(Cf Eatonii) from the Antarctic Waters O

Home , Arhynchobatidae, Bathyraja, Bathyraja maccaini, Notoraja, Pavoraja, Rhinoraja

THE COMPARISON OF TWO UNDESCRIBED SPECIES OF SKATES, BATHYRAJA SP. 2 AND BATHYRAJA SP (C.F. EATONII) FROM THE ANTARCTIC WATERS OF THE SOUTH ORKNEY ISLANDS

Heather Kalisz

A Thesis Submitted to the Faculty of

The Wilkes Honors College

in Partial Fulfillment of the Requirements for the Degree of

Bachelor of Arts in Liberal Arts and Sciences

with a Concentration in Marine Biology

Wilkes Honors College of

Florida Atlantic University

Jupiter, Florida

May 2013

THE COMPARISON OF TWO UNDESCRIBED SPECIES OF SKATES, BATHYRAJA SP. 2 AND BATHYRAJA SP (C.F. EATONII) FROM THE ANTARCTIC WATERS OF THE SOUTH ORKNEY ISLANDS

Heather Kalisz

This thesis was prepared under the direction of the candidate’s thesis advisor, Dr. Jon Moore, and has been approved by the members of his/her supervisory committee. It was submitted to the faculty of The Honors College and was accepted in partial fulfillment of all the requirements for the degree of Bachelor of Arts in Liberal Arts and Sciences.

SUPERVISORY COMMITTEE:

______

Dr. Jon Moore

______

Dr. Nicholas Quintyne

______

Dean Jeffery Buller, Wilkes Honors College

______

Date

ii ACKNOWLEDGEMENTS

I would like to thank Dr. Jon Moore of Florida Atlantic University for giving me the opportunity to conduct my research on both the Bathyraja sp. 2 and Bathyraja c.f. eatonii specimens, allowing me access to the laboratory and tools needed to conduct the research, and for being my thesis advisor. I would also like to thank Dr. Nicholas

Quintyne for being on my thesis committee and assisting me in improving my thesis.

iii ABSTRACT

Author: Heather Kalisz

Title: The comparison of two undescribed species of skates, Bathyraja sp. 2 and Bathyraja sp. (c.f. eatonii) from the Antarctic waters of the South Orkney Islands Institution: Wilkes Honors College of Florida Atlantic University

Thesis Advisor: Dr. Jon Moore

Degree: Bachelor of Arts in Liberal Arts and Sciences

Concentration: Marine Biology

Year: 2013

Skates of the genus Bathyraja belong to the subfamily Arhynchobatinae in the family Rajidae. This family is comprised currently of 228 recognized species and about

50 unnamed species (McEachran and Dunn, 1998). Some authors elevate the

Arhynchobatidae to the rank of family (Nelson, 2006). Two unnamed species of skates

Bathyraja sp. 2 and Bahtyraja cf. eatonii were examined and measured in the preparation of formally describing these species. A total of 20 preserved specimens of Bathyraja sp. 2 and a total of 4 preserved specimens of Bathyraja cf. eatonii, collected during the 2008-

2009 AMLR survey cruise of the South Orkney Islands, were measured. The measurements of each skate were taken following the measurement descriptions in Hubbs and Ishiyama (1968). The body proportions of B. sp. 2 and B. cf. eatonii were compared and contrasted and a preliminary species description of each species is given.

To Anita and Robert Bottoms, for without you, I would not be who I am

I Love You

TABLE OF CONTENTS

Introduction ……………………………………………………………………………….1

Materials and Methods ……………………………………………………………………8

Results …………………………………………………………………………………...19

Discussion ……………………………………………………………………………….21

References ……………………………………………………………………………….26

v LIST OF TABLES

1. Illustrates the corresponding station numbers, date, latitude, longitude, and average

depth for the specimens. The data used to create this table contains information

provided by Jones et al., (2009). ……………………………………………………...9

2. Illustrates the Specimen I.D number (tissue tag numbers) from Table 1 and the

correlating catalog numbers for each specimen. …………………………………….10

3. The proportional dimensions are expressed in percentages of disc width and total

length. This table was created using the same format as Springer, 1971. …………..20

LIST OF FIGURES

1. Smith et al., (2008) Illustrates through a phylogenetic tree the relation between

Bathyraja sp. 2 (in this research it is known as Bathyraja sp. (dwarf)) and Bathyraja

cf. eatonii. ……………………………………………………………………………7

2. Illustrates the station locations, particularly station numbers 15, 89, 21, 24, 27, 73,

and 5 from Leg II of the 2008-2009 AMLR survey, from which the studied specimens

were collected. These stations are all located in the South Orkney Islands (Jones et

al., 2009). ……………………………………………………………………………..8

3. Photograph of a preserved specimen from the AMLR 2008-2009 survey cruise,

Bathyraja sp. 2. Photograph credit: Heather Kalisz ………………………………...12

4. Photograph of a preserved specimen from the AMLR 2008-2009 survey cruise,

Bathyraja cf. eatonii. Photograph credit: Heather Kalisz …………………………...13

5. Technical terms and method of measurements referred to and used in the study of

skates (from Stehmann and Bürkel, 1990; originally found in Stehmann 1981). …...14

vii Introduction:

Skates belong to the suborder Rajoidea and are typically placed in the family

Rajidae (McEachran and Dunn, 1998) or split between the families Rajidae and

Arhynchobatidae (Nelson, 2006). Skates are unique to the class of cartilaginous fishes,

Chondrichthyes, due to their high species diversity yet low morphological differences

(McEachran and Dunn, 1998). Fishes of the family Rajidae, as characterized by

McEachran and Dunn (1998), range in size from 20-30 cm to more than 2 m in total length (Stehmann, 1981) and are located worldwide in marine waters ranging from the shoreline to 3000 m in depth, but are not found in the Pacific plate or the Red Sea

(McEachran and Dunn, 1998). There are currently 228 recognized species and about 50 unnamed species (McEachran and Dunn, 1998).

The following is the description of the characteristics given to the family Rajidae

(Skates) by Stehmann (1985) in the FAO species identification sheets of the Southern

Ocean. The Rajidae fishes have a body consisting of the head, trunk, and enlarged pectoral fins, which are dorsoventrally flattened forming a rhombic to roundish disc.

Their pectoral fins are completely fused to the sides of the head and trunk from tip or the midlength of the snout to the insertion of the pelvic fins. The tail is moderately slender, yet distinctly marked off from the disc, and its length is less than two times the disc width, with a narrow fold (lateral tail fold) along each of the tail’s edges. The eyes and spiracles are located on the dorsal side of the body. The spiracles are located immediately behind the eyes and include a pseudobranchial fold at their anterior wall. Stehmann,

(1985), also stated that the shape of the snout can range from acutely angled and long to obtusely rounded and short. The front of the cranium is extended in most species as a

1 rostral process, which can be stout or delicate, and in the latter case can be segmented distally or basally. The anterior pectoral fin rays and their basal elements are either extending almost to tip of the snout (soft-snouted species, with a delicate or even reduced rostral process) or to about the midlength of the snout only (hard-snouted species with a stout rostral process). The transverse mouth gap located on the ventral side of the body is straight to more or less arched in shape. There are numerous rows of teeth present in bands on the upper and lower jaws and are obtuse or pointed in shape, showing sexual dimorphism in many species. The teeth bands are placed in a pavement pattern also known as quincunx, in parallel rows, or in a combination of both. The nasal apertures are small and located shortly anterior of the mouth on the ventral side. The nasal aperture’s inner margins expand rearward as a large bilobed nasal curtain with both lobes joined to form a broad transverse isthmus, which is close to the front of the mouth and basally fused to the upper jaw. The pelvic fins of the Rajidae family are bilobed with the two lobes separated externally by a more or less deep notch in their outer margins only. On the tail there are two small dorsal fins on the far posterior end. A caudal fin is also present at the most posterior end of the tail, as well as a rudimentary ventral fold or keel is also sometimes present. The dorsal surface of the skin is densely to sparsely set with spinules (prickles) and often thornlets and or thorns are present too. The pattern of the spinules, thornlets, and/or thorns consists of an arrangement of patches, rows, and/or single tubercles in distinct regions. There is at the minimum a median row of thorns present along the midline of the tail (except in some species of Malacoraja), and sometimes extending forward onto the midline of the back. Malar and alar thorns on the lateral portions of the disc may also be developed in sexually mature males only. The

2 ventral surface of the skin is smooth to more or less prickley, rarely also with some irregularly distributed thorns. Patterns of spinules, thornlets, and thorns may vary with growth, age, and sexual maturity. The dorsal color of skates is in nearly all shades of grey to brown. A few species are reddish, or blue-violet, and coloration can occur in many different patterns. The ventral surface may be uniformly dark or light, or mottled, or a light centre of the disc with dark edges, while some species have darkly pigmented pores.

Deep water skates can, as a rule, be characterized as plain dark on both surfaces, whereas shallow-water species are predominately white ventrally and often extremely variegated on the dorsal surface. The color pattern may vary with the nature of the bottom substrate and also with growth and age.

According to McEachran and Dunn (1998), the characters that help distinguish the Rajidae from all other batoids include: oviparous development; alar and/or malar thorns in mature males; lateral muscle bundles of tail converted into electric organs; second hypobranchial cartilage fused with basibranchial cupula; anterior portion of 2nd hypobranchial cartilage absent, therefore 2nd hypobranchial cartilage lacks articulation with 2nd ceratobranchial; clasper skeleton with dorsal terminal cartilage; clasper skeleton with ventral terminal cartilage.

The subfamily Arhynchobatinae, called the “soft-nose” skates, is comprised of the genera Arhynchobatis, Atlantoraja, Bathyraja, Irolita, Notoraja, Pavoraja, Psammobatis,

Pseudoraja, Rhinoraja, Rioraja, and Sympterygia (McEachran and Dunn 1998).

Characters that distinguish this subfamily (McEachran and Dunn, 1998) include: alar thorns with crown oblique to long axis of base and lacking barbs; nasal capsule broad and oval; basihyal with lateral projections; and clasper glans with component projection.

The two species of skates, that were examined in this study, belong to the genus

Bathyraja. Bathyraja is the most speciose and widely distributed genus of skates

(Stehmann 1986). Stehmann (1986) stated there are at least 40 species and Compagno

(1999) listed 41 valid species and two undescribed species, including Bathyraja sp. 2, which is treated here. Stehmann (2005) and Ebert and Compagno (2007) raised the number of species to 50 or more. The Catalog of Fishes (Eschmeyer, 2013) presently lists

56 valid species of Bathyraja. A unique feature of all Bathyraja is the rostral cartilage is very slender and uncalcified along the entire length (McEachran and Dunn 1998). Smith et al., (2008) provide molecular evidence that the two species described in this study are placed well within the genus Bathyraja. Stehmann (1986) stated the individuals belonging to Bathyraja present a uniformity within each morphotype group, not only in external morphology, but in all features of the skeletal anatomy and the terminal structure of the claspers. The claspers of mature males are long and slender with a proportionally short and not widened glans (Stehmann, 1986). The glans clasper has few components and reflects a terminal clasper skeleton composed of few and little differentiated cartilages (Stehmann, 1986). The scapulocoracoids of the genus Bathyraja are longer than high and are symmetric with regard to their short pre- and much longer post- mesocondyle length (Stehmann, 1986). Stehmann (1986) also describes Bathyraja as having the anterior fenestra divided by an anterior bridge, and there are several post dorsal foramina of varing sizes as well as even more numerous small postventral ones.

The two species investigated here are at present informally named. The first is

Bathyraja sp. 2 (in Stehmann, 1985) and also called Bathyraja sp. (dwarf) in Smith et al.

(2008), and the second undescribed species is called Bathyraja sp. (c.f. eatonii in Smith

4 et al., 2008). Bathyraja sp. 2 is an undescribed species of skate that has been known to scientists for over 20 years (Jones et al., 2009) [note: Stehmann informally named it in

1985, so that is 28 years ago] and is currently being studied by Dr. Jon Moore, Florida

Atlantic University, to formally describe this species. The other species of skate that was measured in this study is Bathyraja sp. (cf. eatonii). According to Smith et al,. (2008:

1170),

“based on sequence divergence, the species that has been referred

to as Bathyraja eatonii from the Antarctic continental shelf and

slope is a species distinct from B. eatonii from the Kerguelen

Plateau and is a new and undescribed species Bathyraja sp. (cf.

eatonii). There was no sequence divergence among samples of

Bathyraja sp. (dwarf) from the Ross Sea and the South Atlantic.

However, for both Bathyraja sp. (cf. eatonii) and Bathyraja

maccaini in the Ross Sea and the South Atlantic Ocean, the DNA

sequence divergences indicate differentiation among ocean basins

and within Bathyraja sp. (cf. eatonii) divergences are similar to

those among recognized species of Bathyraja in the North Pacific

Ocean”.

Both of these species are deep-water morphotypes, found in the Circum-Antarctic and Subantarctic waters (Stehmann, 1981). Previous to the Smith et al., (2008) study, it was assumed that the species Bathyraja eatonii, occurred in the Atlantic and Pacific sectors of Antarctica and the Southern Ocean. Bathyraja eatonii was originally described from Kerguelen Island in the Indian Ocean sector of the Southern Ocean (Günther, 1876).

Stehmann (1985) described Bathyraja eatonii in the FAO species identification sheets as having at least the centers and posterior margins of the pectorals smooth (except for small juveniles that are entirely prickley dorsally). Adults have a band of fine spinules around disc margins and along the midbody. There are 8-16 widely spaced median tail thorns up to the first dorsal fin, all small and indistinct, the posterior ones often reduced. The snout is relatively long and narrowly angled from adolescent specimens on, but not in juveniles.

The underside of the tail is entirely or partly brown, with a brown median strip, or at least with brown spots, or rarely white in Indian Ocean sector specimens (true B. eatonii), but usually plain white or rarely with a few pale brown spots in Atlantic sector specimens (B. sp. c.f. eatonii). If present at all, there are only 1 or 2 large thorns medially on nape/shoulder.

Stehmann (1985) described Bathyraja sp. 2 in the FAO species identification sheets as upper side of disc always entirely and densely set with coarse spinules. There are 18-29 relatively indistinct median tail thorns to the first dorsal fin. The ventral side of the disc and tail are whitish in colour, and pale dark spots may occur centrally on disc and on tail. Dorsally the skate is a plain dark colour, except in juveniles (up to 250 mm in total length) which show a distinct pattern of light dots and strokes. Typically the mouth cavity and laterally the underside of the nasal curtain are pigmented dark, at least in part.

Although Smith et al., (2008) illustrates in the phylogenetic tree that Bathyraja sp. 2, or known in his study as Bathyraja sp. (dwarf) is most closely related to Bathyraja maccaini, comparisons will focus in this study between Bathyraja sp. 2 and Bathyraja cf. eatonii due to the presence of the two species in the collection samples from the 2009

AMLR cruise and the data composed from the collection of their measurements.

Comparisons to B. macaini will be made using the literature (Springer 1971).

Figure 1. Smith et al., (2008) Illustrates through a phylogenetic tree the relation between Bathyraja sp. 2 (in this research it is known as Bathyraja sp. (dwarf)) and Bathyraja cf. eatonii

Materials and Methods:

All of the specimens measured in this study, a total of 24 individuals, were captured and preserved from the Antarctic Marine Living Resources 2008-2009 cruise.

During the AMLR survey cruise a random, depth-stratified bottom trawl survey of the

South Orkney Island was performed (Jones et al., 2009). All 24 specimens are catalogued in the Yale Peabody Museum of Natural History (YPM).

Figure 2. Illustrates the station locations, particularly station numbers 15, 89, 21, 24, 27, 73, and 5 from Leg II of the 2008-2009 AMLR survey, from which the studied specimens were collected. These stations are all located in the South Orkney Islands (Jones et al., 2009).

Table 1. Illustrates the corresponding station numbers, date, latitude, longitude, and average depth for the specimens. The data used to create this table contains information provided by Jones et al., (2009).

Station Latitude Longitude Avg. Specimen No. Date (S) (W) Depth (m) I.D. Species Sex 15-10 12-Feb-09 60°31.82 44°44.39 310 YFTC14857 B. spp2 F 89-09 12-Feb-09 60°29.67 44°37.86 798 YFTC14875 B. spp2 M 21-21 15-Feb-09 61°03.53 42°50.48 425 YFTC14976 B. spp2 M 24-22 15-Feb-09 61°08.49 43°06.16 469 YFTC14984 B. spp2 F YFTC14983 B. spp2 F YFTC14982 B. spp2 M YFTC14981 B. spp2 M 27-24 16-Feb-09 61°09.38 43°32.66 455 YFTC14996 B. spp2 F YFTC14997 B. spp2 F YFTC14998 B. spp2 M YFTC14999 B. spp2 F 73-38 20-Feb-09 61°42.08 45°07.88 375 YFTC15102 B. eatonii M YFTC15103 B. eatonii M 05-67 28-Feb-09 60°30.47 46°35.45 457 JAM4 B. spp2 F JAM2 B. spp2 F JAM5 B. spp2 F JAM7 B. spp2 F JAM6 B. spp2 F JAM8 B. spp2 F JAM3 B. spp2 M JAM1 B. spp2 M 67-65 28-Feb-09 60°55.02 45°37.86 299 YFTC15322 B. eatonii F

The two additional specimens came from a 2010 cruise to the islands on the west side of the Antarctic Peninsula (YFTC20737 = YPM ICH24025 Bathyraja sp. 2 from 15

Apr 2010, S64° 5.63’ W62° 46.14’, off Brabant Island on the Antarctic Peninsula, depth

160 m and YFTC20886 = YPM ICH24025 Bathyraja sp. c.f. eatonii from 15 Apr 2010,

S63° 29.15’ W62° 41.76’, off Low Island on the Antarctic Peninsula, depth 151 m).

Table 2. Illustrates the Specimen I.D number (tissue tag numbers) from Table 1 and the correlating YPM Ichthyology catalog numbers for each specimen from the 2009 cruise. The specimen I.D. numbers were used to keep track of each individual measured.

Specimen I.D. YPM # YFTC14857 ICH22684 YFTC14875 ICH22653 YFTC14976 ICH22584 YFTC14984 ICH22699 YFTC14983 ICH22699 YFTC14982 ICH22699 YFTC14981 ICH22699 YFTC14996 ICH22558 YFTC14997 ICH22558 YFTC14998 ICH22558 YFTC14999 ICH22558 YFTC15102 ICH22591 YFTC15103 ICH22591 JAM4 ICH22403 JAM2 ICH22403 JAM5 ICH22403 JAM7 ICH22403 JAM6 ICH22403 JAM8 ICH22403 JAM3 ICH22403 JAM1 ICH22403 YFTC15322 ICH22407

The twenty specimens of Bathyraja sp.2 and four specimens of Bathyraja cf. eatonii were measured in a large dissection pan with calipers or a meter stick, depending on their size. Calipers were used for the smaller specimens consisting of 15 cm or less, while the meter stick was used to measure the individuals that were 15 cm or larger. A total of seventy-one different measurements were taken (Hubbs and Ishiyama, 1968), but due to the large quantity of information only 37 measurements will be compared and displayed in a table illustrating the proportions. Other measurements averages will be

10 addressed in the discussion. Measurements were recorded in centimeters to the nearest hundredth. Other tools were used, such as a magnifying glass and tweezers. These tools were used during the counting of the number of teeth rows and predorsal median thorns.

The measurements of each skate were taken following the measurement descriptions in

Methods for the Taxonomic Study and Description of Skates (Rajidae), (Hubbs and

Ishiyama, 1968), which are modified from and expansions of the original measurement descriptions from Studies of the rajid fishes (Rajidae) found in the waters around Japan

(Ishiyama, 1958). Figure 1(Smith et al., (2008)) was also referred to for the technical terms and method measurements used in the study of these skates. The measurements were entered into Microsoft Excel and the averages for each type of measurement were calculated for both the B. sp.2 and B. cf. eatonii. The proportional dimensions, expressed as percentages, for each of the measurements were also calculated using Microsoft Excel.

Due to the preservation of the specimens initially in a 10% formalin and then over a four-year period in a 75% ethanol solution, the individual specimens have been warped and slightly shrunken due to water loss and distorted bodies, therefore the measurements will not be accurate as to when the specimen was first brought up from the sea on the cruise (Fowler and Smith, 1983). Cranial dimensions, number of vertebrae, and egg capsule measurements were not taken. The ages of each individual were not specified, but total body length and disc width may provide insight to further research as to the age of the individual. The two specimens, YFTC 20866 and YFTC 20737, came from a separate 2010 cruise to the islands right off the west side of the Antarctic Peninsula.

Figure 3. Photograph of a preserved specimen from the AMLR 2008-2009 survey cruise, Bathyraja sp. 2. Photograph credit: Heather Kalisz

Figure 4. Photograph of a preserved specimen from the AMLR 2008-2009 survey cruise, Bathyraja cf. eatonii. Photograph credit: Heather Kalisz

Figure 5. Technical terms and method of measurements referred to and used in the study of skates (from Stehmann and Bürkel, 1990; originally found in Stehmann 1981).

Below are the following descriptions of measurements (Hubbs and Ishiyama,

1968) used for the comparison of measurements between Bathyraja sp. 2 and Bathyraja cf. eatonii. These measurements are shown in Table 2, illustrating body proportions.

1. Total length: from tip of snout to posterior most point, on body axis or on caudal fin, whichever projects; expressed in mm and as a proportion of disc width (2).

DISC MEASUREMENTS

2. Disc width: greatest measurement between outermost tips of "wings"; base for all proportional measurements of disc, tail, fins, head, spines, and ocellus.

3. Disc length: greatest distance from snout tip to posterior margin of pectoral (not pelvic) fin.

4. Anterior projection: from snout tip to point on midline of back where line of greatest width crosses.

7. Precaudal length: from snout tip to front of underlying cartilaginous (usually calcified) tubercle (first or second hemal spine), marking position of hemal spine of first or second tail vertebra, located a short distance behind cloaca; this tubercle can usually be felt with a fingernail, which imprints a transverse crease into which the point of dividers or calipers is readily inserted.

TAIL MEASUREMENTS

8. Tail length: from crease thus formed (see 7) to tip of tail (as defined under 1).

9 and 10. Tail width, end P2 (9), and Tail depth, end P2 (10): measured at middle of line joining distal most margins of pelvic fins across tail; as also for 11 and 12, exclusive of spines, prickles, and lateral fold.

11 and 12. Tail width, origin D1 (11) and Tail depth, origin D1 (12): measured oppo-site extreme origin of first dorsal fin.

14. D1 origin to tail tip: from extreme front of base of first dorsal fin to farthest tip of tail

(as defined under 1).

FIN MEASUREMENTS

15. D1 basal length: from extreme front of base of first dorsal fin to point where fin membrane, if normal, contacts upper surface of tail.

16. Between D bases: interdorsal space, from end of base of D1 (defined under 15) to extreme front of D2 base.

17. D2 basal length: second-dorsal-fin base, measured as for D1 base (15).

19 and 20. Dorsal fin 1 vertical height (19), and Dorsal fin 2 vertical height (20).

22. Lateral-fold length: from front end (often only approximately determinable) to rear end (more obvious) of the dermal fold on each lateral edge of tail.

23. Lateral-fold width: measured adjacent to origin of second dorsal fin, where fold is widest in most species.

25. Between front tips, Pl: least distance between anterior most tips of pectoral radials, left and right (the tips are usually visible through the skin, noticeable to touch, or

16 locatable by a slight external indentation, and show well on radiographs; when tips are obscure, measurement 38 may be substituted).

26. P2 width: from midline of cloacal slit to tip of anterior pelvic lobe, when lobe is held approximately at right angle to longitudinal axis of body.

27. P2 length: Pelvic-fin length from front tip of hemal spine (as defined under 7) to farthest point on margin of inner-posterior lobe.

29. Clasper length: from front tip of hemal spine (as defined under 7) to extreme tip of clasper. This dimension increases rapidly during the elaboration of the clasper (the stages are defined below, on page 490).

31. Preocular length: snout length, from its tip to front margin of eyeball.

32. Preoral length: from snout tip to mouth slit on midline, taken with mouth in normal closed position (upper and lower jaws in contact).

33. Prenarial length: from snout tip to nearest point on outer rim of nostril.

34. Internarial distance: least distance between nostrils at sides of nasal curtain.

35. Nasal-curtain length: from front mar-gin of nostril to rear margin of curtain, including fimbriae of curtain. When fimbriae are well developed, length of longest may be taken.

36. Nasal-curtain width: width of rear, largely fimbriate edge of left or right lobe of curtain.

39. Mouth width: greatest dimension across tooth band of upper jaw (more definitive than, and approximating, distance between rims of mouth).

40. Eyeball length: greatest diameter, more or less longitudinal, across eyeball, including skin obviously covering eyeball, but not loose surrounding tissue.

41. Between orbits: least interorbital width between inner edges of left and right eyeballs; taken by pressing dividers or calipers lightly together, so as to measure width, including the moderately firm underlying tissues, but not necessarily the cartilage; corresponds roughly to more precise interorbital width measurement (65) on cleaned cranium.

42. Between spiracles: least interspiracular width, between inner rims.

43. Spiracle length: greatest diameter, more or less longitudinal, across spiracular depression, from inner-posterior margin to anterior most angle beyond opening; dividers or calipers are pressed against the skin of the depression.

44. Over 1st gill-slits: greatest distance between outer ends of left and right first gill-slits; approximating and more definitely determinable than greatest distance across soft branchial area between the pectoral elements (propterygia) of the two sides.

45. Prefontanelle length: from snout tip to anterior margin (usually determinable approximately without dissection) of anterior fontanelle; approximating measurement to point where rostral cartilage forks on the ventral side, and more precise, because that point represents merely the culmination of a very gradually disappearing concavity; 60 is the corresponding measurement made directly on cranium.

Number of tooth rows – Used methods in Figure 1 to measure tooth row counts.

NUMBER OF SPINES (OR THORNS)

G. Predorsal median tail series: comprising mid-dorsal spines between lumbar series and origin of first dorsal fin.

Results:

A total of 37 measurements for each species were conducted and then averaged for the 20 individual specimens of B. sp. 2 and the 4 individual specimens of B. cf. eatonii. Separately, for each species the averages were calculated to express the measurements as percentages, in thousandths, for both disc width and total body length.

These results are shown in Table 3.

Table 3. The proportional dimensions are expressed in percentages of disc width and total length. This table was created using the same format as Springer, 1971.

Bathyraja sp. 2 Bathyraja cf. eatonii % % Total % Disc % Total DiscWidth Length Width Length (1) Total Length 162.6 100.0 142.6 100.0 (2) Disc Width 100.0 61.5 100.0 70.1 (3) Disc Length 82.4 50.7 82.3 57.7 (4) Anterior Projection 45.2 27.8 47.5 33.3 (7) Precaudal Length 74.6 45.9 74.1 52.0 (8) Tail Length 81.5 50.1 63.7 44.7 (9) Tail width at end pectoral 5.9 3.6 4.9 3.5 (10) Tail Depth at end pectoral 3.9 2.4 2.7 1.9 (11) Tail width at origin 2.8 1.7 2.6 1.8 (12) Tail Depth at origin first dorsal 1.6 1.0 1.5 1.0 (14) First Dorsal origin to tail tip 16.0 9.8 17.5 12.3 (15) Base First Dorsal 6.2 3.8 6.4 4.5 (16) Between Dorsal Bases 1.7 1.0 2.4 1.7 (17) Base Second Dorsal 5.1 3.1 3.8 2.7 (19) Vertical Height D1 3.0 1.8 4.2 3.0 (20) Vertical Height D2 3.2 1.9 3.0 2.1 (22) Lateral Fold Length 38.3 23.6 37.9 26.6 (23) Lateral Fold Width 1.0 0.6 1.0 0.7 (25) Between Front Tips Pectoral Radials 3.8 2.3 2.8 2.0 (26) Cloaca to extended tip pelvic 26.5 16.3 23.0 16.1 (27) Pelvic Fin Length 16.9 10.4 16.1 11.3 (29) Clasper Length 12.9 7.9 11.0 7.7 (31) Preocular Length 19.0 11.7 23.2 16.3 (32) Preoral Length 19.3 11.9 24.2 17.0 (33) Prenarial Length 15.5 9.5 19.5 13.7 (34) Internarial Distnace 10.8 6.7 10.7 7.2 (35) Nasal Curtain Length 4.4 2.7 4.9 3.5 (36) Nasal Curtain Width 4.3 2.7 3.5 2.4 (39) Mouth Width 11.5 7.1 10.2 7.2 (40) Eyeball Length 7.0 4.3 6.2 4.3 (41) Distance Between Orbits 7.1 4.4 6.7 4.7 (42) Between Spricales 13.1 8.1 10.9 7.7 (43) Spiracle Length 4.2 2.6 4.0 2.8 (44) Distance between Outer Ends First Gill Slits 28.6 17.6 25.2 18.1 (45) Prefontanella Length 11.1 6.9 15.7 11.0 Number of Tooth Rows (avg) 25.7 28.3 Number of Predorsal Medial Tail series Thonr (avg) 20.7 14.0 20

Discussion:

Body Proportions:

In comparison to Springer’s (1971) data, there were only a few differences between the body proportions of Bathyraja sp. 2 studied here and Springer’s (1971) specimen of Bathyraja sp. 2, misidentified as Bathyraja griseocauda. One of the reasons for these differences may be that Springer only studied one mature male with a total body length of 48.5 cm, and a disc width of 31.5 cm, and the measurements of this study are the averages of 20 individuals with an average of 28.34 cm total body length and an average of 17.43 cm disc width. Taking this into consideration the only measurements that had a large discrepancy between these data and Springer’s (1971) data was the lateral fold length measurements. Springer’s (1971) data illustrates the lateral fold length is

68.6% of the disc width and 44.5% of the total body length. The measurements in this study illustrate the lateral fold length is 38.3% of the disc width and 7.9% of the total body length. This discrepancy could possibly be caused by biases in measurements between researchers or differences in the maturity of the specimen.

As illustrated in Table 3, the measurements between Bathyraja sp. 2 and

Bathyraja cf.eatonii are fairly similar. The measurements with significant differences are percentages in tail lengths for disc width. In Bathyraja sp. 2 the tail length is 81.5% of the disc width, in comparison Bathyraja cf. eatonii tail length is 67.3% of the disc width.

Species Analysis:

Genus Bathyraja:

In accordance with Stehmann’s species description (Stehmann, 1985) I do regard

Bathyraja sp. 2 and Bathyraja cf. eatonii as belonging to the genus Bathyraja, because all of the species studied had a rostral process which was delicate and flexible, opposed to the genera in the subfamily Rajinae which has a stout and firm rostral process. Bathyraja sp. 2 and Bathyraja cf. eatonii also conforms to Stehmann’s description due to the presence of the extremities of the pectoral fin rays extending very close to the tip of the rostral process.

Bathyraja sp. 2:

In agreement with Springer (1971), who referred Bathyraja sp. 2 as Bathyraja griseocauda, Bathyraja sp. 2 can be distinguished from other Antarctic and subantarctic skates by its external characteristics. In each of the specimens measured, the dorsal surface was entirely covered with dense coarse spicules. It was found that in only two of the larger individuals measured, YFTC14857 and YTFC20737, there were noticeably larger spines present around the edges of the pectoral fins, known as the malar and alar hooks, but they were not large enough to be distinguishably counted. The absence of larger thorns on the disc distinguishes Bathyraja sp. 2 from other described Antarctic rajid species (Springer, 1971) as well as the Bathyraja cf. eatonii measured in this study, of which had a completely smooth ventral disc besides the row of predorsal median tail thorns and the very fine sinules present on the mid dorsal body between the scapulars posterior along the tail. Each specimen had a row of predorsal median tail thorns present.

Although through preservation or of natural causes some thorns may have been missing, the present predorsal median tail thorns and predorsal median tail thorn scars were counted for accuracy. The average number of predorsal median tail thorns was 20.70, with the range being between 15 and 26. Stehmann describes B. sp. 2 as having 18-29 median tail thorns. There were no thorns present in the orbital, rostral, scapular, mediscapular, prescapular, lumbar, interdorsal, upper lateral tail, or lower lateral tail series. There were also no spines present between scapulars. Due to the preservation of the specimens in the 75% ethanol solution, the color may have been altered, but the individuals ranged from a tan to brown in color dorsally, with the underside being white/tan in color. In all of the individuals measured there was no anterior and posterior concavity. The anterior convexity average was 1.29 cm and the posterior convexity average was 1.28 cm. The average distance between ocelli was 2.34 cm. On the anterior side of the disc the average length between front tips was 0.66cm. The average number of pelvic radials for B. sp 2 was 15.45 with a minimum of 14 and a maximum of 18. There was an average of 0.29 cm between dorsal fin bases, and an average of 1.08 cm for dorsal fin 1 bases length and 0.88 for dorsal fin 2 base length. Dorsal fin 1 base length was on average longer than dorsal fin 2 base length. The average caudal fin height was 0.15cm.

The average number of tooth rows was 25.70, with a minimum of 23 and a maximum of

33.

Smith et al., 2008, illustrated in their phylogenetic tree that Bathyraja sp. 2 is most closely related to Bathyraja maccaini. Springer (1971) originally described

Bathyraja maccaini and compared the specimens body proportions to Bathyraja sp. 2.

Springer (1971) described Bathyraja maccaini as having the tail length consist of 62.8% of the disc width, while the study found Bathyraja sp. 2 to have a tail length consisting of

81.5% of the disc width. Bathyraja maccaini also had a lateral fold length of 56.0% of the disc width and 40.5% of the total length (Springer 1971), in comparison to B. sp. 2 having a lateral fold length of 38.3% of the disc width and 23.6% of the total length.

Finally, Bathyraja maccaini also had a clasper length of 21.3% of the disc width and

15.4% of the total length (Springer 1971), in comparison to B. sp. 2 having a clasper length of 12.9% of the disc width 7.9% of the total length. These measurements of

Bathyraja sp. 2 are almost half of those belonging to Bathyraja maccaini. Finally,

Bathyraja maccaini has a total of 20 – 30 (Springer, 1971) tooth rows in the upper jaw in comparison to this data in which Bathyraja sp. 2 that had an average of 25.7 tooth rows in the upper jaw. Bathyraja maccaini also has a range of 9-15 median tail thorns

(Springer, 1971) in comparison to Bathyraja sp. 2 which has a range of 18-29 median tail thorns (Stehmann, 1985) and in this data had an average of 20.7 median tail thorns.

Bathyraja cf. eatonii:

In the FAO identification sheets (1981), Stehmann states that the centers of each pectoral and posterior margins of the pectorals are smooth, except in juveniles, and in adults a band of fine spinules are present around the disc margins and along mid body.

The 4 specimens in this study, ranging from 27.9 – 34.3 cm TL, the entire dorsal disc was smooth with very small spinules present along the mid body line ranging from the scapulars posterior to the end of the tail. There were also zero scapular thorns present in any of the individuals studied. Each Bathyraja cf. eatonii had a row of predorsal median tail thorns present. The average number of predorsal median tail thorns was 14.00, with a

24 range of 13 minimum and 15 as the maximum. Stehmann (1981) described Bathyraja eatonii as having 8-16 predorsal median tail thorns, all small and indistinct, although, the

B. cf. eatonii specimens measured had distinct predorsal median thorns present. Due to being preserved for four years, the color may have been altered from the true live coloration. Dorsally, Bathyraja cf. eatonii was a dark brown in color with lighter and darker spots covering the entire disc. The underside ranged from completely white/tan to white/tan with dark brown spots. Pelvic radials were present in the range of 15 to 23 and an average of 18.75. The average length between ocelli was 2.76cm and 0.62 between front tips. In the individuals measured there was no anterior and posterior concavity present. The anterior convexity was an average of 1.31 and the posterior convexity was an average of 1.51 cm. There was an average of 0.53 cm between dorsal fin bases, and an average of 1.42 cm for dorsal fin 1 base length and 0.85 cm for dorsal fin 2 base length.

Dorsal fin 1 base length was on average longer than dorsal fin 2 base length. The average caudal height was 0.20 cm. The average number of tooth rows was 28.25 with a range of

25 as the minimum and 36 as the maximum.

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