolds numbers in Fig. 70 and Fig. 71 are presented here for comparison purposes only and are not intended to represent those in free-swimming fish. However, under similiar flow conditions and Reynolds numbers, three general trends can be observed. Etmopterus princeps, E. cookei and O. centrina exhibited the highest predicted total drag. Likewise, D. calcea, I. brasiliensis and S. acanthias exhibited the lowest total drag of the squaloids examined. Consequently, under similiar flow conditions, D. calcea, I. brasiliensis and S. acanthias would be expected to be better swimmers than those species experiencing higher total drag. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 179 Figure 70. Drag coeffiecient vs Reynold’s number for nine species of Squaliformes; (1) C. granulosus, (2) C. coelolepis, (3) D. licha, (4) D. calcea, (5) E. cookei, (6) E. princeps, (7) I. brasiliensis, (8) O. centrina and (9) S. acanthias. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced Cd-TURBULENT o> I X CO Re (MILLIONS) 180 Figure 71. Total Drag vs Reynold’s number for nine species of Squaliformes; (1) C. granulosus, (2) C. coelolepis, (3) D. licha, (4) D. calcea, (5) E. cookei, (6) E. princeps, (7) I. brasiliensis, (8) O. centrina and (9) S. acanthias. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CM Re Re (MILLIONS) D) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 181 Conclusions Although optimal morphologies can be defined for specialized swimming behaviors, body form is generally a result of a mosiac of selection pressures. Consequently, although the extrapolation of swimming behavior from body morphologies is limited, it is often the best insight we have to the swimming capabilities. When other factors, such as bouyancy, stomach contents and natural histories are incorporated, a more reasonable guess into the swimming behavior can me made. Keeping in mind the limitations and assumptions made with the data set, three general body forms can be defined in the squaloids examined. Within the three types, differences in fin shape, aspect ratio and placement contribute to differences in the flow and hence swimming performance of the different species. Oxynotus centrina exhibits a very robust body with a fineness ratio approaching the optimal value of 4.5 although having surface areas in excess of optimal. This large surface area suggest an increase in volume at the expense of surface area. The increase in volume appears to be anterior and associated with a large, high aspect ratio, first dorsal fin, minimizing the recoil from the lateral transverse motion of the caudal fin. Furthermore, the increased volume may be in response to increase bouyancy through an increased body cavity and the concentration of low density lipids. The fins exhibited high aspect ratios and were generally shifted forward with relatively large inter-dorsal and pectoral to pelvic fin distances. Pectoral fins showed high growth rates and the pelvic fins low. Furthermore, the cross sectional Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 182 body shape was almost triangle, with a flat ventral surface and a subterminal mouth. Very little is known about this species, or the family Oxynotidae. Compagno (1984) suggested that at least one species might attain neutral bouyancy through the static lift of its large oily liver and might hover, swimming slowly above the substrate without the need for dynamic lift. However, the pectoral and caudal fin size and aspect ratios suggest that some lift is needed to remain aloft. It is probable that O. centrina rests on the bottom where currents are favorable to maintain sufficient dissolved oxygen concentration. The large caudal fin is probably used in conjunction with horizontally aligned pectoral fins to achieve the forward thrust and lift to arise from the substrate and swim slowly, feeding on benthic animals. The large dorsal fins and spines might function in protection from predation from above. The high aspect ratio, large dorsal fins might also help in orienting the body into the direction of any bottom current. Centrophorus granulosus, C. coelolepis, and D. licha were characterized by a moderate diameter profile and a moderately high fineness ratio with optimal surface area. This, along with a shoulder in a more posterior postion suggest a body form designed to delay boundary layer seperation. Low aspect ratio fins, and a large caudal and small dorsal fins suggest this body form would optimize moderate speeds with limited lift provided from the pectoral fins. Thomson and Simanek (1977) noted that the pectoral fins of Centroscymnus and Dalatias are inserted particularly high on the body, suggesting a high degree of control in the vertical direction. This correspond to the general notion thatC. coelolepis and D. licha obtain near neutral to Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 183 neutral bouyancy through low density lipids (Corner, Denton and Forster; 1968, Deprez, Volkman and Davenport; 1990) concentrated in enlarged livers. In general, these sharks exhibit moderately rounded to blunt snouts and fairly flexible pectoral fins. Their body in cross-section was generally circular from head to caudal peduncle. Centrophorus granulosus, C. coelolepis, and D. licha are all considered deepwater sharks of the upper and middle continental and insular slopes. Known as a farily common shark on or near the bottom at depths from 100 to 1200m (Compagno, 1984), C. granulosus is probably a cruiser of the ocean depths. Considered to concentrate squalene in quantities to provide near neutral bouyancy and pectoral fins in a more vertical oreintation and flexible suggest that this species is not obtaining a significant amount of dynamic lift from the pectoral fins. Freed from primarily providing dynamic lift, the pectoral fins probably function in controlling vertical attitude and alltitude. Stomach contents of hake, epigonids and laternfish (Compagno, 1984), suggest moderate swimming speed capabilities. Characterized as a wide-ranging, shark living on or near the bottom on the continential shelf, C. coelolepis is reported from depths ranging from 330m to 2,718m (Yano and Tanaka, 1983). Generally more flacid in musculature and known to have high concentrations of oils and specifically squalene in their livers (Deprez, 1990), this species is probably neutrally bouyant. Stiff pectoral fins inserted laterally by a narrow relatively flexible base, suggest a high degree of vertical Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 184 control. Reported to feed on Myctophidae and Ommastrephidae (Yano and Tanaka, 1983), this species is probably a generally strong swimmer with good directional control in the vertical plane. Dalatias licha is considered a powerful and versatile predator inhabiting continental slopes from 37m to at least 1800m depth (Campagno; 1984, Yano; 1991). Feeding primarily on Myctophidae and cephalopoda (Yano, 1991), stomach contents have included skates, catsharks, spiny dogfish ( Squalus, Etmopterus and Centrophorus) and fast-swimming epipelagic fishes such as bonito (Compagno, 1984). Compagno attributes the presence of bonito as evidence of either a scavaging or ambush feeding methods. Howewver, it is probable that these sharks can obtain moderate to high swimming speeds with good vertical control, allowing for unobserved attack from either above or below their prey. Near neutral bouyancy, lateral insertion of flexible pectoral fins support this idea. Generally flacid in body musculature, this species is not designed to sit or rest on the bottom. A third general trend in body shape is characterized by a narrow diameter profile, high fineness ratio and surface areas well below predicted optimal values. This body form is optimal in delaying the seperation of the boundary layer and would reduce frictional drag through reduced surface areas. Squalus acanthias, D. calcea and I. brasiliensis are typical of this body form. The fin aspect ratios and position are variable within this group and probably reflect differences in buoyancy control mechanisms. S. acanthias probably utilizes dynamic lift of the pectoral fins and is more maneuverable in the horizontal direction. Isistius brasiliensis and D. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 185 calcea highly moveable pectoral fins probably provide directional stability in the vertical plane. Squalus acanthias, is a common dogfish of the contential and insular shelf waters and the upper slopes and is considered a powerful, voracious predator that feeds primarily on bony fishes (Compagno, 1984). Furthermore, Compagno (1984) describes them as a slow, inactive swimmer, which keeps a steady pace in its nomadic movements. The body form, large, high aspect ratio pectoral fins and high fineness ratio would tend to confirm this idea. The necessity of the pectoral fins to provide dynamic lift constrain their shape and placement. The long, narrow body and relatively low surface areas are probably optimal for continuous cruising at slow to moderate speeds. Deania calcea, is a deepwater dogfish of the outer continental and insular shelves and upper slopes reported from depths of 73 to 1450m (Compagno, 1984). The elongated rostral region suggests an enhanced ampullary system and a greater sensitivity in prey detection. Reported to feed on Myctophidae fishes and cephalopoda (Yano, 1991) combined with the possibility of being neutrally bouyant (Deprez, 1990), this shark probably has a more mesopelagic lifestyle. The flexible, paddle-like pectoral fins and the shift of the dorsal fins posteriorly suggest an increased flexibility and manuverability in the head region. This species, capable of feeding on squid and mytopid fishes, is probably a moderate swimmer with good directional control in both the horizontal and vertical plane. Further more, feeding in the mesopelagic with a subterminal mouth suggest either feeding from above or Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 186 good flexibility. The posterior position of the second dorsal fin in close proximity of the caudal fin suggests a quick acceleration or lunging ability. Isistius brasiliensis, a wide ranging, epipelagic to bathypelagic shark caught at depths ranging from the surface to 3500m, is thought to be a diel vertical migrator (Compagno, 1984). Compagno (1984) suggested that the small paired fins, long body cavity and enormous, oily liver point to its being neutrally bouyant and not dependent on dynamic lift. The cookiecutter shark gets the name from its apparent ability to remove plugs of flesh from large predators such as tuna, marlin, dolphinsihes and cetaceans (Jones, 1971 and Seigel, 1978). The crater wounds suggest a forward attack and Jones (1971) concluded a lever motion of the shark’s body, after the initial contact, alligning the shark with the forward motion of the prey would remove a chunk of flesh in a similiar fashion as a mellon-ball cutter, consistant with the crater wounds. The narrow, gently tappering body to a narrow caudal peduncle and reduced surface area for its fineness ratio would suggest a body designed for fast swimming speeds with reduced frictional drag. Neutral bouyancy has allowed for the reduction and lateral positioning of the pectoral fins. Combined with the reduced, posterior positioned dorsal fins, this body forms suggest a further reduction in drag associated with hydrofoils. The luminous organs are restricted to the ventral surface with counter shading on the dorsal surface (Reif, 1984). This suggests an animal designed for the mesopelagicand epipelagic zones. This shark probably is capable of obtaining moderate to fast swimming speeds with excellent vertical and Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 187 braking control in tracking down and capturing prey of formidable swimming capabilities. Etmopterus princeps is a lanternshark that occurs on the continental slopes, on or near the bottom at depths ranging from 567 to 2213 m (Compagno, 1984). Although other species within the genus are known to be bioluminescent, (Reif, 1985), there is no indication that this species is. Slightly broader in profile, the body shape tends to be a composite of the previous two types. Generally, very similiar to I. brasiliensis, the body form gentely tapers posteriorly from a weakly defined shoulder region. The pectoral fins are paddle shaped and their origin is shifted to a lateral position. Lateral compression of the enlarged, flacid body cavity, probably produces a more oblonged cross-section and might aide in transverse stability. This species most likely achieves near neutral buoyancy, freeing its paired fins from providing lift to control vertical directioning and braking. Etmopterus princeps is probably a moderate swimmer, cruising in proximaty to the bottom. The strong dorsal spines suggest a benthic lifestyle, however, the lack of ventral body stiffness suggests it does not live or rest on the bottom. The paddle-like fins probably function in vertical and horzitontal directional control as well as braking. The relatively narrow caudal suggests a cruising lifestyle, although the postioning and orientation of the second dorsal fin suggest an ability for quick starts or lunges. Echinorhinus cookei, although not sampled qualitatively enough to draw extensive conclusions, probably presents a body morphology that optimizes Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 188 sinusoidal swimming. Known to be a slow swimmer, it has been observed throughout the water column along the walls of the Montery Canyon (per. comm.) and is thought to be neutrally bouyant. In addition, the body form and median fin placement is similiar to those of a pike, and probably represents an ability for quick acceleration. This species probably meanders through the water column along the walls of steep slopes and canyons at speeds dictated by respiration requirements in search of prey, which it captures by quick lunges. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. PLACOID SCALE MORPHOLOGY Intraspecific, sexual dimorphism and sex specific spatial variabilty was observed in all species examined with the exception of O. centrina and E. cookei. Lacking a sufficient number of specimens, sexual dimorphism was not examined in either species. Although the variability was statistically significant, interpreting biological significance was difficult. Without specific details about the swimming mechanics and the nature of the flow across different sections of the body, suggestions as to the functional morphologies of placoid scales are enlightened guesses at best. Consequently, accessing the biological significance of the sexual dimorphic variability, on a site to site bases, would provide little useful insight into the morphological impact on function. However, the general biological implications, of sexual dimorphic variability in placoid scale squammation patterns, accompanied by swimming behaviors gained from body morphologies and natural histories provide insight into the functional morphologies of placoid scales and sexual dimorphic natural histories. Overall, five gross placoid scale morphologies were observed among the nine species. C. granulosus and D. licha were characterized by lanceolate placoid scales. Cuspid, plate-like crowns were characteristic of C. coelolepis and S. acanthias. Spike-like or thorn-like scales lacking a true crown were common among E. cookei. E. princeps and O. centrina. Unique crown morphologies were exhibited 189 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 190 by D. calcea and I. brasiliensis. Deania calcea scales were characterized by a tricuspid, or three pronged crown lacking a true plate-like form. The placoid scales of I. brasiliensis were trapezoidal in shape tapering to a concaved crown surface. Centrophorus granulosus Centrophorus granulosus exhibited little sexual dimorphic variability in overall mean scale morphologies. In males and females, site specific, mean scale widths and lengths ranged from 0.2 to 0.8 mm. The crowns of head scales were generally small and wide as they were long. Posterior scale crowns were generally larger and longer than they were wide. This trend was most apparent in the caudal peduncle region were scale crown lengths were 15% to 20% greater than the widths. Mean crown area, per sampling site, ranged from 0.05 to 0.3 mm2, with the lateral body region, B2, in males exhibiting an uncharacteristically large crown area with a mean of 0.6 mm2. The caudal regions exhibited the longest crowns, while the head was characterized by small crowns. The anterior gill region exhibited the smallest scales. The mean percentage of the integument overlayed by scale crowns exhibited little correlation with crown area. Mean, site specific PC values ranged from 30% to 60%. Again, the caudal region exhibited the highest PC values and the anterior gill region the lowest. Site specific mean scale weight exhibited a stronger correlation with crown size in males than females and ranged from 20 to 200ug. Furthermore, males tended to exhibit heavier scales per size than females. In both males and females, the caudal region had heaviest scales and the anterior gill region the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 191 lightest. In males and females, placoid scale crowns generally increased width, length and area in a posterior direction. Furthermore, both sexes exhibited three general categories of placoid scale morphology. The first scale type was characterized by crowns that were relatively short and wide that covered a large percentage of the integument, and that exhibited relatively high weight to area ratios. In females, these scales were characteristic of the ventral posterior head and the lateral and dorsal anterior body. In males this scale type was present on the ventral and lateral head and the anterior body. Scales, in both sexes, increased in size posteriorly across the region, by increasing width. An increase in crown width, without a corresponding increase in length, would provide for greater flexibility in the transverse plane and greater stiffness in the radial plane. A second scale type was characterized by crowns equal in length and width. These scales covered a relatively low percentage of the integument and were relatively small and light in specific weight. In females, these scales were found on the anterior and dorsal head and the ventral and posterior body. In males, this scale type was restricted to the dorsal head and the posterior body. These regular sized scales, with decreased PC values, would increase flexibility in all planes. The third scale type was restricted to the caudal peduncle and caudal fin in both sexes and was characterized by long, narrow crowns covering the largest percentage of the integument (60% - 80%). Long, narrow, densely packed scales would provide extra stiffness in the longitudinal plane of the caudal region during Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 192 the transverse motion of the fin during a power stroke. Furthermore, narrow scales would still allow the flexibility to roll the tail in a dorso-ventral orientation to controll the direction of thrust. The body shape of these sharks suggest that they are designed for constant cruising with some lift being provided by their pectoral fins. Attached, laminar boundary layer is probably the flow environment anterior to the shoulder region. Posteriorly, the boundary layer flow would probably be turbulent and separated. An increase in scale size in a posterior direction would be required if the scales were functioning in a hydrodynamic capacity and influencing the boundary layer because boundary layer thickens with distance from snout (Schlichting, 1968). The dorsal surface, exhibited smaller scales follows that if the flow is faster over the dorsal surface, the scales would necessarily be smaller (Ref). The flow will be faster if a water parcel needs to travel a greater distance over the dorsal surface than the ventral surface. The placoid scales from all sampled regions exhibited longitudinal crown ridging. The snout scales, even though blunt and knob-like, a morphology suggestive of a protective function, exhibited posterior crown edge ridging. Here the boundary layed would be the thinnest, and the weakest ridging might have an effect on the flow. This ridging was more prominent on the body and caudal scales and became apex oriented. Considering the diversity in scale morphology across the body in relation to theoretical hydrodynamics, it is probable that these scales are influencing the boundary layer flow in some capacity. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 193 Centroscymnus coelolepis The palcoid scales of C. coelolepis were relatively large, heavy and the scale crowns overlayed a large percentage of the integument. Although the mean SL for males (580 mm) and females (607 mm) was generally similiar, males exhibited larger scale crowns. Site specific, mean scale lengths ranged from 0.5 to 1.5 mm in females and 0.5 to 2.0 mm in males. Scale crown widths averaged 0.8 to 1.5 mm and 1.0 to 2.0 mm in females and males, respectively. Mean crown areas ranged from 0.4 to 1.5 mm2 in females and 0.6 to 3.0 mm2 in males. Three general scale types were exhibited in similiar patterns across the body in both males and females. Scales, characterized as relatively small and light weight were exhibited on the anterior and dorsal head region in both sexes. In males, these scales were also typical of the ventral posterior head. Scales moderate in size and weight were characteristic of the posterior head and dorsal anterior body in males and females. A third scale type, characterized as relatively large and heavy was common throughout the body from the anterior ventral body through the caudal peduncle. Although similiar in morphology to the scales characteristic of the posterior body, the caudal peduncle scales covered a much greater percentage of the integument. Likewise, the caudal fin scales were most similiar to the moderate sized scales of the posterior head but again covered a considerably greater percentage of the integument. The percentage of the integument overlayed by scale crowns exhibited little correlation with crown area. However, there was a general trend for PC to Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 194 increase in a dorsal ventral direction. The only exception to this was in the shoulder or anterior body region. This increase in PC is a result of an increase in scale density and not crown size. This would tend to suggest an increase in the structural integrity and possibly protection in a generally flacid region of the body. The ventral region in these sharks lacks the muscle mass of the dorsal region and combined with a rather enlarged body cavity to accomadate an enlarged liver, results in a somewhat jelly-like consistancy. An increase in scale density and PC would increase the stiffness of the integument, helping to maintain the overall shape. Although scale weights generally reflected scale crown size, regional differences in the scale weight to crown size relationship probably reflect differences in regional functional balances. The scales of the anterior and lateral head region were of similiar weight but crown dimensions varied. The ventral rostrum scales were the smallest, suggesting a thicker crown or base functioning to increase protection. The crowns of the anterior gill scales were the largest, and more delicate implying a hydrodynamic rather than proctective function. Furthermore, although scale weights were similiar between males and females, female scale crowns were consistently smaller. This would suggest that the females scales are thicker than their male counterparts and might represent a modification for increased protection. Sexual dimorphic variability in placoid scale functional morphology implies behavioral difference. Sexual segregation or resource partioning could alter the flow regime or the balance of protection and drag reduction. An increase in protection Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 195 for females may be in response to a male biting courtship behavior. The trend to increase scale size in a posterior direction without a change in PC has two functional implications. From a hydrodynamic standpoint, an increase in scale size may be correlated with an increased boundary layer thickness. In terms of flexibility, an increase in scale size would decrease the flexibility of the integument and provide for a stronger, caudal fin power stroke. Dalatias licha The placoid scales exhibited on D. licha were characterized as relatively small, moderate in weight and spatially arranged leaving a large percentage of the integument exposed. Although the mean SL for males (618 mm) was considerably larger than females (530 mm), scale crown size was similiar. Site specific, mean scale widths ranged from 0.4 to 0.9 mm and mean crown length from 0.6 to 1.1 mm. Mean crown area ranged from 0.1 to 0.5 mm2. The percentage of the integument overlayed by scale crowns exhibited little correlation with crown area and ranged from 20% to 40% in males and 20% to 60% in females. Placoid scale weight exhibited a strong correlation with crown area. Two striking similiarities between males and females were observed. The ventral rostrum scales were obviously larger, although not necessarily heavier than the rest of the scales examined. Likewise, the crown width of the caudal fin scales were considerably narrower. Five distinct scale type morphologies were observed in males and Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 196 females. Regional boundaries of similiar scales, with the exception of the head region, exhibited similiar distribution patterns between males and females. However, the placoid scales characteristics of each region were different between the sexes. In males, the anterior head exhibited the largest scales covering the greatest percentage of the integument. The posterior head scales were characterized as moderate in size but relatively short. The anterior body scales were similiar in width to the posterior head scales but exhibited greater crown lengths and surface areas. The posterior body, including the caudal peduncle, exhibited scales that were characteristicly narrow and light weight, variable in length and PC. The caudal fin scales were unique in morphology. Characterized by narrow crowns of moderate length, these scales exhibited the smallest crowns of the lightest weight. In females, the placoid scales exhibited narrower crowns in the head, dorsal body, caudal peduncle and caudal fin regions than the lateral and ventral body regions. The scales of the head region were characterized as relatively small in size and moderate in weight. The anterior and ventral posterior body and caudal peduncle region was characterized by scales with relatively large crown areas and high scale weights. The dorsal posterior body scales were among the lightest in weight and smallest in crown size. Similiar to males, the caudal fin scale crowns were of moderate length but extremely narrow and among the lightest in scale weight. Although differences were observed between males and females, general trends of variability common to both sexes were observed. The ventral rostral (H2) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 197 scales were the largest and heaviest scales, and covered the greatest percentage of the integument. This might be expected for added protection in the mouth region. If this shark feeds on large, epipelagic animals as its tooth morphology would suggest, added protection to the snout would be benaficial. The upper jaw teeth are designed for grasping and penetrating while the lower teeth are designed for a sawing or cutting function suggesting the ventral snout is more sucseptible to abrasion. Overall the head scales are generally heavier for their size suggesting an increase in protection during feeding. The caudal fin scales in both sexes exhibited the smallest crown size and scale weight while covering a relatively high percentage of the integument allowing for an increase in flexibility. In general, the body scales were relatively large and heavy. Furthermore the dorsal scales were lighter, although of similiar size, than the ventral scale. Although it appears that these scales function in a primarily protective function, all the scales exhibited an apex oriented ridging pattern. Along with the overall dimensions of the scale and its relative spacing on the integument, this ridging might be funtioning in a hydrodynamic capacity. Likewise, this ridging might be an artifact of reducing scale weight and hence integument weight in an effort to achieve overall neutral bouyancy. Deania calcea The placoid scales of D. calcea were generally small in size, moderate in Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 198 scale weight and covered a relatively small percentage of the integument in any given area. General scale dimensions were similiar between males and females with mean SL of 647 and 618 mm respectively. Site specific, mean scale crown width and length ranged from 0.3 to 0.85 mm. Mean crown areas generally ranged from 0.05 to 0.20 mm2 with females exhibiting a slightly larger crown than males. The percentage of integument overlayed by scale crowns ranged from 25 to 60% in both sexes and exhibited little correlation with crown area. The caudal fin scales of females exhibited uncharacteristically large crowns with areas of 0.28 mm2 that covered over 100% of the integument. Placoid scale weight ranged from 15 to 130 ug, with males exhibiting a stronger scale weight to crown area relationship than females. Although there were three palcoid scale types defined for females and four scale types for males, a similiar trend in variability was observed in both sexes. Placoid scale crown size and scale weight generally increased from the snout to the posterior body region, where scale crown size and scale weight decreased. Ventral body scales in both sexes were the largest and the heaviest. The placoid scales on the head and body region were tridentate in shape and erect in orientation. Consequently, the crown width was also a measure of the distance or spread of the two lateral spikes. The anterior head scales were relatively short, narrow and light weight. The posterior head and body scales were characterized as relatively large, with crown widths considerably larger and heavier than those on the anterior head scales, and heavy. In the caudal peduncle region, Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 199 the scale morphology became more plate-like than tridentate. The scale neck widend, the lateral points weakend and the overall shape was more weakly tricuspid. On the caudal fin, the scales completly lost the tridentate shape and were lanceolate with apex oriented longitudinal ridging. These scales generally were narrow, relatively light weight and covered a high percentage of the integument. The abrupt change in scale morphology fom the body to the tail suggests an abrupt change in function. The tail region, with its lateral motion in swimming, experiences faster flow velocities than the forward speed of motion, and the boundary layer is probably separated and turbulent. Consequently, the caudal fin scales might be better designed to influence turbulent, seperated boundary layer flow than the head and body scale morphologies. It might further be reasoned that if the tridentate scales are functioning in a hydrodynamic capacity, the boundary layer conditions on the head and body is attached, laminar flow. The body shape, natural history and hypothesised swimming behavior support this conclusion. The surface area to fineness ratio relationship suggest a decreased surface area, a condition suitable for reducing frictional drag under attached boundary layer flow. It is probable that this shark swims slowly over the bottom with good directional capabilities under laminar flow. Echinorhinus cookei Unfortunately, placoid scales were only examined from a single, juvenile specimen. Still, the general morphologies and their distribution can provide limited Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 200 insight into their function. The genaral shape of the placoid scales characteristic of E. cookei could be described as multiple ridges radiating out and downward from a central apex to a relatively large circular base. Site specific, mean scale crown widths and lengths ranged from 0.4 to 2.2 mm and crown area ranged from 0.05 to 3.55mm2. The site specific, mean percentage of the integument covered by scales ranged from 10 to 60% and exhibited a weak correlation with crown area. The mean scale weights ranged from 10 to 160 ug and exhibited a moderate correlation with scale crown size. The dorsal head and dorsal anterior body exhibited larger scales that covered a greater percentage of the body than the corresponding ventral region. Scale weights in the dorsal anterior region generally reflected scale size. On the anterior ventral surface, scale weights increased in a posterior direction although the scale size was generally constant. The posterior body scales were generally smaller and lighter than the anterior scales. Furthermore, they covered a relatively low percentage of the integument. The caudal peduncle and caudal fin scales covered a relatively high percentage of the integument although moderate in scale size. Although Compagno (1984) described E. cookei as a sluggish bottom shark, it has been observed swimming slowly in a sinusoidal fashion throughout the water column by personnel at the Monterary Aquarium (per. com.) The species is commonly found in the Eastern Pacific, New Zealand and Hawaii, where the bottom topography is generally steep canyons and vertical walls reaching to gr Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 201 Consequently, instead of a sluggish bottom shark, this species probably achievies neutral bouyancy through reduced body density (J. A. Musick, per. com.) and squalene concentrations and slowly swims along these cliff faces looking for food items. The placoid scale morphology probably represents an adaption towards protection. The fact that the head and caudal regions exhibited larger scales that covered a greater percentage of the integument might reflect either an increase in protection required from abrasion in these areas due to the nature of feeding or it might be in response to a hydrodynamic function. If an animal is feeding along a vertical wall, it seems logical that the anterior and posterior regions have a greater chance of coming into contact with the substrate and these areas would require greater protection. In contrast, animals feeding on the bottom should exhibt a dorsal lateral difference in placoid scales when they are functioning in a protective capacity. The posibility for these scales to function in a hydrohydrodynamic capacity should not be dismissed too lightly. The differences observed across the body may not represent regional protective requirements but some other influence. The degree of protection required may be homogeneous across the body and the varaibilty could represent differences in flow patterns, suggesting a hydrodynamic function as well as a protective one. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 202 Etmopterus princeps The palcoid scales of E. princeps were generally spine shaped curving in a posterior direction. The diffference in the mean SL between males (443 mm) and females (428 mm) was reflected in a difference in mean scale dimensions. Site specific mean crown lengths ranged from 0.4 to 0.7mm in females and 0.3 to 0.6 mm in males. Mean scale crown areas ranged from 0.06 to 0.12 mm2 and 0.03 to 0.09 mm2 in females and males, respectively. The percentage of integument overlayed by scales was similiar between the sexes and ranged from 10 to 25%. Scale weight exhibited little correlation with crown area in either sex and ranged from 25 to 50ug in females and 15 to 35ug in males. The scale crown width and length exhibited similiar patterns in spatial variability in males and females. From anterior head, through the posterior head, body and caudal fin, scale crown length increased and crown width was generally constant. Furthermore, within the head region, there was a general trend for dorsal scales to be wider than the ventral scales in both sexes. A pattern of the percentage of integument covered by scales was less discernable, however, the dorsal and ventral rostrum exhibited the highest PC values in both sexes. Likewise, very little could be said about the variability in scale weight. Reif (1984) concluded that similiar scale morphologies observed on the closely related, E. spinax would not absorb much light from the surface photophores and would protect against ectoparasites and the settlement of epibionts. However, Moss (Moss, 1984) noted that ectoparasites were found more often on naked skin Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 203 elasmobranchs, implying a factor, or factors, other than spine shaped placoid scales is responsible. If the placoid scales were functioning in some capacity to influence the boundary layer flow, an inrease in crown length would be expected in a posterior direction. The boundary layer will increase thickness in a posterior direction and for a surface structure to influence the boundary layer it must traverse the boundary layer, it follows that it would be advantagous to increase the spine length. This assumes that the spine length and scale height are correlated. Likewise, the difference in scale crown length between males and females might represent a difference in swimming speeds associated with difference size fish. Based on the assumption that larger fish (SL) swim faster, the males would be expected to have shorter crowns than females. The lack of differentiaion in general morphology probably indicated similiar flow conditions across the entire body and caudal fin. Isistius brasiliensis The placoid scales observed on I. brasiliensis were trapizoidal in shape with a concaved facet on the distal surface. Little variability was observed in mean scale morphologies either spatially or sexually. Site specific mean scale crown width and length ranged from 0.18 to 0.28 mm and 0.2 to 0.28 mm respectively. Mean scale crown area ranged from 0.014 to 0.035 mm2. Mean scale weight ranged from 1.5 to 5 ug and exhibited a very weak correlation with scale crown size. General patterns in the distribution of placoid scales was similiar in Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 204 males and females. The head scales were generally the smallest and overlayed the least percentage of the integument. Body scales were moderate in size and the percentage of integument covered. The ventral body scales exhibited the highest mean crown areas and percentage of integument covered. Caudal region scales were somewhat variable in relative size between the sexes but the caudal fin scales covered the greates percentage of integument in both males and females. Any relationship between scale weight and crown area or scale location was obscured, probably because of a lack of precision in measuring such minute scales. Although Reif (1985) and Compagno (1984) recognized that this species is a diel vertical migrator, traversing distances in excess of 2000 to 3000 m, and that it preys on large, fast swimming bony fishes such as marlin and tuna. However, they both are of the opinion that this species ambushes its prey because it is bioluminescent. Reif (1985) suggests that the bioluminescenus is a counter shading phenomena making the shark invesible and obscuring the location of the mouth. Compagno (1984) suggested that the bioluminescenus may serve to lure other predators to attack it, only to be parasitized by I. brasiliensis. A third hypothesis that the bioluminescense is functioning in species recognition is not even postulated. The torpedo body shape and nearly homocercal tail with an almost horizontal, notochordal axis and a narrow caudal peduncle suggest a individual capable of reaching moderately fast swimming speeds relative to its small size. Neutral bouyancy and the lateral insertion of the small, flexible pectoral fins suggest a high degree of directional manuverability and braking. It is possible, therefore, Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 205 that this shark, traversing the water column, attacks large bony fishes as it comes upon them. If Isistius attacked in a head fashion, as suggested by Compagno (1984) it would be successful if it suprised its prey by from either above or below and were capable of out manuvering it. Reif (1985) suggested that the placoid scales of this species represents a modification for the distribution of bioluminescent organs. However, as he points out, photophores are concentrated on the ventral side and there was no dorsal ventral pattern of variability in placoid scales to suggest a relationship between photophores and scale morphology. The similarity between the overall appearance of the placoid scales observed on I. brasiliensis and the dimpling on golf-balls, designed to reduce drag, might provide insight into the functional morphology of these scales. Oxynotus centrina The placoid scales of O. centrina had a medial point or spike with lateral wings. The transition between the medial axis and the lateral wings was concave, creating a medial, longitudinal ridge. Although there was little difference between the mean SL of males (359 mm) and females (369 mm), the placoid scales from males were generally larger and heavier than females. Mean, site specific, scale crown widths and lengths ranged from 0.5 to 1.0 mm in males and 0.35 to 0.80 mm in females. Scale crown areas ranged from 0.06 to 0.35 mm2 in males and 0.035 to 0.18 mm2 in females. The percentage of integument overlayed by scales exhibited little correlation with scale crown area and ranged from 10 to 35% in both sexes. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 206 The scale weight exhibited a stronger correlation with crown area in males than in females and ranged from 50 to 400 ug in males and 25 to 225 ug in females. The spatial distribution of placoid scale morphologies was generally similiar in males and females. The dorsal surface from snout to caudaal fin tended to exhibit relatively large, heavy scales in relation to the ventral surface. This could be explained in terms of a fish swimming near the bottom. If, indeed, this species slowly swims just off of the bottom, and the large dorsal fins and spines are functioning in a predation protective capacity, than it would follow that the scales might also function in a similiar capacity. Thus, it would be expected that the dorsal surface scales would be larger and heavier than the ventral surface. However, it would be short sighted to eliminate the possibility of a hydrodynamic function. Squalus acanthias There was a definite shape variability in placoid scale morphology between the anterior snout and the body and caudal regions. The rostral region scales were larger, rhombodial in shape and were arranged in a fashion that resulted in a large percentage of the integument covered by scales. Scales were regular in their distribution at almost all locations. The difference in mean SL between females (767 mm) and males (571 mm) was reflected in a difference in placoid scale dimensions. Site specific, mean crown width and length ranged from 0.25 to 0.50 mm and 0.35 to 0.52 mm respectively for females and 0.18 to 0.40 mm and 0.28 to 0.40 mm respectively in Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 207 males. Mean scale crown area ranged from 0.035 to 0.145 mm2 in females and 0.015 to 0.085 mm2 in males. Mean scale weight exhibited a strong correlation with crown area and ranged from 5 to 30 ug. There was a similiarity in the distribution of placoid scale morphologic variasbility. In both sexes, the rostral scales were the largest, covered the greatest percentage of integument and were the heaviest. These scales exhibited a bifurcated vee-shaped longitudinal ridge and appear more stout than the body scales. The caudal peduncle and caudal fin scales were also relatively large, covered a high percentage of the integument, and were among the heaviest. These scales are probably functioning in both a protective and hydrodynamic capacity. There was a general trend for the placoid scales from the ventral surface to be heavier, enhancing their protective function. However, the concave facet of the lateral wings, and a medial, longatudinal ridge created a crown with a major longitudinal ridge flanked on ether side by a lateral, minor ridge and valley. These lateral wings suggest a function other than protection. The body shape of this species suggests that the pectoral fins are required to provide dynamic lift. This notion is supported by the fact that these sharks do not concentrate squalene in their livers and are probably negatively bouyant. This species is probably a constant cruiser in search of potential prey. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. X X X X X X X X X X X X X X X X X X SCALE MORPHOMETRICS X X X X X X X X X X X X X X AREA SURFACE X X X XXXXX X X X X XXX XXXX X X X X XXX X X BODY MORPHOMETRICS 530 390 756 804 866 930 466 440 630 672 750 430 257 295 325 749 773 505 254 394 1258 1160 1398 STANDARD LENGTH (mm) F F F F F F F F F F M M M M M M M M SEX AD6389 VIMS-uc VIMS-uc UF42105 UF77859 UF77859UF30156 F AD6442.1AD6442.2 F NUMBER VIMS08157 V1MS08155 V1MS081 54 F VIMS08159 V1MS081 60 V1MS081 V1MS08162 F VIMS081 61 F COLLECTION SPECIES APPENDIX 1. Collection data. Centrophorus granulosus Centrophorus granulosusCentrophorus granulosus Centrophorus granulosus UF30158 Centrophorus granulosus Centrophorus granulosusCentrophorus granulosus UF42105 Centrophorus granulosus Centrophorus granulosus UF30160 Centrophorus granulosusCentrophorus granulosus VIMS-uc Centrophorus granulosus Centrophorus granulosus Centrophorus granulosus Centrophorus granulosus Centrophorus granulosus UF30157 Centroscymnus coelolepis Centroscymnus coelolepis Centroscymnus coelolepis Centroscymnus coelolepis VIMS05040 Centroscymnus coelolepis Centroscymnus coelolepis AD6442.5 Centroscymnus coelolepis Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. X X X X X X X X X X X X X X X X X SCALE MORPHOMETRICS X X X X X X X X X X X X X X X X X X X X X X AREA SURFACE X X X X X X X X X X X X X BODY MORPHOMETRICS 220 X 800 866 145 X 705 770 X 640 266510 554 708805 890 X X 695 X 625 X 255 270 639 X 700 485560682 X X 398 STANDARD LENGTH (mm) F F F M M M M M SEX UF42106 M UF36968UF44976 F F NUMBER V1MS07356 F USNM202648 USNM203484 USNM220861USNM1 87625 M USNM206066 F USNM1 57834 USNM1 57844 F COLLECTION SPECIES Dalatias lichaDalatias licha USNM1 88501 M Dalatias licha Dalatias lichaDalatias licha VIMS08196 VIMS081 95 M Dalatias licha Dalatias licha Dalatias licha UF44759 Dalatias licha Dalatias licha Deania calcea Deania calceaDeania calcea VIMS081 64 UF41427 M Deania calcea Deania calcea Deania calcea Deania calcea Centroscymnus coelolepisCentroscymnus coelolepisCentroscymnus AD6442.6 coelolepis8158 SO VIM M V1MS08153 M Centroscymnus coelolepis VIMS081 52 M Centroscymnus coelolepisCentroscymnus coelolepis AD6442.3 AD6442.4 M M Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. SCALE MORPHOMETRICS X X X X X X X X X X X X x X X X x X x x X X X X X X X X X X X X X X X X X X X X X X X X X X A REA SU R FA C E X X X X X X X X X X X X X X X X X X X X X X 500 422 X 474 412 415 415 305 409 445 458 655 695 810 433 443 653 680 175 178 566 480 552 260 STANDARD BODY LENGTH (mm) MORPHOMETRICS F F M M M SEX UF41736UF42596 M F UF35683UF35683 F UF44630 NUMBER VIMS7356VIMS7356 M VIMS08176 F VIMS08170VIMS08171 M M VIMS08165VIMS08169 M M VIMS08173VIMS08172VIMS08166 F F F VIMS081 75 VIMS08174 VIMS08168 F VIMS08163VIMS08284 M M COLLECTION USNM203489 M USNM220273 M USNM220263 M SPECIES Deania calcea Deania calcea Deania calcea Deania calcea Deania calcea Deania calcea Deania calcea Deania calcea Echinorhinus Echinorhinus cookei Echinorhinus Echinorhinus cookei Etmopterus princeps Echinorhinus Echinorhinus cookei Etmopterus princeps Etmopterus princeps Etmopterus princeps Etmopterus princeps Etmopterus princeps Etmopterus princeps Etmopterus princeps Etmopterus princeps Etmopterus Etmopterus princeps Etmopterus princeps Etmopterus princeps Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. X X X X X X X X X X X X X SCALE MORPHOMETRICS X X X X AREA SURFACE XXXXXX XX XXXX XXXXXXXX XXXXX XX X XX BODY MORPHOMETRICS 166314 350352 371 376 X X X X 143 X X X 446 X 278 369 270 X X 333 325 332 290 295320 323 X X X 585 448 558617 X X 726 STAN DARD LENGTH (mm) F F F M M SEX VIMS-ucVIMS-ucVIMS-uc M VIMS-uc F F F UF35686UF79884 M M UF35686UF41669 M UF41669 F M NUMBER VIMS08167 M COLLECTION USNM190037 F USNM188385USNM221 045 F USNM221 043USNM164173 F USNM220863 M USNM188385 USNM206065 M brasiliensisbrasiliensis 88382 USNM1 brasiliensis USNM221044 brasiliensis brasiliensis USNM215947 M brasiliensis brasiliensis US221044 M SPECIES Squalus Squalus aanthias Isistius brasiliensis Isistius Isistius Isistius brasiliensis Isistius Isistius brasiliensis Isistius Isistius Isistius brasiliensis Isistius brasiliensis Isistius brasiliensis Isistius Isistius Isistius brasiliensis Oxynotus centrinaOxynotus centrina Oxynotus centrina USNM21 3756 F Oxynotus centrina Squalus acanthias Squalus acanthias Squalus acanthias Etmopterus Etmopterus princeps Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. X X X X X X X SCALE MORPHOMETRICS X X X X X X X AREA SURFACE X X X X X X BODY MORPHOMETRICS 835 890 490 X 601 645 780 490 535 S T A N D A R D LENGTH (mm) 2 1 1 1 2 2 2 2 SEX NUMBER COLLECTION SPECIES Squalus acanthias VIMS-uc Squalus acanthias VIMS-uc Squalus acanthiasSqualus acanthiasSqualus acanthias VIMS-UC VIMS-UC Squalus acanthias VIMS-UC Squalus acanthias VIMS-uc VIMS-uc Squalus acanthias VIMS-uc Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. P 0.0001 0.111 7 2.026.48 0.1 832 0.0257 0.000.01 0.9553 0.91 80 1.701.63 0.21 91 0.2252 4.941.71 0.0482 0.21 52 2.99 22.27 0.0001 F 1 39.071 0.0001 333.17 0.0001 387.44 497.21 0.0001 N/A 9.0021 0.0001 793.69 0.0001 SLOPE MEAN MEAN MEAN REG MEAN MEAN REG MEAN REG 0.978 R 0.779 SLOPE 0.969 SLOPE 0.9630.998 REG SLOPE Y =a+bX -0.290.873X + 0.995X .23 -1 + 0.979 0.450.770X + 0.959 0.250.859X + 0.970 REG -0.700.858X + -1.530.966X + 0.984 0.990-0.030.880X + SLOPE -0.600.955X + 0.987 0.976 REG SLOPE Fem ale Male Female 0.570.758X + Male Character Pop !nG-P2 InG-CP Male lnG-D1 Male lnG-D2 0.0001 0.0001 0.3981 0.3795 0.0001 Centrophorus granulosus 0.79 0.3906 1 71.361 0.0001 InG-OB Male 2376.1 5 5320.98 REG MEAN 0.64MEAN 0.4387 0.05 0.8277 MEAN 3.1 9 0.0993 REG MEAN 0.83 MEAN REG 253.46 0.0001 lnG-P1 Male RFP 0.980 0.972 REG 0.977 SLOPE 0.77 Y =a+bX -0.661.020X + 0.999 -0.34+0.887X 0.995-0.1 2+0.980X SLOPE 0.998 0.60 0.4563 Female -0.890.997X + -1.090.769X + Fem ale Female -0.22+0.993X 0.999 SLOPEFemale 0.57 -0.91+1.048X 0.4654 0.998 SLOPE 1.07 Female 0.3238 Female Male Male Female -0.46.705X + Male -0.92+0.899X Female -0.64+0.874X 0.985 SLOPE 0.1 3 0.7264 Female APPENDIX II. Analysis of covariance for sexual dimorphic variability in body shape. Character Pop lnD1 MalelnD2 -0.760.929X + 0.984 REG 463.91 InPI lnP2 Male InEYE Reproduced with permission of the copyright owner. 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CO M- r * CO N 0 5 ■O’ o CO o N CO o 0 4 o o o M* 0 4 o 0 4 CO o to CO o r - T" o CO o o o Is- o 0 4 in o CO N o 0 ) h - o 0 5 o o o v * in o 0 5 0 4 o o o o o d o o o o o o d o O o 0 4 0 4 0 5 r - o o CO o 0 4 0 5 o 0 4 w o T— CO O r — 0 4 o O i 0 5 o V CO T- o 0 4 o o d d o d o d d o 0 4 o d d CO m - m - 0 4 T~ N/A V“ UJ UJ UJ UJ UJ CL CL z CL z CL z CL CD cd < O < CD < CD CD £ 3 o o o o UJ o UJ _ l U i UJ _ i UJ UJ _ i UJ UJ UJ UJ UJ 2 g (t co 2 a: CO 2 a: CO 2 o: CO 2 ec CO 2 a: co 2 04 04 03 fs. o r - o h - in CM T” 5T CM h - 03 CO CO h - h - CO CO m 05 CO 03 0) CO03 05 03 03 03 CO 05 a : o o o d o o o o o o o o XX XXXXXX X X XX CO CO o in CM in CO 03 CM CO N o h* 04 CO o o CO 03 CO M* CO CD K O o 05 03 03 CO T* O CO CO X o o V“ y— o o o o T~ r “ o o X) + + + + + + + + + + + + + h» CO in K in 03 h - in in CO ra CO T- 03 o M- O o M* T" N. 03 ll d d o i T— T- o CO CM > • • i I 1 1 i i 7 a) Q> 0) 0 0 0 ra ra ra ra ra ra 0 ra 0 0 0 0 a . 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Further reproduction prohibited without permission. O i y ** CO o T f T f T f CO CM o i n CO i n o CO CO T f T— O ■*— i n Y- O 0 0 o O) CO CO CO CO CO o> CM rv. CO CO o o co o O ) CM o h - CD o CO h . o CM CO CM h*. CO o i n o o CO o CD CO o o CO o r*. T f o o o o o o o d d o o o d o o o o o o r*. CO CO CO CD o CT> o o> CO o CO CO CO CO CD T“ o CO i - T f CM o o o> Y" o o o o CO Y- CO Y" o d o o i n o Y“ o o o CM d o d o o Y“ CM CO y - UJLU LULU LUUJ CL 5 Q. a . z Q. z a 5 a . 0 o < 0 o 0 o CD o CD o < 0 o UJ UJ UJ UJ u i _J UJ UJ UJ LU UJ UJ UJ DC to s DC CO S DC co S DC CO 2 0 1 ( 0 £ DC i n 5 CM o O i CM m i n CM T f i n CD o o o CM T f r* . O i h - CD 0 0 CD CM CO Y“ o O i o > h - CO CO 0 5 CO CO h - CD GO a: o o d o o d o o d o o o V/» s > X X XX XX XX XX ? s ✓% OJ r* . N - CO i n O i CO T f i n i n i n T - CM CM m i n O i i n CO T f CO o m o o > T— o o o CM o o o > CO Y“ s o Y” Y— Y** Y* Y~ o o o o + + + + + + + + + + + + T- CD r - CD CO T f O) T f T f o CM r - T f CO r * . 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Z Ou O o 0 o < 0 o < CD o < O o < UJ _J UJ UJ _ j UJ UJ UJ LU LU UJ UJ dc C/3 £ o : co 2 DC CO 2 DC CO s DC i n S i n T f CO GO CO CO h - CO GO h - o CO o > O ) CO CM O i CD h - O) O i O i O) O i O i O i O i O) DC o d o o o d o o o o XX XXXX v * X X o T ~ CO o T f CM CO y T" Y“ »*s o o T f CO CM h * o Oi O) CO CD h - CD o CD O CD Y“ CO CO o o o o Y** o o > yC o + + + + + + + + o CO CO Y~ CO i n + CM CD o + i n CO T f CO o i n CO i n CO o o o o d o Y" i i v i d 1 d 1 r a J 0 r a r a CD r a r a r a r a r a 0 ) r a r a r a r a E r a E r a E r a E r o E r a ra r a r a r a r a 2 L i. 2 u . 2 LL 2 LL S LL UJ > y — CM CM UJ Q D £ L CL c c c c c o — Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0.5194 R 0.0375 0.0033 0.3068 0.0012 P > IT > | P 0.0001 0.4891 0.0001 0.8392 0.0001 0.0024 0.0322 0.0001 0.9040 0.0001 0.66710.0001 0.0147 0.1775 0.3922 0.3931 0.4981 6.2000000E-06 -7.4000000E-06 -0.000023 -0.000033 -0.00010 -5.2000000E-06 MEAN MEAN MEAN MEANMEAN 0.5206 MEAN 0.2733 SLOPE Regression SLOPE % G-CP C haracter % % G-PD1 SLOPE % G-PD2 SLOPE % G-PP1 SLOPE R 0.7264 % G-PP2 SLOPE 0.7924 % G-POB 0.6416 Centrophorus granulosus P > IT> P I 0.0017 0.32240.000064 0.0001 0.6815 0.0004 0.0001 0.1424 -0.000014 0.3232-0.000056 0.0974 0.0100 0.5009 MEAN MEANMEAN 0.4247 0.0001 0.8265 0.0001 MEAN MEAN % POB SLOPE% PD1 -0.000048 SLOPE 0.0001 -0.000070 % PD2 SLOPE % PP1 SLOPE % PP2 SLOPE Character Regression as a ratio of standard length to standard length. APPENDIX III. Regression analysis of the body morphometric variabilities Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. GO v_ in o CO CM T" COCDCO m O in o> CM cm V" o T“ o CM 01 o d o d d o 00 CM CO V” CD o CO T~ in o h*. o h- O CM o CD o CO o Is- o CO o in O CO o O) o CO o A o o CM o M" o T- o in o o o OL o d d o o d d o o d d d r 1 V O or - o o O o o CM o in o m o CO o in o o o q o CM o in o CO o T“ o o d o o o o d d o o o 0c ‘ to (/> LU UJ LU UJ UI UJ CO T*“ CM T” CM o O G Q CL CL CL CL CL CL CL CL O ico— o ra 6 6 6 6 6 6 sz vO to O & £ 0s* SP as r CO O CO M" CO in O) CO o o O) CD S T— o' CM o O o to cc d o o o d © T“ in T“ CM CD 4b M* CO o> o in o CM o M* o R COo T~ o O) o r* o in o O A CM o o CMo o CO o O Q. o o o o o d o d o d T~ T” T- o o o o o o in o CDo CDo CO o CO o o m; o COo CM o h*- o d o o o o o o d d oc ’ o CO ca CM CM I— O Q Q a. CL CO a. sz CL a. CL a. o Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CD C D T r T— LO CD CM r- CD o CM O to COCMCD CD OCO CM o CM a: o o o o o d lO CD CM CO h - T— CD o CM o o o TT o T ~ o O o CO o CD o T~ o CD o CO o A o o CD o o o T“ o CO o T- o CL o d d d d d o o d d o o T— CO CD T— o o CD o CD o o o o h - o o o v o T“ o C O o h - o CO o LO o CM o in o CO o T“ o o o o o o o o o o o o c o ’(/) in LU LU LU UJ UI d) CL CL CL CL Z z i _ 3? °- a. D) O < o < O < O < O < o < 0) _J l u y LU _l LU —I LU _ l LU _ l LU CL CO 2 co CO CO CO CO CQ 0 CM CM O a Q CLCL CL Q ra a . CL CL C L C L o •S I 6 6 6 t i > 6 6 s P y O n P a 5 ? a s a S 0 s 0 s 0 s to Q CM i n ■M- ■M- CO O C O o r * o C O CO a O o O C O o a a: d d o o o Q CD T ~ T— o CM T“ o V* o o o o C O o T ~ o T— o C O o i n o h - o A N o CO q q o o o i n o Q. o d d d d d d d d d T_ o o o o o o C D o M " o o o o M - o o o o C O o C O o o d o d o d o d o d i i i i i 0c ’(/) cn LU LU UJ _ U J UJ Q) 1 CL CL z CL 3? CL CL CD o < O < o < o < O < a) _J UI _J UJ _J lu y LU _ l UJ 0C CO CO co 5 co CO 0 CQ ro C\J CM 1 o a Q CL CL ra CL CL CL CL CL JC O Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CD CN 00 CD CD GO ■q- IT) in in CO CNJ CNJ CN o v- o LO CO o cm o o o d o o e- O) x- CD CO CO T“ CD T. CO o CD o T“ T" CNI o r * o in o o o o> o h - o O o CN o o o A o o T- o in o o o O o o o o. d d d o o o d o o o o d in c o Ui Ui lu UJ UJ UI UI (D CL CL z CL Z CL L. a. i? CL ra O o < O < o < O < O < a) _ i u j a LU _J UJ _J LU _ l LU _] LU 0: CO 2 co CO CO CO CO CD T“ e g eg Q o O QQ CL a. Q. CL 0 . a. Q_ a. 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Further reproduction prohibited without permission. r — CM CD 00 CO CD t t 05 CD T f o CD CO 00 CJ) CD o 00 o> q q q o c c d o o d o o «— T f o CM CD CD O) 00 O) 00 CM ID h - o o CD N* T f r - ID ID CM h - T“ CM T f T f CD o CD o T f o CO CO h - A CM o o o O o o o CO o CD o a . ooododooodod CM T_ o o o o o o o o o T— o a> o o o 00 o 00 o LO o CO o T— o LO o CO o V- o o o d d o o o o o o o • i co 't o (/) UJ UJ UI UI UI UJ Z I.0) o . z CL z CL CL CL CL D) o < o < O < O < o < O < 0) —I UJ —I UI _ i UI _ l UI _ l UJ _l UJ CD CC cn CO CO CO CO CO O m O CM CM o o Q D 0 . CL CL ra 0 . 0 . 0.. CL CL O to L_ I I I I a ra 6 a CD CD 6 CD a sz •»»* O - a l . o 0£ c * rvi - a p A D. CO 0 0 T- 0 0 T f o T f ID CD T" o 0 0 o ID O r * CD o T— o CM o o O q T“ o q o o o o o T“ o o o c o 'w c/> UJ UJ UJ UI UJ Q) i_ Q. 5 CL a . CL CL z O) o < O < O < o < O < 0) _J UI UJ _ i UI —I UJ _ i UJ CL CO CO CO CO 2 CO 0 m CM CM TO 1 O ra a a CL CL sz Q. CL CL CL CL O Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0 CO T“ CM h - h - 00 CO CM in 0 CO x— 0 CM 0 0 0 0 0 0 QC 0 0 d d d d 0 0 CO CD CM T- CD CO 0 0 0 O) CM CD 0 CD 0 O) T— 0 0 CO 0 CDCD T ~ 0 0 0 CM O A 0 0 h - 0 r- t — O 0 CO 0 CD O CL 0 d 0 0 d d d 0 0 0 O d i n T“ i n T™ x — 0 O 0 0 0 O 0 in O in 0 CO 0 CO 0 00 O co 0 in O M* 0 CM 0 CD 0 CO O x— 0 0 O 0 0 0 0 O 0 0 O d oC CO CO LU LU LU LU LU LU z »_d) Q- Z 0 - z Q. z CL Z CL CL < < < O) O O O < O 0 < 0 < 0) -J LU —1 LU _J LU _J LU _J UJ -J UI a: CO CO 5 CO 2 CO 2 CO 2 CO 03 m 4 Is- CMCO CO T“T“ CO T“ c o O r - 0 0 O O) O i n O 0 O co 0 CD O t - O T" O o > O 0 0 CD O CN OO 0 O d 0 O O O d d d cl CM T- X- 0 0 O O 0 0 O 0 M- O O O i n 0 0 0 v - 0 i n O 0 0 O CO 0 CO 0 O 0 d O d O d 0 d 1 1 1 1 1 oc 03 03 111 UJ UJ UJ UJ <13 D. ? °- Z Q. 2 CL CL O) o < o < O < o < O < <13 —I UJ y UJ j UJ _1 UJ _l UI DC co 5 co 2 CO 2 CO CO 03 0 (0 CQ co co 1 o Q Q Q. CL SITO CL D. CL CL CL O Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. COLO o ^r h - CO 03 h- LO o eg CO T— T “ h- 03 V ^ r o V " T- eg IT o d d o o d T- ^ 3- CNJ CO T" eg 03 T" m o T f o t— o CD o O) o CD o o o CO o CO o CO o t — o 03 o o o CD o CNJ o t- o V- o o o o o o d d o d d d o o o T" oCN OV o oT“ o o o CNJ o CO o CO o o ti- o in o CO o CN q eg o o eg o ■*- o o o o d o d o o o o o c o t/> w LU UJ LU UJ UI LU 0 z z Z u. a. CL 3? °- a. CL CL 03 o < O < O < o < O < O < 0 - j LU _ i UJ UJ _ i UJ _J UJ _J UI Q£ co w CO CO 5 CO CO »a to CD CM R CM a O a a CL CL CL 0 Q. CL o . CL CL o u i i I i I ra cd cd 10 j 6 CD CD CD : vO vO vO v P vO a O o'- o'- O'" 0 s 0 s" <5V. 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CL CL Z CL z CL z 05 O < o < o < o < O < O < 0 _J UJ _l UJ —I UJ _J UI _l UJ —I UJ VC CO CO CO CO CO CO <3 K CO CM CM O 0 Q Q CL Q. CL l. CL CL CL CL CL o ■*»* u0 . 1 t I I K 0 o o 6 C3 6 o O OSZ a f- CO CMCOCM in CM Tf CM 0 CO f- h- CO K CM Tf q CM Tf 1 CL O d d o o i 05 CM in CO 05 CO 05 in co r* r~ CM r- f - Tf 00 CO o CO CO 05 co in N- h* o h- in CO o A in o CO o r* o Tf o CO o 0. o d d d o d d o o o T“ T f CMCMCM o o o o o o o o CO o in o T f o h- o T- o CO o q o CO o 00 o o o o o o o o o o c o tf) tf) UJ UI UJ UI 0 CL Z CL CL Z CL O)L_ o < O < o < o < 0 _l UJ _J UJ 2 UI UJ _J UJ VC CO CO 2 co CO CO o co CM CM i_0 O Q Q CL CL 0 CL CL CL CL CL x : O Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0 0 CO in CO r r V CD LO CO T“ CO OLO o LO T ~ CO CM o x— o T l o eg a: d d d o o d ___ 00 CNJ CD CO CO LO T— CD T“ CD i— T“ CD h - o CO o CO o to o T“ O T“ r * CN o eg o CO o LO o CD O A O ) o CNj q oo o eg o N- o o O CL d d o d o d d d d d d T~* T“ oT ~ o o T"o o o o CD o CO o CO o CO o o o o CN| o CO o eg o CO o CO o o d d o d o d o d o o • i i c o in in LU LU LU LU LU LU 0 . Z Z Z t0) _ CL CL CL CL CL O) O < o < O < o < O < O < 0) _ l LU _ l LU _ l LU _J LU _ l LU _ l UJ cc C/3 03 03 0 3 03 03 m eg eg a o O Q O 5! CL CL -s; ra CL CL 0. CL CL O TOi— 6 6 6 6 6 6 a JO u O as aS aS as £ aS a o o LO o 03 fs- O CO CO a o o o CO LO a h- o o T- m ; a o: o d d d d to eg T” CD CD eg o o o CD o CD o CO o o o 0 0 o O o CO o eg o A o o q o 0 0 o eg o o o CL o o d o o d d o o o T“ CO LO o o o o o o o o o o o eg o r ~ o o o CD o eg o T“ o o oo o eg o CD o o o o o o o o o o 0c to to LU LU LU LU LU 0) 1 CL Z CL Z CL CL a. z O) O < O < O < O < O < Q) _ l LU _J LU _ l LU —I UJ _ j UJ o: 03 03 03 03 03 O ro m CM CM i— o Q a CL CL ra CL CL CL CL CL . c O Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2 R 0.0836 0.3171 0.21500.0360 0.1492 0.6249 0.00248 0.0001 0.3975 0.0725 0.0001 0.3619 0.5100 0.0566 0.0176 0.71580.0001 0.0138 0.04340.0001 0.3482 0.0373 0.3000 0.1067 1.42 45.99 0.0009 -0.0140 MEANMEAN 0.48 MEAN 0.51 MEAN 28.16 MEAN MEAN 1.90 MEANSLOPE 0.93 MEAN 0.40 HYP SLOPE FR SLOPE 0.0001 D2-AR SLOPE -0.0002 C-AR SLOPE 0.0015 Character Regression P > |T| 2 0.0001 **0 .9 96 80.0168 P2-AR SLOPE0.0001 **0 .9 7 5 4 HET 0.0004 SLOPE 0.0022 0.1539 0.3770 0.0001** 0.9867 0.0045 0.0001 ** 0.9803 0.0001 **0.9843 D1-AR SLOPE 0.0002 0.8703 0.0001 ..0.9729 P P > 1T| R Centrophorus granulosus -4.49 0.5861 11.16 18.54 0.0001 0.132 0.248 0.0001 **0.9791 P1-AR 26.54 0.273 0.0001 ** 0.98130.482 0.418 -25.35 -13.57 -2.422 Regression MEANMEAN 18.10 0.0352 MEAN MEAN MEAN 2.78 0.6729 MEAN MEANSLOPE -15.76 0.4027 MEAN SLOPE MEAN MEAN 20.57 0.0432 SLOPE MEAN POB SLOPE 0.075 0.0001 ** 0.9586 PD1 SLOPEPP1 0.339 PP2 SLOPE 0.770 Character PD2 SLOPE 0.812 0.0001 **0 .9 9 8 6 G-D1 SLOPE 0.539 G-P1 SLOPE G-OB SLOPE 0.266 0.0001 **0 .9 1 2 5 G-D2 G-CP G-P2 SLOPE APPENDIX IV. Regression analysis of the body morphometric variabilities to standard length. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CD CO CO CO T f T f ID CO O O CO CO 1 0 c o O i O LO T f CM O i 0 CM CO T f O T*" CM T f O 0 t o CM OO OO) O i O 0 0 0 O OO O d d CD T~ T- lO CO h » T f c o t t T“ T- O CDO v - LO T- T- CO 0 0 O T— T“ ID 0 CO 0 10 O T f CD CO OO OOOO O 0 CO O CO CM O 0 LO 0 CDO T f O 00 O O OOO CO 0 h - O CM OO 0 0 0 T f O CD O CD O O OOO Q. d d d OO d d d d d d d O d O d O d d d CO r— CM 1 0 CO T f CD O i CD 0 OO CO 0 0 0 CD CO CO 0 T f O T f OO 0 O i 0 0 0 N. 0 T f O CO CD T f CO T f 0 LO O CO O CO 0 0 CM 0 CD 0 CM O CM CD CD CM CM d O d O d d CO 0 T“ d T~* 0 d O CO T f LO CD T f I I I 1 T“ CO CM LO CM CO oc Ui Ui LU UJ LU LU UJ _ UJ LU _ UJ CD UJ UJ w CL CL CL 0 . CL CL CL $ CL 5 CL Z O) O o O O O O O < o < o **• o < CD _J -J 55 _J _ j _ 1 _ 1 y l u y m y w LU VC CO CO w w 03 03 C/3 2 C/3 2 C/3 2 03 o u ro VC VC VC VC o VC < ra < < < < H a . < 1 1 < r tL nJJ XT VC T~ CM ■T- CM 1 UJ > - f CO a O LL a a Q. a . O X X CO h 1- s r** 10 0 1 0 CM CD 0 0 CM CO CO CM CM CO T f CM CD CD m CO O CD 1 ^. h - T- CO 0 CD CD 1 0 CD T f CO h - CO T f CD T— CO o i h » T— r - T— CD CO CO 00 i n t — 0 CD O CM h - CD CM CM CO ■*-; CM T f i n m CM T f T f i n CO CD T“ d 1 0 d 1 0 O T f d CO d CD d T f 0 d d T— d CM O CM d CM T"* CM CM CO T f T— T f Ui ui Q) UJ UJ _ UJ _ UJ UJ _ UJ _UI_,IU_,IU_,LU_,UJ L_ a 5 CL 5 CL 5 CL 5 CL 5 CL Z ilZ u.Z ilZ ilZ d. O) o ^ n ^ n > n O < O <1> _ 1 UJ j IU j UJ j UJ -J iif -J “J J u J w J ^ J w J vc 03 5 0 3 5 03 5 03 2 03 2 03 2032032032032 03 MEAN 14.55 0.1280 0) o (0 u . CQ T~ CM CM CL CQ CM ra CM 9 Q QCLQ. O x: o Q a Q. CL O CL CL CL CL CL 6 6 6 6 6 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. a > o CM CO O) CO r - CD m * CO T— CO o CO o CO lO CM o V** o CO T— o o o o O o CM CM cc d d d d d d d d « _ CO T“* h- o CO Tj* T~ CO CO o CM cn o I— CO o y — o CD CO CM o «r~ o m - o o M* in CO CM CD CM T“ to o o CO o o o O T“ CD o CO o h - o o o CO o CM O cn o CD CM O) o CO o CM o m o o > o CD O T“ o CM O CO d CM o o d o o T“ d d d CM d CM d CO i i i CM y - c o (/) U) LU LU 0 LU LU LU LU LU u_ CL 2 : CL z CL z Q. z CL z 0 - z CL z D) o < O < O < O < o < o < O < 0 LU _] LU _ l LU -4 LU -J LU -J LU LU _ 1 LU CC CO CD 2 CO 5 CO CO 2 CO 2 CO 2 CO Q 0 cu o to CC a: cc a: o w < < or ro i - O LL a a. o X X CD *r~ CO T- CO T— CO CD cn co h - in h - CO o in CO CD M* CM CO cn CO CO m- in CM CM cn h - a > cn cn CD cn in cn cn CC o d d o o d d o d d * * *«« * «« ** «« * * * «** ** i CO T— CO *r— CO T— CO T“ 's r y - cn T— t— T*“ CO r~ m o o CM O o o o o o in o CO T“ CM o M- o o CO o O CO o o o CM o cn o cn o cn o o o cn A o o o o o lO o o o co o ■*- o in o c n c n M* CD h - CO c o c n i n O T~ o M* r ^ . M - c n CM CM CO T— CD h - m CO m c n M* in CD i n o CM i n M’ CM T“ i n CM CM h - CM CM v - h - *r“ Y ~ CO CO c n CM M- CO o CO CM d d o i n d o d o o d o c o o d d o o 00 m T“ CM CM CM G-CP G-CP SLOPE 0.1003 0.0001 0.9390 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CNor H A <; <. <. < . a. z z Z Z z z co h- h- CO CO o CO n- CO CO CO CD CO o CO o in N- CD h- CN o CO CO CO o o CO CO o T- T“ in in CN o Is- N' o o o o CO CO co o CD o CO d o d d o o CN i t CN i O T“ CN CO c o *(/) cn LU LU LU LU UJ 0) UJ LU LU u. CL z CL Z CL z a. z CL z CL z a. z CL z < < < < < < < D) O < o O O O O O O a> —I LU LU —J LU LU _J UJ LU _ j UJ _J UJ cd CO CO 5 CO 5 CO 2 CO 5 CO 2 CO 2 CO s o o CO or DC o: (Z o k_ < < < < CZ CO I ■ i < CL o JC a: CM T™ CM i UJ > - O a Q. CL o X X 03 s o O o CN o O O o o CD CO s o O o in o CD O o o CD CO •*»* o o o CO o CD O o o CD CD CN o o o h - o CD O o o CD CD ! < a: T“T- d d T- T" O d o s ; o CO co CO CN co CN CO o N- N* co co CO CD CO CO CO o T— CO CN CO CO CO CN r*. CN m V- CO O N* CN in CN N* CO CO CO CD CD t— o CO o CD O CN CN CO o m CN N- O N* O N* o CO O CO CN CO o o o o O co CO N- o o O T“ O o O o o o O r^ O CD o d d o o d d d d d o o d d o o d d d d o d N* o h- CO CO CO CO CT) N- CO CO CD CO o V" CO CO CN CD in T— o CO Tj- CD o in h - CN r * N* o CO o N1 o Tf in CO CN co CN T“ h - CN CO CN CN CO Is- CO CO CN CO h- CN CD N* CO CO CO < r CN d N" d CN d d N" o CD d co d o o CD d Y“ d d d o Y"“ CO CN T- i CN i * c o l/> cn LU UJ UJ UJ UJ LU LU UJ LU UJ U 1 i—a> a . CL z CL z CL z CL z CL z CL z CL z CL CL z < 5 CL O) O < o < O o < O < O < O < O < O — o o < a> _ i UJ _1 LU —1 UJ UJ _1 UJ _J LU _J LU _J UJ _J UJ 2 —I UJ q: CO CO 2 CO 2 CO 2 CO s CO 2 CO 2 CO 2 CO 5 co CO oa CM CM CL CO CM CM 0 Q a CL 0 o Q Q CL CL 1 I I 1 o Q_ a. CL CL CL o CO CO CO CO CO Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. O T- CO T” i n CO m CO CO o m o> ■M* i n CO CM o o o T— CO CM CM o T“ o o T- T- o CC d d d d d o o d ___ CO o o CM 0 0 o CO CM h - CO o M’ CM CO o H- CO CO CO CO h- i n CO o 00 CO CO M- CO CO o CO M" m o CM i n o 0 0 o i n CM CO CO o A *<* o CM CO 0 0 CO h - CM CM o CM m CO o CM CO d d d d d d d d d d d d d d d d Q- h - o CO i n CO r r o o CO o T- o o o TT CO O ) o o CO o i n o CO o o O CM CO o CO o o o T- o m o O) o o o O) o CM o CO o xC d o d d o d o o d o d o M" i i CM r* C o U) (/) UJ UJ UJ LU UJ UJ UJ 1__0) o. CL a. CL CL CL CL CD o o O o o < O o < 0 ) —I _J UJ _J _J _Jo UJ >) VC to co CO c/3 C/3 CO C/3 CO 5T u o s; ro cc CC cn cn < < < < cc (0 I I < H CL sz a CM CNJ I UJ > cu O Ll_ a CL o I X oa 3 CO o CO CO o ■M* CT) CD T" Sk O) CM T“ O)TT i n t— o i n 00 00 h - CO CO CO M - CO o r j . CM CO 00 O ) CO G)M* h - CM CO CC O o d o o o o o d d « * « « * * *« & « * * * * * * * * j---- T” f^ - t - T“ i n o CO V“V- CO o M * CO N. O o o CO o CO o CM o CO o o t — o CM CO CM CO T“ OCD o CO o CM o o o CO o 00 o CM o O) h - CM ■M* o O fci A o 0 0 o Y— o O) o x j* o r — o O o CO o CO o O o CD d d d d d d d d d d d d o d o o CL o o o o CM CO CM o h - CO o o CD lO T— o ■M- M 1 CO r - CM CD CO h *. c o o CO 00 CO i n c o h - T— c o o r r T— CO CO O o o c o 00 o CM M* CO CO CO i n 00 CO i n CM O ) CO CO d d CD d o o i n o CO d i n o i n o i n d CO d CO CM CM CO 00 T” i T“ o ’(/) (/) UJ UJ __ a) UJ UJ Ul UJ 111 ui LU UI a a a a a 5 CL a a a a 5 CD O O o O O *< o O O O O & Q) _J _ i _ i ui y _ j _ i LU q: CO CO CO co co 5 co CO CO CO CO m CM CM m t - CM CM 9 0 Q a a O a a a a 1 ■ o CL a a a a 6 CD 6 6 CD G-CP SLOPE 0.1208 0.0020**0.5953 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CNO CO CN CN O T"~ 0 CO CO T- t o l^ . CO CN 0 1— t o CN CN T*“ 0 O 0 O 0 O d 0 d d d d d d « « CO f-'- N" CO CN 0 0 CD CN CO CO CO ■N* CN O N* CD N- O t o T*“ t o T“ 0 XT 0 r r O CD CO CD CD O CD O 0 t o CN h - CO 0 T ~ O CO LO T- CDO CO O 0 CO CO T— t o 0 OOO d O d d d d O 0 d d O d d CD O ) IO 0 CN t o CN CD OO O 0 O CO CN O CO O O CD 0 CN O co 0 CN t * CD 0 OCNOCNO CO 0 h * O t o 0 0 CO 0 CO O CN OO O 0 d Y“" O 0 0 0 0 O 0 0 oc in in HI UJ UJ UJ UJ UJ UJ <>5 R c c CC CC cc cc < 1 < £ < < < f H * 0 . < c c X*“ CN T— CN 1 LU > - (0 05 LLQQ CL Q. 0 X X Q 5s. N-CN h - CD CO f-» CNN*N- CO hCS N " t o CO CN T“ T— CD 0 N* 0 CO CO CD CD T“ CD CO V “ CO CO t o 05 CO CDCD CD CD CO CD CO a > CD h - s cc d d d d d d d d d d d ***« * ««** « «« ««* ***« * h - CO T“V“ f '* - T " V- t o T— N- T— V-T— N" T- T— T— 0 CN O N. O 1 0 0 CN 0 CN 0 N- 0 c o 0 CO 0 N- 0 N - 0 0 CO O CO O CD 0 CN 0 0 0 O ) 0 CO 0 CN 0 CO 0 h - 0 A 0 N ; O CO O T“ 0 CO 0 t o 0 0 0 h - 0 0 CN 0 0 0 d d O d d 0 d d 0 0 0 d 0 d d d d d d d CO CO N* CD CO CN t o CN r * - CN CO T— O CN 0 CN CD CD CO N- CO T- ' T- CO CO CN h - N* CO V- CO 0 CD CD t o t o CN CO CO 0 O CO h - t o CO T“ CN CO N - CN CN CO CO N- T— CN CO x r CN N- T“ d CN d N* d CD d CO d N" d CN d CN d t o 0 CD d d ? c o in m 0) UI UI UJ UI UI UJ UI UI UI UJ UJ 1— CL 0l CL a CL CL CL CL CL CL CL C D o 3 o o o o o O o O O O CD _ l UJ _ l _ l _! _ l _J _J _J _J _ l CC CO CO CO CO CO CO CO CO CO CO CO MEAN 5.91 0.2613 L_ Q) 0 2 DO CN CN CL ro CD CM CN O a a CL CL SZ 0 a a CL CL V 1 1 1 O a a. a CL CL CL C5 o o 6 o 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CO CO T— co T“ CM m in o CO in •M- cn O) T“ ’ CM in in O) CM CO o o CM r - in in CM T- o CO o CC O o o d d o o o CD T— CO v CO TT O) CO o CO in CO in m Is- T- T— CO co r - m Is- V- T— Is- Is- o V CO m CM CM co CM CO CM CO CO CO CM CO in cn (O o CM T- CM o in CM CO in CO o CM O) cn i — o d d d d d d o d d d d d d d o CO *r“ in CM CO CO o LO X— o o CO o m O CM o CM o CO o co o CO h - in o CM o CM O o o in o in o in o o CM o CD d r - o o CO d in d d d CM o o x-* i i i i 1 CO c o ’(/) CO 0 UJ UJ UI UI UJ UJ UI UJ t_ CL Z CL z Q_ z CL z CL z CL z CL z 0 l Z O) o < O < O < O < O < o < o < O < 0 UJ _J UJ _ l UJ _J UJ _ j UJ _ 1 UI —J UI _ j UJ CC C0 £ CO s CO 5 CO S CO 2 CO 2 CO 2 CO 2 G •S a c c c c c c O' < CC t — s 0 < f < CL sz c c CM X“ CM i UI > - O LL QQ CL CL o X X >5 r " ■M- CO m CO CO CO in CO CO m N - M- CO h - m o O) CO cn CO 3 O) CO O) CO CO O) Is- cn CO -K* CO ■M- cn h» o> o> in cn CO cn cn 0 *fc o o o o d d d o d d o s: « « «« « «* * «* « CJ> o CO CT) O) CM CM CO CO CM CO N*O) CM CO o Is- CM cn CO OO CO T— CM m CO r - CO co CM CO o O CO O’ CM O cn CO lO CO CO T— o o> V o o> T— CO CO o O o CO CO O o o 1 o CO CO o x— 'T - m o CM o ■*- CM CO O o o CO O o o 0. o d d d o d d d d o o d d d d d o d d d d CM CO o Is- o> CO CO in CO co o in CO CM T— Is- CM CO co CM CO N. CM ■M- T“ CM M- o CM t - T— M- in CM o CO o CO ■M* h - o CO T" T * CO CM CM CO h - co CO in h - CO r r CO in CO •*- d CO d d d d d d d d d o in d d o o d d CO CM T- CM CM CO m CM i 1 i (/) W UJ UJ UJ 0 UJ UJ UJ UJ UJ UJ UJ UJ k . CL 2 CL z CL Z CL z D- z CL z CL z CL z CL z CL z CL O) O < o < o < o < o < O < o < < < O < o 0 UJ UJ -J UJ -J UJ —1 UJ _ j UJ UJ o_J UJ o-J UJ - j UJ _ 1 CC c o s CO 5 CO 2 CO s CO S CO 2 CO CO 2 CO 2 CO 2 CO MEAN 5.54 0.4242 CO r * CM T~ CL CO CM CM T~ CM 0 o Q CL Q. O o 5 O CL CL 1 i i 1 i CL CL CL CL CL CD CD CD CD CD 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CM CM X™ CO CM o o CO CO o c n CO CM o o CO o h - in CM X- o o o o T- CM a: o o d d d d d o 0 5 X"* (O o r - . CO uo TT x— T“ cn r>. cn x— T" T“ o T ~ v - o r - CO CM CM CM o CO CO CM o CO o co O N- M*TT T— o> T“ N- o cn T— t— o A CM o O) o G) O CM o in CO cn o T“ o x - o o d d d d o d d d d d d d o d o CL (O o o O) in o o o o o o o o in r^. o CO o CO o co o CM o CO o CD CM CO X- CM o CO o c n o CO o i n o CO o i n o o CM d CM o o d d d v - ’ d d d CM o i n d CM i i CO i M* (/) if) 0 -p, U J _ LU _ LU _, LU _ LU _ u j _ LU k . 5 0- ? a J a 5 o- 5 Q- 5 CL 5 CL U i < O o **• o o <5- o CO CO X*“ o M* cn CO CO in CO cn T“ cn o CM CM o M- m CO cn X™ T— CO M* CO CO N. CO o v- M; in h- CO CM CO T** CM T j* M* in CM x— CO CO x- o o d CM d o O M* d CO o CM o in o x— o a > d M* d i i x— X“ CM m CO x— 18.65 0.0808 c o if) if) UJ UJ LU _ UJ UJ UJ UJ UJ UJ UJ LU 0 z 2 ! Z z Q_ z z z u CL 3 ? ° - CL 5 CL a . a . CL Q. CL CL 0 5 < < < < < < < o < n o < o O O O O o o O 0 _ l uj y J “ j J LU _ i UJ - j UJ _ l UJ _ i UJ -J UJ -J UJ _1 QC CO 2 w C/3 2 C/3 c n 2 CO S CO 2 CO 2 CO 2 CO 2 CO MEAN CQ CM CM CL CM CM 9 a a CL CL Q Q CL CL I O O CL CL CL CL 6 6 o 6 e > 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. P> F LSMEANS 0.289 N/A 0.403 0.023* 0.701 0.140 0.090 0.068 0.157 0.210 0.401 0.067 0.136 0.660 0.017* N/A 0.844 0.048* 0.215 0.279 0.213 0.713 P > F SLOPES 0.330 0.509 0.595 0.664 <0.001** 0.464 0.141 0.572 0.204 PC PC 0.109 InAREA 0.719 0.608 InAREA 0.531 InAREA 0.054 InAREA 0.996 InAREA 0.245 InWIDTH InWIDTH 0.908 InWIDTH InWIDTH 0.053 InWIDTH DENSITY 0.609 DENSITY 0.520 InLENGTH InLENGTH 0.474 InLENGTH 0.329 CHARACTER B5 LOCATION LSMEANS P > F N/A 0.7396 DENSITY N/A 0.064 InLENGTH 0.091 N/ADENSITY <0.001** PC 0.019* Centrop horus granulosusCentrop SLOPES P > F 0.553 0.016*<0.001 ** N/A B1 0.073 0.193 0.1391 <0.001** PC 0.004** <0.001 ** PC 0.329PC <0.001** <0.001* N/A PC PC 0.888 InAREA 0.001** N/A InAREA InAREA 0.034* N/A InAREA <0.001 ** N/A InAREA InWIDTH DENSITY 0.025* N/A DENSITY DENSITY <0.001** N/A DENSITY InLENGTH InLENGTH 0.015* N/A InLENGTH 0.2477 0.242 InLENGTH 0.017* N/AInLENGTH 0.074 InLENGTH 0.499 HI H2 InWIDTH 0.067 0.038* B2 H5 InWIDTH 0.001** H3 InWIDTH 0.044* N/A B3 H4 InWIDTH 0.003* N/A B4 LOCATIONCHARACTER APPENDIX APPENDIX V. by location. variables Analysis ofscale for morphometric covariance Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. P>F LSMEANS N/A 0.402 0.172 N/A 0.098 N/A 0.044* 0.428 N/A N/A 0.833 N/A 0.214 0.713 0.084 0.046* 0.704 0.231 <0.001 ** SLOPES P>F 0.792 0.1636 0.333 0.109 0.395 <0.001** 0.477 0.764 0.091 PC InAREA 0.022* InWIDTH 0.346 InWIDTH 0.502 InWIDTH DENSITY 0.032* DENSITY 0.004** DENSITY <0.001** InLENGTH InLENGTH 0.730 InLENGTH B8 LOCATIONCHARACTER LSMEANS P>F N/A N/AN/A B6 PC 0.098 0.722 0.001** Centrophorus granulosus P>F SLOPES 0.524 0.016* PC 0.074 0.0640.039* InLENGTH 0.572 0.024* 0.760 0.237 0.404 0.074 0.074 0.327 0.864 PC PC PC PC PC InAREA 0.002** N/A InAREA 0.245 InAREA 0.091 0.019* InAREA 0.004** N/A InAREA 0.039* InAREA 0.151 0.005** InAREA InWIDTH DENSITY <0.001** N/ADENSITY DENSITY 0.274 DENSITY DENSITY 0.265 0.734 InLENGTH InLENGTH 0.179 0.012* InLENGTH InLENGTH 0.005** N/A Cl InWIDTH 0.033* N/A B7 H5 InWIDTH 0.001** N/A B5 InWIDTH 0.141 C2 H6 InWIDTH 0.021* LOCATIONCHARACTER Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. N/A 0.073 LSMEANS 0.350 N/A N/A N/A 0.001 P>F 0.031 N/A N/A 0.001 N/A N/A N/A N/A 0.001 0.260 0.001 0.001 0.099 0.994 0.092 0.7990.807 0.010 0.060 0.295 0.003 0.210 0.005 0.001 0.001 0.225 SLOPES P>F 0.717 0.3330.004 0.019 N/A 0.0020.001 N/A 0.030 0.109 PC PC PC PC InAREA InAREA InAREA 0.009 InAREA InAREA InWIDTH InWIDTH DENSITY DENSITY DENSITY DENSITY InLENGTH 0.011 InLENGTH InLENGTH InLENGTH InLENGTH B3 InWIDTH B4 InWIDTH 0.011 B2 B1 B5 LOCATIONCHARACTER LSMEANS P>F 0.002 0.725 N/A 0.141 0.622 N/A N/A Centroscymnus coelolepis 0.115 0.201 SLOPES P>F 0.476 0.119 0.536 0.001 0.1000.519 0.001 0.643 0.2300.001 0.009 0.021 N/A 0.001 N/A 0.029 N/A PC 0.008 PC 0.003 N/A PC PC 0.678 0.369 InAREA 0.019 N/A InAREA 0.011 N/A InAREA 0.001 N/A InAREA 0.002 InAREA 0.366 0.335 InWIDTH InWIDTH DENSITY 0.046 N/A DENSITY DENSITY 0.001 N/A DENSITY InLENGTH InLENGTH InLENGTH InLENGTH InLENGTH 0.043 N/A HI InWIDTH H2 InWIDTH H3 H4 H5 LOCATIONCHARACTER Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0.005 0.012 0.004 LSMEANS N/A N/A N/A N/A N/A N/A N/A 0.001 0.001 0.0020.530 N/A 0.011 0.499 0.5750.287 0.019 0.001 0.001 0.014 0.035 N/A 0.001 N/A 0.001 N/A 0.002 N/A 0.160 0.830 0.001 0.001 N/A 0.214 0.001 0.001 PC InAREA InWIDTH InWIDTH InWIDTH InWIDTH DENSITY DENSITY DENSITY 0.7226 DENSITY InLENGTH InLENGTH InLENGTH CHARACTER SLOPES B6 B8 B5 0.011 0.001 0.0050.001 InAREA 0.003 InLENGTH N/A N/AN/A InAREA PC N/AN/A N/A InAREA PC N/A N/A N/A N/A N/A Centroscymnus coelolepis 0.043 0.003 0.014 N/A0.949 PC 0.003 0.001 PC PC PC 0.037 PC 0.010 InAREA 0.006 InAREA 0.002 N/A InAREA 0.017 InAREA 0.811 InWIDTH 0.029 InWIDTH 0.003 DENSITY 0.344 DENSITY 0.397 DENSITY DENSITY 0.010 InLENGTH 0.015 N/A InLENGTH InLENGTH InLENGTH 0.811 CHARACTER SLOPES LSMEANS LOCATION C2 Cl InWIDTH 0.947 0.003 B7 H5 H6 InWIDTH LOCATION Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LSME/ P>F 0.38 0.49 0.15 N/A 0.98 0.017 0.28 0.015 0.020 0.002 0.22 0.61 0.008 0.37 0.40 0.37 P>F SLOPES 0.77 0.93 0.08 0.58 0.08 0.09 0.82 0.13 0.75 0.98 0.97 0.26 0.54 PC InAREA 0.22 InAREA 0.20 InAREA 0.56 0.38 InWIDTH DENSITY 0.13 InLENGTH 0.15 InLENGTH 0.76 0.33 InLENGTH 0.78 InLENGTH 0.85 0.86 InLENGTH 0.59 B1 InWIDTH 0.028* B2 InWIDTH 0.54 B4 B5 InWIDTH LOCATIONCHARACTER Dalatias licha LSMEANS P>F 0.0020.22 DENSITY 0.66 0.020 0.008 0.07 0.38 0.63 0.65 0.35 0.10 0.64 InAREA 0.0030.980.41 0.75 B30.70 0.23 InWIDTH PC 0.0060.58 PC PC N/AN/A DENSITY 0.43 DENSITY 0.29 0.80 InAREA 0.09 P>F SLOPE 0.19 0.93 0.41 0.32 0.99 0.57 0.69 PC PC PC 0.38 PC 0.57 InAREA 0.64 InAREA 0.07 InAREA InAREA InAREA 0.70 InWIDTH InWIDTH 0.77 DENSITY 0.20 DENSITY 0.80 DENSITY 0.001 DENSITY 0.002 InLENGTH 0.51 InLENGTH InLENGTH 0.62 InLENGTH 0.94 InLENGTH 0.40 HI InWIDTH 0.10 H2 InWIDTH H3 H4 InWIDTH 0.40 H5 LOCATIONCHARACTER Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. P> F P> LSMEANS 0.40 0.79 0.33 0.34 0.011* 0.45 0.83 0.35 0.031* 0.53 0.27 0.004** 0.26 N/A N/A SLOPES P>F 0.81 0.540.044* 0.37 N/A 0.65 0.12 0.460.22 0.09 0.66 0.29 0.62 0.09 0.37 0.24 0.59 0.15 PC PC PC PC InAREA InAREA InAREA 0.11 InAREA InWIDTH 0.97 InWIDTH InWIDTH 0.039* InWIDTH 0.86 DENSITY DENSITY DENSITY DENSITY 0.029* InLENGTH 0.93 InLENGTH InLENGTH 0.89 InLENGTH CHARACTER B5 LOCATION Dalatias licha LSMEANS P>F 0.039* 0.80 0.58 0.088 0.38 0.24 0.03*0.15 0.34 B6 0.420.06 0.051 0.001** B7 0.027* <0.001** N/A N/A B8 N/A N/A N/A SLOPES P>F 0.21 0.55 0.18 0.014* <0.001 ** 0.54 0.77 0.72 PC PC PC PC InAREA 0.084 InAREA 0.70 InAREA 0.53 InAREA 0.54 InWIDTH InWIDTH 0.80 InWIDTH 0.57 InWIDTH 0.013* DENSITY DENSITY DENSITY 0.028* DENSITY 0.63 InLENGTH 0.019* InLENGTH 0.40 InLENGTH InLENGTH 0.11 CHARACTER C2 C l H5 H 6 LOCATION Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LSME/ >F P N/A N/A N/A 0.017 N/A N/A N/A 0.480 N/A N/A 0.412 N/A N/A N/A N/A N/A N/A N/A P>F SLOPES 0.001 0.849 0.046 N/A 0.001 0.0010.065 N/A 0.001 0.0010.001 0.001 N/A 0.343 0.001 N/A 0.001 0.001 0.001 0.001 0.001 0.001 N/A 0.001 0.001 PC PC PC InAREA InAREA InAREA InAREA InAREA InWIDTH InWIDTH InWIDTH InWIDTH InWIDTH DENSITY DENSITY DENSITY DENSITY 0.001 InLENGTH 0.001 InLENGTH InLENGTH InLENGTH InLENGTH 0.001 CHARACTER LOCATION Deania calcea LSMEANS P>F N/A 0.225 N/A B4 N/AN/A N/A N/A B1 N/A N/A N/AN/A N/A B3 N/A N/A N/A 0.057 PC N/A N/A B5 N/A 0.669 N/AN/A 0.649 B2 P >F P SLOPE 0.001 0.001 0.964 0.001 0.546 0.001 0.001 0.001 0.001 0.001 0.001 0.007 0.001 0.001 0.001 0.005 PC PC PC 0.134 PC 0.604 InAREA InAREA InAREA InAREA InAREA InWIDTH 0.001 InWIDTH 0.007 InWIDTH InWIDTH DENSITY DENSITY DENSITY 0.001 DENSITY InLENGTH InLENGTH 0.001 InLENGTH InLENGTH InLENGTH 0.001 CHARACTER HI H2 H3 H5 H4 InWIDTH LOCATION Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 0.399 0.264 N/A N/A N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A 0.001 N/A InAREA DENSITY 0.825 PC 0.109 0.530 0.001 DENSITY 0.596 PC 0.163 0.026 PC0.601 0.142 PC N/A InAREA 0.001 N/AN/A InAREA 0.001 N/A N/A InLENGTH N/A InLENGTH 0.001 N/A Deania calcea 0.165 0.001 0.001 N/A0.008 N/A DENSITY InLENGTH 0.005 0.001 0.001 0.001 PC 0.253 PC 0.105 PC 0.128 PC 0.764 InAREA InAREA 0.001 N/A InAREA InAREA InAREA 0.001 DENSITY DENSITY DENSITY 0.001 N/A DENSITY 0.001 DENSITY InLENGTH 0.001 N/A InLENGTH InLENGTH InLENGTH InLENGTH Cl InWIDTH 0.001 N/A B7 InWIDTH C2 InWIDTH 0.001 N/A B8 InWIDTH H5 InWIDTH 0.001 N/A B5H6 InWIDTH InWIDTH 0.001 N/A B6 InWIDTH Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. P>F LSMEAI 0.134 N/A N/A 0.0762 0.001 0.883 N/A 0.001 0.001 N/A N/A SLOPES P>F 0.001 N/A 0.955 0.001 0.0080.025 N/A 0.016 N/A N/A 0.165 0.398 0.001 0.034 N/A PC 0.765 PC 0.360 PC InAREA 0.001 InAREA InAREA InAREA InAREA 0.328 InWIDTH 0.502 0.001 InWIDTH InWIDTH InWIDTH InWIDTH 0.202 0.001 DENSITY 0.215 DENSITY 0.764 0.001 DENSITY 0.001 DENSITY 0.463 0.001 InLENGTH 0.001 N/A InLENGTH 0.005 InLENGTH 0.215 InLENGTH 0.003 InLENGTH 0.001 LOCATIONCHARACTER P>F LSMEANS N/A B4 N/A 0.436 N/A N/A 0.001 N/A 0.001 B5 N/A 0.933 PC N/A 0.001 0.557 0.003 0.001 B2 0.001 0.001 0.498 0.0310.005 0.919 B3 0.006 B1 0.005 Etmop terus p rincep s princep terus Etmop P>F SLOPE 0.187 0.222 0.760 PC 0.472 PC 0.001 PC 0.777 PC 0.988 InAREA 0.001 InAREA 0.522 InAREA 0.529 InAREA 0.630 InAREA 0.369 InWIDTH 0.001 InWIDTH 0.180 InWIDTH InWIDTH DENSITY 0.001 DENSITY 0.727 DENSITY 0.001 DENSITY 0.019 InLENGTH 0.026 InLENGTH 0.001 InLENGTH InLENGTH 0.734 InLENGTH 0.901 *13 H5 InWIDTH 0.049 HI H2 H4 LOCATIONCHARACTER Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ** ** ** ** ** ** ** * * ** 001 001 001 0 0 1 . . . . 0 0 1 002 0 0 2 022 022 0 0 0 0.001 0 . . . . . LSMEANS P> F P> 0.545 0.958 0.387 0.055 0.003** 0.084 0.133 0 0 0.496 < 0 < 0 0 < < < N/A N/A SLOPES P> F P> 0.195 0.215 0.164 0.184 0.393 0.765 0.361 0.048* 0.268 0.046* 0.351 0.163 0.246 0.834 0.930 PC PC PC PC InAREA 0.177 InAREA InAREA InAREA InWIDTH 0.016 InWIDTH InWIDTH 0.007** InWIDTH DENSITY DENSITY 0.784 DENSITY 0.781 DENSITY InLENGTH InLENGTH InLENGTH CHARACTER B6 B8 LOCATION LSMEANS P> F P> 0.144 0.001** 0.469 <0.001 ** N/A InLENGTH N/A B5 Etmopterus princeps SLOPES P>F 0.795 0.491 0.983 0.554 PC 0.538 <0.001** PC 0.978 0.817 PC PC 0.750 0.589 InAREA 0.522 <0.001** InAREA InAREA 0.412 0.039* InAREA 0.826 0.003** InWIDTH 0.807 InWIDTH 0.049* InWIDTH 0.032* <0.001 ** B7 InWIDTH 0.331 <0.001 ** DENSITY 0.079 <0.001 ** DENSITY 0.728 0.012* DENSITY 0.113 <0.001 ** DENSITY InLENGTH 0.684 0.003** InLENGTH 0.026* InLENGTH 0.240 0.002** InLENGTH 0.372 CHARACTER C2 C l H6 H5 LOCATION Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LSME/ P>F N/A N/A N/A N/A N/A N/A N/A N/A N/A 0.308 N/A 0.012 N/A N/A 0.006 0.829 0.947 SLOPES P>F 0.001 N/A 0.001 0.006 N/A 0.807 0.014 N/A 0.001 0.001 N/A 0.001 N/A 0.001 PC InAREA InAREA 0.016 InAREA InAREA InAREA 0.001 InWIDTH InWIDTH 0.001 InWIDTH 0.001 InWIDTH 0.352 InWIDTH 0.001 DENSITY 0.895 DENSITY 0.115 DENSITY 0.615 DENSITY InLENGTH 0.001 InLENGTH 0.001 InLENGTH 0.001 InLENGTH 0.001 N/A InLENGTH 0.001 CHARACTER LOCATION LSMEANS P>F N/A PC 0.001 0.001 0.0650.013 B3 0.0010.001 0.001 B2 PC 0.038 0.796 0.3400.518 B1 0.237 0.017 0.062 0.001 B5 0.002 0.107 0.2790.070 B4 0.008 0.037 PC 0.103 Isistius brasiliensis SLOPE P>F 0.491 0.604 0.004 0.289 PC 0.476 PC 0.037 PC PC 0.797 InAREA 0.328 InAREA 0.157 InAREA 0.015 InAREA 0.025 InAREA InWIDTH 0.007 DENSITY DENSITY 0.036 DENSITY 0.234 DENSITY 0.207 InLENGTH InLENGTH 0.397 InLENGTH 0.215 InLENGTH 0.003 InLENGTH 0.183 HI InWIDTH 0.178 H2 InWIDTH 0.088 H3 InWIDTH 0.021 H5 H4 InWIDTH 0.331 LOCATIONCHARACTER Reproduced with permission of the copyright owner. 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LSMEANS P>F 0.401 <0.001** <0.001** <0.001 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A SLOPES P> F P> 0.179 0.086 0.004** 0.726 <0.001 ** <0.001** <0.001 ** <0.001** <0.001 ** N/A <0.001 ** N/A <0.001** N/A <0.001 **0.607 N/A <0.001** N/A <0.001** <0.001** <0.001 ** <0.001** PC PC PC InAREA InAREA InAREA InAREA InWIDTH 0.005** InWIDTH <0.001** InWIDTH InWIDTH DENSITY DENSITY DENSITY DENSITY InLENGTH InLENGTH InLENGTH InLENGTH CHARACTER B8 B6 LOCATION P>F LSMEANS 0.099 0.751 0.138 0.080 0.019* 0.003** 0.033* N/A B7 N/A PC N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A B5 Isistius brasiliensis SLOPES P> F P> <0.001 ** <0.001** 0.662 <0.001** <0.001** <0.001** 0.007** PC 0.088 PC <0.001** PC PC 0.178 InAREA 0.243 InAREA InAREA InAREA 0.015* InWIDTH InWIDTH InWIDTH 0.796 InWIDTH DENSITY 0.753 DENSITY 0.001** DENSITY DENSITY <0.001** InLENGTH 0.981 InLENGTH <0.001 ** InLENGTH <0.001** InLENGTH 0.003** CHARACTER C l C2 H6 H5 LOCATION Reproduced with permission of the copyright owner. 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LSME/ P>F N/A N/A 0.370 N/A N/A 0.804 N/A N/A 0.732 P>F SLOPES 0.010 0.0130.288 0.617 N/A 0.390 0.001 0.001 0.208 0.001 N/A 0.265 0.010 0.4270.007 0.306 N/A 0.027 N/A 0.0020.2540.001 N/A 0.108 N/A 0.001 0.144 0.212 0.001 0.028 N/A 0.225 0.007 0.0100.238 N/A 0.816 PC PC InAREA InAREA InAREA InWIDTH InWIDTH InWIDTH DENSITY DENSITY InLENGTH InLENGTH InLENGTH InLENGTH B4 InWIDTH B1 InWIDTH LOCATIONCHARACTER Squalus acanthi as Squalus acanthi P>F LSMEANS 0.666N/A 0.001 N/A N/A B2 N/AN/AN/A B3 PC InLENGTH InAREA N/AN/A DENSITY N/A N/A N/A 0.373 0.194 0.370 0.243 0.079 0.061 0.334 DENSITY N/A0.424 PC InAREA 0.733 B5 P>F SLOPE 0.023 0.396 0.266 0.003 0.665 0.019 0.012 PC PC PC 0.254 PC 0.001 InAREA 0.759 InAREA 0.027 InAREA InAREA 0.005 InAREA 0.965 InWIDTH 0.406 InWIDTH 0.551 DENSITY 0.004 DENSITY 0.059 DENSITY DENSITY 0.022 InLENGTH InLENGTH 0.062 InLENGTH InLENGTH 0.009 InLENGTH 0.008 HI InWIDTH H2 H3 InWIDTH 0.010 H4 InWIDTH 0.004 H5 LOCATIONCHARACTER Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LSMEANS P>F 0.816 0.370 0.021* 0.532 0.560 0.626 0.077 0.185 0.218 <0.001** 0.002** 0.192 0.002 N/A N/A N/A N/A N/A N/A N/A SLOPES P> F P> 0.884 0.135 0.476 0.704 0.393 0.078 0.227 0.038* <0.001 ** 0.140 0.332 0.135 <0.001** PC PC PC InAREA 0.237 InAREA InAREA InAREA InWIDTH 0.007** InWIDTH InWIDTH 0.066 InWIDTH 0.016* DENSITY DENSITY DENSITY DENSITY InLENGTH InLENGTH 0.173 InLENGTH 0.037* InLENGTH 0.010* CHARACTER LOCATION Squalus acanthias LSMEANS F P> 0.027* PC 0.8580.797 0.743 B7 0.811 0.085<0.001** 0.026* B8 0.424 0.7330.264 B5 0.220 0.046* B6 0.019* N/A N/A N/A N/A N/A N/A * o SLOPES P>F 0.728 0.384 0.184 0.060 0.123 0.206 0.006** 0.131 0.938 0.022* <0.001 ** 0.551 0.008** 0.965 0.222 0.662 0.814 0.021* o PC PC PC PC InAREA InAREA InAREA InAREA InWIDTH InWIDTH InWIDTH InWIDTH DENSITY 0.267 DENSITY DENSITY DENSITY InLENGTH InLENGTH InLENGTH InLENGTH CHARACTER C2 Cl H5 H 6 LOCATION Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. N/A 0.001 0.120 0.088 0.002 0.001 0.999 0.145 SLOPE MEANS MEANS MEANS MEANS SLOPES PCSLOPES DENSITY N/A N/A N/A 0.001 PC SLOPE 0.001 Centrophorus granulosus MEANS MEANS MEANS MEANS 0.001 MEANS 0.001 MEANS 0.001 SLOPES 0.001 InAREA InAREA SLOPES 0.197 InWIDTH SLOPES InWIDTH SLOPES 0.064 DENSITY InLENGTH SLOPES InLENGTH SLOPES 0.094 CHARACTERPCHARACTERP among the sixteen locations. APPENDIX VI. Analysis of covariance for placoid scale morphologic variables Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. P SLOPE 0.001 SLOPE 0.011 MEANS N/A MEANS N/A MEANS N/A MEANS N/A SLOPES 0.001 SLOPES 0.001 PC PC DENSITY DENSITY CHARACTER p 0.001 Centroscymnus coelolepis MEANS N/A MEANS N/A MEANS N/A MEANS N/A MEANS N/A MEANS N/A SLOPES 0.001 SLOPES SLOPES 0.001 SLOPES 0.001 SLOPES 0.001 SLOPES 0.001 InAREA InAREA InWIDTH InWIDTH InLENGTH InLENGTH CHARACTER Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced Dalatias licha o X DC < o o X < CC < O < I— UJ CC I— UJ X o o Q H- 05 _l O X 05 05 CL C/5LU X CL LU Q LU >- 9?. o o co co co LU < LU < X in CD 05 UI X 0 05 _l O O 05 I- X Q. LU CL CL c/5LU LU < LU < m X - O LU COCO CD < CC UI 05 D. < c 7 O O LU < MO CM Q I— O 05 O X 05 _1 CL LU 05 O o CO CM Q LU X >- 05 —I LU 05 I— CL LU < 05 LU 05 d o X < X * x— o CL O 05 O O O o § LU X 0 _l CL ^ UJ (/) 05 J ^ UJ c/3 05 I— X <0 S UJ < 2 InAREA SLOPES 0.097 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced Deania calcea o X L o CL < o I— UJ X o X X < O H-* >• x ^ O CL < < Q H X s O £ UJ CO co tu . OJ CO CO H < O Q LU O 2 CO 0 o < o < < - (f) z < LU CO 0 COLU ID O o CD ^ z e> H X o 0 ^ LU CO O O LU CO z . . LU < t z < LU < - X LU < CO O CL ^ UJ CO < _i CD ■ X CO O o o X LU CO < O Q h- CO o X UJ z CO I— >- CO _1 Q LU 2 § CO UJ < z CO UJ < z O CO < UI CJo g S LU z o CO X InAREA SLOPES 0.001 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced Etmopterus princeps X I— LU o x < cn < o cn o O I— LU < DC < a.: O DL UJ o T" Q CO - > CO Q CO _l o LU z co - I i _ 9?. o o CL UJ o < o o T_ o o co Z z UJ I U CO LU < < z < U ^ LU —I UJ z CD h" X CO l _ O CL c/3 CO d o CL o o l U o V" o t CL c — z UJ < < < z CO < cn CO _J O CL UJ CO q d UJ < o c z CO z LU < < 0CO 00 < O n g LU Q - F - > CO Q h- X CO o I U CO _ \ /* CL o z CO O o X— o T— LU d LO m 1 2 LU Z LU CO 00 < < Z d CO UI Z _l CD I— X 5 2 § 2 O CL O CO _ CL O LU CO o o O o c S > I g Z LU z < < <: InAREA SLOPES 0.001 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced Isistius brasiliensis o < O DC X L O o CL O o DC < I— LU X DC | LU DC CL < < -- CO O O o lO o CO to w CO CO CL LU _l LU CO - v CO CL O LU z Z LU Z < LU < _l LU z CD h" X CO _l O O < O CO LU CL LU CL ^ LU CO l _ Z CL c LU < Z < DC UJ < CO _1 O LU CO 0 c . UJ z CO < LU c CO Q I- X CO J _ O CO CO z CO CO O CL LU o o Q LU H >- $ CL 3 UJ 3 < uj /5 /5 ? ? O CO CO z o h- X CO _l O CO CL CO O CL LU LU CL LU O O o O c J U Z < LU < 3 z CO < * InAREA SLOPES 0.001 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced Oxynotus centrina o X O - > I— LU DC < ° n O UJ L - < o ° CL n < DC < S O 0. O X < DC < I— DC Q CO H UJ CO _J O Z CL CO LU CO UJ z S M § UJ o Q < (/) 2 2 3 ; < O Z COCL LU O < CM CO CL O 5 UJ CO l _ CO _i O a. UJ < o z o I— X § _l UJ c CO 2 UJ < z LU c CO < m § < QC UJ c S 3 2 /3 /3 ? Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. without prohibited reproduction Further owner. copyright the of permission with Reproduced Squalus acanthias o X < O I— LU DC DC < o X < O h- LU DC O O 2 CO < O COLU CO _l D LU CO9?. Q LU z £0 > J LU_J 2 CL I— l LU < z CD X LU Z H ^ CO S o ? p 0 c LU CO 0 < O Z OL LU < o O LU CO J _ § < < - . 2 CO 2 /3 DC < CO _l O Q. LU < LU c LU < Z CO Q H X CO O CL LU (/) CO o o Q LU z CO > O 0 ^ LU (/3 CO O _l O . z LU < J U < z <; CO O O _l O CL o o —I UJ z CD I— X CO —I CL ^ LU 0JCO O CL O c UJ < z < LU < InAREA SLOPES 0.001 LITERATURE CITED Affleck, R.J. 1950. Some points in the function, development and evolution of the tail in fishes. Proc. Zool. Soc. Lond., Vol. 120:349-368. Aleev, Y.G. 1977. Nekton. Junk, The Hague, Netherlands. Alexander, R.McN. 1965. The lift produced by the heterocercal tails of Selachii. J.Exp.Biol., 43:131-138. ______1974. Functional design in fishes. A.j. Cain (ed). Hutchinson University Library, London. ______1982. Basic mechanics, appendix. Locomotion in animals, pp. 140-153, Blackie, Glasglow, 1982. ______1982 Swimming, chapter 2. Locomotion of animals, pp. 13-38, Blackie, Glasglow 1982. ______1982. Locomotion in general, Chapter 7. Locomotion in Animals, pp. 126-139, Blackie, Glasglow, 1982. Alexander, D.E. 1990. Drag coefficients of swimming animals: effects of using different reference areas. Biol. Bull 179:186-190. Bainbridge, R. 1958. The speed of swimming as related to size and to the frequency and amplitude of the tail beat. Journal of Experimental Design 35:109-133. ______1963. Caudal fin and body movement in the propulsion of some fishes J. Exp. Biology: 40, p.23-56. 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Bushnell, D.M. and K.J. Moore. 1991. Drag Reduction in Nature. Ann. Rev. Fluid Mech. Burdak, V.D. 1973 Scale types as stages in the historical development of the hydrodynamic function of fish skin. Zoologicheskiy Zhumal, 8:1208-1213. Chao, L.N. and J.A. Musick, 1977. Life history, feeding habits, and functional morphology of juvenile sciaenid fishes in the York River estuary, Virginia. Fish. Bull., 75(4):657-702. Compagno, L.J.V. 1984. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 1 - Hexanchiformes to Lamniformes. FAO Fisheries synopsis No. 125. Fao Species catalog. Vol. 4. United Nations Devel. Prog., FAO, Rome. ______1988. Sharks of the order Carcharhiniformes. Princeton University Press, Princeton NJ. Comer, E.D.S., E.J. Denton and G.R. Forster. 1969 On the bouyancy of some deep- sea sharks. Proc.Roy.Soc.London, Series B, 171:415-433. Daily, J. W. and D. R. F. Harleman. 1966. Fluid dynamics. Addison-Wesley Publishing Co., Inc. 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Yano, K. 1991. Catch distribution, stomach contents and size at maturity of two squaloid sharks, Deania calceus and D. crepidalbus, from the Southeast Atlantic offNambia. Bull.Japan.Soc.Fish. Oceanogr., 55:189-196. ______and S. Tanaka. 1986. A telemetric study on the movements of the deep sea squaloid shark, Centrophorus granulosus. Indo-Pacific Fish Biology: Proceedings of the Second International Conference, 1986: 372-380. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. VITAE Christopher Tabit Bom in Newark, NJ, April 30, 1958. Garduated Lewisburg Area Highschool in 1976 and went on to earn a B.S. in Biology at Pennsylvanis State University, State College, PA in August of 1980. Earned a M.S. in Biology from Bucknell University, Lewisburg, PA in December 1985. Entered the Ph.D. program in Marine Science at the College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, VA in Janurary, 1986. Defended the dissertation October 17, 1993. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.