Osteological and Myological Comparisons of the Head and Thorax

Brigham Young University BYU ScholarsArchive

Theses and Dissertations

1968-08-01

Osteological and myological comparisons of the head and thorax regions of cnemidophorus tigris septentrionalis burger and ameiva undulata parva barbour and noble (family teiidae)

Don Lowell Fisher Brigham Young University - Provo

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BYU ScholarsArchive Citation Fisher, Don Lowell, "Osteological and myological comparisons of the head and thorax regions of cnemidophorus tigris septentrionalis burger and ameiva undulata parva barbour and noble (family teiidae)" (1968). Theses and Dissertations. 7681. https://scholarsarchive.byu.edu/etd/7681

This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. OSTEOLOGICALAND MYOLOGICAL COMPARISONS OF THE HEAD ANDTHORAX REGIONS OF CNEMIDOPHORUSTIGRIS SEPTENTRIONALISBURGER AND AMEIVA

UNDUIATAPARVA BARBOUR AND NOBIE / --V V (FAMILYTEIIDAE)

A Thesis

Presented to the Department of Zoology and Entomology Brigham Young University

In Partial Fulf'illment

of the Requirements for the Degree

Master of Science

Don Lowell Fisher August 1968 This thesis, by Don Lowell Fisher, is accepted in its present form by the Department of Zoology and Entomology of the Brigham

Young University as satisfying the thesis requirement for the degree of Master of Science.

Typed by Kathleen Ro Steed TABLEOF CONTENTS

Page

ACKNOWLEDGEMENTSo o o e e e o o o o o e o o G • o • o o o o o o vi

INTRODUCTION., ., 0 0 0 o O O O O O O O O O O O O O O 8 0 0 0 0 0 1

MATERIALSAND METHODS 000000•00•00•00000000 6 OSTEOLOGY

General Description of the Skull ... o o o o ., o ., ., ., o 9 Description of Skull Elements., ., •• ., • ., • ., ., o o o ., 10 Lower Jaw • .. ., • ., o o ., .. • • • • ., • • o • • ., o • " o 21 Foramina of the Skull and Lower Jaw., " • o ., • ., o o o • 24 Teeth o o o o o o o o o o o o o o ••• o o o o o o o o o 28 Wrist o o o o • o • o o o o o e o o ~ o o o o o o o o o o 29

MYOLOGYooeo-ooooooooeoeooeoooooooooo 40

DISCUSSIONo o. e -0 0 C O e. 0 0 0 e O O O • ·,O ,0 0 •·-0 ,,.,e O t.O .o. ,0 D .0 69

LITERATURECITED ••oo•ooo••••o•••oooe•ooo 76 LIST OF ILLUSTRATIONS

Page Am.eiva undulata parva. Dorsal view of skull. ( 6o2X) o o ., o .. • • o 0 0 0 O O e O O O O O O O O O O O 31 Ameiva undulata parva .. Ventral view of skull. (6.,2X) o o o • • • • .. ooooooo•oooooqooo 32 Am.eivaundulata parva. Lateral view of skullo (6 ..2X) 0 0 0 0 0 0 0 • • o o o o • o o o o e o o o o o o 33

Cnemidophorus, ~ septentrionalis. Dorsal view

of skull., (8.,4X) ...... 0 0 0 0 0 0 o 0 0 Figo 5. Cnemidophorus tifis septentrionalis. Ventral view of skull., (8.4X • ., • o .. ., ..... ••00000 • 0 35 Cnemidophorus tiris septentrionalis. Lateral view of skull. ( 8 o4X • • ., ., ., ., • • • ., 0000000 0 0 '.36 Figo 7. .Ameiva undulata parvao Lower Jaw., Ao Lateral view. B. Medial view. C. Dorsal view. (4.9X) o .. ., •• o o • 37 Cnemidophorus tigris septentrionalis. Lower Jaw., A. Lateral view. B., Medial view .. c. Dorsal View., ( 7 0 .5X) 0 0 0 0 0 0 0 0 0 " 0 • • 0 0 0 • • 0 0 0 0 0 0 O 38

Fig., 9 .. Ameiva u.ndulata. parvao Teeth. A. Maxillary teeth 0 (7.0X). B. Dentary teeth. (5.8X). Cnemidophorus tigris septentrionalis c. Maxillary teeth., (lloOX)o D. Denta.ry teeth. (9.7X). E. Pterygoid teeth. (20X). o 39 Fig., 10. Ameiva undulata parva. Musculature dorsal viewo Superficial depth., B. First depth .. (2.,9X) ... & 0 0 0 .58 Fig. lL Ameiva undulata parva., Musculature dorsal view. Second depth. B.. Third depth. (2.9X) ., ., ••• ct O O 0 59 Fig. 12 .. Ameiva undulata parva.., Musculature dorsal view. A. Fourth depth. B. Fifth depth .. (2.9X) ••• o •• 0 0 0 60

Fig. lJ., Ameiva undulata parva.. Musculature ventral view., A.,

Superficial depth. B. First depth. (2.9X) • ., .. 0 0 0 61

Fig" 14., Ameiva undula.ta parva. Musculature ventral view 0 Second depth. B. Third depth. (2.9X) o ., o • o ., • • • 62 Figo 150 Ameiva undulata pa.rva. Musculature ventral view. Ao Fourth deptho B0 Fifth depth. (2.9X) 0 0 0 0 0 0 0 63 Fig. 16. Ameiva undula ta parva. Musculature lateral view. First

depth. (2. 9X) o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 64 Fig. 17. Ameiva undulata pa.rv)o Musculature lateral view-o Second depth. {2.9X 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 65 Fig. 18. Ameiva undulata parv;• Musculature lateral view. Fourth depth. (2.9X 0 0 • 0 0 0 0 • 0 0 0 0 0 0 0 0 0 66 Fig. 19. Ameiva undulata parv). Musculature lateral view. Fourth depth. (2.9X 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 67 Fig. 20. Ameiva undulata pa.)a. Musculature lateral view.

Fifth depth 0 {2.9X o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 68 ACKNOWLEDGEMENTS

I wish to extend my deepest gratitude to Dro Wilmer Wo Tanner 9

as my major professor 9 and to Dro Bertrand Fo Harrison, professor of

Bota.ny9 for their suggestions and encouragements. I also express my gratitude to Dro Lee Fo Braithwaite of the Department of Zoology and Entomology for his guidance in preparation of the illustrations necessary for this thesiso

Appreciation also goes to the Department of Zoology and Entomology for a teaching assistantship which provided me with much needed experience and financial support during my tenure in graduate schoolo The specimens used in preparation of this thesis were accessioned in the vertebrate natural history museum collections of the Brigham Young Universityo I also extend my thanks to Dr. Robert To Swenson and the X=ray technologists of the Utah Valley Hospital for the excellent radio= graphs of wrist elements ma.de for use in this reporto

To my wife also 9 I express my gratitude for her patience and understa.ndingo

vi INTRODUCTION

There has long been a need for a comparative study of the osteological and myological structures of the reptilian family Teiidaeo This present study is organized to increase our understanding of the anatomical features of the head and thorax regions of two members of distinct phylogenetic branches of the family Teiidaeo The two genera discussed are Cnemidophorus and Ameivao Although the entire family is in need of a comparative study,

these two genera were chosen because they are, according to Burt (193lb) 9 closely allied and also because a number of study specimens were avail= ableo The study is limited to the head and thorax regions inasmuch as this area, according to Patten (1951), seems to be the most plastic region of the body as far as adaptive radiation is concerned and thus is of special significance to the study of the phylogenetic development of genera within a familyo Studies dealing with taxonomy, physiology, ecology and general anatomy of the two genera have been :ma.deby various workers. Those reports which are pertinent to this study are cited below. An extensive taxonomic study of the genus Cnemidophorus was :ma.de by Burt (1931b) with complete synonomy of the various species and subspecies to that dateo A revision of the genus Ameiva was completed by Barbour and Noble (1915). Smith and Laufe (1946) in their summary of the Mexican lizards of the genus Ameiva dealt with the taxonomy of that genuso It will not be necessary, therefore, to give a detailed 2

account in this report of the taxonomy which has been completed to dateo We can thus confine ourselves more to the comparative anatomical aspects

of the two generao

The family Teiidae was established by Gray (1827==Philoso Mago 9 sero 2, vo. 2, p. 55)o Today, the family consists of ~bout ~O genera (Smith and Taylor, 1950). The genus Ameiva (of the family Teiidae) was ti'· established by Meyer (1795-..Synopsis reptilium., •• sistema gener'Ulll~

methodum o .. ., pp. 27) with the genotype being Lacerta americana Seba= Ameiva ameiva (Linnaeus). There are 13 species with about 28 subspecies in the genus (Smith and Taylor, 1950)0 The genus Cnemidophorus was established by Wagler (1830--,?Jatiirliches System der Amphibian ••• ,

p. 1.54).. The genotype is Seps murinus Laurenti.. There are about 18 species of Cnemidophorus with about 47 subspecies (Smith and Taylor, 1950). Since 1950 a few new species and subspecies in each genus have been described ..

Ameiva undulata parva was established by Barbour and Noble (1915, p., 476-477). The type is MCZ5831 with Van Patten as the collector., The

type locality is Guatemala., This was later restricted by Smith and

Laufe (1946) to Mazatenango. The range is on the pacific slopes from the Isthmus of Tehuantepec in Oaxaca to Costa Rica.

Cnemidophorus tigris septentrionalis was established by Burger

(1950, Po 8)., The type is CNHM38217. The type locality is Una0 Garfield County, Colorado. The range is the Colorado Plateau (Maslin, 1959b) including the northern half of Arizona, the northwestern quarter of New Mexico, the southeastern half of Utah, and the southern quarter of Colorado (Burger, 1950).

A synopsis of the genus Cnemidophorus was first completed by E., Do Cope (1892b) wherein he made a most memorable statement to all individuals who further attempt to resolve the phylogenetic relationships with the genuso He considered the discrimination of the species within the genus Cnemidophorus the most difficult problem in herpetologyo

A later work by Burt (1931) using ecology, scutation, and distribution has helped much in unravelling the problems of the phylogenetic relationships within the genus Cnemidophorus. Other large and compre- hensive works on groups within the genus Cnemidophorus have been recently completed. These include a report by Zweifel (1959) on the distribution

and variation of the sacki group, a report by Duellman and Wellman (1960) 0 a systematic study of the de;gpei group, and a report by Duellman and Zweifel (1962) which is a systematic study of the se:xlineatus group. These works were all done using an analysis of characters.such as scutellation, coloration, dorsal patterns, size, and distribution. The systematic relationships of the genus Ameiva have also been determined. Barbour and Noble (1915) published an extensive work on the genus. A phylogeny of the group is determined and a des~ription of the species and subspecies is includedo The relationships of the Ameiva undulata group were determined by Stuart (1942)., This work includes a diagnosis of each species a..s well as a key to the species based. on determination by scutellationo

A SU1JU11aryof the Mexican species of the genus Ameiva wa,published by Smith and Laufe (1946). Their report is informative and extensive. It includes a historical summary, an analysis of characters by means of scutellation, a phylogeny, a key to the Mexican Ameiva, and an account of the'subspecies. Some of the factors relating to behavior and evolution have also been reportedo A thorough study for its time by Gadow (1906) on evolution 4 was based on the Mexican species of Cnemidophorus. His report helps us to realize the great variety possible in a genus which has evolved in a land filled with the diversity of bionomic conditions found in Mexico.

Other studies include those by Broom (1925), Maslin (1959a, 1961 9 1966) 9 Zweifel (1962), Beargie and McCoy (1965), Pennock (1965), Light (1966), Lowe and Goldberg (1966), McCoy (1966) and Taylor and Medica (1966). Much of the literature available on the family Teiidae deals with old and new collecting localities and taxonomy. Some such papers are those by Grey (1825), Boulanger (1884, 1899), Nopcsa (1928), Burt (1929, 1931a, 1931c), Beebe (1945), Smith and Burger (1949), Burger

(1950) 0 Smith and Taylor (1950), Maslin, Beld.ma.nand Lowe (1958),

Maslin (1959b, 1963), Peters (1964), Zweifel (1965), Da~1ington, (1966) 0 and Stebbins (1966). The family Teiidae has not been overlooked as fossils. rhey are reported in studies such as those of Brattstrom (1954), Etheridge (1960),

Gehlbach (1965) 0 and Romer (1966) • . There are a number of anatomical works which are of importance

to those working in herpetology in the areas of osteology and ll\YOlogy0 These include the works of Boulanger (1891), Cope (1892a), Howes (1902), Bradley (1903), Broom (1903), Huntington (1903), Kinsley (1905), Kesteven (1919), Camp (1923), Reese (1923), Romer (1924), Sinitsin,(1928), Edgeworth (1931), Broom (1935), Davis (1936), Howell (1936), Gnanamuthu (1937), Dubois (1942, 1943), George (1948), Tanner (1952),' Adams (1953), Poglayen=Neuwall (1954), Snyder (1954), Oelrich (1956), Romer (1956),

Hofer (1960), Jollie (1960), Robinson and Tanner (1962), Avery and Tanner ' (1964), and Romer (1964, 1966). Although most of the anatomical works mentioned above do not deal to any;extent with the family Teiidae, there are some which are of speeia: 5 importance to a. study of this family. Camp (1923) compares anatomically the families of reptiles and emphasized the genus Tupinambis as a member of the family Teiidae. Two other works of osteological import for Tupinambis are those by Reese (1923) and Hofer (1960)0 To date, only one work has been published on the complete osteology of Cnemidophorus and that was done on £,. sexlineatus and £,. gularis by Dubois (1943L No osteological report on Ameiva of any extent has been done to dateo The myology of the family Teiidae has been studied only to a limited extent. Camp (1923) included work done on Tupinam.bis and Poglayen...Neuwall (1954) included work on Tupinambis with a few references to deep skull musculature of Ameiva. A more thorough study of the myology of Cnemidophorus or Ameiva has not been determined to date.

The position of the family Teiidae is unique in its phylogeny amon@ the other saurianso This was observed by Stokely (1950) in his.report on the occurence of an intermediWll in certain lizards. He found the intermediWll present in several species of Cnemidophorus, but absent in Ameiva ameiva praesigniso Camp (1923) considered the presence of this wrist bone an indication of an older position in phylogenyo The apparent differences within the family Teiidae on this structure warranted a more detailed investigationo The purpose of this paper, therefore, is to present a report on the anterior osteology and myology of a subspecies of the genus Ameiva and relate it to a member of its closely allied genus Cnemidophorus. With this comparative report, it ms.y then be possible to develop a method of determining the possible phylogenetic ·relationships between

Cnemidophorus and Am.eiva within the family Teiidae 9 MATERIALS /L!fil METHODS

9..n~!!E;doRhor!!§_tigris septentri2n~ Burger and Ameiva undula.ta parva Barbour and Noble are the principal subspecies used in this studyo

In the body of the text they will be designated as£. • .!:,o septentrionm

!ill, and!_., ~" JZ!rva respectivelyo Spe,::-:,.mensof Cnemidophorus tigris ll~ Baird and Girard and Cnemidophoru.~ tigris gracilis Baird and Girard were also dissected for comparative purposes.

The specimens of£, • .!:,. septentrionalis were collected from south= eao5tern Utaho Five specimens came from North Wash by Hog Spring (BYU

31903 0 31904, 31905 9 .31906; .31907). Two specimens came from Star Sprir~ (BYU31908, 31909)0 One specimen from Bullfrog Basin (BYU31910).

T'hree :specimens came .from North Wash along highway U95 between Star Spring and Hanksville (BYU319llt 31912, 31913L Nine specimens came

from Snow~s Canyon, Saint George 9 Utah (BYU.31914, .31915, 31916, )1917~ 319189 31919, 319209 31921, 31922). The specimens of f.,o 1• tigris were collected in western Utaho specimens ea.me from the west side of Utah Lake (BYU31923, 31924. 31S2~.

31926, 31927, 31928).. One specimen came from Milford, Utah (BYU319::;9' o The specimens of f.o ,1o gracilis Baird and Girard examined were collected 11 miles ea:st of Bowie, Cochise Co., Arizona (BYU13.555~

The specimens of !,o !!:,o parva used in this report were collected from Finca Tinajas 9 Pan:z.,JS9 Alta Verapaz, Guatemal~ (BYU14389, 14395g 1> 7

The specimens used for X-ray analysis of the wrist elements were the following: g_.i• septentrionalis (BYU31904); £,. t. gracilis (BYU 1360); £,. 1• canus VanDenburgh and Slexin (BYU30159); g_.i• aethiops Cope (BYU30196); £,. i• tigris Baird and Girard (BYU30552); £,. sacki comminus Cope (BYU24017); £,. ~• gu.laris Baird and Girard (BYU12876); ·~~ £,. deppei deppei Wiegmann (BYU22541); g_.g,. lineatissisimus Cope (BYU f:' 24018); .Q.. burti Taylor (BYU31901); £.. hyperythrus hypery;thrus (Cope) rci ·ru--, (BYU21782); c. lemniscatus lemniscatus (Linnaeus) (Bro 22599); A. u. - ...... ;,;;;;,...... - -- ha.rtwegi Smith (BYU22523); !o Y.• sinistra Smith and Laufe (BYU24013) ~

!• Y.• R!;rva (BYU14398); and!,. auberi Cocteau (BYU30326). Radiographs were ta.ken with an X-ray machine using eleven milli= amps at one and one=half seconds with a medium.KVP. X-ray negatives were then enlarged in a slide projector and examined.

All specimens with a BYUnumber are accessioned in the vertebrate natural history museum collections of the Brigham Young University.

Skulls were cleaned by various methods. One specimen of !, 0 y_0 pa.rva (Bro 144.51=~snout-vent length 100 mm.) was skinned and placed in 35% ammoniumhydroxide for two months, boiled for two hours and then cleaned by hand. It was then treated with Chlorox bleach at full strength for 15 minutes with excellent results. Another specimen of!,. Y.• parva (BYU14450-=snout=vent 86 mm.) was skinned. hand cleaned of muscle tissue and then boiled for two hours. The skull was then soaked in Chlorox bleach at full strength for 35 minutes with adequate results obtained. Care must be taken not to leave the skull too long in the bleach as disarticulation occurs after a certain length of time depending on the size and thickness of the skull bones. The preparation of c. t. septentrionalis (BYU31924 and 31926-- 8 snoutmvent length 84 mm.), and£,. ,i. g,;:acilis (BYU13559, 1356l==Snout= vent length 70 and 71 mm. respectively) was accomplished by skinning, hand cleaning the skulls and boiling for two hours. The skulls were then soaked in full strength Chlorox bleach for 15 minutes with adequate results obtained.

Myological studies were made on£,. 1• septentrionalis (BYU31906 9

31907, 31908P 319.0, 31924 0 3192 -~snout-vent length 77, 84, 74, 92 0 84 mm. respectively) and !o Y.• parva (BYU14396, 14444, 1448, 1449, 14453== snout-vent length 111, 108, 91, 75, and 127 mm. respectively). All specimens were carefully skinned and muscles dissected using small pieces of a new razor blade held securely in an x...a.cto knife handle. All specimens studied had been preserved in lo% formalin. All drawings were made on Clearprint "fade outtt paper. The specimens were examined under a 10X=40Xbinocular dissecting scope and then drawn in pencil using a mm. grid eyepiece for exactness. The draw= ings were then enlarged by use of an opaque projector and drawn in ink using a #4 Koh-I=Noor drawing pen. Stippling and line shading methods described by Zweifel (1965) were accomplished using a #0000 Koh-I-Noor drawing pen. Lettering was made with Prestype futura demi 18 and 36 point., Photographs of all work accomplished were made for comparison purposes using an Exa.cta camera with an f22 aperature at 1/25 of a second and a double flash attachment. Expansion rings were used to obtain a

4: 1 rai,ie:i enlargemento Kodak plus...X:ASA 125 pan film wa=5used. OSTEOLOGY

An extensive study of all the skeletal elements of the body is

not the primary purpose of this reporto The discussion, therefore 9 will be limited to the skull, wrist bones, and comparison of the teetho In each case, a full description of two skulls of !o ,l!o pa.rva is given under ea.ch element and listed as "!"o This is followed by only the comparative differences noted in two skulls of £,o !,o septentrionalis under each

11 element and listed as nf. • Two skulls each of£,. 1• tigris and£,. ,1. gracili! were also examined for comparative purposes. If not otherwise stated, items not listed in"£" are essentially the same as those in n~:.8'"

General Description of the Skull

!,. Generally 9 the skull can be considered heavily ossified for members of the family Teiidae having the dorsal surface rather rugose with prominent indentations present indicating positioning of overlying scutellation. There are prominent dorsolateral orbital fenestrae domi= rutting the middle portion of the skullo Posteriorly, two prominent fenes" trae are presentg A posterodorsal supratemporal fenestra and a poster= oventral infratemporal fenestra separated by a temporal arch composed of the fused postorbital=postfrontal and the squamosal boneso Such a condition is termed diapsid and is typical of the condition seen in the fossil ancestors of modern lizards (Romer, 1966). The foramina of the ventral surface anteriorly are those for the vomero=nasal organs of Jacobson followed by the elongate internal nareso 10

The floor of the orbit in the central portion of the skull is opened by the infraorbital foramen. The occipital portion of the skull forms a posterior union for dorsal and ventral segments to enclose the brain. The occipital bones ar highly fused and relatively difficult to differentiate. The brain case is composed of ventral projections of the parietal, anterior projections of the supraoccipital, exoccipital, and the basioccipital. The foramen magnumposterocentrally is bordered by the supraoccipital dor= sally, the ba.sioccipital ventrally and the exoccipitals laterally. The occipital condyle is tripartate and is located on the posterior end of the basioccipital and the medioventral projections of the exoccipital. The large quadrate bones of the posterolateral portion of the ventral surface are loosely attached to the occipital processes and thus appear to allow for greater expansion of the lower jaw. £. Generally, the skull is lighter with a larger portion rela~ tively glabrus on the dorsal surface. There is little indication of indentation for scutellation. The anteromedial border of the orbit is cartilagenous. The occipi.tal portion of the skull is not highly fused and most elements are more easily distinguishable. More specifically, the differences between the two genera will be considered with each of the individual skull elementso

Description of Skull Elements

All elements, for the sake of clarity, will be discussed in alpha= betical ordero Only bones which are paired will be indicated as sucho 11

Basioccipitalo (Figo 2, J. 5, and 6) !_o This bone is partially fused into the occipital complexo It forms the posteroventral border of the foramen magnumand extends anteri~ orly to articulate with the basisphenoido It is bounded laterally by the exoccipitals and forms the floor of the brain case having fused anter=

olaterally with a pair of processes from the basisphenoido Posteriorly 9 a pair of strongly developed basioccipital tuberosities can be seen which extend ventrally and slightly laterally. A slight median ridge extends along the suture line between the basioccipital and the exoccipi=

talso

£0 The bcm.e is very thin on the ventral surf ace and the suture lines between it and the exoccipital are prominent.

Basisphenoido (Fig. 2 0 Jo 5 0 and 6) !• This is the ms.in bone of the floor of the cranium. It is bordered posteriorly by the basioccipital and anteriorly forms a forward projection which proceeds along the base of the brain called the rostral parasphenoid will be considered a separate elemento Ventrally, articula=

tion is with the pterygoid bone by means of two ventral foot shaped basipterygoid processeso Lateral extensions form an irregular suture with the basioccipitals. The dorsomedial portion forms the sella tursica, £,o Relatively little difference is notedo

Ectopterygoido==paired bones (Fig. 1, 2, 3, 4, 5, and 6)

!o Posteriorly 0 it articulates with the anterolateral projection of the pterygoidso A prominent ectopterygoid process is noted as a

ventral projection. Laterally, articulation is with the maxilla, jugal 0

and pterygoids 0 but a complete separation of jugal from the pterygoid or 12

separation of ma.xilla. from the jugal is ma.de. Anteriorly, articulation is with the palatine bones. The medial border forms the lateral margin

of the infraorbital foramen. Dorsally, it forms the posterolateral floor of the orbit. £.. The ectopterygoid process is very pronounced and separation

of the jugal from the pterygoid is complete, thus forming a small anterior border of the infratemporal fenestra.

Epipterygoid.==paired bones (Fig. 3 and 6)

!,. This pilar shaped bone forms the anterolateral wall of the brain case. Articulation is with the pterygoid ventrally by means of

a small depression and dorsally with an anteroventral projection of the

parietal. A prominent lateral ridge is visable for the entire length of

the bone., f. Relatively little difference is noted.

Exoccipital.==paired bones (Fig. 1, 2, 3, 4, 5, and 6) !,. The limits of this bone are difficult to determine as there

has been an extensive amount of fusion. Articulation sutures with the opisthotic were not located. The opisthotic, therefore, has been included

in the description. Jollie (1960) concurred that sutures were not

observable, and Dubois (1943) called a part of this bone the oto=

occipital in Cnemidophorus. An extreme posterior projection of the

exoccipital forms the lateral portion of the occipital condyle. Medially,

it forms the posterolateral wall of the brain caseo A large postero=

lateral pa.raoccipital process extends to articulate with the tabular 9

parietal and quadrateo Ventral to the paraoccipital process a portion

of the membranous labyrinth is housedo The sutures separating the 13 exoccipital from the prootic are not definite, but appear to be along the anterior margin of the paraoccipital process. No young specimens were available in the collection to determine if this is but a function of age. The suture for articulation with the supraoccipital is lightly marked by a posterodorsolateral ridge extending from the foramen magnum anteriorly to the base of the parietal. Several foramina can also be

noted on the posterolateral walls which include the foramen rotundum 9 two small hypoglossal foramina for the twelfth cranial nerve and the posterior border of the foramen ovaliso

£,. Th• paraoccipital process articulates by means of a small cartilagenous projection with the posteromedial portion of the squamosal bone as well as articulating with the tabular, parietal, and quadrateo The suture lines for articulation with both the prootic and the supra= occipital bones are more distinct. The ridges denoting position of the semi=eircular canals are not as definite.

Frontalo (Fig. 1 and 3) A,. The dorsal surface of this bone is very rugose possessing deep indentations for overlying scutellation. The posterior margin is butressed by the parietal and posterolaterally articulation occurs with the anterior projections of the postorbital=postfrontalo The ventral surface is convex medially tending to flatten posteriorly when seen in cross section. When viewed dorsally, the middle portion appears to extend laterally to cover the medial borders of the infraorbital foraminao Laterally, the dorsal Margin of the orbit is formed., In the anterior aspect, three processes are produced of which the middle is the longest and inserts between the two nasal bones. The lateral processes insert between the nasals and the prefrontals., Ventrally, the anterior portion is arched into ventral columns to allow passage for the olfactory tracts. No pineal foramen is present at the posterior margin. £,. The middle portion is much narrower with the entire infraorbital foramina appearing visable in a dorsal view. The ventral portion of the frontal is deeply grooved with prominent anterior arches noted. Of the three anterior processes, the lateral two are slightly longer than the central median process.

Jugal.==p&ired bones (Fig. 1, 2, 3, 4, 5, and 6) !o This is a long curved bone forming the ventrolateral margin of the orbit and the anterior margin of the infratemporal fenestra. Articulation posteriorly is with the ventral surface of the postorbital= postfrontal and ventrally a small projection is sent to articulate with the pterygoid posteriorly and the ectopterygoid anteriorly. The anterior most border articulates with the lacrima.l dorsally and the maxilla ventrally. A small spur is noted on the posterior margin of its ventral surface. £,. Ventrally, articulation is completely with the ectopterygoid and not with a portion of the pterygoido No spur is noted on the posterior margin of the ventral surface.

Lacrimal.==paired bones (Figo 3, 4, and 6) !o Found in the anteroventral portion of the orbit, this bone articu+ates posteriorly with the jugal, ventrally with the ms.xilla and dorsally with the prefrontal. In the anteromedial aspect·the lacrims.l duct is found, but no part of the palatine canal is formed. £. The dorsal most portion of the palatine canal is formed by the lacrima.l. 15

Nasalo=-paired bones (Fig. 1, J, 4, and 6) !o The nasals form the anterodorsal portion of the rostrum and enter the extreme posterior border of the external nareso Posteriorly, separation is by the central process of the frontal. They then meet in the center for a short distance only to be separated anteriorly by the posterior projection of the premaxilla. Posterolaterally, articulation is with the prefrontal being separated from it on the extreme posterior ms.rgin by the lateral process of the frontal. Ventrally the dorsal surface of the nasal canal is formed and the dorsal surface is perfora= ted by several irregular spaced nasal foramina •

.Q. 0 The central union of the two nasals is much longer and the nasal foramina seem to be more regularly placed as well as a large posterior border of the external nares being formed.

Q!,E.8.lpabrae.==p&ired bones (Fig. 1 and J) !,. This is a small triangular ossified bone in the anterodorsal border of the orbit which articulates entirely with the prefrontal. £. Theos palpabrae is not present in an ossified structure.

Palatine.-=paired bones (Fig. 2 and 5) !,. The palatine articulates posteriorly with the pterygoid and anteriorly with the ectopterygoid and maxilla. The anterior most articulation is with the vomer and then a central union is formed be~ neath two strong ridges of the primary palate with the other palatine. A strongly developed depression marks the dorsal and lateral surfaces of the nasal canal and internal nares. The medial border of the palatine canal is also formed.

£,. The anterior medial processes are also joined beneath two 16 strong ridges of the primary pa.late contrary to the findings of Dubois (1943).

Parietal. (Fig .. l, 3, 4, and 6) A,o The parietal is a rugose bone with deep indentations indica=

i ting overlying scutellation and is roughly rectangular in shape. Two large posterior projections form the parietal arch and articulates with the tabular, squamosal, and the paraoccipital processes of the exoccipi= talo Anterolaterally, articulation is with the postorbital-postfrontal and the remainder of the anterior border buttresses the frontalo Large ventrolateral flanges deflect downward to enclose the posterodorsal por= tion of the brain articulating then with the supraoccipital, exoccipital, and the epipterygoid. Ventrally, there is no central ridge, but the posterior central margin contains a deep indentation which may hold a remnant of the synotic tectum. of the chondrocranium.o Q.. A small median ridge is present on the ventral aspect of this bone which :maypartially fill the area of the central fissure of the brain. The dorsal surface is only lightly rugose posteriorly with the anterior portion essentially glabruso

Postorbital=postfronta.lo==pa.ired bones (Fig. l, 2, 3, 4, 5, and 6) !• The postorbital and postfrontal of most saurians appears to have fused i.nto one bone, although there is a very light fusion line marked on the dorsal median surfaceo This bone divides the orbit from the supra.temporal fenestra and also has a posterior projection which forms part of the temporal arch dividing the supratemporal fenestra from the infratemporal fenestra. Dorsally, articulation is anteriorly with the frontal and posteriorly with the parietal. Ventrally, articulation 17 is anteriorly with the jugal and posteriorly with the squamosalo A small flange is observable in the anterior central positiono f,o The postorbital and postfrontal are completely fused with no evidence of suture lineso No small flange is observable in the anterior central positiono

Prefrontalo==p&ired bones (Figo 1. 3, 4, and 6)

A,0 The prefrontal lies anterolateral to the frontal and articu= lates with its posterodorsal surface. Anteromedially, articulation is with the nasals and laterally with the maxillao Posterodorsally, articu= lation is with the os palpabraeo A small posteroventral projection contacts the lacrima.l and ventrally this projection then articulates with the pala.tineo The posterovent~olateral aspect forms a portion of the lacrima.l ducto

~- ~ ~ f,o A small posteroventrolateral projection forms the dorsal portion of the palatine canal. There is no os palpabrae to articulate with the posterodorsal bordero

Premaxillao (Figo 1 9 2, 3, 4, 5, and 6) !o The anterior most bone of the skull, the premaxilla, inserts dorsally between the nasals for some distance posteriorlyo Medially it is quite broad and ventrally articulation is with the vomer and'with the maxilla ventrolaterallyo The dorsolateral margins form the medial border of the external nares and the nasal canalo The ventral surface contains 10 peglike plurodont teetho f,o The posterior projection is for only a short distance between the nasalso On the ventral surface, 8 peglike plurodont teeth are con= tainedo Medially the bone is rather narrow and less massive trui.n in !o Prootic.-=paired bones (Fig. 3 and 6) !,. The position of the prootic is highly complex with most of the suture lines i.ndefinite. Forming part of the posteroventrolateral wall c

the brain case 9 it encloses the area of the anterior semicircular canalo Posteriorly, the anterior border of the fora.men ovalis is formed and anteroventrally a well developed ridge then proceeds to the base of the basipterygoid processo Dorsally articulation anteriorly is with the parietal and posteriorly with the supra.occipital and exoccipitals. Ventrally, the basioccipital posteriorly and the basisphenoid anteriorly are met. The central portion is dominated by a lateral flange anterior to the foramen ovalis. £.. The suture lines are more readily definable, but the posi= tioning of the semi-circular canals is more difficult to determine as the external ridges are less pronounced in the bone.

Pterygoid.==paired bones (Fig. 1, 2, 3, 4, 5, and 6)

!• A i,yn shaped bone on the ventral surface of the skull, the pterygoid articulates posteriorly with the quadrate and anteriorly with the palatine medially and the ectopterygoid laterally. The central portion forms the posterior border of the infraorbital foramen. Ven= trally, articulation is with the basipterygoid process which fits into an oblique groove on the ventral surface. On the dorsal surface directly opposite the basipterygoid process, the epipterygoid articulates in a small depressiono The posteromedial margin is expanded into a knifelike ridge extending horizontally to the posterior endo There are no teeth present on the anteromedial portion. The lateral border, along most of its length, forms the medial edge of the infratemporal fenestra. The rostral parasphenoid rises dorsally between,the pterygoids 19

f. The anteromedial margin contains five pterygoid teeth. (Dubois, 1943, reported three on the pterygoid of fo sexlineatuso) The posteromedial margin is less expanded and the central gap between the two pterygoids is wider at the posterior margins.

Quadrateo==p&ired bones (Fig. 1, 2, 3, 4, 5, and 6) !o The quadrate is found on the posterolateral edge of the skull where it serves for articulation of the skull with the articular of the lower jaw. Loosely connected, articulation on cartilagenous pads thus allows for larger jaw expansion. Medially, articulation is posteriorly with the pterygoid and anteriorly with the squamosal, tabular and para= occipital process of the exoccipital. The lateral border is expanded

into a slightly recurved tympanic crest and the medial border also forms a smaller crest for loose articulation with the prootic. The union of the posterior margins of these two crests forms the seat of the middle

£,. The tympanic crest is not as greatly expanded laterally 9 but it is highly recurved, thus forming an anterior tympanic recess.

Rostral parasphenoid. (Figo 2, J, 5, and 6) A,. This is a long pointed foil=like projection proceeding antero= dorsally from a fused position with the basisphenoid, between the two

pterygoids, and rests beneath the lower surface of the brain 0 The ros= tral parasphenoid is considered a separate element from the basi= sphenoid a~ its identity has been established embryologically, struc= turallyo and paleontologically (Dubois, 1943). £.o Relatively little difference is notedo 20

Septomaxilla. (Fig. 3 and 6) !• The septomaxilla is a thin plate extending from the vomer posterolaterally to the ventral margin of the :maxilla with a small pro= jection extending anteriorly into the nasal canal.

£.o Relatively little difference is noted.

Sguamosal.==paired bones (Fig. 1, 2, 3, 4, .5, and 6) !,. The squamosal is a relatively simple bone which is flared posteriorly to articulate with the parietal, tabular, and loosely with the quadrate. Anteriorly articulation is with the postorbital=postfrontal

It forms the posterior half of the temporal arch separating the supra= temporal fenestra from the infratemporal fenestra. ...c. Relatively little difference is noted • fu!.praoccipital. (Fig. 1 and 4) !• Posteriorly. the supraoccipital forms the dorsal margin of the foramen magnum and anteriorly union is with the parietal. Centrally, a large ridge divides the bone into left and right halves. The lateral sutures with the exoccipital and the prootic are not distinct except for a small ridge which proceeds anterodorsal from the paraoccipital process of the ex~ccipital dividing supraoccipital from prootic. The posterior end of the anterior semi=circular canal and the medial end of the posterior semi=eircular canal enter anterfu~J.y and uniteo

f._o Tha central ridge is not sharp, but the suture lines for the exoccipital and prootic are definableo

r.·, Tabular.==pa~ed bones (Fig. 1, 3, 4, and 6) A_. Posteriorly, the tabular inserts between the squ.amosal, quadrate, paraocc:i.pital process of the exoccipital and the posterior 21 end of the pa.rietalo Anteriorly, a small projection is sent forward along the ventral margin of the parietal arch for a short distanceo

£,o Relatively little difference is notedo

Vomer0 ==paired bones (Figo 2 and 5) A,. Medially, the vomers exist as pa.ired elements of the central anteroventral surface of the skull joining the palatine posteriorly and anteriorly the maxilla and premaxilla on the ventral surface and the septomaxilla on the dorsal surface. Small foramina on the anterolateral edge mark the position of the vomero=nasal organs of Jacobson and con= nect them with the nasal canal. Posterolaterally, the medial border of the nasal canal and external nares is formed. A small medial groove beginning centrally and proceeding posteriorly holds the beginning of what appears to be a cartilagenous support for the rostral parasphenoido

£,o Relatively little difference is noted.

Lower Jaw

!,o The lower jaw is united arteriorly by a mental symphysis and posteriorly articulation is with the quadrate of the skull by means of

a loose connection. Each ramus is composed of six bones: the angular 9 articular, coronoid, dentaryp splenial and supra=angularo The articular makes almost a right angle with the angular and the anterior end of each ramus has a distinct lateral tortion (Figo 7c). The ventral surface is rugoseo The dentary of each ramus bears a single row of plurodont teeth, whereas the remaining bones are edentateo The pre=articular is fused to the articular in the adult and will not be considered in this report as a separate element of the ramuso 22

9.,o The articular and the angular are essentially in a straight lineo No lateral tortion is seen in the anterior end of the ramus

{Figo 8c)o The ventral surface of the ramus is essentially glabruso

Articularo (Figo 7 and 8) !o This is the posterior most bone of the ramuso Fusion with the pre=articular is so complete that separate elements are not detect= able in the adulto The articulating surface for the quadrate on the anterodorsal margin is somewhat fused with the supra=angular so that suture lines are determined only with diffieultyo The retroarticular process of the posterior edge is winglike and extends medially in the horizontal plane. Posteriorlyv articulation is with the supra=8.ngular dorsally and the angular ventrallyo The element then extends forward along the medi.al surf ace to meet the ventromedial surface of the coro= noido There is articulation with the extreme posterior extension of the dentary and also the splenialo The inner aspect forms the posteromedial border of the large mandibular forameno

9.,o The suture line between this bone and the supra=angular is more distincto The retroa.rticular process extends in a ventrally pro= jecting oblique planeo

Coronoido (Figo 7 and 8) !o The coronoid is the central bone of the ram.us articulating posteriorly with the articular medially and the supra=angular laterally and forming posterocentrally the anterior border of the mandibular

forameno Anteriorly, articulation is with the splenial and the dentary 0

On the medial surface, an arch over a small posterior extention of the

dentary is formed as well as a large coronoid process dorsally 0 23

fo The coronoid process is much sharper and possesses a small posteriorly directed hook.

Dentaryo (Figo 7 and 8)

!,. The denta.ry is the tooth-bearing bone and comprises the entire anterior half of each ra.mus. Union is ma.de anteriorly by means of a

:mandibular symphysis with the dentary of the other ramus. Articulation is medially with the splenial, dorsally with the coronoid, posteriorly with the angular and posterodorsally by means of a projection with the supra-angularo A dorsal projection proceeds posteriorly beneath the anterior process of the coronoid and unites under the coronoid arch with the articularo On the dorsal surface, there are 23 to 24 plurodont teeth. Beneath the splenial on the medial surface, the sulcus carti= laginis Meckelii is found with a small Meckel's groove proceeding anterior

to this sulcus to the mandibular symphysis. On the anterolateral surface 0 approximately six irregularly placed mental foramina are locatedo fo The Meckel 1s groove proceeding anterior from the sulcus cartilaginis Mecklii to the mandibular symphysis is more ventrally placed and there are eight fairly evenly spaced mental foramina found along the lateral surfaceo

§;glenial. (Figo 7 and 8) !o The splenial is found entirely on the medial surface of the ramu.s and articulated anteriorly with the dentary along most of its lengtho Posteriorly, articulation proceeding from dorsal to ventral is with the coronoid, articular, and angular. One large foramen and one or perhaps two small splenial foramena are evident. This bone covers the area of the sulcus cartilaginis Meckelii. 24

fo Relatively little difference is noted.

Supra...a.ngular. (Fig. 7 and 8) !• The supra...angular forms the posterolateral wall of the ramus and articulates anteriorly from dorsal to ventral with the coronoid~

dentary 9 and angular. The angular then proceeds along the ventral mar= gin to the posterior end where articulation is with the articular. There are one large and two to six small supra=angul.ar fora.Mina found along the upper half of the boneo The supra=angu.la.r forms the lateral wall of the mandibular foramen. £.. There are only two foramina, one large and one small, located in the supra=angular.

Foramina of the Skull and Lower Jaw

In all cases, the foramina will be considered comparatively in alphabetical order and positioning of margining elements will be from anterior to posterior, from dorsal to ventral, or lateral to medial as the case applies.

Angular fora.men. (Fig. 7 and 8) !o The angular foramen is located entirely within the angular. £,. No difference.

External nares. (Fig. 1, 3, 4, and 6) !,. The external nare is surrounded by the premaxilla, nasal, and maxilla and is found at the anterior end of the rostrum. fo No differenceo 25

Foramen Magnum. (Not figured) !• The fora.men magnum is the posterior most fora.men of the skulL It is bounded by the supraoccipital, exoccipitals, and ba.sioccipital. The lower border forms a tripartite occipital condyle composed of a medial projection from each exoccipita.l and ventrally from a posterior projection of the basioccipital. £. No difference.

Foramen ovalis. (Not figured) !,o The foramen ovalis is formed by the prootic and exoccipital bones and lies anterior to the para.occipital process. £. No difference.

Foramen Rotundu.m. (Not figured)

!,. The fora.men rotundum is formed by the prootic and exoccipital and lies ventral to the foramen ovalis. £. No difference.

Hzyoglossal foramen. (Not figured) !• The hypoglossal foramen is found on the posteroventral side of the skull lateral to the occipital condyles and entirely within the ex:pccipital.

£,. No difference.

Internal Nares. (Fig. 2 and 5) !• The internal nares are in the anteroventral surface of the

skull and are surrounded by the maxilla, palatine, and vomer 0 They form directly posterior to the vomero=nasal organs of Jacobson.

_£,., No differenceo 26

Infraorbital foramen. (Fig. 1, 3, 4, and 6) -!_. The infraorbital foramen is surrounded by the palatine, ectopterygoid, and pterygoid and lie on the anteroventral surface of the skull posterior to the internal nares.

£,. No difference.

Infratemporal fenestrao (Fig. 3 and 6) A,. This is the large fenestra of the posterolateral margin of the skull. The edges are formed by the ju.gal, postorbital-postfrontal, squamosal, pterygoid, and quadrate bones.

£.0 The ectopterygoid enters the anterolateral margin.

Lacrimal foramen. (Not figured) A• The lacrimal foramen is formed from the lacrimal and prefrontal to allow passage of the lacrimal canal.

£,. No differenceo

Mandibular foramen. (Fig. 7 and 8)

!_0 This is the large foramen of the posterodorsal surface of

each ramus 0 It is formed from the coronoid, supra-=-8.ngula.r, and articularo

£0 No difference.

Mental foramina. (Fig. 7 and 8)

!_0 These are six irregularly spaced foramina of the lateral surface of each dentary bone. £.o There are usually eight regularly spaced foramina on each dentary bone.

Nasal foramina. (Fig. 8)

A0 Usually, 0=1 foramen are found in the anterior end of the nasal 27

£.. Usually, l-2 foramina contained in the nasal.

Orbital fenestra. (Fig. 1, 2, 3, 4, 5, and 6) !,. The orbital fenestra is located dorsally in the central position of the skull and is formed by the prefrontal, os palpabrae, frontal, postorbital-postfrontal, lacrimal, and jugal.

£,. No os palpabrae is found on the anteriomedial border.

Palatine canal. (Not figured)

!,. Located ventral to the lacrim.al foramen, this canal is formed by the lacrimal, palatine, maxilla, and pterygoid. A small arch exists internally which appears to belong entirely to the maxilla. (Definite determination necessitates sectioning.) £.. A lateral projection of the prefrontal enters the margin of the canal.

Splenial foramina. (Fig. 7 and 8) !• Located entirely within the splenial there occurs two foramina, one large and one small.

£,. There are three foramina, one large and usually two small, all within the splenial.

Supra=&ngular foramina. (Fig. 7 and 8) !,. There are several foramina found along the dorsal portion of the supra=&.ngular bones. These usually consist of one large and 2-6 small foramina,, £.. There are norm.ally only one large foramen and one small fora= men found in the supra=S.ngular. 28

Supralabial roramina. (Fig. 3 and 6) !• The supralabial foramina consist or approximately six small regularly spaced foramina on the lateral margin or the maxilla positioned directly beneath the supralabial scales. £.. The foramina are usually irregularly spaced and number four or five on each side.

Supratemporal fenestra. (Fig. 1, 2, 4, and 5) !• This is the large posterodorsal fenestra or the skull and is formed by the postorbital-postfrontal, squamosal, parietal and tabular.

£,. No difference.

Vomero=nasal organs -2!, Jacobson foram.ina. (Fig. 2 and 5) A,. The vomero=nasal organs of Jacobson foramina are small, usually three in number, which lie on the anteroventral surface of the skull on each side of the midline. Housed in the vomer and bordered by the maxilla, they serve for olfaction entrants by the tongue to the vomero=nasal organs of Jacobson located within the nasal canal.

£,. No difference.

Teeth

Dentary teeth. (Fig. 9a and 9c) !,. The teeth are of plurodont type with succession occuring throughout life by receiving replacement teeth which project into the base of the hollow, thinwalled old tooth. There are 22~3 teeth with the first 5 containing no accessory cusps. Beginning about tooth 6, there is a small anterior accessory cusp developed. About tooth 9, a posterior accessory cusp develops. Both of these accessory cusps 29 continue posteriorly to the last tooth.

f_o The teeth also number 22-23, but only the first 4 are peglike (without accessory cusps). Beginning with tooth 5, a small anterior accessory cusp develops and at tooth 20, the posterior accessory cusp developso

Maxillary!!!!! Premaxillary teeth. (Fig. 9b and 9d) A,. The teeth of the premaxilla and maxilla are of the same type as those of the dentaryo Only the lateral four of the premaxilla are figuredo The prem.axilla contains 10 peglike teeth. The maxilla contains 18=21 teeth. The first tooth is peglike, but the second (6 in the figure) has an anterior accessory cusp. The third (7 in the figure) contains a posterior accessory cusp and both cusps are retained posteriorly to the last tooth (23 in the figure).

£.0 There are 8 peglike teeth on the premaxillao The first tooth of the maxilla (5 in the figure) contains an anterior accessory cusp and the sixteenth (20 in the figure) develops a posterior accessory cuspo

The last tooth (22 in the figure) may or ma.y not possess the posterior accessory cusp.

Pterygoid teeth. (Fig. 9e)

A,0 There are no pterygoid teeth found.

£,0 There are five small peglike teeth occuring medially in the central portion of the pterygoid.

Wrist

The wrist of most teiids seems to consist of 8 or 9 carpal bones including carples 1=5, a radiale, a proximal central, an ulnare, and an 30

J intermedium which may or may not be present. A discussion of each of i !/ the separate elements is fully described by Avery and Tanner (1964), so •I the discussion will be limited to the highly variable member of the carpel elements for the family Teiidae-=the intermedium. Stokely (1950) indicated that although this bone is highly charac= teristic of the lower tetrapods, particularly the amphibians, extinct reptiles and turtles, its presence is highly variable in several saurian

familieso One of these was the family Teiidaeo He t.found the intermedium absent in Cnemidophorus perplexus, f_o melanostethus, Ameiva ameiva ~esignis, Bachia intermedia, and Ophiognomon abendrothi; but present in Cnemidophorus gularis, f_o h.yperythrus beldingi, and £.. !,o tessel- la tus o This extended the list of Camp (1923) for the family Teiidae which included an intermedium in Tupinambis nigropuncta.tus, Te.jus tejuexin and Ameiva vulgaris. Because of the apparent differences within the genus Ameiva and the genus Cnemidophorus, those specimens of these two genera accessioned in the vertebrate natural history museum collection of the Brigham Young

University were X=rayed and the radiographs carefully studied by means of a slide projector with the following results obtained for the specific individual specimens studied: lo Intermedium. present in£.. sacki c o:mminusO 2,o sacki ajar is O £.o burti, £.. sexlinea tus, !• :g,.. parva, ! 0 :g,0 hartwegi, and !o .Y,osinistra. 2o Intermedium absent in £.0 ! 0 tigris, f_o .t_o septentrionalis, Q,. sexlineatus gul.a.ris, and A,. auberio J. The presence of the intermedium in£.. io gracilis, Q.. io canus, Q.. ,i. aethiops 1

Q.o sacki exsanguis. Q.. deppei deppei, 12,o£• lineatissisimus, £.0 hyperythrus merythrus and£.. lemniscatus lemniscatus is questionable. Fig. 1. Ameiva undulata parva. Dorsal view of skull. (6.2X)

Skull Bones QU. ===== Quadrate RPS. ==== Rostral Parasphenoid BO. ===== Basioccipital s. ======Squamosal BS. ===== Basisphenoid SM.====- Septomaxilla EC. ===== Ec:topterygoid VO. ===== Vomer EO. ====- Exoceipital EP. ===== Epipterygoid· FR. ==-=- Frontal Foramina of the Skull JU. ===== Jugal LA. ===== Lacrimal EXN. ==== External nares M. ====""- Maxilla;:,~ .. IN. ==--= Internal nares N. ======Na.sa.l IOF. =-== Infraorbital foramen OSP. ==== Os Palpabrae ITF. __ Infratemporal fenestra PAL. -=== Palatine NF. ===== Nasal foramen PAR. ==== Parietal OR. ===== Orbital fenestra PF. ===== Prefrontal SLF. ===- Supralabial foramen PM. ===== Premaxilla STF. ==== Supratemporal fenestra PO.=POF.= Postorbital=postfrontal VOJ. ===- Vomero=nasal organs of PR. =•~=== Prootic Jacobson foramen PT. ===== Pterygoid 31

------PM. ------SM ...... E X N • ------N. ------M.

------PF.

------OSP.

PAL. I OF. EC. JU. FR. PT. OR. PO.-POF. STF. PAR.

-QU. s. EO. soc. T. Fig 0 2 0 Ameiva undulata parvao Ventral view of skullo (6o2X)

Skull Bones QU. ===== Quadrate RPS. ==== Rostral parasphenoid BO. ===== Basioccipital s. ======Squamosal BS. ===== Basisphenoid SM» ===== Septomaxilla EC. ===== E9tpptecygoid VO. ..,====Vomer EO. ===== Exoccipital EP. ===== Epipterygoid FR. ===== Frontal Foramina of the Skull JU. ===== Jugal LA. ===== Lacrimal EXN. -=== External nares M. -===== Maxilla• IN. -=--= Internal nares N. ====~- Nasal IOF. =--= Infraorbital foramen OSP. ==== Os Palpabrae ITF. -=== Infratemporal fenestra PAL. =-== Palatine NF. =-=-= Nasal foramen PAR. ==== Parietal OR. -""=== Orbital fenestra PF. ==-== Prefrontal SLF. ==== Supralabial foramen PM. ===== Premaxilla STF. ==== Supratemporal fenestra PO.=POF.- Postorbital=postfrontal VOJ. ==== Vomero=nasal organs of PR. ===== Prootic Jacobson foramen PT. ----- Pterygoid 32

PM.

------M. ········--·--··········--·----············VOJ.

IN.

PAL.

IOF. EC. OR. JU. RPS. PT.

PAR. PO.- POF. STF. BS. -----S. --au. BO.

EO. Fig. 3. Ameiva undulata parva. Lateral view of skull. (6.2X)

Skull Bones QU. -==== Quadrate RPS. --== Rostral parasphenoid BO. ===== Basioccipital S. -====- Squamosal BS. ===== Basisphenoid SM.===== Septo:maxilla EC. ===== Ectopterygoid VO. ===-= V omer EO. ===== Exoccipital EP. ===== Epipterygoid FR. ===== Frontal Foramina of the Skull JU. ===== Juga.l LA. ===== Lacrimal EXN. ==== External nares M. ======Maxilla IN. ===-= Internal nares N. ======Nasal IOF. -=-- Infra.orbital fora.men OSP. ==== Os Palpabrae ITF. --== Infra.temporal fenestra PAL. ==== Palatine NF. -==== Nasal fora.men PAR. ==== Parietal OR. ===== Orbital fenestra PF. ===== Prefrontal SLF. ==== Supralabial foramen PM. ===== Premaxilla STF. ==== Supratemporal fenestra PO.=POF.= Postorbital=postfrontal VOJ. ==== Vomero-nasal organs of PR. ===== Prootic Jacobson fora.men PT. ===== Pterygoid .33

PM. EXN. SM. N.

M. SLF. PF.

OSP. LA.

FR. JU. EC. OR. ITF. RPS. PO.-POF. PT. E P. BS. PR. QU...... -.,., ------s . ------PAR. ------EO. ------T. ------BO. Figo 4o Cnemidophorus tigris septentrionalis. Dorsal view of skull.

Skull Bones QU. ===-- Quadrate RPS. =--= Rostral parasphenoid BO. ===== Basioccipital S. -===== Squamosal BS. ===== Basisphenoid SM. ===== Septoma.xilla EC. ===== Ectopterygoid VO. ===== Vomer · EO. ===== Exoccipital EP. ===== Epipterygoid FR. ===== Frontal F oramina of the Skull JU. -==== Jugal LA. ===== Lacrimal EXN. ==== External nares M. ======Maxilla IN. --=-=Internal nares N. ======Nasal IOF. -=--Infraorbital fora.men OSP., =-=- 0~ Palpabrae ITF. ---- Infratemporal fenestra PAL. ==== P~latine NF. --==-Nasal foramen PAR. ==== Parietal OR. -==== Orbital fenestra PF. ===== Prefrontal SLF. ==== Supralabial foramen PM. ===== Prem.axilla STF. ===- Supratemporal fenestra PO.=POF.= Postorbital=postfrontal VOJ. ==== Vomero-nasal organs of PR. -==== Prootic Jacobson f oramen PT. ===== Pterygoid ------PM.

------SM. EXN. ------M ...... NF. N.

------PF.

FR. LA. EC. PAL. Ju. IOF. PT. OR. PO.-POF.

PAR. STF. QU. s. soc. EO. T. Figo 5. Cnemidophorus tigris septentrionalis. Ventral view of skull.

Skull Bones QU. ---=-Quad.rate RPS.--== Rostral parasphenoid BO. ===== Basioccipita.l S. =-===- Squamosal BS. ===== Basisphenoid SM. ===== Septoms.xilla EC. ===== Ectopterygoid VO. --=== Vomer EO. ===== Exoccipital EP. ===== Epipterygoid FR. ====- Frontal Foramina of the Skull JU. ===== Jugal LA. ===-= Lacrima.l EXN. ==== External nares M. ======Maxilla IN. -=-== Internal nares N. ======Nasal IOF. -=== Infraorbital foramen OSP. ==== Os Palpabrae ITF. ==== Infratemporal fenestra PAL. ==== Palatine NF.====- Nasal foramen PAR. ==== Parietal OR. ==--= Orbital fenestra PF. ===== Prefrontal SLF. ===- Supralabial foramen PM. ===== Premaxilla STF. ===- Supratemporal fenestra PO.=POF.= Postorbita.l=postfrontal VOJ. ==== Vomero-nasal organs of PR. ===== Prootic Jacobson foramen PT. ===== Pterygoid 35

· ------PM.

----PO.- POF. ----PAR. ··················STF. ----- BS. -----5. ---QU. ---- BO.

---- EO. Fig 0 6. Cnemidophorus tigris septentrionalis. Lateral view of skull.

Skull Bones QU. ===-=--Quadrate RPS. ==== Rostral parasphenoid BO. ===-= Basioccipita.l S. -====- Squamosal BS. ===== Basisphenoid SM~ ==== Septomaxilla EC. ===== Ectopterygoid VO. ===="" Vomer EO. ==~=- Exoccipital EP. ==-== Epipterygoid FR. ===== Frontal Foramina of the Skull JU. ===== Jugal LA. ==~== Lacrim.al EXN. ==== External nares M. ======Maxilla IN. ====- Internal nares N. ===-== Nasal IOF. ---- Infraorbital foramen OSP. ==== Os Palpabrae ITF. -=== Infratemporal fenestra PAL. ==== Palatine NF. --=== Nasal foramen PAR. -=== Parietal OR. ===== Orbital fenestra PF. ===== Prefrontal SLF'o ==== Supralabial foramen PM. ===== Premaxilla STF. ==== Supratemporal fenestra PO.=POF.=Postorbital=postfrontal VOJ. ==== Vomero-nasal organs of PR. ===== Prootic Jacobson foramen PT. ===== Pterygoid J6

PM. EXN. SM. SLF. M.

PF. LA. OR. Ju. FR. -- EC. IT F. RPS -- PT. PO.-POF. BS. E p. s. PR. QU. PAR. EO. T.

BO. Figo 7o Ameiva undulata P8:I"!!,o Lower Jawo (4.9X) Ao Lateral viewo

Bo Medial view o

C. Dorsal view o

Lower Jaw Bones Foramina of the Lower Jaw A. ======Angular AF. =----Angular foramen AR. ===== Articular MAF. -=== Mandibular foramen CP. ===== Coronoid MF. ----=Mental foramen D. ======Dentary SAF. ---=Supra-angular foramen SA. ===== Supra=11ngular SF. -==== Splenial foramen SP. ===== Splenial 37

AR. I SAF. I I

A MF.

MAF. SA. I co. I I I I I I I I I

I I B I I I SP. A. AF. SF.

AR. I I I

C MAf. SF. Fig. 8. Cnemidophorus tigris septentrionalis. Lower Jaw. (7 • .5X) A. Lateral view. B. Medial view.

Lower Jaw Bones Foramina of the Lower Jaw A.======Angular AF.====~ Angular foramen AR.===== Articular MAF.-=== Mandibular foramen CP. ===== Coronoid MF. -=-== Mental foramen SA.===== Supra=angula.r SF. ----=Splenia.l foramen Do======Dentary SAF. ==== Supra....angular fora.men SP. ===== Splenial 38

SA. SAF. I I I I I . .- ··<<::ii I I I I I A I A. MF. D.

SA. I co. I I MAF. I I I I I I I I I

I I I I I I I I AR. A. SP. B SF. AF.

SA. co. I I I I I I I

C MAF. Figo 9o Ameiva undulata parvao Teeth. A. Dentary teeth. (?.OX) B. Maxiallary and Premaxillary teeth. (5.BX) Cnemidophorus tigris septentrionalis. Teeth. C. Dentary teeth. (11.0X)

D. Maxillary and Premaxillary teeth., (9.?X) E. Pterygoid teeth. (20.0X) 39

24 !1Jl A

~ .. ,. C ~

s 1 ,,.---~ E MYOLOGY

The determination of muscles and the naming of them aocording to priority nomenclature is difficult in the reptiles because of extreme variability as well as a lack of homologous histories. For the most part, names were chosen which were of the oldest origin as long as the muscle fit the general description of the original authoro Where this was not possible, descriptive terminology for naming was appliedo The deep skull musculature is not described here as PoglayenoaoNeuwall(19.54) has a very detailed account of greater accuracy than was possible with th technique used in this reporto These muscles include the levator bulbi dorsalis, levator bulbi ventralis, levator pterygoidei, protractor ptery~ goidei, pseudotemporalis profundus, and pseudotemporalis superficialis

(Abbo lC and 9B)o Muscles are named in alphabetical order rather than by groupings into body areas in order to facilitate cross=reference with the figureso

Comparative descriptions will be listed the same as in the osteology section with n!o 11 indicating the five specimens of Ameiva undulata erva observed and "£,011 representing the six specimens of Cnemidophorus tigris septentrionalis observedo

l{0 Adductor Mandibulae Externis Mediuso (Figo 10, 16, and 17) Poglayen=

Neuwall (l954).

!o The fibers of this muscle originate from the medial surface of the squamosal, the posterolateral parietal projection, the dorsolateral beveled surface of the parietal, and from the anterior and dorsal surface 41

of the quadrate. The fibers extend anteroventrally with the dorsal ones more anteriorly directed. The insertion is along the dorsomedial sur= face of the supra...angular and the posterior surface of the coronoid. The body of the muscle fills the supratemporal fenestra and lies immediately medial to the adductor mandibularis externus superficialis and dorsolateral to the adductor mandibularis externus profundus from which it is

only faintly separable. £.. Little difference is noted.

!:!_•. Adductor Mandibulae Externis Profundus. (Fig. 17 and 18) Poglayen= Neuwall (19.54). !• The muscle originates from almost the entire posteromedial border of the posterolateral projection of the parietal, from the para= occipital process of the exoccipital and from the dorsolateral surface of the posterior process of the prootic. The muscle then turns ventrally to enter the infratemporal fenestra and insert on the posterior ,surface of the coronoid. The muscle mass is not clearly separable from the adductor mandibularis externus medius in the dorsolateral positiono 2.,o Little difference is noted.

H,. Adductor M.andibularis Externus Superficialis. (Fig. 10, 16, 17) P oglayen=Neuwa.11 ( 19 .54) • A,. The origin is from the ventral surfaces of the postorbital= postfrontal, squamosal, a portion of the jugal and from the dorsal and anterior surface of the typmanic crest. The fibers of the muscle then extend anteroventrally to insert along the depressed lateral surface of the supra=angular with the more anterior fibers inserting on th$ lateral and posterolateral surfaces of the coronoid and the lateral surface of 42

the angular 0 The body of the muscle fills the greater portion of the infratemporal fenestra with the medial portion scarcely distinguishable from the adductor mandibulae externus medius. £.. Little difference is noted.

!i• Adductor Ma.ndibulae Posterior. (Fig. 17 and 18) Poglayen-Neuwall

(19.54). :A,. Some of the fibers of this muscle arise from the lateral and medial surfaces of an aponeurosis which extends along the medial crest of the quadrate whereas the other fibers originate from the posterior pro~ cess of the prootic. The fibers all pass anteroventrally and insert on the dorsal surface of the articular. The body of the muscle is thin and lies lateral to the typ:manic cavity and medial to the mandible and the adductor mandibul.aris externus.

£,. Little difference is noted.

!1_0 Biceps Brachii. (Fig. 10, 11, 13, 14, 16, 17, and 18) Howell (1936). !• The fibers of this muscle arise near the proximal head of the humerus on the posterior edge of the scapulae, form a long, broad tendon, and pass along the ventral surface of the humerus to insert on the proxi= ma.l head of the ulna.

£,G Little difference is noted.

~. Ceratohyoideus. (Fig. 12 and 15) Gnanamuthu (1937). !o This is a thin muscle which proceeds between ceratobranchial land ceratobranchial 2o Dorsally, it contacts the oral membrane and lies dorsal to the byoglossus. c. Little difference is noted. 43

!!_0 Cervicomandibularis. (Fig. 10 and 13) Camp (1923). !• The fibers of this muscle extend from the :middorsal fascia to the midventral raphe proceeding posterior to the external auditory meatus and superficial to the pterygomandibularis and the majority of throat

muscles 0 It lies just deep to the skin and posteriorly, the muscle is separated from the constrictor colli by a narrow area of aponeurosis lacking muscle fiberso £0 The division between the cervicomandibularis and the constric= tor colli dorsally is less dictinct with an anteroventral extension pro= ceeding almost to the center of the dentary which covers most of the geniohyoid and some of the mylohyoideus complex.

Ii• Constrictor Colli. (Fig. 10 and 13) Camp (1923) o !o The muscle is the most superficial of the cervical tne thorax region arising from the superficial dorsolateral fascia of the neck and passing ventrally to insert on the extensive ventral raphe. It is deep only to the connective tissue of the skin and a few scattered fat padso It is superficial to the depressor mandibulae and the sternocleido= mastoid dorsally and ventrally it overlies the sternohyoideus, m. omohyoideus and a portion of them. deltoideuso £,. The extent of the constrictor colli is more difficult to

determine dorsally as it is somewhat fused with the cervicomandibularis 0

!o Coracohwneralis. (Fig. 13 and 14) Howell (1936). A,. This is a short muscle arising from the anterior margin of the scapulae slightly dorsal to the biceps brachii and inserting mostly under cover of the deltoideus and the pectoralis on the proximal end of the humerus. 44

f,o Little difference is noted.

!!• Deltoideus. (Fig. 10, 13, 14, 16, and 17) Howell (1936). !,. The origin of the deltoideus is at the inner margin of the ventral two=thirds of the clavicle with fibers fusing at the insertion with those of the dorsalis scapulae and attaching upon the lateral portioi of the proximal end of the humerus •

. £,o Little difference is noted.

!!,. Depressor Mandibulae. {Fig. 10, 16, and 18) Poglayen=Neuwall (19.54). !,. The depressor mandibulae originates on the "1.ddorsal fascia in the area of the cervicle vertebrae 1-5 and inserts on the posterior end of the retroarticular process of the articular. The body of the muscle lies on the lateral surface of the cervicle region and borders the auditory meatus anteriorly and in this area is superficial to some of the posterior fibers of the adductor mandibularis externus medius and

posterior border of the tympanum. Posteriorly, it passes superficial to

the anterior fibers of the trapezius and the sternocleidomastoideus 0 The cervicomandibula.ris and constrictor colli overlie most of the body of the muscle. £. Little difference is noted.

!!,. Dorsalis Scapulaeo (Fig. 10, 11, 16 0 17, and 18) Howell (1936) 0 !,o The dorsalis scapulae originates along an oblique line ex~ tending from a point near the dorsocaudal portion of the suprascapula to the clavicle. Here origin is both from the dorsal portion of the clavicli and the dorsal margin of the girdle. The insertion is fused with those of the deltoid and attachment is upon the lateral portion of the proximal end of the humerus. The body of the muscle is deep to the trapezius 45 and superficial to the serratus ventralis complex and the proscapul= ohumeralis. A part of the origin is covered by the latissimus dorsio

f_o Little difference is noted.

!!,0 Geniohyoideus. (Fig. 13, 16, and 18) Camp (1923). !,. The origin of the geniohyoideus is along the anterior margin of ceratobrancial 2 of the hyoid apparatus and inserting in five slips along the medial surface of the dentary. The medial edge is continuous with most of the processes etoglossus. The body of the muscle is super= ficial to the mandibulohyoideus complex, a greater portion of the ventral furface of the pterygoma.ndibularis, the styloglossus and hyoglossuso It

is deep to the mylohyoi.deus complex and the cervieomandibularis 0 Q.. The insertion is by three slips with the anterior portion continuously in contact with the posterior one=third of the processes etoglossus.

!!0 !Lumerotriceps Lateralis. (Fig. 10, ll, 13, 14, 16, and 17) Howell (1936)0

!,. A muscle of the laterocentral surface of the humerus, the humerotriceps lateralis has its origin on the head of the humerus with fibers running distally to insert on the olecranon process of the ulna. £0 No difference is noted.

,M.Humerotriceps Medialiso (Not figured) Howell (1936). A,. This is a muscle of the mediocentral surface of the humerus with its origin of the medial side of the humeral head and extending along the entire sha.ft of the humerus to insert on the olecranon process of the ulna. 46

£,. No difference is noted.

!1• Hyoglossus. (Fig. ll. 12. 14, 15. 17. 19) Oelrich (1956). !. The hyoglossus originates on the posterior portion of the ceratobrachial 2 of the hyoid apparatus and forms the body of the tongue.

It is a thick broad muscle lying lateral to the ceratobrachial 2 and medial to the mandibulohyoideus III and the pterygomandibularis and is deep to the ma.ndibulohyoideus I and II, the styloglossus and the genio= hyoideus. It is superficial to the ceratohyoideus and the esophagus.

C0 Little difference is noted.

!!,. Iliocostalis. (Fig. 12. 15, 18, 19, and 20) George (1948). !,. The iliocostalis takes a multiple origin from the ilium and facia of the longissimus with some insertion on the anterior ribs. The anterior insertions, however, are on the atlas vertebra and the occi= pital region of the skull. The body of the muscle lies ventrolateral to the longissimu.s and dorsal to the longis colli. £,. Little difference is noted.

!1• Intercostalis Externis. (Fig. 11, 12, 14, 15, 17, 18, and 19) (Smith (1960). !• !• The fibers of the intercostalis externis originate on the ribs and extend posteriorly to insert on the next posterior rib. It is deep to the obliquus abdominus externus, the serratus complex and the levator scapulae complexo It is superficial to the intercostalis internis and transversus thoracis. £.o Little difference is noted.

!!o Intercostalis Internis. (Fig. 12. 15. 19. and 20) Smith (1960) 0 47

!• The origin of the intereostalis externis is on the ribs with the fibers extending ventrally and slightly anteriorly to insert on the next anterior rib or the sternal portion of the same rib. It is deep to the intercostalis externis and superficial to the transversus thoracis.

£,. Little difference is noted.

!,1. Laryw:o (Fig. 15 and 20) Smith (1960). A,. Muscles of the larynx are small and complex with complete dis"' section difficult with the technique used in this report. They are here considered as one group of muscles surrounding the laryngeal cartilages. Homologies within the vertebrates need to be determined before the individual muscles of the larynx will be of significance. £,. Little difference is notedo

,!i0 Latissimus dorsi. (Fig. 10 and 16) Howell (1936). !,. The 1atiS$im.us dorsi originates in the thorax region of the middorsal fascia with its anterior fibers running posteroventrally and its posterior ones anteroventrally to insert near the origin of the scapulotriceps of the brachium onto the proximal end of the humerus.. It is a sheetlike muscle which covers an extensive portion of the lateral body surface having anterodorsal fibers deep to the trapez;us.while the remaining ones are deep only to the skino It is superficial to the

serratus ventralis superficialis and a portion of the dorsalis scapulae 0

Q,o Little difference is noted.

!,1. Leva.tor Sca}?Ulae Profundus. (Fig. ll, 14, 16, 17, and 18) Howell

(1936). !o This muscle originates from the transverse process of the atlas and inserts on the ventral one-third of the anterior border of the 48 suprascapulaeo It is a ventral partner to the levator scapulae super= ficialis and lies in approximately the same position with relation to the surrounding muscleso £,o Little difference is noted.

H,o Levator Scapulae Superficialiso (Figo 10, 11, 14, 16, 17, and 18)

Howell (1936) o !o The muscle originates by means of a tendon in coll'lillonto the levator scapulae profundus from the diapophysis of the atlas extending posterodorsally to insert on the dorsal two-thirds of the anterior border of the suprascapulaeo It is a broad, fan-shaped muscle which lies dor= sal to the levator scapulae profundus and superficial to the axial musculature and the posterodorsal fibers of the iliocosta.liso The body muscle is deep to the constrictor colli, the trapezius and the posterior ,("_• portion of the depressor mandibulae. ,.~ , '\.' £,. LitUe difference is notedo

1 H,0 Longis Colli. (Figo 15, 19, and 20) Smith (1960). !o This is the most ventral of the deep neck muscles originating on the centra of the first thoracic vertebrae and inserting on the lower

portion of the centra of each of the cervicle vertebrae 0 £,o Little difference is noted.

M. Longissimus. (Fig. 11, 12, 17, 18, 19, and 20) George (1948). !• The longissimus originates from the ilium, sacrum, and the neural arches proceeding anteriorly to insert on part of the neural

1It is to be noted that the terminology of this muscle has not been determined in the literature. The name of a similarly placed mammale ian muscle is temporarily adopted until complete homologies can be determinedo 49 arches of the anterior vertebrae and on pa.rt of the skull at the junction between the parietal, supraoccipital, and a small portion of the para= occipital process of the exoccipital. £,. Little difference is noted. t!o Mandibulohyoideus lo (Figo 14) Oelrich (1956). !o This is a slightly triangular muscle originating on the central portion of the dentary and extending two=thirds the length of the ramus to insert on the ceratohyalo It lies medial to the mandibulohyoideus II extending deep to the cervicomandibularis and superficial to the stylo=

glossus, hyoglossus, and mandibulohyoideus III. £. Little difference is noted.

!• Mandibulohyoideus g. (Fig. 14) Oelrich (1956)0 !o This is a short pointed muscle which originates on a posterior portion of the dentary and inserts on the anterior portion of the cera= tohyal. It lies lateral to the mandibulohyoideus I and medial to the mandibulohyoideus III running deep to the cervicomandibularis and super= ficial to the tongue, styloglossus and the hyoglossus. The body of the muscle is approximately the same width as the mandibulohyoideus I. £.. The muscle is much reduced in width to about one=half that of the mandibulohyoideus Io

!o Mandibulonyoideus illo (Fig. 14) Oelrich (1956)0 !• This is a fairly flat sheet of muscle originating on the posterior most portion of the dentary and a small portion of the angular with insertion on the ceratobranchial 1. It runs almost parallel to the mandibular ramus across the mass of the pterygomandibularis and more or less attached to it by connective tissueso The body of the muscle is 50

deep to the mandibulohyoideus and geniohyoideus, but is superficial to

the styloglossus, hyoglossus and ceratohyoideus at its posterior endo £0 Little difference is noted.

!:10Mylohyoideus Anterior. (Fig. 13) Camp (1923). !• The mylohyoideus anterior is a small strip of muscle extending anterilaterally on the ventral surface of the throat originating on the midventral raphe and inserting between the genioglossus and the genio=

hyoid onto the medial surface of the dentary. g_. This is the most prominent portion of the mylohyoideus and makes a definite division between the genioglossus and the geniohyoid.

M.Mylohyoideus Posterior. (Fig. 13) Camp (1923) !,. The mylohyoideus posterior or~ginates on the midventral raphe

just posterior to the mylohyoideus anterior and immediately breaks into

9 separate divisions (4 prominent and 5 minor) which insert by inter= digitation with slips of the geniohyoideus. The most posterior of the divisions is partially covered by the cervicomandibularis. f. The muscle has only 5 divisions (3 major and 2 minor) and these are rather small and indistinct.

M,. Obliguus Abdominus Externus. (Fig. 1, 14, 16, and 17) George (1948). !• The origin of this muscle is by separate heads from aponeurotic tendons of the lateral and posterior surfaces of the second through eighth

ribs near their dorsal articulations. The fibers then extend postero= ventrally to insert along the lateral border of the abdominal musculature. The muscles of the abdominal region are highly fused to the ventral

scutellation and thus difficult to separate. The body of the muscle is a thin, extensive sheet which covers most of the lateral surface of 51 the body and is deep only to the trapezius and the latissimus dorsi. £.. Little difference is noted.

!:[. Omohyoideus. (Fig. 13, 14, 16, and 17) Gnanamuthu (1937). !• This is a thick muscle of the ventrolateral surface of the neck having its origin on the anterior border of the scapula and then proceeding anteroventrally to insert on the proximal end of the basi= hyal and along ceratobranchial 2. It is deep to the posterior portion of the cervicomandibularis and the anterior portion of the constrictor colli and is superficial to the anterior portion of the sternothyroideus and a small portion of the esophagus.

£,. The muscle is much broader covering the sternohyoideus to a spot midway between the hyoid apparatus and the sternum.

!:[. Pectoralis. (Fig. 13) Camp (1923). !• The pectoralis is an extensive superficial muscle of the sternal region originating from the inner angle of the clavicle, the interclavicle, the sternum and the m.idventral raphe to insert on the proximal end of the humerus. It is superficial to the sternum, some of the sternal ribs and the coracoid and is deep only to the s~in of the chest region. £,. Little difference is noted.

!• Proscapu.lohumeralis. (Fig. 12, 15, and 19) Howell (1936). !• The proscapulohumeralis originates on the anteroventral margin of the scapula with fibers proceeding ventrally which immediately join those of the coracohumeralis of the same layero Toward the insertion the latter muscle passes over a small ligament while the former passes beneath it to insert upon the humerus between the medial and ateral .52 heads of the hwnerotriceps. It lies superficial to the sternocoracoideus superior and deep to the deltoideus. £,o Little difference is noted.

!!o Pterygomandibulariso (Fig. 10, 11, 13, 14, 16, 17 and 18) Oelrich (19.56)0 !,o This is the largest muscle of the lateral surface of the skull originating on the pterygoid along the margin of the infraorbital foramen by means of a large tendon to the ectopterygoid processo The fibers extend posteriorly and then posterodorsally to cover the ventral and lateral surfaces of the angular and supra...a.ngular then continue posterior= ly along the condyle of the quadrate and insert to the angular process of the articularo It is deep to the cervicomandibularis dorsally and the m.andibu.lohyoideus III ventrally and lies superficial to the esophaguso

f.,o The muscle is not as bulky, but otherwise little difference is noted.

!!• Scapu.lotricepso (Figo 11, 13, 14, 16, 17, and 18) Howell (1936)0 !,. The origin of the scapu.lotriceps is on the scapula near the glenoi.d fossao The fibers then loop around the insertion of the latis= simus dorsi and proceed distally to insert on the olecranon process of ) the ulna. f.,o Little difference is notedo

A J:!_.Serratus Dorsalis. (Fig. 11, 12, 18, and 19) Howell (1936). !,o This muscle consists of three ribbonlike slips of muscle which partially overlap one another in such a way that they appear serra= tuslike from the dorsal view when the suprascapula is pried away from the lizard's body (as in Fig. llB). It arises by fasiculae from the lateral 53

surfaces of the three cervical ribs and then passes slightly dorso= laterally to insert separately, but slightly overlapping one another, along the medial surface of the suprascapula near its dorsal bordero Al= though the muscle is partially continuous with the serratus ventralis

complex, it lies medial and somewhat dorsal to the ventral slipso Q,o Little difference is noted.

!1,0 Serratus Ventralis !• (Fig. 11) Howell (1936). !o The serratus ventralis I originates centrally slightly be= neath the serratus dorsalis on the first two ribs and inserts on the

anteromedial border of the scapula. The body of the muscle is deep to the subscapularis and superficial to the intercostalis externus. Q.o Little difference is noted.

M,. Serratus Ventralis II. (Fig. 11 and 18) Howell (1936). ,l. This muscle originates immediately ventral to the last slip of the serratus dorsalis and its origin is centrally on the postero= medial portion of the scapula and is immediately ventrolateral to the serratus ventralis I. Q.. Little difference is notedo

!• Serratus Ventralis Superficialis. (Figo 10, 14, and 17) Howell (1936). !o The muscl& originates by means of several slips from the first two ribs then proceeds anterodorsally to insert on the posterior border of the scapulaeo The body of the muscle is deep to the latissimus dorsi

and superficial to serratus ventralis I and II as well as intercos= talis externis. £.. Little difference is notedo 1,ioSpinalis Capituso (Fig. 11, 12, 17, 18, and 19) George (1948)0 ~. This is the large anterior back muscle whose origin is in commor. wj.th the cervicis longus of the back and inserts on the posterior margin qf the parietalo It is deep only to the middorsal fascia and the dorsal portion of the cervicoma.ndibularis and is superficial to the longissi= mus, iliocos~lis and longis collio 9.,o Little difference is noted.

1,ioSternocleidomastoideus. (Figo 11, 13, 14, 16, and 17) Howell (1936). !,o Sometimes called the episternocleidomastoid (Robinson and

Tanner, 1962), it is a thick, ribbonlike muscle obliquly crossing the lateral surface of the cervicle region originating by a superficial apneurosis from the posterior cranial region along the extreme posterio= lateral margin of the parietal and the parietal process and inserting along the dorsal margin of the clavicle with a small slip attaching to the anterior portion of the sternum. Anterodorsally, it is deep to the depressor mandibularis, otherwise, it lies superficial to the sterno= thyroideus, levator scapulae profundus and superficialis, and the deep back musculature. £. Little difference is noted. g. Sternocoracoideus Inferior. (Fig. 11, 12, 14, 15, 17, 18; and 19) Howell (1936). A,. This is a somewhat confusing muscle which arises from the ventral surface of the sternll.Pl and proceeds anterior over the end of the clavicle and inserts on the ventral coracoid end of the scapulae thus covering the clavicle almost entirely. f,o Little difference is noted. 55 I~ !o Sternocoracoideus Superior. (Fig. t:S"and 20) Howell (1936). !• The sternocoracoideus superior is an internal sternal muscle originating from most of the dorsal surface of that element and inserting by a broad thin tendon to the ventral portion of the scapula appearing to insert on the clavicle. £.. Little difference is noted.

!• .§.ternohyoideus. (Fig. 13 and 14) Ca:mp(1923). !• The sternohyoideus is a relatively broad flat muscle of the ventral surface of the neck region. It originates on the sternum and inserts to portions of the basihyal and anterior section of cerato= brachial 2. It lies medial to the omohyoideus anteriorly and the sternocleidomastoideus posteriorly. It is deep to the posterior portion of the cervicomandibularis and anterior portion of the constrictor colli and lies superficial to the esophagus. £,. Little difference is noted.

!• Sternothyroideus. (Fig. 14, 17, and 18) C~mp (1923). !,. This is a large flat muscle extending along the ventrolateral side of the neck originating in a sheet from the anterior portion of the sternum and inserting along most of the posterior length of cerato= brachial 2. The body of the muscle lies deep to the sternocleidomas= toideus and the posterior portion of the omohyoideus. It is superficial to the esophagus. £.. Little difference is noted.

!• Styloglossus. (Fig. 11, 13, 14, and 17) Smith (1960). !• Although the exact extent of this muscle is somewhat ques= tionable because of the fascia on its posterodorsal surface, it appears 56

to originate by means of a thin sheet of fascia from the posterior region

of the cranium and quadrate inserting on the mandibular symphysis of the dentarieso It covers the hyoglossus and forms a small part of the basal sheath which covers the posterior margin of the tongueo

£,o The origin appears almost tendinous posterodorsally and antero=

ventrally no basal sheath for the tongue is contributedo

M,oSubscapularis. (Not figured) Howell (1936)0 !,o The subscapularis arises from the base of the medial side of the suprascapula and adjoining portion of the scapula with its fibers converging to a tendinous insertion upon the retractor process of the

humerus. It is deep only to the scapula, but is superficial to the

serratus ventralis complex as well as a portion of the serratus dorsalis 0 £,. Little difference is noted.

Supralabial Ligament. (Fig. 16) New Nameo !• This is a strong superficial ligament of the lateral surface extending beneath the supralabial scales of the skin from the rostral area to insert on the anteroventral margin of the quadrate. It is deep only to the fascia of the skin and is superficial to the pterygomandi= bularis.

£,. Little difference is notedo

!!o Transversus Thoracis. (Figo 19 and 20) Smith (1960)0

!o In contact with the peritoneal membrane internally 0 the trans= versus thoracis arises by means of fascia from the pelvis to the neck region and lies, for the most part, between the second thoracic vertebra and the humeruso Its fibers extend almost vertically and insert on the

inner surfaces of the thoracic ribs, the lateral border of the sternwn 9 57 and the dorsal surface of the abdominal musculature. It is deep to all of the thoracic musculature. £. Little difference is noted.

~. Trapezius (Fig. 10 and 16) Howell (1936). !• This is an extensive, superficial muscle located on the dorsolateral surface of the cervical and thoracic regions. It is the most superficial muscle of the area with the exception of the depressor mandi= bularis and the constrictor colli originating on the m:iddorsal raphe in the area of the lower cervicals and inserting on the crest of the anterior margin of the suprascapula, the superficial fascia along the clavicle and the anterior margin of the pectoralis to the origin of the sterno= cleidoma.stoideus. This muscle varies greatly in thickness throughout its extent. Posteriorly, it is considerab)J developed, this being the major part to insert on the suprascapu.lao However, anteriorly, it comes to be only one muscle fiber in thickness. The body of the muscle is super= ficial to the levator scapulae superficialis and profundus as well as the dorsal portion of the dorsalis scapulae.

£,. Little difference is noted. Figo lOo Am.eiva undulata Qarvao Musculature dorsal viewo (2o 9X)

Ao Superficial deptho

Bo First deptho 58

A B

OBL. ABDOMINUS EXT. ------IJ------INTERCOSTALIS EXT. Figo llo Ameiva undulata parvao Musculature dorsal view. (2. 9X)

Ao Second depth.

Bo Third depth. 59

A B

LEV. SCAPULAE PRO. ------,"1'/:;i,i, LEV. SCAPULAE SUPER.------11,~ DELTOIDEUS------,'fff/ DORSALIS SCAPULAE --.------1111,

------SERRATUSDORSALIS

SERRATUSVENT. II

SERRATUS VENT. SUPER.----

OBL. ABDOMINUS EXT. ----- Figo 120 Ameiva undulata parva. Musculature dorsal viewo (2o9X)

Ao Fourth deptho

Bo Fifth depth. 60

HYOGLOSSUS------

STERNOCORACOID.INF.------

PROSCAPULOHUMERALIS--- Figo 130 .A.meiva undulata. parva.o Musculature ventral view. (2. 9X)

A~ Superficial depth.

B. First depth. 61

A B

MYLOHYOIDEUSPOST,

CERVICOMAND.

PECTORALIS Fig .. 14.. Ameiva undulata parva. Musculature ventral view. (2. 9X)

A~ Second depth.

B. Third depth. 62

A B

MAND, HYOIDEUS Ill

LEV. SCAPULAE SUPER.------i

LEV. SCAPULAE PRO.------,!! STERNOCORACOID. INF.------,~~

SCAPULOTRI. Figo 150 Ameiva u.ndulata parva. Musculature ventral view. (2.9X) Ao Fourth depth.

Bo Fifth depth,. 63

A B

M. ESOPHAGUS------#+llli4llclitl!-I

ILIOCOSTALIS------lllllli!!llnll 1------LONGIS COLLI

STERNOCORACOID.INF. Figo 160 Ameiya undn]ata parya.. Musculature lateral view. (2. 9X) First deptho 64

!:s:ii~------ADD. MAND. EXT. MED. +-,e,1,--~;;;,,+~~e'l.\------SUPRALABIAL LIG.

DEPRESSORMAND.

GENIOHYOID ------.....\\

~r,i~~f------LEV, SCAPULAE SUPER,

STERNOCLEIDOMAST, ------l ~w,l~~~~~------LEV, SCAPULAE PROF. OMOHYOID------

~~~~~ll,:,o:o-,:?>....,,?=-,.....,,.;:i.------DORSALIS SCAPULAE

-...__.... .,.....------TRAPEZIUS

DELTOIDEUS------

BICEPS ------i'.Ul1

HUMEROTRICEPSLAT. ___ --11,w,...;::..,'- F'ig. 17. Amei va. undula. ta. parva.. Musculature lateral view. ( 2. 9X) Second depth. "'·

ADD. MAND. POST.

PTERYGOMAND. STYLOGLOSSUS

HYOGLOSSUS STERNOTHYROIDEUS OMOHYOIDEUS SPINALIS CAPITUS STERNOCLEIDOMAST. LONGISSIMUS STERNOCORACOID. INF.

LEV. SCAPULAE PRO, LEV.SCAPULAE SUPER. DELTOIDEUS

DORSALIS SCAPULAE

BICEPS

HUMEROTRICEPS LAT.

SERRATUS VENT SUPER.

SCAPULOTRI.

OBL. ABDOMINUS EXT. INTERCOSTALIS EXT. Figo 180 Am.eiva undulata pp.rvao Musculature lateral view. (2.9X) Third depth. 66

f,• .. .,

.+,,.+.+++++------SPINALISCAPITUS

GINIOHYOIDIUl------""11 l,ljl,14-i-!4,~-+++++++41------LONGISSIMUS

STERNOTHYIOIDIUS------lt'f7'»1/.o~M'i'1'1 ~~e+-+-++++t+t-H-H+------ILOCOSTALIS

M. ESOPHAGUS------,

STHNOCORACOID,INF,------

DOISALIS SCA,ULAE Fig. 19. Ameiva undulata parva. Musculature lateral view. (2.9X)

Fourth depth. ,··.,

M. ESOPHAGUS------,lttl!tttH1ttttttl

r-H1t1:------SPINALIS CAPITUS

~tnttttt+t-t+iffir------ILIOCOSTALIS HYOGLOSSUS,------. LONGIS COLLI

TRACHEA------, ~~r+t++-ttttl'"------LONGISSIMUS

PROSCAPULOHUERALIS Fig. 20. Ameiva undulata parva. Musculature lateral view. (2.9X)

Fifth depth. 68 DISCUSSION

Attempts at phylogenetic determinations of reptiles have beer. directed in three areas: 1. the fossil record, 2. the geographic dj bution, and 3. the comparative morphology of living genera (Camp, lS The third area has been the rqain focus of attention in this report. determination of phylogeny can be determined only by careful examina of all the various aspects, so no complete phylogenetic relationshiI be undertaken in this studyo Howes (1902) discussed the idea that c parative morphology is the basis of working classification. He furt noted that comparisons should be first made on close and nearly rela forms, passing later to larger groups. Comparisons were, therefore, restricted to Cnemidophorus and Ameiva. The ~anus Cnem.idophorus bej a probable offshoot of Ameiva as explained by Barbour and Noble (191 as well as Burt (19Jlb). Camp (1923) in his classification of the lizards listed 34 d1 ent paleolithic characters which contribute to phylogeny determined means of comparative morphology. Although some of these characters little significance on the family level, those which are of importa~ phylogeny of the genera discussed in this report include in the orde significance listed by Campi 1. fusion of median skull elements, 2. postor9ita.l=postfrontal, 3. the lacry:mal, 4. mandibular teeth, 5. pa tine teeth, 6. the throat musculature, 7. the lower jaw, 8. the os intermedium, 9. the epipterygoid, and 10. the shoulder musculature. are not all of the significant characters of phylogeny which have be ~ 7( discussed in such texts as those by Smith (1960) and Romer (1964), but the list may lend an index to phylogentic studies. For the purpose of order, those elements of variation determined by osteological comparisons will be discussed first followed by the varis tions encountered in myological comparisons. Both of these should help determine phylogenetic relationships to a greater extent than one of theE aloneo As pointed out by Nopcsa (1928), the osteological characters alone are insufficient to enable us to distinguish all of the Teiidae from all of the Iguanidae, for example, and it is probable that the reve1 is also trueo

Osteology. Elements of the skull and lower jaw (as indicated in fig. 1=8) show considerable variation between the members of the two genera des= cribedo Considerable variation is noted in the general appearance of the skull and lower jaw. In A,. y_. parva, the skull can be considered heavily ossified with a rugose dorsal surface. Deep indications of indentation for scutellation are evident and an os palpabrae is evident in the anteromedial border of the orbit. In the lower jaw, there is a slight lateral tortion of each ramus, the articular and angular are at almost right angles to each other, and the ventral surface of the dentarj is rather I'IU.gose. In£.. 1• septentrionalis, the skull is comparatively lighter with a relatively glabrus dorsal surface. There is little in= dication of indentation for scutellation and the anteromedial border of the orbit is cartilagenous. In the lower jaw, there is no lateral tor= tion, the articular and angular essentially form a straight line, and the ventral surface, of the dentary is relatively glabrus. 71

Further references to variation of the separate elements is noted in the general description. Elements discussed where a difference is noted include the basioccipital, ectopterygoid, exoccipital, frontal, jugal, lacrimal, maxilla, nasal, os palpabrae, palatine, parietal, post= orbital-postfrontal, prefrontal, premaxilla, prootic, pterygoid, quadrate, supraoccipital, and most of the elements of the lower jaw except the splenialo The most unstable element of osteological import appears to be the intermedium. of the wrist. Romer (1956) points out that fusion and some= times complete loss of some wrist bones is commonin lizards. With the methods used in this report, an element as minute as the intermediw,r is difficult to locate on small specimens and may account for its absence in some of the species and subspecies observed. Possession of this element ma.y indicate primitiveness, but this is questionable because of its vari= ation even between subspecies. The degree of ossification of this struc=

ture and other carpals is probably a function of age of the individual 0 It is recognized that a need for using larger series in most of the specie is necessary for a complete study; however, the data presented seem sig= nificant in that all of the heiva undulata group examined appear to possess the element while it is seemingly absent in the Cnemidophorus tigris group examined.

Teetho

The teeth of A,. B.• pa.rva and£,. 1• septentrionalis show some simi= larity of shape and relative size, but they differ considerably in the positioning and numbering of cusps on specific teeth. Perhaps the greatest difference noted was in the absence of pterygoid teeth in the

!,o B,o J?!rv&o Camp (1923) pointed out that the presence of these teeth 72 may be of paleolithic significance, but he hastened to add that the ab= sence of such teeth may or may not be of significance owing to the likeli hood of dropping out or the migration and development of cutaneous tooth buds from one bone to another in the course of recent phylogenyo Age is also exhibited by tooth structure of both genera as the older specimens have some of the posterior accessory cusps well worn or reduced to small swelli.ngs. Several of the teeth will also be missing, broken, or bent.

&ology. The problems of myological research are at times rather complex. Huntington (1903), Camp (1923), Romer (1956) and Smith (1960) indicate the musculature of major groups such as orders and classes is rather plastic and variable and are, thus, rather difficult to interpret. At the family level, however, myology appears to be of significantly stable character to be of phylogene~ic use. Tanner (1952) working with Mexican and Central American groups of the family Plethodontidae indicated that the musculature is consistent enough to define genera. This conclusion has been further supported by Wake (1966) on the osteology of the pletho= dontid salamanders and by work in reptilian myology by Robinson and Tanna:

(1962, Avery and Tanner (1964), and by Jenkins and Tanner (1968)0 The two genera of the family Teiidae ex.a.mined in this report seem to support this conclusion. Of the forty~nine muscles dissected in!.•:!!• parva and compared to £,o 1• septentrionalis, only six differed significantly betwee1 the two genera as far as configuration, origin, insertion, or size was concerned. Because of the relative stability of the myology within these two genera, this could perhaps be used as a tool for interpretation of phylogenies and variationso 73

The greatest myological variation appears to be centered around the anterior segment of the ventral musculature. In!, • .!!• parva, the mylohyoideus complex interdigitates frequently with the geniohyoideus by

9 separate bundles, whereas, in£,. 1• septentrionalis, this complex inter. digitates in only 5 bundles of rather simple structure. Camp (1923) seem! to feel that the variation in this musculature is a good indicator of primitiveness. He pointed out for variation above the family level a primitive saurian condition is represented by a number of eight or more interdigitation bundles of these two muscle groups. Other myological variations for A,.!!.• pa.rva include a distinct division of the cervicomandibularis with the constrictor colli, a mandi= bulohyoideus II which is the same width as the mandibulohyoideus I, and an omohyoideus which is rather narrow and located ventrolaterally in the neck region. In£. 1• septentrionalis, there is a dorsal fusion of the cervicomandibularis with the constrictor colli, the mandibulohyoideus II is only one-half the width of the mandibulohyoideus I, and the omo= hyoideus is relatively broad extending ventrally to the midcentral region of the neck.

The differences in configuration of these muscles may indicate that the variability is not suited for phylogenic comparisons between these two genera, or they ma.y indicate and support the distinction of the two genera. at perhaps a sub=fa.mily level. Further study of the entire family would be necessary before complete conclusions could be reached. CONCLUSIONSAND SUMMARY

Those anterior osteological elements of the skull, lower jaw, and wrist along with the anterior :myological characters discussed and

figured in this repor~ suggest that!, • .!!• pa.rva and£,. 1o septantrio= n!,_lis are members of distinct groups which can be differentiated by internal morphologic characters. Though comparisons were restricted to highly geographically separated individuals of the same family, their general body form and structure appear to be similar.

A great number of anatomical structures are shared in coinmon, but these two genera differed in the following anterior osteological and myological elements as indicated in the descriptions and discussion:

1 0 general skull appearance; 2o skull elements consisting of the basi=

occipital, ectopterygoid, exoccipital, frontal, jugal, lacrima.1 0 maxilla, nasal, os palpabrae, palatine, parietal, postorbital=postfrontal, pre=

frontal, prema.xilla 0 prootic, pterygoid, quadrate and supraoccipital;

)o the lower jaw elements consisting of the anj;Ular, articular, coronoid 0 dentary, and supra.""8.ngular; 4. the foramina of the skull and lower jaw consisting of the infratemporal fenestra, mental foramina, nasal foramina, palatine canal, splenial foramina, supra"'8.ngular fora.Mina, and the supra= labial foramina; 5o the teeth of the maxilla, dentary, and pterygoid; 60 the intermedium wrist element; and 7. the MUsculature of them. cervi= comandibularis, mo constrictor colli, m. mandipulohyoideus II, mo mylo=

hyoideus anterior, me :mylohyoideus posterior, and them. omohyoideus 0

An intermedium was found to be present in the ma.nus of C0 sacki

comminus, £,o sacki gularis, £,. burti, 9.,o sexlinea tus, !_. :!!,opa.rva, !, 0 75

.:!!ohartwegi, and A,• .:!!• sinistra. Its presence was either absent or ques= tionable in£.. 1• tigris, £. i• septentrionalis, f.q 1• gracilis, £. i• canus, £. i• aethiops, £. sexlinea.tus gµlaris. £. ~ exsanguis~ g_. deppei deppei, £. deppei lineatissisimus, g_.hyperythrus hyper;ythrus 0 g_. lemniscatus lemniscatus, and !o auberi. In comparing those anatomical structures observed which seem to be of paleolithic significance, the previous conclusions by Barbour and Noble (1915) and Burt (1931b) based upon external morphology seem to support their conclusion that!, • .:!!• parva. appears to be more primitive than£. i• septentrionalis. The presence of pterygoid teeth in the latter subspecies and their absence in the former presents a perplexing problem which cannot be solved by our present understanding of their signifi= cance to phylogenies of genera. LITERATURECITED

Adams, WoEo 19.530 The carotid arch in lizards with particular refer= ence to the origin of the internal carotid artery. Journal of Morphology, 92:115-1550 Avery, Do F. and W. WoTannero 19640 The osteology and m;rology of the head and thorax regions of the obesus group of the genus Sauro= ,!!!;l.us Dumeril (Iguanidae). Brigham Young University Science Bulletin, Biological series, 5(3):1-30. Barbour, To and Go Ko Noble. 19150 A revision of the lizards of the genus Ameiva. Cambridge Mass. Bulletin of the Museum of Compara= tive Zoology, 59(6):417=479.

Beargie, K0 and Co J. McCoy. 1964. Variation and relationships of the teiid lizard Cnemidophorus angusticeps. Cqpeia, 1964 (3)~561- 570.

Beebe, W0 1945. Field notes on the lizards of Kartobo British Guyana and Caripito Venezuela. III Teiidae. Zoologica, New York, 30:7=31.

Bogert, C0 M. 1949. Thermoregulation in reptiles, a factor in evolution. Evolution, 3(3):195=211. Boulanger, G. A. 1884. Synopsis of the families of existing lacer= tilia. Annual Magazine of Natural History, Ser. 5, 14(80): 117=122. (reprint of the Ohio Herpetological Society, 1966~ 86=112). -==-=• 1891. Notes on the Osteology of Heloderma horridu.m and!!, suspectum, with remarks on the systematic position of Heloderma= tidae and on the vertebrae of the lacertilia. Proceedings of the Zoological Society of London, 1891:109=1180

=====o 18990 Description of a new lizard of the genus Ameiva from Equador. Proceedings of the Zoological Society of London, 1899: 5170 Bradley, Oo C. 19030 The muscles of mastication and the movements of the skull in lacertiliao Biologisohe Jahrbticher~=a.btheilung ftir Anatomie u.nd Ontogenie der Thiere, 18:475=488. Brattstrom, Bo H. 19540 Amphibians and reptiles from Gypsum Cave, Nevada. Bulletin Southern California Academy of Sciences, .53 (1)~8=12o 77

Broom, R0 19030 On the development of the pterygoquadrate arch in lacertiliao Journal of Anatomy and Physiologie Normal and Patho= logical, 17(2):107-111. ==---• 1925. On the origin of lizards. Proceedings of the Zoological Society of London, 1925(1):1=16.

-====• 1935. On the structure of the temporal region in lizard skullso Annals of the Transvaal Museum, 18:13-22. Burger, W. Lo 1950. New, revived, and reallocated names of the North American whipta.iled lizards, genus Cnemidophorus. Chicago .Academy of Science Natural History Misc., #65:1-9.

Burt, C0 E. 1929. The genus of teiid lizards, Verticaria Cope, 1869, considered as a synonym of Cnemidophorus Wagler, 1830, with a key to the primitive genera of the teiidaeo Proceedings of the Bio= logical Society of Washington, 42:153-156.

1931a. The status of the spotted race 00 runner, Cnemidophorus sexlineatus gula.ris (Baird and Girard). Proceedings of the Biological Society of Washington, 44:73=78.

1931b. A study of the teiid lizards of the genus Cnemidophorus with special reference to their phylogenetic relationships. Bulle= tin of the United States National Museum, 1.54:1....280. 1931c. South American lizards in the collection of the .American Museum of Natural History. Bulletin of the .American Museum of Natural History, New York, 61:227~395.

Camp0 C. Lo 1923. Classification of the lizards. Bulletin of the American Museum of Natural History 48(11):289=4810

Cope, Eo Do 1892ao On the homologies of the posterior cranial arches in the reptiliao Transactions of the .American Philosophical Society, 27:ll=26o

1892bo A synopsis of the species of the teiid genus Cnemido=

phoruso Transa.ctions of the American Philosophical Society 0 27: 27=.52. Darlington, Po Jo Jr. 19660 Zoogeography: The Geographical Distribu= tion of .Animals. Wiley and Sons, New York. Po 1-36, 177=235, 411...6160

Davis, Do Do l9J6. The terminology of reptilian musculature. Herpe= tologica, 1:12=17. Dubois, E. Po 19430 Technique for sectioning small skulls. Copeia, 1942(1):55=.56 ..

=====o 19430 Osteology of the skull of Cnemidophoruso .American Mid= land Na.turalist, 30(2):,510=517. 78

Duellman, W. Eo and J. Wellman. 1960. A systematic study of the lizards of the deppei group (genus Cnemidophorus) in Mexico and Guatemala. Misc. Publications of the Museum of Zoology, Univ. of Michigan, #lll:1-80.

DuelJ..ma.n,W. E. and R. G. Zweifel. 1962. A synopsis of the lizards of the sexlineatus group (genus Cnemidophorus). Bulletin of the American Museum of Natural History, 123(3):158=210. Edgeworth, F. H. 1931. On the muscles used in shutting and opening the mouth. Proceedings of the zoological Society of London, 1931: 817=818. Etheridge, R. 1960. Additional notes on the Cragin Quarry fauna. · Papers of the Michigan Academy of Science, Arts~ and Letters, 45:113=117.

Gadow9 Ho 1906. A contribution to the study of evolution based upon the Mexican species of Cnemidophorus. Proceedings of the Zoologi= cal Society of London, 1906(1):277=375. Gehlbach, F. R. 1965. Amphibians and reptiles from the pliocene and pleistocene of North America; A cronological summary and selected bibliography. Texas Journal of Science, 17(1): 56=70. George, J. c. 1948. The muscular system of Uromastix hardwickii (Gray). Journal of the University of Bombay, 17(3):1=23.

Gnanamuthu0 c. P. 1937. Comparative study of the hyoid and tongue of some typical genera of reptiles. Proceedings of the Zoological Society of London, Ser. B., 107:1=63. Goin, c. Jo and O. Bo Goin, 19620 Introduction to Herpetology. Freeman and Company, San Franciscoo p. l-lJ9 37-85, 107=199, 26J=286p 319-325 .. Gray, J.E .. 1825 .. A synopsis of the genera of reptiles and amphibia, with a description of some new species .. Annals of Philosophy, Ser. 2, 10:193-217. (Reprint by the Ohio Herpetological Society, 1966)0

Hofer 9 H. 19600 Vergleichende untersuchungen am Schldel von Tupi= nambis und Varanus mit besonderer Berftcksicktigung ihrer Kinetik. Gegenbaurs Jahrbuch, 100:706=746 ..

Howell, Ao B. 1936. Morphogenesis of the shoulder architecture part IV. Reptilia. Quarterly Review of Biology, 11(2):183=2080 Howes, G., B.. 1902 .. The morphological method and progress. Nature, 66: .522=5300 Huntington, G.. s. 1903 .. Present problems of myological research and the significance and classification of muscular variations. Amari= can Journal of Anatomy, 2(2):157-1750 79

Hyman, Lo Ho 19560 Comparative Vertebrate Anatomy. Univo of Chioagoo Chicago, Ill. International Anatomical Nomenclature Committeeo 1964. Nomina.Anatom.ica Exoerpta Medica Foundation, New York.

Jenkins 0 R. L. and W. Wo Tanner. 1968. Osteology and myology of Phryppsoma !.• platyrhinos Girard and Phr:ynosoma £• hernandesi Girard. Brigham Young University Science Bulletin. Biological Series 9(4):1=34.

Jollie 9 M. T. 19600 The head skeleton of the lizard. Acta Zoologica, 41:1=64. Kesteven, Ho Lo 19190 The pterygoids in amphibia and reptiles and the parasphenoid. Journal of Anatomy, 53:223-238.

Kingsley, J. s. 1905. The bones of the reptilian lower jaw0 The American Naturalist, 39:59=64. Licht, Po 1966. Reproduction in lizards: Influence of temperature on photoperiodism in testicular recrudescence. Science, 154: 1668 ...1670,.

Lowe9 Co H,. and Sa R,. Goldberg. 19660 Variation in the circumtesti= cular leydig cell tunic of teiid lizards (Cnemidophorus and Ameiva) Journal of Morphology, 119(3):277-282. Maslin, T. P. 1959a. The nature of amphibian and reptilian species.

Journal of the Arizona Academy of Science, 1(1):8-17 0 1959b. An annotated check list of the amphibians and reptiles

of Colorado. University of Colorado Studies, Biology, 6:1=98 0

1961. All=female species of the lizard genus Cnemidophorus 9 Teiidae. Science, 135(3499):212=213. 1~3. Notes on a collection of herpetozoa. from the Yucatan peninsula of Mexicoo University of Colorado Studies, Biology, 9il=20. 19660 The six hatchlings of five apparently unise:x:ual species of whiptail lizards (Cnemidophorus, Teiidae). The American Mid- land Naturalist, 76(2):369=378.

Maslin, To Po, R. Go Beidleman, and Co H. Lowe, Jro 19580 The status of the lizard Cnemidophorus perplexu.s Baird and Girard (Teiidae)o Proceedings of the Uo So National Museumo 108(J406):331-J45o McCoy, c. J. 19660 Geographic variation in ovarian cycles and clutch size in Cnemidophorus tigris (Teiidae)o Science, 154:16710

Nopcsa, Fo 19280 The genera of reptiles. Paleobiologica l(l):163=1880 80

Oelrich 9 To M. 19560 The anatomy of the head of Ctenosaura Eectinata (Iguanidae) Misco Publications of the Museum of Zoology, Univer= sity of Michigan, #94:1=118, figs. 1-57. Patten, Bo Mo 1951. The Embryology of the Chieko Blakiston and McGraw= Hill, NewYork. p. 85. Pennock, L.A. 1965. Triploidy in parthenogenetic species of the teid lizard, genus Cnemidophorus. Science, 149(368)):539-540. Peters, J. A. 19640 The lizard genus Am.eiva in Equadoro Bulletin of the Southern California Academ;y of Sciences, 63:113=127.

Poglayen-Neuwall, Io 1954. Die Kiefermuskulature der Eidechsen und ihre Innervation. Zeitschrift ffir Wissenshaftliche Zoologische, 158:79=132. Reese, A. M. 1923. The osteology of the Tegu, Tupinambis nig;ropunc= tatus. Journal of Morphology, Philadelphia, J8:1=17. Robinson, G. W. and W. Wo Tanner, 1962. A comparative study of the species of the genus Crotophytus Hplbrook (Iguanidae) Brigham Young University Science Bulletin, Biological Series, 2(1)~1-31. Romer, A. s. 1924. Pectoral limb musculature and shoulder girdle structures in fish and tetrapod.so Anatomical Record, 27(2): 119=143.

1956. Osteology of the Reptiles. Univ. of Chicago, Chicago 0 Illo p. 1=772. 1964. The Vertebrate Body. Saunders, Philadelphia. 1966. Vertebrate Paleontology. Univ. of Chicago, Chicago, Ill. p. 1=396.

Sinitsin, D. T. 19280 The types of skull in the family Teiidae 0 Zoologische Anzeiger, 76:2J2=236o

Smith, Ho M. 19600 Evolution of Chordate Structureo Holt, Rinehart and Winston, New Yorko Po 1...4920 Smith, Ho Mo and W. Lo Burgero 19490 The identy of Ameiva tesselata Sayo Bulletin of the Chicago Academ;y of Science, 8(13):277=2840

Smith, Ho M. and L. Eo Laufeo 1946., A summary of Mexican lizards of

the genus Ameivao Univo of Kansas Science Bulletin, 3l(l)i7=7J 0 Smith, Ho Mo and E. Ho Tayloro 19500 An annotated checklist and key to the reptiles of Mexico exculsive of the snakeso Bulletin of the U. So National Museum, 199:170-192. Snyder, R. Co 1954. The anatom;y and function of the pelvic girdle and 81

hindlimb in lizard locomotiono The American Journal of Anatomy0 95(1):1-450

Stebbins, R. Co 19660 A Field Guide to Western Reptiles and Amphibianso Riverside, Cambridge, Mass. p. 125-133. Stokely, Po s. 1950. The occurrence of an intermedium in lizards. American Midland Naturalist, 43(1):179-1820 Stuart, L. c. 1942. Comments on the undulata group of Ameiva (Sauria). Proceedings of the Biological Society of Washington, 55:143=1490

Tanner, W.W. 1952. A comparative study of the throat musculature in the Plethodontidae of Mexico and Central America. Univo of Kansas Science Bulletin, 34:583=677.

Taylor, Ho L. and P. Ao Medica. 1966. Natural hybridization of the besexual teiid lizard Cnemidophorus inornatus and the unisexual Cnemidophorus perplexus in southern New Mexicoo Univo of Colorado Studies Series in Biology, 22:1-9. Wake, D. B. 1966. Comparative osteology and evolution of the lungless salamander, family Plethodontidae. Memoirs of the South Cali= fornia Academy of Sciences, 4(Oct. 25):1-111.

Zweifel 9 F. W. 19650 A handbook of Biological Illustration 0 Univ0 of Chicago. Chicago, Illo p. 1-131.

Zweifel, R. G. 1959. Variation in and distribution of lizards of western Mexico related to Cnemidophorus sacki. Bulletin of the American Museum of Natural History, 117:60-1160 1962. Analysis of hybridization between two subspecies of the desert whiptail lizard, Cnemidophorus tigriso Copeia, 1962(4): 749-766. 1965. Variation in and distribution of the unisexual lizard,

Cnemidophor'!!! ~sselatus. American MuseumNovitates, 2235:1=49 0 OSTEOLOGICALAND MYOLOGICAL COMPARISONS OF THE HEAD

AND THORAXREGIONS OF CNEMIDOPHORUSTIGRIS SEPTENTRIONALISBURGER AND AMEIVA UNDULATAPAR.VA BARBOUR AND NOBLE (FAMILYTEIIDAE)

A Thesis Presented to the

Department of Zoology and Entomology Brigham Young University

In Partial Fulfillment

of the Requirements for the Degree

Master of Science

Don Lowell Fisher August 1968 This abstract of thesis, by Don Lowell Fisher, is accepted in

its present form by the Department of Zoology- and Entomology- of

Brigham Young University as satisfying the thesis abstract requirement

for the degree of Master of Science.

Typed by Kathleen R. Steed ABSTRACT

A basic description of the skull, lower jaw. teeth, wrist elements and anterior myology of Ameiva undu.lata parva is com.pared to the similar anatomical structures of Cnemidoworus tigris septentrionaliso Figures are provided for use in determil1ing phylogenetic relationships between these two genera and other genera of the family Teiidaeo

X=ray study of the wrist structure has shown the intermedium ele= ment to be rather variably present in the family Teiidaeo Its presence is noted in Ameiva undulata parva, !,o :J!o hartwegi, A,o ]!o sinistra, Cnemi=

dophorus sa.cki comminus9 £,o sacki gulariso f,o burti, and f,o sexlineatuso Its presence is questionable or absent in Ameiva auberi, Cnemidophorus

~ ~ ',.l tigris tigris 0 Q.o i• septentrionalis, f.o io gracilis, £,o io canus 0 £,. 1o aethiops, f,o sexlineatus gularis, £,o sacki exa.nguis, £,. deppei deppei, £. deppei linea.tissisimus, f_o hyperythrus hyperythrus, and£.. lemniscatus lemniscatus. Variations of anterior osteological and myological elements are

indicated by description and discussed.

Anatomical structures described in the discussion which are of paleolithic significance indicate that Ameiva undu.lata parva appear~ of more•primitive phylogeny than Cnemidophorus tigris septentrionalis.