Evolution of the Iguanine Lizards (Sauria, Iguanidae) As Determined by Osteological and Myological Characters

Home , Agamidae, Amphisbaenidae, Anniella pulchra, Aristelliger, Boidae, Brachylophus

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Theses and Dissertations

1970-08-01

Evolution of the iguanine lizards (Sauria, Iguanidae) as determined by osteological and myological characters

David F. Avery Brigham Young University - Provo

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BYU ScholarsArchive Citation Avery, David F., "Evolution of the iguanine lizards (Sauria, Iguanidae) as determined by osteological and myological characters" (1970). Theses and Dissertations. 7618. https://scholarsarchive.byu.edu/etd/7618

This Dissertation 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]. EVOLUTIONOF THE IGUA.NINELI'ZiUIDS

(SAUR:U1., IGUANIDAE) .s.S DETEH.MTNEDBY

OSTEOLOGICJJJAND MYOLOGIC.ALCHARA.C'l'Efi..S

A Dissertation

Presented to the

Department of Zoology

Brigham Yeung Uni ver·si ty

Jn Pa.rtial Fillf.LLlment

of the Eequ:Lr-ements fer the Dz~gree

Doctor of Philosophy

David F. Avery

August 197U This dissertation, by David F. Avery, is accepted in its present form by the Department of Zoology of Brigham Young University as satisfying the dissertation requirement for the degree of Doctor of

Philosophy.

30 l'/_70 ()k ate

Typed by Kathleen R. Steed A CKNOWLEDGEHENTS

I wish to extend my deepest gratitude to the members of m:r advisory committee, Dr. Wilmer W. Tanner> Dr. Harold J. Bissell, I)r.

Glen Moore, and Dr. Joseph R. Murphy, for the, advice and guidance they gave during the course cf this study. To Dr. Tanner I am e::pecfa.1- ly indebted for his help :in procuring specim'jns and [seneral support.

I would also like to thank the Department of Zoology o::.' Brigha.m You1;.g

University for the financial assistance provided rne during part of this study. I wish also to express my thanks to Sou::.he?n CorE\ect:Lcl't

State College for providing sone financi.a1 a:i.d and the use of equipEent c:1..1.rinr:thf. stud~;.

I also ac.:knoi,dedge the kindness and coul'teGy of Drs. Edwir1

TJr, • Colbert and Bobb Schaeffer of the Departrr:er,i·. o{ Vertebra,te Paleon- tology and Dr. C. W. Y.iyers of the Department of Herpetology who allowed

!'!i-2-t,11e use of many speci1ns11s fro:r:-1the col].ectivr1s of t~e P,__YJ18ricc1,n

E;.;.seuJn of Natural History. Dr. ,Tohn H. O.strrnn and Mr. Jaues Hcp.:oon of the Peabody J.Iuseum, Yale University were ye,ry helpfu1 to me du:d.YJg ,Ly visit to that ir1stitution, and were in13tr1.mtcnta1 in rny borrov,:ing spec.:i-• mens fro,,t the rr,u.t,ewn cullection:~', Dr. Hi chard Est et, vJas 1':ir..d ir._ loa.ni~1g

1,1e an extensive sed es ot· osteological materi:i.l from tb,i Mvseum cf

Cc;mpara.t:i.ve Looloey at !12.:rvard Uni versit~,. Dr. ,Jam'.,s Pet.ers lent two

Withod, the 1n,-'.lnygiftc; of i:,eecimcw > tbi~c:. ::,t,udy couJ.rl not have iv of J',mbJvrh;:.'.22£h:S.~ from the Ca1ifornia, Aca.derrzy-of Sciences, two specimens each 0£' A:r.t1~1,yr'h"vrcr1 u::, c:.nd Conolor;hus from the Awerican Musm;_mof Natural

History_; four spec:Lmens of Chalarodon rnadagasearier,sis, one of Op1urus gn8dr-i ..,,::icuJE~!,_::,~, one Or,lurus sebae, one incomplete specimen of B.ra,chylophus f,:1sciatus_, and 1,wo specimens of Cvclura nuchalis from the Muse'Jm of Comr...arative Zoolog,1,, at Harvard University; several specimens of

Dipsosaurus dorsaJi,o and Saurorr::::l.us obesus donated by Hr. William

Ingram. I am especi""lly er:.dc:bted to Mr. Bert Ni.xon oi' Liahona CollegE: ,,

1'-Iukualofa, Tor:ga, for sending rr_e several specimer.,s cf BracrrrJ.ophns fasciatus from that localitv. ·------u

To those w}10 have loaned rne books or have been so ki:1d as to read and criticize this p:3,per_. I arr-1a.lso grateful and express rny thanks. V

TABLEOF CONTENTS Page

ACKNO'WLEDGF,}IBNTSI> • • 0 • • 0 r, 0 0 • e 0 • 0 0 0 0 iii

LIST OF TABLES • 0 • • ~ w • ~ e o • ~ $ • ~ ~ o o o • • o n vi

LIST OF ILLU[:;TRA'l'IOl{S o c • • • ~ o & o o e e • o o o • • • • • viii

INTRODUCTION• 0 e 0 G 0 0 0 0 l .. " • • " "

LITERATURE 0 0 0 0 0 0 0 0 0 • • • • • • " " 3

MATERJJIJ...SAl'.JD M:E:THODS 0 • e ♦ 0 0 0 ,r, • • 1-'- 0 O eoo•e• 2i.,.

03TEOLC'..GY • • • o • C ~ ~ • • o & o o • • o o • o o o • e ~ o o 2'7I

Skl1ll and Jaws • 0 0 0 • 0 0 • " • 27 Teeth 0 0 0 • .. 0 0 Ct • 5 0 51+ Hyoid Elements~ 0 0 0 • 0 0 G C ~ • 57 Sterna and R:i.bs • • 0 '.> 0 0 .• 58 .. " • •

HYOLOGY e O C ft • • e • • • 0 Cl • o • 95

Thro2,t Nnsculature 0 C 0 • " " 95 Neck 1-.{usc·uJat ure a o. ,. 0 0 101 • • " " 'l'e:npur·al l-1u.scu.12-ture • 0 0 0 • • 0 • 106 ., ., OTUER CE.lRAC'J.'ERS 0 .. 0 0 .. • 0 0 ll.3 'l'ongues 113

Herr1iper1es 4 • • e • n O O O C e O • & ~ Q ~ G ~ • ~ a 114

DISCUSSION o C e 0 0 0 0 117 " " • " ..

Ot::teoJcgy " C, • 0 • • .. e 118 J"1,yoloc;Y 0 0 0 0 0 0 0 I) • • 123 ~ ~ 0 ., Tongues • • • 0 0 • • • e 125 Hemi.pr.:n-~s o .. 0 • 0 125 It.;ua.ni:;e D:i.stribution ., .. • 0 0 126 ccnc.r.usmNs o • · ~ o 9 ~ o • ~ e o ~ • • ~ o o o

3UMlvlARY C" 0 C, ti • 0

LITERATURE CI'IED • ,. " 1.35

PLATES I·-XXXVI:f vi

LIST OF TABLES

Table Page 1. Skull Length and Width . . 61 2. Skull Length and Height 62 3. Basisphenoid Bones 63 4. Basioccipital Bones 64 5. Ex.occipital Bones 65 6. Supraoccipital Bones 66

'/. Pterygoid Bones 67 8. Ectopterygoid Bones 68 9. Varner Bones 69

10. Palatine Bones 70 11. Premaxillary Bones 71 l2. Maxillary Bones 72 13. Nasal Bones 73 l4. Prefrontal Bones 74 15. Lacrimal Bones 75 16. Frontal Bones 76 17. Postfrontal Bones 77 18. Jugal Bones 78 19. Parietal Bones 79 20. Parietal Wings 80

21. Postorbital Bones 81

22. Squamosal Bones 82 vii

Table Page

2.30 Quadrate Bones " • • • • • • a O O a • • 0 e e e O ♦ 0 • • 83

24. Supratem:r::oral Fossa • a C e O • • a • • • e O O • 0 e O • 84

25. Orbits o 0 • • " 0 0 0 • 0 0 • 0 0 0 0 O O • 0 • • • 0 • • 85

260 Fenestra Exonarina •• • • • er, O C O O O • • • 0 0 0 0 0 0 86

27. Dentary Bones 0 • • 0 • 0 e O e O O O e O O 6 e O O • 0 0 87

280 Articular Bones 0 O e 8 0 • e O • e 6 • 0 ♦ 0 0 0 0 ♦ e • 88

29a Angular Process 0 • • • • e O e O O O O e O O O • e O e 0 89

.30o Surangular Bones •••• a o e o • o o o o o o •• o o •• 90

310 Splenial Bones o • 0 • • • O • 0 0 0 0 9 0 0 e . . • 0 • 0 91

32. Angular Bones • • • D e • ♦ ♦ 0 ■ O • 0 0 0 0 0 0 0 0 0 • 92

33. Coronoid Bones. 0 • • 0 ■ 0 e O O • 0 • 0 • • • • • • • • 93

.34o Teeth o • 0 0 • 0 0 • • e O O • e • O O O • O O ■ 0 • 0 • 94

.350 Summary o.f J.mporLant, Hyologieal Differences ♦ e • 0 • 0 ~ 112

360 Tongue Measurements O e • • e a e ♦ 8 0 0 0 • O 8 0 0 ♦ 0 ll6

37. The Number of Osteologic~ Similarities Between Genera 0 • 132 viii

LIST OF ILLUSTRATIONS

Plate Page I. Ventral view of skull ...... 150 II. Ventral view of skull ...... 152 III. Dorsal view of skull . . . . 154 IV. Dorsal view of skull ...... 156 v. Lateral view of skull ...... 158 VI. Lateral view of skull ...... 160 VII. Medial view of mandibles ...... 162 VIII. Ventral view of hyoid bones . . . 164 IX. Ventral VlGV-l of sterrlum ...... 166 x. Ventral vie.-, of sternum ...... 168 XI. Ventral view of throat musculature; superficial layer shm,rn at left and first depth at right ...... 170 XII. Ventral view of throat musculature; superficial layer shown at left and first depth at right • • • 172

XIII. Ventral view of throat musculature; second depth at left and third depth at right ••••••••• 174

Y..IV. Ventral view of throat musculature; second depth at left and third depth at right •••••••.• 176 xv. Ventral view of throat musculature; fourth depth at left and fifth depth at right • • • . • • . • • 178

XVI. Ventral view of throat musculature; fourth depth at left and fifth depth at right ••••••••• 180

XVII. Do:rsal vi.et of throat and neck musculature; superficial depth at left and first depth at right 182

XVIII. Dorsal view of throat and neck musculature; superficial depth at left and first depth at right 184 ix

Plate Page

XIX. Dorsal view oi' head and neck musculature; second depth at left and third depth at right •••• 186 xx. Dorsal view of head and neck musculature; second dept:,h at left and third depth at right . . . . 188 XXI. Dorsal view of head and neck musculature; fourth depth at left and fifth depth at right ...... 190 XXII. Dorsal view of head and neck musculature; fourth depth at left and fifth depth at right . 192 XXIII. Lateral view· of head and neck musculature; superficial depth ...... 194 XXIV. Lateral view of head and neck musculature; superficial depth ...... 196 XJ...'V. Lateral view of the head and neck musculature; first depth ...... 198 XXVI. Lateral view of the head and neck musculature; first depth...... 200 XXVII. Lateral vie-w of head and neck musculature; second denth ...... 202 XXVIII. Lateral view of head and neck musculature; second depth ...... 204 XX.IX. Lateral view of head and neck musculature; third depth ...... 206 XXX. Lateral view of head and neck musculature; third depth ...... 208 XX.XI. Lateral view of head and neck musculature; fom~th depth ...... 210 XX.XII. Lateral view o_f' head and neck musculature; foarth depth ...... 0 212 XXXIII. Lateral view of head and neck musculature; fifth depth ...... 214 XX.XIV. Lateral view o.f head and neck musculature; fifth depth ...... 216 xxrv. Dorsal view of the tongue ...... 218 X

Plate Page

XX.XVI. Hemiper1es • • • • • • • • • • 220

XXXVII. Phylogenetic relationships of the Madagascar Iguanidae and the genera of iguanine lizards • • • • • • • • • 222 INTffiDUCTION

The family Iguanidae is almost completely restricted to the

Western Hemisphere with its main radiations occurring in North and South

America. There are also representatives on Fiji, Tonga and the Galapagos

Islands, in the Pacific Ocean. Distantly related forms are also found

on Madagascar off the Southeastern Coast of Africa. Although the

iguanid lizards are familiar to most scientists interested in the

tropics, their anatomy and evolution is poorly understood.

The iguanine line, in the Family Iguanidae, contains these

genera: Amblyrhynchus and Conoloprns from the Galapagos Islands, Brach-t:-

lo_pJ-1.l!-.~from the Fj_ji and Tonga Islands, E'!,valiosaurus from Central

America, Ctenosaura and I_guana from Central and South P.merica, Cyclu.ra.

from the West Indies, and D_jJ;sosaurus and SauroEJ.alus from North America.

Chalarodon and Qplurus, from Madagascar, are closely related to the

iguanine line and_. because they possess abdominal ribs, are considered

to be the most pri:mitive members of the familyo

The iguanid :i.:Lzards that are discontinuously distributed all

belong to the iguanir.e li~1e or are the most primitive members of the

family., Explaining the discontinuous distribution pittern between the

Western Hemisphere rrainland iguanines> the Pacific Island forms, and

their Madagascar relatives has proven to be much of an enigma for

zoogeographers and herpetologistso

The purpor3e of this study is to establish the degree of rela-

tionship bet.ween the :iguai;ines of thG Galapagos, Fiji, and Tonga Islands 2 with the mainland genera. I will also attempt to define more completely

the relationships between the V,adagascar genera and the iguanine line.

In order to ascertain these relationships, the anterior osteology and myology of each genus has been investigated, along with such specialized features as the tongue, hyoid bones, sterna and hemipenes. Hopefully the morphological relationships between the ten genera can be clarified by the use of these relationships and the evolution and distribution of the iguani.ne iguanids can be explained. Of all the genera listed above, only Enyaliosaurus has not been studied in detail as only two skulls were available for examination. 3

LITERATURE

Literature concernii7.g the anatomy of lizards is varied, ·widely scattered and incomplete. Because of the large amount of 111o,terial dealing with this subject, this discussion will be limited, with excep- tions, to that literature which pertains to those anatomical features treated in this paper; namely the anterior osteology and myology, hyoid bones, sternum, the tongue and the hemipenes.

One of the earliest discussions of the head-osteology or myology of lizards, is that of Mivart (1867) ,vho published a detailed account of the myology of Iguana tuberculata (Iguanidae). This work was I foll.owed in .1.870 by Ni.vart s oaoer on the mvolog:v of QJ.13 1:11~._e,l_e_cmp.,ar-sonti (Chawaeleonidae). These papers are detailed and constitute two of the most complete discussions of lizard rn;yolog._,vin the literature.

In 1870 Sanders published on the myology of Platydactylus japonicus (Gekkonidae). This paper is a comprehensive presentation but lacks adequate illustrations. In 1872, Sanders again published on lizard myology, with an account on the musculature of Liolepis belli

(Agamidae). As with the earlier papers of Mivert, this paper is well illustrated. Gervais (1873) published a brief note on the skull and teeth of the Australian agamid Molock. Notes and illustrations dealine with the rnyology of Phr;ynosom.a corona tum ( Iguanidae), were related by

Sanders (1874).

In 1880 Parker described the skull of Lacerta agilis, b_. viridis and Zootoca vivinara (Lacertidae). This work was followed 4 in l883 by DeVis 1s r,aper on the myology of Chlarnydosaurus k:i.ngii

(Agamidae). Unfortunately, his p:3.per is poorly illustrated.

From 1885 to 1887 Boulenger published his monumental catalogue of lizards in the British Museum. Scattered throughout this work are observations on the osteology of lizards, including a discussion of the distinctive cranial features of Amblyrhynchus, Brachyloµrn3_. Conolophus,

Ctenosaura, Cyclura and Iguana (Iguanidae). In 1886, Gill reviewed

Boulenger 1s classif'ication system for lizards and SUJT$narizedthe irnpor- tant osteological differences between the families. Boulenger (1890) further surnnarized his osteological observations on the distinctive cranial characters of the iguanid lizards-related to Igua.Q§;_, It is interesting to note that even at this early stage of :investigation, the iguanine line of evolution was recogni~ed in the family Iguanidae as a natural groupa All seven genera listed by Boulenger are today still considered to be iguaninesa In l891 Boulenger pubiished a series of remarks concerning the osteology of Heloder~a and presented a conclu- sion for the systematic position of the family Helodermatidaeo

E. D. Cope was also actively publishing on lizard anatomy during this periodo In 1892 Cope commented on the homologies of the posterior cranial arches in reptiles. His conclusions in this matter have J.aid the foundation for understanding the components of the posterior skull of lizards by later workers. During the same year,

Cope 1s classic work on lizard osteology was published. Not onl;r does

Cope provide a comparison of the cranial osseous elements, but he describes in detail osteological features of the iguanines, Dipsosaurus and Sauromalus. This material was also incorporated into Cope1s comprehensive taxonorr.ic wo:rk of 19000 5

The German worker Siebenrock, during the close of the 19th

century, made several contributions to our knowledge of the anatomy o.f

lizardso In 1892 he published a brief paper on the skeleton of Uro-~

platu~ f:L~briatus (Gekkonidae) and a more lengthy discussion on the

skulls of skinks, anguids and Gerrhosaurus (Cordylidae). These papers were followed i:p 1893 by Siebenrock 1s discussion of the skeleton of

Brookesia superciliaris (Chamaeleontidae); an 1894 account of the skele-

ton of Lacerta simon;yi (Lacertidae); and in 1895 a comprehensive dis-

cussion on the skeleton of the agamid lizards.

In 1903, Bradley discussed the muscles of mastication and the

movement of the skull in lizards. Broom, in the same year, named

Paliguana whitei (Eosuchia) from the Triassic beds of South Africa.

This find is of considerable importance as it may represent animals

ancestral to lizards. The pre3ence of this fossil also establishes the

great geologic age of lizards in general. Following these investigations,

Beddard (1905) published notes on the skull of Uromastix, (Agamidae),

and in a separate paper discussed some aspects of Chlam,ydosaurus kingi

and other agarnids. In 1907 Beddard examined the internal anatomy of

several genera of lizards and described the uniqueness of various

characters to particular families.

In 1911 Br1Jant revised the iguani.d genus Phrynosorria and its

synonym Anota. In this paper he presented some osteologi.cal observations

on the species and genera treatE\d in the study.

A most useful paper on.the phylogeny of jaw muscles in verte-

brates was published by Adams in 1919. Although the paper covers

reptiles in general it describes the jaw musculature of Iguana (Iguanidae)

and Varanus (Varanidae) in particular. 6

Rice (1920) described the development of the skull in the skink Eurr,eces g_uhy:::ialineatus. In 1923 Camp published his classic work on the classification of lizards, bn5ed on their anatomy. In this account

Camp figured the th-roat musculature of Sphenodon (Rhynchocephali.a),

Amphisbaenia (Amphisbaenidae), Coleony~ (Eubleph.nidae), Uroplatus

(Gekkonidae), Typhlops, (Typhlopidae), Tupinambis (Teiidae), ya~~l_Q1::!§.

(Varanidae), Gerrhosaurus, ~~~, Chamaesaura (Cordylidae), Li.;,i_lis

(Pygopodidae), Brachvlophus, Phrynosoma (Iguanidae), Cdotes (Agamidae),

Chamaeleon (Chaw3eleonidae), x~ntusia (Xantusidae), Tr"!..chysaurus

(Scincidae), Lacerta (L'lcertidae), Heloderma (I-Ielodermatidae), £:errhono-

~ (Anguinj_dae), Xenosaurus (Xenosauridae), Anniella (Anniellidae), and Gekko (Gekkonidae). In the same year Reese analyzed the osteology of Tupinambis nigropunctat us (Teiidae).

In 1924 Broom discussed the origin of lizards by tracing the cranial elements of the fossil form~: Youngina, Mesosuchus and Paliguan_a_

(Eosuchia). These genera were compared with modern skinks, chamaeleonids, varanids and agamids. Broom indicated the closeness of Pal iguana to the modern lizards and suggested ways whereby Pal.iguana_ could have evolved into recent forms.

In 1925 Dubecq discussed the elevating muscles of the lower jaws in reptiles and Williston published his treatise on the osteology of reptiles. This latter work is of interest as Williston figured skulls of £Q_nolophus (Iquanidae), Vara nus (Varanidae), Amph:i.sbaena (Amphis- baenidae) and a charr.aeleon. He also classified the Squamata in the

Subclass Parapsida with the lizard like fossil Araeoscelis.

In 1928 three i!l'portant papers were published. Gilmore sur1.1marized the fossil lizards of North America and discussed the osteology 7 of many forms as well as establishing the existance of some fainilies of lizards in North America as early as the Upper Cretaceous. During the same year Nopcsa presented a s;ynopsis of the genera of reptiles o For each family he presented osteological characteristics and summarized the fossil and recent genera found in each. Lastly, Sinitsin analyzed skulls in the family Teiidae and separated the family into tvrn divisions based on cranial osteology.

Goodrich (19.30) published his :rnajor work on the structure and development of the vertebrates. In it he figured and described the skulls of Varanus (Varanidae) and Lacerta (Lacertidae). In 19.31

Edgeworth prec,ented two papers on reptile anatomy. In one he discussed the development of the eye, masticatory and hyoid muscles of Sphenodon

(Rhynchocephalia). This paper was followed shortly by an account of muscles us8d in opening and shutting the mouth of vertebrates. }Iis remarks in the second paper were restricted to the lizards Lace1'ta

(Lacertidae), Platydactylus (Gekkonidae) and Calotes (Agamidae). Brock continued early investigations into lizard anatomy with a paper in 1932 on the developmental stages in the skuJ_ls of the geckos L;ygodactylus capensis and Pachyda.ctylus maculosa. During the same year Kingman made a study of the skull of the skink, Eumeces obsoletus.

In 1934 Davis published one of the most complete studies on lizard anatomy with a laboratory manual for Crotaph:ytus (Iguanidae).

In the year 1935 important papers on lizard anatomy were published by

Brock, Broom and Edgeworth. Brock 1 s discussion dealt with the problem o.f temporal bones in lizards, birds and mammals. Most of Brock 1 s comment~ were relegated to skinks and geckos. Broom 1s work of 1932 also dealt with the temporal bones and correlated the information known for the 8

fossil Paliguana and Youngina (J!.;osuchia) with the structure of the modern genera lg~ (Iguanidae), Agama (Agamidae), Cnemidophorus,

Teiis, Callopistes (Teiidae), Varanus (Varanidae), Scapteira (Lacertidae),

Gerrhosaurus, Zonurus, Platysaurus (Cordylidae), Gerrhonotus, Angui~

(Anguinidae) and Uroplatus (Gekkonidae). The highlight of the year, for

lizard anatornists, was the publication of Edgeworth 1 s classic work on the cranial muscles of vertebrates. In this paper Edgeworth described the myology- of Iguana (Iguanidae) and correlated it with members of the related families of lizards Chamaeleontidae and Lacertidae.

The problerr~ of terminology of muscles of reptiles were treated in a short p.3.per by Davis in 1936. Howell (1936) presented a

comprehensive study on the shoulder of reptiles. Much of the description

contained in the paper pertains to the shoulder of Iguanc!: (Iguanidae).

Bahl ts comn:-ehensive mper on tl-1e sl-nill of >'l\1'.:.{3,IJ.2-"?.(VaraLidae) was published in 1937. This is one of the most detailed accounts of lizard osteology in the literature.

In 1938 Brock presented a discussion of the cranial muscles of geckos and El Toubi analyzed the osteology of Scincus scincus

(Scincidae). The final paper of the decade was Evans 1 (1939) discussion of the evolution of the atlas-ax:is complexo This paper not only discussed fossil reptiles but also provided an account of the atlas-axis complex as it exists in Sphenodon (Rhynchocephalia) and Iguana (Iguani- dae)o

In 1941, Brock analyzed the skull of the chamaeleon Lopho- saura ventralis in one paper; and the skull of Acontias (Scincidae) and the affinities between snakes and lizards in a second paper. During the same year Gilmore published accounts of fossil lizards of the iguanid 9 genus Acinrion from the Oligocene formations of Wyoming. In this pa.per he indicated the affinities of Aciprion to the .recent Crotaphytus

(Iguanidae). Malam (1941) provided a description of the cranial anatomy of Ger.rhosa.urus ( Cordylidae).

In 1942 Angel 1 s synopsis of Madagascar lizards was publishedo

In this paper skeletal characteristics of Chalarodon and Oplurus

(Iguanidae) were reviewed. Hoffstetter (19li-2) reviewed the remains of fossil iguanids from the Eocene and Oliyocene of Europe. Iyer, during the same year described the skeleton of Cal otes versicolor (Agaruidae).

Mittleman (19li-2) presented a taxoi1omic summary of the genus Urosaurus

(Iguanidae). He also discussed the general evolution of North An:erj_can members of the family Iguanidae, and on the basis of osteology broke the faIPily into lines of evolution, presenting a phylogenetic tree, in which he placed _Qtenosaura as a primitive ancestral type from which two main lines of evolution were formed. One line contained the sceloporine lizards and Phr:.vnoso~~ while the other contained the crotaphytine lizards, Dinsosaurus and Sauro;nalus. Mittleman aJ_so indicated that

Dipsosaurus, Sauroma_lus and Ctenosaura are all very closely related.

The genus Uromastix (Agamidae) has been a popular subject of investigation among Old World workers. In.1942 the bony palate of this agamid was described and figured by Saksena. During the same year

Young published on the cranial morphology of Xantusia (Xantusidae). In the following year DuBois (191.i.3) analysec~ the skull of Cnemidophorus

(Teiidae) and Iyer followed his earJ_ier work with a detailed description of the skull of Calotes versicolor (Agamidae).

Kestevens' :rr.ajor 1::1:1.peron the evolution of the skull and cephalic: muscles appeared in 194Li.. The head musculature was described 10 for Physignathus, JLmphibolurus (Agamidae), ,Anolis, Basiliscus (Iguani- dae), Chamaeleon ( Chama.eleonida.e), Tiligua (Scincidae), Var2.nus

(Varanidae), and Sphenodon (H.11.ynchocephalia). In the same year Zangerl discussed the skull of the Amphisbaenidae. In this pg.per are figured skulls of Anmhisbaenc!:..i..BiDes, Geocalamus, Monapeltis, Leposternon, and

Trogonophis. Prolacert~ (Eosuchia) and the Protorosaurian reptiles were discussed by Camp (1945) who indicated that the Lower Triassic

Prolacerta is intermediate between Youngina (Eosuchia) and modern lizards.

In tlw same year Za.ngerl completed his analysis of the Amphisbaenidae with a discussion of the post-cranial skeletono

Pletzen (1946) examined the cranial morphology of _Cordylus

(Cordylidae) and discussed the cranial kinesis· of that lizard. The genus Xenosaurus (Xcnosauridae) was the topic of study for Barrows and

Smith (1%7). The authors descdbArl t.he osteology in detail and con•• eluded that this lizard has affinities with the family Anguidae but should be retained in its own family. El Toubi published two papers in 1947. Ir: one he described the osteology of Agama stellio (Agamidae) and in the other discussed the cranial osteology of Urornastix aegyptia (Agamidae).

In 1948 Broom described and figured the skull of Phrynosoma cornutum ( Ig'.:anidae). George (1948) examined the musculature of Uromas- tix hardwickii (Agamidae). The latter paper is accompanied by excellent figures dealing with limb musculature. El Toubi completed his investigation of Urorrastix aeg.yptig_ (Agamidae) in 1949, and published an account of the post cranial osteologyo Mahendria (1949) described in detail the skull of the gecko Hemidactylus flaviviridis.

Several pg.pers were published in 1950 dealing with lizard anatomy. Bellairs presented the cranial anatomy of Anniella (Anniellidae) 11

Detrie analyzed the skull of Phrynosoma cornutum (Iguanidae); Haines discussed the flexor muscles in the forearm and hand of lizards and mammals; Stokely surveyed the occurrance of the intermediumwrist bone in lizards; and Toerien also presented an account of the cranial morphology of Anniella (:Anniellidae).

Only two papers dealing with lizard anatomy were published in

1951. Norris and Lowe discussed the osteology and myology of Phrynosoma m1callii (Iguanidae), and figured parts of the skull of several

Phr.ynosoma. Webb presented the cranial anatomy of the geckos Palma.to~ gecko ran_gei_ and Oedura karroica.

El Toubi and Khalil summarized the structure of the cranium in Egyptian geckos in 1952. In 1953 Barry added some observations to the cranial anatomy of fi.gama (Agamidae); and Brattstrom outlined the occurrance of Pleistocene lizards from Californiao Among the forms listed in Brat tstrom I s paper are remains of Sceloporus, Crotaph;v:t_~

(Iguanidae), Cnernidophorus (Teiidae), and Eumeces (Scincidae).

George (1954) dealt with the cranial osteology of the agamid

Uromastix hardwickii and figured the skull. McDowell and Bogert (1954) studied the skeletons of Lanthanotus (Lanthanotidae), and compared it with Shinisaurus, Xenosaurus, Melanosaurus (Xenosauridae), Heloderma

(Helodermatidae), Varanus (Varanidae), A_igialosaurus (Aigialosauridae),

Tylosaurus (Mososauridae), ;python (Boidae), Leptotyphlops (Leptotyphlo- pidae), Typhlops (Typhlopidae), E.zgopus, DelIE@:,Lialis, !.J2rasia,

Ophioseps (Pygopodidae), Aristelliger (Gekkonidae), Coleonp: (Euble- pharidae), Xantusia (Xantusidae), Cordylus, GE:rrhosaurus ( Cordyl.i.dae),

Peltosaurus, Diploglossus, Gerrhonotus, Angnis, Abronia, Celestus

(Anguinidae) and Aru1iell.a (Annielidae). The authors were able to prese::1.t 12 a phylogeny for the Anguinomcrphan lizards. This paper is well illustrated and is probably one of the best anatomical studies performed on lizards since Camprs paper in 19230

.Edinger (1955) discussed the parietal foramen in rtptiles as to function and size and figured the skull roof of Iguana (Iguanidae)o

George (1955) completed an earlier work on Uromastix hardwickii (Agamidae). In his pa.per the post cranial osteology is discussed.

In 1955 Hoffstetter in the reptile volurne of the French treatise on Paleontology reviewed general osteological features of the lizard skull and presented a summary of fossil lizard remains from Europeo Also in

1955 Hotton surveyed the dentition and diets of North American Iguanidae. It j_s interesting to note that his analysis of teeth confirms the sus- pected close relationship between Dipsosaurus, Sauromalus and Ctenosaurus,

Islam's 1955 description of the skull of Uro::nastix hardwickii (Agamidae) is one of the most comprehensive yet presented for that genus.

The iguanid genus Amblyrhynchus was revised by Eibl-Eibesfeldt

(1956). In this review the dorsal aspect of the skull of!•..£• cristatus is figured. Islam completed his analysis of the skeleton of Uroma.stix hardwickii (Agamidae) in the same year. He described and figured aspects of tl:e post cranial skeleton. Oelrich (1956) published his excellent, well illustrated account of the anatomy of the head of

Ctenosaura pectinata (Iguanidae). In the same year Romer published his monwnental work on the osteology of the reptiles. Besides giving a general account of the evolution of the reptile skeleton, Romer figured the skulls of Varanus (Varanidae), Iguana (Iguanidae), Brookesia

(Chamaeleonidae), Chalddes (Scincidae), Xantusia (Xantusidae), Cordylus

( Cordylidae), Amphisbaena. (Amphisbaenid2.e) and Typhlops (Typhlopidae). 13

Lundelius (1957) analyzed skeletal adaptations in Sceloporus

(Iguanidae) and figured the skull. Brattstrom published two p:3.pers on fossil lizards in 1958. He recorded Crotaphytus, Sceloporus, Sauromalus

(Iguanidae) and Cnemidophorus (Teiidae) from the Pleistocene sediments of California and in a second paper, Acinrion (Iguanidae) from the

Oligocene .formations of Wyoming. Also during 1958 Savage investigated the genera Urosaurus and .!Ii@: (Iguanidae). After an anatorr~cal analysis of iguanids Savage was able to sep:3.rate the family into a sceloporine line of evolution and an iguanine line of evolution. The iguanine line is charaeterized by having an 11S11-shaped nasal canal and the possession of zygosphenes and zygantra on the verte~rae. The sceloporines lack the vertebral projections and the 11S11-shaped nasal pa,ssages. Besides the eight iguanine genera outlined earlier, Savage included Crotaphytus

In 1959 El Toubi and Kamal presented a well detailed and illustrated discussion of the -skull of Chalcides ocellatus (Scincidae).

The following year Haas (1960) presented a ·discussion of the trigeminus muscles of Xenosaurus and Shinosaurus (Xenosauridae). This paper is detailed and filled with detailed illustrations. Jollie 1s 1960 discussion of the head skeleton of lizards is an excellent summary of evolution in that saurian. Besides detail, this paper contains illustrations of the skulls of Tupinambis (Teiidae), Amphisbaena (Amphis- baenidae), Anguis (Anguinidae) and Uromastix (Aganudae). Lastly in 1960

Srnith 1s book on chordate evolution treated the theoretical development of the lizard skeletons and rrmsculature in detail.

In 1961 Colbert published his book on the evolution of the vertebrates. In it he discussed the problem of lizard affinities with 14 other reptiles and places them with the diapsida. The 1961 paper by Sukhanov investigated the musculature of lizards and concluded it to be of two types: Scinco-Geckomorphous and Iguanomorphos. The author then presented a phylogeny of lizard families depending on their type of musculatureo

Skeletal variations in Satar ,grandaevus (Iguanidae) were summarized by Etheridge (1962) while Kluge (1962) discussed the comparative osteology of Coleonyx (Eublepharj_dae). This latter J)c1.peris highly detailed and well illustrated. Another discussion of liza2'.'d anatomy was that of Robison and Tanner (1962) who outlined the anterior osteology and myology of Crotaphytus (Iguanidae). This paper is also well illustrated.

In 1963 Estes reported on fossil lizards from the Miocene strata of Flori.da, Among those genera found were Leiocephalus

(Iguanidae), Eumeces (Scincidae), Cnemidophorus (Teiidae) and unidenti- fied Iguanidae, Gekkonidae and Anguinidae. Also during 1963 Harris 1 pa.per on the anatomy of Agarna agama (Agamidae) was published. This is a well illustrated account in the form of a laboratory guide. Osteo- lop,Y and lli'JOlogy of the anterior body regions are well covered. Ostrum

(1963) presented a short discussion on the lack of herbivorous lizards in the modern fauna. He indicated that this is probably because of the difficulties in eating caused by the streptostylic and kinetic nature of the skull.

In 1961+Avery and Tanner described the anterior osteology and myology of Saurornalus obes 1 ,s ( Iguanida,e). This paper has several illustrations of that region. Brattstrom (1964) identified fossil lizards from cave deposits in New Mexico. Estes (1964) in a major publication l5 described the fossil ve:::·tebrates from the Late Cretaceous Lance Forma- tion of Wyoming. It is interesting to note that no Iguanidae were recorded and some of Gilmore 1s (1928) Cretaceous iguanids were transfered to other families. Estes and Tihen (1964) recorded Jv'".iiocene-Pliocene vertebrates from Nebraska and listed among their finds Phry:nosoma

(Iguanidae)~ Cnemidophorus (Teiidae), Eumeces (Scincidae), and Gerrhono- tus (.Anguinidae). Etheridge (1964.) also discussed the fossil record of

Late Pleistocene lizards from the West Indies. 'l'hecadactylus (Gekkonidae)

Leiocephalus, Anolis (Iguan:i.dae), Ameiva (Teiidae) and a braincase from an iguanine type lizard are listed among the remains. In another

paper of the same year Etheridge examined the skeletal morphology of the

sceloporine lizards. After an osteological examination Etheridge

presented a phylogenetic tree for the sceloporines. He removed Crota-

.J21:i.,yt_~from the i3;uanine line of Savage (1958) and allied it to the

sceloporines and Phrynosoma_. He also indicated from osteological data, that the iguanine li.ne of evolution is a natural grouping. Eyal-Giladi,

l964, described the development of the chondrocranium of .Agama stellio

(Aga:m:idae). Hollman (1964) described some Pleistocene amphibians and

reptiles from Texas. The fauna does not differ appreciably from the

modern fauna. Lastly in 1964 Tilak report:;d on the osteology of

Uromastix hardwickii (Agamidae).

In 1965 Blanc described the skeleton of the Madagascar

iguanid, Chalarodon. Etheridge examined some fossil lizards from the

Dominican Republic and listed among the remains !Aristelliger (Gekkonidae),

Anolis, Leiocephalus (Iguanidae), Ameiv2. (T0iidc.1.e), and Diploglossus

(Anguinidae). Gelback (1965) presented a most useful ruper SU1Tu'1larizing

the Pliocene and Pleistocene amphibians and reptiles from North America. 16

The paper also has an excellent bibliography. Ray (1965) analyzed the number of marginal teeth in Ctenosa.ura and Anolis. Lastly in 1965

Weiner am Smith exainined the osteology of the crotaphytiform lizards.

The paper illustrates skulls of that group of iguanids.

Etheridge (1966) dealt with the systematics of Leiocephalus as based on the osteology of that iguanid genus. Lateral views of the mandibles are figured. In the same year Romer published his third edition of 11vertebrate Paleontology 11 which contains a summary of the evolution of lizards as well as illustrations of the skulls of Youngina,

Prolacerta (Eosuchia), Sphenodon (PJlynchocephalia) and PolyglYPhanodon

(Iguanidae).

Tho morphological literature of 1967 includes a pc.per by

Duda comparing the cranial osteology of Agarna tuberculata (Agamidae) with the skulls of other aga,,,ids; and a discussion oy Etheridge of lizard caudal vertebrae.

In 1968 several r..apei:-s were published dealing with lizard morphology. Criley described the cranial osteology of the Gerrhonotifon~ lizards; Gase analyzed the osteology and morphology of Diba.YJ.us novaeguineae (Dibamidae). Iordansky discussed the muscles of the external ear in lizards in one paper, and cranial kinesis in the skulls of lizards in a second :p3.per. The osteology and myology of Phrynosoma platyrhinos and P. hernandesi (Iguanidae) was treated by Jenkins and

Tanner in a well illustrated paper. In the same year Montanucci compared the dentition of the iguanid liza,rds Iguana, Ctenosaura,

Enyaliosaurus and Basiliscus and Secoy described the myology of SceloD- orus clarki (Iguanidae). Romer· (1968) presented a summary of lizard relationships to other reptiles and analyz,ed the Mesozoic .fossil lizards. l7

In 1969 Presch analyzed the evolution of species in the genus

Phrynosorra (Iguanidae) by utilizing osteology.

In sU11l!J1.arythe literahire dealing with anterior osteology and

~.yology of lizards is scattered and varied. Descriptions of skulls

representing almost all families can be found. With the exception oi'

such papers as Camp (1923), McDowell and Bogert (1951+), Savage (1958),

Etheridge (1964), and Fresch (1969), little has been done, utilizing

osteology, to analyze the evolutionary lines within families. The

myology of lizards is even less well known ,-rith no attempt having been

made to analyze the musculature of a particular family or evolutionary

line within a faJnily.

The fossil record of lizards is very incomplete, as indicated

by the above smmnary, but the fossil record does indica.te that lizards have been in existence since Triassic time and in North America since

Cretaceous time. Little has been done to trace the degree of change

between fossil osteology and recent genera.

Besides dealing with the osteology and myology of the head

region, this paper utilizes the anatomy of the sternum. Some of the

earliest discussions of the sternum are those of Howes (1891) and

Parker (1891),. who described the sterna of .fossil reptiles. Sabatier

(1897) examined reptile sterna and clavicles, and commented on their origin. One of the most complete, early attempts at discussing the

osteology of the sternum, was that of Hanson (1919) who described the

sterna of Cnemidophorus (Teiidae), Anguis (.Anguinidae), Stellio (Agamidae)

Varanus (Varanidae), Chirotes (Amphisbaenidae), £hamaele<2_(Chamaeleonidae)

Draco, Calote (Agamidae) and Iguana (Iguanidae).

Camp (]_923) described the stern3. of lizards in detail. He 18 presented a su.rn:maryof all elements as found in the recognized families and figured the sterna of Gerrhosaurus (Cordylidae), Xenosaurus

(Xenosaurid.ae), Bachia (Teiidae), and X..A.ntusia (Xantusidae). In 1932

Gladstone and Wakeley presented a survey of the morphology of the sternum and its relationship to the ribs. Reese (1923) figured the sternum of Tubinambis (Teiidae). In 1947 El Toubi included a descrirr- tion of the sternum in his account of the osteology of Agam stellio

(Agamidae). The same author published a photograph of the sternwn of

Uromastix aegyptia (Agamidae) in 1949. Islam figured the sternum of

Uromastix in 1956~ In his "Osteology of the Reptiles 11, Romer (1956) discusses the evolution of sternum and figures that of Lacerta (Lacer- tidae), and Bachia (Teiidae). Savage (1958) utilized the sternun in his discussion of Uta and Urosaurus (Iguanidae). He figured the sterna of bath genera..

Potter (1961) described and figured the sternum of Phr:ynosorna

(Iguanidae) as did Kulge (1962.) for Coleonyx: (Eublepharidae). In 1964

Etheridge exa..imned and figured the sterna of Phr:vnosornB, Uma) Callisaurus,

Holbrookia, Petrosaurus, Uta, Urosaurus and Sator in his analysis of the evolution of the sceloporine line of iguanids. In 1965 he discussed the abdominal skeletons of lizards and figured sterna and ribs of

Stenocercus, Amblvrhmchus, Anolis and Chalarodon (Iguanidae). In this paper Etheridge notes four patterns of attachment of ribs to sterna, which is of value in separating the various groups of iguanid lizards.

Weiner and Smith (1965), in their discussion of the crotaphytiform lizards, figured the sterna of two species of Crotaphytus. The sternal structure of Leiocephalus (Iguanidae) was discussed by Etheridge in 1966.

The sternum and ribs of Phrynosoma (Iguanidae) rediscussed by Jenkins 19

and Tanner (1968). Lastly, Presch (1969) presented and figured the

sterna of Petrosaurus, Uma. and Phrynosoma ( Iguan.idae).

The tongue and associated hyoid elements of lizards h3.ve

received more attention than has the sternum. The earliest p:i.pers on

the lizard hyoid or tongue are thoc:e of Lasana (1834) and M:Lnot (1880).

Each author presented a general discussion of hyoid elements in reptiles.

Cope (1892), in his 110steology of the Reptiles 11 discussed the hyoid

bones and figured those of Sphe11odon (Rhynchocephalia), Chamaeleon

( Chamacleonidae), Gekko, Aristollip; er, Phvllodacty lus, Thecadactvlus

( Gekkonidae), Eublepharis (Eublepharidae), Calotes, Phry_nocephalus,

Uromastix (Agamidae), Holbrookia, Phr:vnosorna, Sceloporus, Uta,

Sauromal us, Crotaphyt us, Anolis, Ct en~£§., Il!ua.na ( Iguanidae),

Anguis, Dracaena, Gerrhonotus, Opisaurus (Jmguinidae), Heloderrra

(Helodermatidae), Xenosaurus (Xenosauridae), Y..a..!§:I.l}lS (Varanidae),

Scincus, Eu..'lleces, Egernia, Liolepisrna, Gongylu~ (Scincidae)) Celestes

(Anguinidae), Gerrhosaurus, Zonurus ( Cordylidae), }funcus (Lacertidae),

Tubinambis, Cnemidophorus (Teiidae), Anniella (Anniellidae), Chirotes,

Amphisbaena and Rhineura (AmphisbaenidaeO. In 1895 Cornig discussed the tongue musculature of reptiles. Chaine analyzed the muscuJ_a,ture in the region of the h3roids in 1902.. Although his paper is very general, he does describe some of the muscles of Chamaelon (Chamaeleonidae).

Beddard (1905) figured and described the hyoid bones of ChlaJnydosaurus kingi and fhysignothus (Agamidae). In 1908 Gandolfi described the tongue of agamids and iguanids. The musculature of the tongue of Agan~,

Amphibolurus, Calotes, Liolaemus (Agamidae), JE.ll~l.:§ and Cycl~

(Iguanidae) are described. Camp (1923) also dealt with hyoids and tongues in his tome on lizard classification. The tongues were described 20

in general and the hyoids of Coleonyx (Eublepharid.ae)., Uroplatus

( Gekkonidae), Brachylophus ( Iguanidae) ., Calotes ( Agamidae)., Phrynosoma.

(Iguanidae)., Gerrhonotus (Anguinidae)., Gerrhosaurus., Charn.a.esaura,

Zonu~ (Cordylidae), and Xenosaurus (Xenosauridae) were figuredo Reese

(192.3) described &"ld figured the tongue of Tupinambis (Teiidae) ~ In

1929 Sewertzoff described the tongues of reptiles in general and pro-

posed a phylogeny based on themo 'I'he tongue of Lacerta (Lacertidae),

Ascalabotes (Gekkonidae), Ophisaurus, Anguis (Anguir1idae), A.blepharus

(Scincidae), Varanus (Varanidae), Ameiva (Teiidae), Calotes (Agamidae),

and Chamaelo (Char:iaeleonidae) were discussed and figured. Ping (1932)

described the tongue of Hemidactylus bouriggii" The hyoids artl ton..gues

of Hemidactylus (Gekkonidae), Habuya (Scincidae), Cabrita (Lacert.idae),

Varan~ (Varanic.ae), Anolis ( Iguan ..i.dae), Calotes (Agamidae), §_:g,ana,

"C(' (~~<1m7..:l,,c\ ,.,.,,,;; r,i-,,,..,.,..,pl,::,r,n 1 Dr•· c~.. --~,, _.E,cL--•--1....1..c...,-..,,J \ CW.1"..J. ....1~.r:- ....__ ..:...,.. _ ....,.....,__--:: (Ch!.lrrJ'>"']eoni·ct·,-).•.·.-1;.l-- !.C'-.,~ . ,, -- c-1,,e ,,,ereY\ ., t'1-isc11csed-L ~:,J a11a

illustrated by Gnanamuth~ (l937), as was the hyoid of Agam~ stellio

(Agamidae) by El Toubi (1947). The tongue of the·anguinimorphs

Gerrhonotus (Anguinidae), Shinisaurus (Xenosauridae), Varanus (Varanidae),

Heloderma (Heloderrnatidae) and Lanthanotus (Lanthanotidae) were analyzed

by McDowell and Boeert in 1954. Oelrich (1956) described the hyoid of

Ctenosaura (Iguanidae) o Romer (1956) has also treated the hyoi.ds of

lizards and illustrated those of Heloderma. (Heloderrnatidae) and

Basiliscus (IgLlanidae). The hyoids of Indian reptiles were described

by Sondhi (1958) who figured the hyoid and tongue of Varanus (Varanidae).

Jollie (1960) described the h;roid of many genera of lizards and figured

that of Amphisbaena (Amp,.½isbaenidae) o Goin and Goin (1962) figured the

tongues of Mabuya (Scincidae), Varanus (Varanidae), Tachydromus

(Lacertidae) ., Ophisaurus (Anguinidae), Ca~ot,~s (Agamidae), Gekko 21

(Gekkonidae), Nessia (Scincidae) and Dibamus (Dibamidae). Kluge (1962) described the hyoid of Coleonvx (Eublepharidae) and Tilak (1964) presented the hyoid of Uromastix (Agamidae). Presch (1969) illustrated the hyoids of Phrynosoma coronaturn and Sceloporus magister (Iguanidae).

'l'he hemipenes have been considered by a few workers as being of evolutionary importance. One of the earliest comprehensive discussions is that of Cope (1896), who described the hemipenes of several genera of lizards and was able to create a key to separate some genera of Iguanidae by their hemipenes. Camp (1923) also utilized the hemipenE in his classification system. He also sUillJT'arized Cope 1s work.

Ortenburger (1923) suggested a method for preparing reptilian hemipenes for study. Mccann (1946) also treated the subject of hemipenes in reptiles. The hemipenes of Uromastix hardwickii was examined by Charles

(1953) and Majupuria (1957). Dcwling and Savage (1960) discussed in detail the hemipenis of snakes. Their paper is a classic and is a primary source of information on structure and vocabulary concerning reptile hernipenes. The latest work on hemipenes is that of Rosenberg

(1967) who described those structures in the Amphisbaenidae.

SeYeral other approaches have been used in studying the problE of saurian prwlogeny. One structure that has been examined is the ear of lizards. Smith (1938) studied evolutionary changes in the middle ear of some agamids and iguanids. Baird (1960) surveyed the periotic labyrinth of reptiles. Hamilton (1964) exawined the gross structure of the inner ear of lizards and was able to divide lizards into four groups on the basis of their ear structureso Schmidt (1964) examined

Uie phylogenetic significance of the lizard cochlea and from his study was able to make some phylogenetic groupings bet:,ieen families. 22

Histological evidence is also useful in interpreting iguanid

phylogenyo In 1955 Hebard and Charipper studied the adrenal glands of

several genera of lizards. The authors' work shows the natural group-

ing of lizards at family level and confirms the phylogenetic conclucions

of Camp (1923) based on osteology and nzy-ology. The thyroid glands of

iguanids and agamids were compared by Lynn, 0 1Brien and Herhenreader

(1966). They concluded that both families are closely related.

In a study of pinworms in lizards, Gambino (1957) and Gambino and Heyneman (19.60) found that the most primitive pinworms are

specific to Dipsosaurus, Sauromalus, Ctenosaura, and Enyaliosaurus.

A further approach to saurian phylogeny has been through karyotype study. Several papers have described the karyotype of

different genera of lizards but the paper by Gorman, Atkins and

Holzinger (1967) is most use.f\il in phylogenetic interpretations.

Fifteen genera were examined, including Ctenosaura, Cyclura, Iguana and

Sauromalus of the iguanine lin.e. They found that the karyotype evolution in iguanids has been quite conservative and there appears to be very little difference in the chromosomes of the genera from Madagascar,

Brazil, the Antilles and North America.

The results of such methods of study as histology, parasito- logy and cytology are suggestive but not sufficiently specific to be

definitive. The complete solution to the problems of iguanid phylogeny must come therefore from studies of gross anatomy and particularly from

osteology and myology.

The problems of iguanine diBtribution have been discussed by Beaufort (1951), Darlington (1957) and Carlquist (1965). All three

considered the Pacific iguanids as waif populations resulting from 23 rafting but were at a loss to explain the presence of iguanids on

Madagascar.

The plausibility of Continental Drift and its effect on ancient flora and faunas have recently been detailed by Hurley, Almeida, Melcher,

Cordani, Rand, Kawashita, Vandoros, Pinson and Fairbairn (1967),

Heirtzler (1968), Ma.xwell (1968), Hurley and Rand (1969), Kurten (1969) and McElhinny and Luck (1970). These authors have reviewed the history of the drift theory and presented new evidence consisting of comparative radiometric ages, sea-i'loor spreading, and paleomagnetismo The fossil remains from Antarctica, Africa and South America have also been cited. 24

MA'rERIALAND :METHODS

The descriptions of the osteology of the ten genera investigated are based on four or more skulls and jaws and two or more sterna and hyoids from each groupo In all cases skeletons were cleaned by soaking in 50%ammonium hydroxide after defleshing, and then boiling for one to three hours in water cmd cleaned by hando Final.. cleaning of sutures and bleaching was accomplished by immersion in Chlorox bleach for a few minuteso Many of the museum specimens were obtained as skeletons and required no cleaningo

One or two s pec:imens of each genus were used .for myological

hyoids and hemipenes were removed from specimens destined to be skeletonized or from individuals on whom the rnyological studies had been completedo All three structures were preserved and stored in 70% alcoholo

All specimens are accessioned in one or another of the natuial history collections of the following institutions: American Museum of

Natural History (AM:NH),Brigham Young University (BYU), Museum of

Comparative Zoology, Harvard University (MCZ), Southern Connecticut

State College (SCSC) and Uo So National Museum (USNM)a Below is a summary list of materials utilized for this studyo

OSTEOLOGY / . Amblyrhynchm; cristatus Bell Mam 24978) Galar:a,gos Islands 25

AMN'ri7591+3, Galo.pagos Islands AMNH76197, Galapagos Islands BYU 22810, Galapagos Islands MCZ2006, Charles Island, Galapagos Islands Brachylophus fasciatus Cuvier BYU2371+3, Nukualoi'a, Tonga Island MCZ5222, Fiji Islands MCZ15008, Vnnisea, Kadavu Island, Fiji Islands MCZ15009, Vunisea, Kadavu Island, Fiji Islands Cha.larodon madagascariensis Peters MCZ11508, Tulear, S. W. Ea.dagascar MCZ11522, Tulea.r, S. W. Madagascar MCZ11531, Tulear, s. W. Madagascar MCZ115 32, Tul ear, So W. :tv'JB.dagascar Conolophus_ subcristatns (Gray) A:tvINH5079?, Galapagos Islands AMI\lH 50798, Galapagos Islands AJvj}JH71301+, Galapagos Islands MCZ2027_, Albrmarle Island, Ga.laps.gos Islands Conolophus p::i,llidus Heller MCZ79772, Galapagos Islands Ctenosaura hemilom ( Cope) BYU30272, St. Esteban Island, Gulf of California Ctenosaura pectinat~ (Wiegman) BYU22796, San Blas, Nayarit, Mexico MCZ11350, Colirna, Mexico MCZ 2176, Acap1_1_.lco,Mexico MCZ24904: Tepic, Mexico Cyclura carinata Harlan MCZ59255, Sand Cay, Turks Island Cyclura cornuta (Bonnaterre) AMl-H--157878, No data, probably Ha:Lti A}Th.11-I57968, No data, probably Haiti Cyclura macclevi Gray MCZ6915, Santiago, Cuba Enyaliosaurus clark~ (Bailey) USJ\J1148965, No data Enyaliosaurus palearis Gray USNM21452, No data Dipsosaurus dorsalis Baird and Girard AMNH79962, Palm Springs, California BYU 21726, PaL~ Springs, California BYU 23760} Palm Springs, California BYU23761, Palm Springs, California Iguana iguana Wiegman BYU22795, El Zacatal, Campeche, Mexico BYD 22852, San Blas, Nayarit, Mexico MCZ 54989, Gorge of Tortugero, Costa Rica SCSC 506, Finca Toboga, GuanacaE:te Province, Costa Rica Iguana delieatissirna Laurenti MC'Z83228, St. Eustatius Oplurus sebae (Dtuneril. and Bibron) MCZZ:3336,No data MC'Z37188, Majunga, Madagascar MCZ37191, Majunga, Madagascar l'-1CZ37192, :VJ.ajunga, Madagascar Sauromalus ohesus (Baird) BYU 21734, Glen Canyon, Utah BYU23762, St. George, Utah MCZZ33.35, 35 miles West Sonoita, Sonora, Mexico MCZ8894, Buckskin Mountains, Arizona Sauromalus hispidus Stejnger MCZ79777, Angel de La Gu.arda Island, Gulf of California Sauromalus s~ Cliff MCZ85533, Isla San Marcos, Gulf' of California Sauromalus varius Dickerson MCZZ333F, No data BYU 30269, St. Esteban Island, Gulf of California BYU 30270, St. Esteban Island, GuJ_f of California BYU30271, St. Esteban Island, Gulf of California

MYOL0GY

Amblyrhynchus crista.tus Bell BYU 22806, Galapagos Islands BYU22810, Galapagos Islands Brachylophus fasciatus Cuvier BYU 237h3, Nukualofa, Tonga Island BYU 31955, Nukualofa, Tonga Island Chalarodon Jrli:J,uc1,gc1,st.:a:r.·.i_e11s:i_;:,I'et6;·;:;, BYU22801, Tulea, Madagascar BYU 22.803, 'I'ulea, Madagascar Conolophus subcristatus (Gray) BYU22811, Galapagos Islands Ctenosaura pectinata (Wiegman) BYU22796, San Blas, Nayarit, Mexico BYU22850, San Blas, Nayarit, Mexico Cyclura nuchalis Barbour and Noble BYU 22799, North Cay, Bahawa Islands Dipsosaurus dorsalis Baird and Girard BYU 21726, Palm Springs; Califo:rnia. BYU 22855, Palm Springs, California BYU 23760, Palm Springs, California BYU 23761, Pa,lm Springs, California BYU3195h, Mesquite, Nevada Iguana iguana Wiegman BYU2279 5, El Zacatal, Campeche, Mexico BYU 22851, San Blas, Nayarit, Mexi8o BYU 22853; San Blas, Nayarit, Mm:ico 0plurus sebae (DlDlleril and Bibron) BYU 11504, Andrambovato, Madagascar ~omalus obesus (Bai.rd) BYU 2173h, Glen Canyon, Utah BYU 23762, St. George, Utah BYU 31953, St. George, Utah 27

OSTEOLOGY

An examination of the osseous elements of the iguanine lizards and the Madagascar iguanids reveals the following structures.

SKULL AND JAWS

'J"he superficial elements of the skull of the iguanines and the Madagascar iguanids have been examined in detail. The analysis of the skull bones and javrn was made from two approaches. One approach was to examine the size of the bones by measuring length and width of ea.ch bone and then computing a percentage between length and width, which was then compa.red with sirrj_lar data for identical bones in other genera. Tables representing the means and the ranges of these values for each genus are presented at the end of this chapter. All measurements are in millimeters.

A second approach to the study of the skull was made through observations and comparisons of the shape of the bones and their relationship to o-!:,her bones o A summary of these observations and comparisons are presented in the text of this chapter. All observations and measurements are based on four to six individuals from each genus.

The skull of the iguanine lizard is streptostylic with a freely movable quadrate bone which articulates dorsally with the paroc- cipital process and ventrally with the quadrate process of the pterygoid.

Such movement can be demonstrated in fresh and preserved specimens of all the genera examined. In general it may be said that the iguanine 28

skull forms a compact and light, yet very strong cage for the brain

and sense organs of the head.

The general shape of the skull is either elongated and flattened

dorsoventrally or shortened and flattened laterally. Measurements of

the 1ength o.f the skull were taken from the tip of the premaxillary bone

to the most posterior extension of the occipital condyle. Width of the

skull was taken at the widest e:;.,-.tension between the suborbital bars in

the area of the orbit. · Height measurements were taken at the posterior

end of the maxillary bone and extending to the skull roof directly

above that point. A summary of the range~ and means of these measurements is presented in tables 1 and 2.

A survey of the means presented in those tables indicates that

Amblyrhynchus (length-width, .789, length-height, .460) has the shortest

continental genera Saurornalus, Ctenosaura, and Cyclura. Table 2 indicates that Sauromalus (.286) has the flattest skull of the iguanines, followed

/ closely by Ctenosaura (.316) and Cyelura (.326) which also have a low

skull roof.

For the sake of convenience the skull has been divided into a posterior occipital segment and an anterior maxillary segment.

The occipital segment forms a median axis for the attachment of the neck and articulation of the remainder of the skull. It consists of two rarts, (a) the braincase (basisphenoid, basioccipita1, prootic> exoccipital, supra.occipital, and the associated semicircular canals), and

( b) the foramen magnum ( enclosed by the basiocdpital, exoccipital and supraoccipital). A tripartate occipital condyle is located on the pas-• terior end of the basioccipital in all genera of iguanine lizards. 29

Basisphenoid (Plates I and II) forms a portion of the floor of the braincase, is bordered posteriorly by the basioccipital, and is attached dorsally to the prootic bone. Anteriorly the bone is expanded into two anterolateral basipterygoid processes which articulate laterally, with the pterygoid bones. Anteromedially the basisphenoid is extended forward as the parasphenoid process. The basisphenoid forms points of origin for the inferior part of the protractor pterygoideus muscle.

Measurements of the length of the basisphenoid were made from the suture between basisphenoid and basioccipital, to the beginning of the parasphenoid process. Width was computed as the distance between the widest extension of the basipterygoid processes, An examination of the ratio means in table 3 reveals that the lowest ratio is possessed by Chala.rodon ( .360) while the highest is that of Oplurus (. 755).

A.t'T!ongthe New World genera, Dipsosaurus ( .469) has the lowest ratio and

Iguanq ( .652) has the highest. A lav, ratio indicates that the bone is much longer than wide, ·whereas the higher ratios indicate bones that have lengths and widths almost equal.

Observations of the bone 1 s position in the skull indicates some variability in the articulation between basipterygoid process and the pterygoid bone. This articulation occurs medial and posterior to an expansion of the pterygoid bone just posterior to the pterygoid 1 s midpoint. This point of articulation is almost completely obscured ventrally by the pterygoid bone in Amblyrhynchus, Chalarodon, and

Oplurus. In Dipsosaurus the articulatfon is visible ventrally but occurs dorsad to the ventral border of the pterygoid. In Brachylophus,

Conolophus, Ctenosaura, Cyclura, _Iguana and Sauromalus the anterior articulating portion of the basipterygoid proceso is partially obscured 30 while two thirds of the articulation occurs on the ventromedial border

of the pterygoid bones, rather than on the medial face.

BasioccipitaJ (Plates I and II) forms part of the occipital condyle and the posterior floor of the braincase. It is the main point of attachment for ventral axial musculature. Anteriorly the basioccipita.l

joins the basisphenoid and dorsolaterally it attaches to the exoccipitals and the prootic bones. The third bundle of the longissimus dorsi muscle attaches here.

Length and width measurerr,ents were made of the basioccipital with the length being ta.ken from the suture between the ba.sisphenoid and ba.sioccipital to the posterior tip of the occipital condyle. The width of the bone was considered as the distance between the tips of the lateral extensions of the spheno-occipital tubercles. An examination of the ratio means in Table 4 indicates that the highest ratios for the basioccipital are possessed by Brachylophus (.709), Ctenosaura (.664), Arrblyrhynchus (.663) and Sauromalus (.649)· while QiJ2,sosaurus

(.369) and Conolophus (.477) possess the lowest ratios. High ratios denote that lengths and widths are nearly equal for the bone.

Prootic bones form the anterola.teral wall of the bra.incase and contains the elements of the ear. Posteriorly, the-prootic is bordered by the supra.occipital, ba.sisphenoid, basioccipital, and the ex.occipital. The anterior portion of the bone is surrounded by membranes that contain the optic nerve. The pseudotemporalis and protractor pterygoideus muscles originate on the prootic bone. Because of difficulties in measuring, the prootic was not studied in detail.

Ex.occipital bones form the posterola.teral 1rmll of the bra.inca.se and the lateral pg.rts of the occipital condyle. MedioJ.a.tera.l articulations form 3l with the µ:i.rietal, supratemporal and CJ).ladrate boneso The exoccipital also articulates at its most lateral projection with the prootic bone.,

The longissimus dorsi and episternocleidornastoideus muscles insert on the paraoccipital process of the bone.

The length of the exoccipital tone was measured from the lateral wall of the foramen magnum to the point of articulation by the paraoccipita1 process with the squamosal and quad.rate bones o Width is represented as the distance between the exoccipital articulation with the supraoccipital bone and the union with the basioccipital at the occipital condyle. As table 5 indicates, the lowest ratio means for exoccipitals are possessed by Dipsosaurus (0594) and Conoloph'Js (.626).

The largest ratios are found in Brachylophus ( .858), Amblyrh;rnchus

( .8.30) and Cha.la.rod.on ( .81.3). As with the other bones, near equal relationships between length and width are expressed as high ratios.

Supraoccipital (Plates III and IV) forms the roof of the posterior part

of the braincase and the dorsal rim of the foramen rnagnum0 It articu~ lates with the prootic bone anterolaterally> the exoccipital posteriorly, and the parietal at its anterior extreme.

The supraoccipital lengths were measured as the distance between its posterolateral sutures -with tl-:te exoccipital bones in the area of the foramen magnUJ!l.. The width was measured as the distance between the suture with the parietal bone anteriorly, and the dorsal lip of the foramen magnum posteriorly. Tab:e 6 indicates that the genera possessing supraoccipitals with the lowest ratios include Chalarodon

(. 583), Oplurus (. 675) and Sauromalus (. 680), while the highest ratios are found in Brachylophus (.982) and Igua~ ( ..979). 32

Orbitosphenoid is a vertical element surround:ing the optic foramen.

The anterior border forms the posterior margin of the optic foramen and the inferior process forms an area of origin for the superior rectu muscles at the eye. The orbitosphenoid also has connections with the

prootic bone and the alar process of the basisphenoid. It was found to be absent in most of the cleaned skulls in the collections examined.

The combination of bones in the anterior region of the skull

is referred to as the maxillary segment. It consists of four parts,

(a) the palate (pterygoid, ectopterygoid, vomer, palatine, premaxilla, and maY..illa), (b) orbits ( frontal, postfrontal, and jugal), ( c) nasal

capsuie (nasal, prefrontal, lacrirnal, and septornaxilla), and (d) temporal fenestra (parietal, supratemporal, postorbital, squamosal, quad.rate and epipterygoid) •. These bones are discussed as listed above.

Pter,:r['.Ojd (Plates I: II, III, IV., V and VI) extends posteriorly as the posterior part of the palate. The pterygoids are paired bones sutured at the anterio:c end of the palatines, anterolaterally to the ectoptery- goids and posteromedially to the basisphenoids. They comprise a major area of motion between the occipital and maxillary regions as the posterolateral portions articulate with the quad.rate which is movable.

Articulating with the pterygoid on the dorsal border of the quadrate projection is the columella. At the ventral border, the pterygoid forms the posterior limit of the oral cavity and contributes an area for the origin of the pterygoma.ndibularis muscle. On the dorsal ridge, medial to the columellar fossa,. is an area of insertion for the levator pterygoideus muscle, The insertion of most of the protractor pterygoid eus muscle is located on the medial surface of the quadrate process of the pterygoid bone. The posterior fibers of the pterygomandibularis 33 muscles arise along the ventrolateral border of the lateral side of the quadrate process.

Measurements taken of the pterygoid bone include length; represented as the distance between the anterior portion of the pterygoid where it sutures w.ith the palatine and the most posterior tip of the quadrate process; and the width as the distance between the articulation with the basipterygoid process of the basisphenoid bone and the suture with the ectopterygoid bone. Table 7 summarized those measurements and a survey of the ratio means indicates that the lowest pterygoid ratio

(long, narrow bones) are JXJSsessed by Cyclura ( .283), Sauromalus (o29J), and Iguana (o.309). The highest ratios (short, wide bones) are found in

Brachylophus (.458) and Chalarodon (.4.35). The unique relationships of the pterygoid to the basipterygoid process of the basisphenoid bone have aJ.:reacly been reviewed, The shape of the medial border of the pterygoid also controls the shape of the pyriform recess (Plates I and

II) of the pg.late. This shape varies from a gradually widening slit as seen in Brachylophus, Chalarodon and Oplurus to a more severe and rapid change in width of the recess as seen in Amblyrhynchus, Conolophus and Cyclura. The remaining genera are intermediate between the above condition.so

Ectopte:rygoid (Plates I, II, Ill, IV, V and VI) forms a brace between the palate and the external roofing bones. Laterally the ectopterygoid sutures with the jugal and the }XlSterior process of the maxilla, and mesially with the pterygoido Dorsally it forms the posterolateral pg.rt of the floor of the orbit.

Measurements m..qdeon the ectopterygoid include the length, taken as the distance between the suture with the pterygoid and the 34

and the suture with the jugal and rr1.a...xilla. The width was measured as

the greatest diameter of the bone at its point of union with the jugal

and m'lxilla. These measurements are surnrnarized in table 8 and an

e.xa:rrj_nation cf the ratio means shows that the lowest ratio (long,

narrow boi1es) is .found in Amhlyrh;vT1chus ( .275) and the form with the

highest ratio (short, wide bones) is DipsosauruQ_ (.600).

Vomers (Plates I and II) are µi.ired bones forming the most anterior part

of the plate, the medial borders of the fenestra vomeronasalis externus and the medial borders of the fenestra exochoanalis. Posteriorly the vomer is attached to the palatines and dorsally to the medial surface

of the maxilla. Medially the vomers support the nasal septum and the

cartilage of Jacobson 1 s organ. At the extreme anterior end the vomer

sutures with the prernaxilla.

Tlie length of the vomer was rne2.sured from the anterior suture with the premaxilla to the most posterior point of the suture with the

palatine bone. Width of the vomer was the distance between the medial border of the vomer at the ventral midline and the most lateral border where it attached to the maxilla. Table 9 swnmarizes the measurements of vorner bones and the ratio means show that shortest, widest, vomers

(lLLghest ratios) are possessed by Chalarodon (. 711) and the narrowest longest vomers (lowest ratios) are possessed by Amblyrhynchus (.253),

Cyclura (.274) and Ctenosaura (.278).

The vomers possess a small blunt projection that protrudes from the late:r-al border of the bone into the opening of the fenestra

exochoanalir, and fenestra vomeronasal:is externa and separates the opening. The possession of this anLerolatoral projection is seen in all ten genera. Some genera have a secondary projection which extends into 35 the lumen of the fenestra vomeronasalis externa .. This projection can be seen in Braclwlophus, Ctenosaura, Cyclura, Iguana, and in Sauromaluso

Palatine (Plates I, II, III and IV) bones form the :main part of the palate, the floor of the orbit and nasal capsule. This bone has three processes; the anLer:l.or or vomerine, forms the posterior floor of the olfactory capsule; the pterygoid process, which attaches dorsally to the pterygoid, forms the medial rim of the inferior orbital fossa and the floor of the orbit; and the .max:i.llary process attaches dorsally to the prefrontal and ventrally to the .jugal and maxillary bones.

The length of the _p3,latine was taken as the distance from the anterior suture with the vomer bone at the midline to the most posterior extension of the suture with the pterygoid bone. The width of the

P3-latine bone was con.sidered to be the distance .from the palatine medial border at the skull ts rrd.dline to the latere.l suture between the palatine and the ma.ulla. Table 10 summarizes these :measurements for the ten genera under discussion. The re.tic means column indicates that the shortest and widest bones (highest ratios) are possessed by Chalarodon (.846) while the longest and narrowest bones (lowest ratios) are found in Cyclura (.466).

Pre:maxilla ( Plates I, II., III, IV., V and VI) is the most anterior bone of the skull, and joins the maxilla laterally and the nasal bones dorsallyo It forms the rostrum of the skull.

The length of the rna.:x:illa was considered to be the distance from the anteroventral tip of the bone to its dorsal union with the nasal bones at the dorsal midline of the skull. The distances between the lateral sutures shared by the prernaxilla with the maxilla on the ventral surface of the bones were considered to be the width of the 36 premaxilla. The length and width values of the premaxilla are expressed in table 11. The ratio mean column indicates the highest ratios

(shortest, widest bones) is found in Conolophus (.914) while the lowest ratio (longest, narrowest bone) are found in Cyclura (.491), Ctenosaura (.512) and Iguana (.~21).

The suture beb,,,een the posterodorsal portion of the premax.illa and the nasal bones differs from genus to genus, in the degree of penetration the premaxilla makes between the two nasal bones. In

Amblyrhynch-q_~, Conolophus, and ,Ig-q_ana;, the penetration of the premaxilla is very shallow with that of Conolophus forming a shallow curve and penetrating the nasals very littl0. Deep penetrations of the prernax.illa are found in Brachylophus, Chalarodon and Op1urus. Moderate penetrations are found in the remaining genera.

Ma_-.d_lJa (Plates I, II, III: IV, V c1nd VI) forms the major lateral surface of the snout. The ventral margin bears a single row of pleurodont teeth. There are three protrusions from the main region of the maxilla. The first protrusion is the prema.xillary process which overlaps and is attached to the maxillary process of the premaxilla. The medial part of the rnaxilla is attached to the vomer whereas the dorsal extension forms the inferior rim of the fenestra exonarina.

The posterior process of the maxilla is attached to the jugal and larcimal bone dorsally, and to the ectopterygoid medially. This process forms the lateral part of the rim of the inferior orbital forar.r1en,

The third process of the maxilla extends dorsally to form the lateral wall of the nasal capsules, the posterior rim of the fenestra exonarina anteriorly, and dorsally attaches to the nasal and prefrontal bones. .37

The length of the maxilla was taken from the anterior most extension of the prema:x:illary process where it formed a suture with the prema.xilla to the posterior most eA'tension of the maxilla where it joined the jugal and ectopter-y-goid bones. The width of the maxilla was considered to be the vertical distance from the ventral border of the maxilla to the dorsal most extension of the bone at the point where it sutured with the nasals and prefrontals. Table 12 summarizes the maxillary measurements. The ratio mean column indicates the longest and lowest maxilla (lowest ratios) are found in Chalarodon (.334), Oplurus (.358), Ctenosaura (.371), Brachylophus (.373) and Sauromalus (.377). The shortest and widest bones (highest ratio) are found in Amblyrhynchus (.619).

Nasal (Plates III, IT, V and VI) forms the sloped top of the snout and po.rtially covers the nasal capsule. The nasals attach posteriorly to the frontals, anteriorly to the prema.xilla, and laterally to the prefrontals.

Part of the anterior border of the nasal bone forms the dorsal border of the fenestra exonarina.

The measurement of length of the nasal bone was taken from the tip of the ventral border as it formed the fenestra exonarina to the posterodorsal extension that sutured with the prefrontal. Width was defined as the widest portion of the bone from its medial suture with its opposite member to the most lateral extension of the bone where it sutured with the maxilla and prefrontals. These measurements are expressed in table 13 where the ratio mean column shows the nasals with the greatest ratio of length to width (short, wide bones) are found in

Ctenosaura (.555) and Brachylophus (.522), while those with the lowest ratio (long, narrow bones) are found in Amblyrhynchus (.375). 38

The basic shape of the nasal bones differs from genus to gen1

The major differences include the amount of nasal bone that borders the premaxilla, the shape of the posterjor border that sutures with the frontal bone, and the shape and position of the lateral border that sutures with the ncs.xilla and pre.frontals. The nasals border a J_arge portion of premaxilla in Brachylophus, Chalarodon and Oplurus o A short border with premaxilla is seen in Amblyrhynchus, Conolophus and Iguana,

The posterior bo:cder of the r1asal forms an interfingering suture with the i.'rontal bone in Amblyrh;vnchus, Conolophus, Dipsosaurus, Iguana, and Saurornalus. The posterior projection forms a smooth suture in the remaining generao The shape of the posterior border of the nasal bone may be roughly straight as in Amblyrhynchus, Conolophus and Igua~ or it may form a posteriorly projecting triangle as in Brachylophu~,

The lateral borders of the nasals form a shallow curve in

Brachylophus, Chalarodon, Conolophus, Ctenosaura., Cyclura, DipsosaurusJ

Iguana and Oplurus. In Junblyrhynchus and Sauro:malus this curvature is disrupted at its ante:cior end by an indention for the dorsal projectior of the maxilla ..

Prefrontal (Plates III, IV, V and VI) forms the anterior angle of the orbit. Medially it attaches to the frontal and nasal bones, ventrally to the maxilla and posteriorly to the lacrimal.

Length measurements were taken from the suture between the prefrontal and lacrimal bones at. the anterior lip of the orbit, to the suture between the prefrontal and frontal bones on the dorsal lip of the orbit. The width of the prefrontal bone was considered to be from the suture between the prefrontal and lacrirnals to the medial point where -r:,he .fro::tal, rQsa·1 and pre.frontal bones suture together as seen in table lL:. '1'11':; prefr.·onLals with tbe, greatest ratio of length to width

(shortest, ':J:t.c~est boY:e,,) arc posse:ssed by Am£1Yrhynchus ( • ?76). Those genera with p:refr<,nta,ls havin3: t.11.c lowest ratio (long, narrow· bones) include .QJ1.:J.1§,roclon(o5.l2)_, Saur(TlC~lcs (.55-3), and Brachylophus (.5?J)o

Laerimal ( Plate~, V and VI) is a srne.11 bone on. the anteroventral rin: of the ot'bit. Dorsally it is attached to the prefrontal, anteriorly to the :rna:x:iJJ.,.:.,ventrally to the j 1.1gal and v,mtromedially to th2 prefrontsJ .•

Mec.surements takAn on the lacrimal include length as the greatest d.iagonal distance from the anterodorso,l border as it sutures with the pref'rontaJ. and maxil..La to the posterior border on the rim of tlle orbit as it sutures with the j ...:.gal. Width was considered as the vertical dif>tance between the dorsal border of the lacrirnal at the rim of the orbit to the ventral border of the 12,crirnal at its suture v:HJ1 .,_, the maxilla c These 1,1easureraents smrirnarized in table 15 shrn·I vne ratio (long_, narrow bones) for the lacrirr.al bone is found in Chalarodon

The highest ratio (short, w:ide bones) is that for Conoloi:hus

(.542), Ctenosa,ura (0;;32), Cvclura (.,526), and Bracb·s.,J.ornus (.523).

In shape the lacrimal cl:i_ffers from genus to genus. The most common form of the bone is tt1c1.t of a slightly curved rhomboid. This rbomb:)id 3hapo is most perfectly reproduced in Co,1olophus, Ctenosa:ura>

Cyclur-:1 and. 1.Ql.~.£1.£..In fipb] :vrh:vr1~ the bone is reduced to a splinter lj_ke struct,ire ..rhile :i ..n B1·cicb,y-l.or.::l1us,C.>ia.Iarodon, Di rsosaur;is and QpLirus the rhomboid ,;lw.pe is distorted b;y the c1u·ve:Lure of the bone to fit the rim of the orbit. In Sa,uromaJ.us t.lie b:nie ha.s its dorsal part reduced so 8.S to fo:r0 m a rough t:,.0 a1=c::ooid shapco

Septoma.xi~l.la :L,; found withi.n the nasal. capsule where it covers ,Jacobson I s 40 organ and houses the anterior pa.r-t of the nasal capsule~ Because of the difficultness in taking measurements of this bone, it has not been studied in detail.

Frontal (Plates III, IV, V and VI) forms the dorsal border of the orbits and the anterior roof of the braincase. At its posterior extreme the frontal is attached to the parietal and postorbital bones. Anteriorly, it is sutured to the nasal and the prefrontal. The pineal foramen penetrates the posteromedial portions of this bone or the suture it shares with the p:i.rietal.

Table 16 represents length and width measurements taken of the frontal bone. Length was considered to be the distance from the most anteromedial suture shared with the nasals to the most posteromedial suture shared with the pa.rietal bone. The width of the frontal was measured as th8 distance between the most lateral posterior projec•- tions as they sutured with the pa.rietal and postfrontal boneso The greatest width to length ratio (short, wide bones) is to be found in

Ctenosaura (0936) and Brachylophus (.907). The smallest ratio (long, narrow bones) is that of Amblyrhynchus (.629).

The shape of the frontal is basically the same for all genera but differs in some small features between genera. The gre3.test difference in shape occurs at the anterior end where the frontal sutures with the nasals and prefrontals. In Conolophus the anterior border interfingers with the nasals but is essentially straight. In Brachvlo- phus, Ctenosaura, _Q,yclura, Dipsosaurus., Igu™, 0plurus, and Sauromalus, the anteromedial portion is shaped like a triangle and forms a wedge between the p:i.ired nasals. This triangle in Dipsosaurus is still more unique by being bifurcated at its tip by a secondary triangular projec- 41 tion of the nasal bones. In Ctenosaura and Sauromalus the lateral sides of the frontal 1s triangular projection is further bifurcated by secondary triangles. The lateral sutures of this process in Brachylo- phus interfinger with the prefrontals and nasals but is essentially straight as it is in Cyclura~ fgnblyrhynchus and Chalarodon lack this anterior triangular projection and in its place possess a depression which fits around a triangular projection formed by the posterior borders of the nasals. Thus in the latter two genera the anterior portion of the frontal bone is bifurcated and sends a projection anteriorly which serves to separate the prefrontals and nasals for a portion of their length.

The frontals of Amblyrhynchus> Brachylophus, Conolophus and

Cyclura are wider than long. In the other genera the frontals are longer than •,\fide.

The placement of the pineal foramen in the frontal bone or the suture between the frontal and parietal bones is perplexingo The foramen was found to be in the suture between the two bones in all specimens examined of Bra,chylophus, Chalarodon, Ctenosaura, and Iguana.

The foramen appears completely embedded in the frontal bones in one specimen eacri of Amblyrhynchus, Conolophus and Oplurus while other specimens of these genera possessed a foramen in the suture. In Qy:clura the pineal foramen was found in the frontal bone in three of four specimens exarn:Lned while it occured in the frontal bone in all four specimens of Dipsosaurus and in five of six specimens of Sauromalus.

Postfrontal (Plates III, IV, V and VI) .forms a small part of the posterodorsal rrargin of the orbit. Posteriorly this bone is sutured to the frontal, and laterally to the postorbital and th0 parietal. 42

The length of the postfrontal was measured as the distance between the extremities of its longest axis. The width was the distance between the pq,ra,llel borders on the a:x:is at right angles to the length. The values for these measurements are presented in table 17 and it can be seen that the genus 1dth the smallest ratio (longest) narrowest bone) is Chalarodon (.200)) while 0plurus (.625) has the largest ratio (shortest, widest bones) o

The postfrontal is usually splinter like in shape as it is in all genera except Cyclura.:- Iguana and .Q.Q;!.urus. In Cyclura the anterolateral portion of the born, forms a short projection out over the posterodorsaJ. p:i.rt of the orbit in some individualso This condition is especially well developed in Cyclur.§: ..£.2mlltao In Iguat§_ the lateral portions of the postfrontal is developed into a pr-ominant knob on the anterodorsal face of the po:=,torbj_tal. boneo In 01.1Lurus the postfrontal is very swall, almost spherical in shape) and in at least one skull

(MCZ 37191) this bone cruld not be located"

Jugal ( Plates I., II., III, IV, V and VI) forms the ventral border of the orbit and a small part of the sup.ratemporal arch. Anteriorly it attaches to the rraxilla., ventrally to the lacrimal and raJ.atine bones, and medially to the ectopterygoido The do~~sal surface forms the anteroventral wall of the orbito

The length of the jugal was considered as the horizontal distance between the anterior most projections of the bone as it sutured to the lacrimal and maxi].la, to the most posterior projection which sutured to the anteroventral border o.f tho postorbitalo The width was the widest distance between the two parallel borders at right angles to the lengtho Measurements of tbe j-:.Jgal bones are presented in 43 table 180 The smallest ratio (longest, narrowest bone) of length to width is found in Q~no[-,aUr§: ( 0136)) Sauromalus ( 0141), and Oplurus

( 0148) • The largest ratios (shortest, widest bones) are found in filllblyrh:ynchus (.207, Conolophus (.195) a.nd Cyclura (.,191). The posterior extension of the jugal may extend so far posteriorly as to touch or overlap the squamosal thereby completely covering the ventral border of the JX)storbital bone. Such a condition exists in Conolophus, Dipsosaurus, Iguana and Opl.urus. In the other genera the jugals and squamosals do not touch. Parietal (Plates m, IV, V and VI) forms the roof of the rnsterior pa.rt of the skullo It articulates ·with the frontal and postfrontal anteriorly and with the post.orbital posteriorly and ventrally. Pos- teriorly the :p3,rietal overlays the supratemporal and articulates with the exnccipitals and supraoccipita.l~

The anterior two thirds of the dorsal surface of the fe,rietal gives origin to the pseudotemporalis superficiatus muscle) and the posterior one-third gives origin to the adductor externus mediuso The rnsterior tip of the supratemporal process supplies the origin for a part of the adductor externus profundus muscle. Laterally the parietaJ_ bone gives origin to the levator pterygoideus. The posterior border of the :p3,rietal provides attachment to the origin of the depressor mandibularis and the insertion of the spinus dorsi, longissimus dorsi, and episternocleidornastoideus mucles.

Measurements were taken of two areas of of the parietal bone.

The anterior two-thirds of the bone was subjected to length-width measurements, with the length being the distance along the rnidline, from the anterior suture with the f:contal to the suture between the parietal 44 and the supraoccipitalo The width of the p:3.rietal was considered as the distance between the two most anterolateral projections of the bone i..-here they sutured with the postorbital and postfrontalse These rreasure- ments are presented in table 19. The greatest length width ratio

(shortest, widest bone) ls found in Conolophus ( o 751) whil.e Dipsosaurus

( .431) and Brach;yloprns ( .448) possess the smallest ratio (longest., narrowest bones) •

The second portion of the p:3.rietal to be measured was the wings or posterior dorsolateral projections of the bone that sutured with the supratemporal., squamosal and articuJ.ated with the quadrateo

The length of the parietal wings was taken as the diagonal distance from the anterolateral portion of the p:3.rietal bone to the opposite posterior tip of the p:3.rietal wingo The ·width was the distance between the r,-ost ]X)sterolateral surface of the two wings a The p:3.rietal wing ratios are summarized in table 20 and show the greatest length uidth ratios (shortest, widest bones) to be possessed by· Dipsosaurus (.945) and Sauromalus (.926). The lowest ratios (longest, narrowest bones) are those of Brachylophus (.765) and Ctenosaura (.781).

Supratemporal provides support for the posterolateral angle of the rarietal bone. Posteriorly, it articulates with the exoccipital_, squamosal., and the quadrate.

On the medial border of the anterior rart is a rartial origin for the adductor rrandibularis externus profundus muscle and on the lateral border is the origin of the adductor mandibularis externus medius muscle. Because of the difficulties in measuring, this bone has not been studied in detail. Postorbital (Plates I, II, III, rv, V and VI) forms rart of the posterior rim of the orbit. The dorsal part is sutu:red anteriorly to the postfrontal and posteriorly to the parietal bone. The anteroventral border has connections with the jugal and the posteroventral border of the squamosal.

The ventral free border of the postorbital gives origin to the anterior half of the levator angularis oris muscle whereas the medial surface of the posterior half gives origin to the adductor mandibularis externus superficialis muscle.

The length of the postorbital was measured as the greatest distance between ant eroventral and posteroventral projections. The width was considered as the distance from the ventral border to the tip of the dorsal projection where it sutured with the parietal and postfrontal bones. Table 21 shows that the greatest length width ratio

(shortest, widest bone:,) is four'.d in Tr::;11~ ( .886). llmhlyrh::'"!lrhm, ( .882), and Conolophus ( .876). The lmvest ratio (longest, narrowest bones) is possessed by Sauromalus ( ,5.56) and Cyclura ( .585).

The postorbital bone is triangular in shape. Its ventral border has been discussed in the description of the jugal. This border is completely covered by the squamosal and jug3l bones in Conolophus, Dip- sosaurus, Iguana and Onlurus. In other genera the central p-3,rt of the ventral border is free. In Arr~lyrhynchus the anterior face of the dorsal process is enlarged and adds to the knoblike structure of the postfrontal.

The post.orbital of Cyclura appears normal and does not contribute to the postfrontal knob over the orbit.

Sguamosal (Plates I, II, III, IV: V and VI) is attached to the postorbital bone on the posterolateral border of the skull. The expanded posterior part of the squamosal is attached to the dorsal surface of 46 the supratemporal and the quadrate.

The lateral surface of the squamosal provides an area of origin for the adductor mandibularis externus superficialis and rart of the levator angularis oris muscle. The medial surface gives origin to the adductor mandibularis externus medius muscle.

The length of the squamosal was measured as the distance between the most anterior and the posterior extremities of the bone. The width was the greatest distance between the parallel borders on an axis at right angles to the length. These measurements are present8d in table 22 and show the greatest ratio (shortest, widest bones) to be found in Amblyrhynchus (.736). The smallest ratio (largest, narrowest bones) occurs in Chalarodon (.063).

The shape of the squamosal bone differs not only in size but in shape as well. The posterior projection cf the bone has a dorsal and ventral hook like projection in Chalarodon and Onlurus. Those of

Opl.urus are not as well pronounced as those in .Qhalarodon. The posterior portion of the bone in other genera is swollen but the projections are in the forms of sm~ll triangular processes rather than curving hooks as in Chalarodon and Oplurus. The greatest development of these triangular projections is found in Ambl;y:rhypchus, Conolophus, Ctenosaura, Cycli..lra,

Iguana, and Sauromalus. The squamosals take the form of a long split in Dipsosaurus and Brachylophus.

Qua.drate (Plates I, II, Ill, IV, V and VI) is found at the posterolateral angle of the skull where it provides the articulating area between skull and lower jaw. It also formr, the seat. of the middle ear and attachment for the adductor musculature and tymranic membrane.

Mesially the quadrate is attached to the parietal, dorsa.lly to 47 the supraternporal, 8.J."ldlaterally to the squamosal bone. Other ,P3.rts of its dorsal s~face provide for the origin of the adductor mandibularis superficialis muscles. The medial half and its crest serve as origin for the adductor 1113.ndibularis posterior muscleo The posterior end of this area·attaches to the prootic bone and the quadrate process of the pterygoid.

The tYJnpanic crest serves as a place of attachment for the tYJnp,mic membrane and the origin of the adductor rrandibularis externus superficialis muscle.

The length of the quadrate was the distance from the dorsal border of the bone where it attached to the squamosal and the ventral extremity of the condyle of articulation with the articular bone of the lower jaw o Width was the greatest di5tance between medial and lateraJ. borders of the bo:-:eo Table 23 sU..'Tifil-:i.ri'.~esthe quadrate measurements o

Quadrates with the greatest length-width ratios (shortest, widest bones) are found in Sauromalus (0737). The smallest quadrate ratio (longest, narrowest bone) is that of Dipsosaurus (.531), Iguana (.537), arrl Brachylophus ( .546) o

Epipterygai.d extends between the IB,rietal and the pterygoido Its dorsal tip apµ,.:;ars to be held in place by the origin of the pseudoternporalis supsrficialis muscle., The upper one-third of this bone serves as the origin for the pseudoternporalis superficialis muscle" The ventral two-thirds serves the pseudotemporalis profundus muscle as

origin 0 This bone was not studied in detail because it is inside the skuJJ .•

Supratemporal fossa (Plates III and IV) is the large cavity that domi- nates each half of the dor'sa1 posterior third of the skull. It is 48 bordered medially, posteromedially and anteromedially by the :r:arietal bone, anterolaterally by the postorbital and posterolaterally by the squamosal.

Length and width measurements were taken of the supratemporal fossa, with length being the inside distance on the longest axis and width being the inside distance on the longest axis at right angles to the length. Table 24 shows the largest length-width ratios (shortest, widest opening) are possessed by Dip0osaurus (.647), Sauromalus (0620),

Amblvrhynchus (.616), and Conolonhus (.609)0 The smallest ratio (longest, narrowest opening) is found in Chalarodon (0443).

Orbit (Plates III and IV) is the dominate lateral cavity of the skull and in life, is the area where the eye is locatedo The orbit is basically circular and is bordered dorsally by the frontal; antericrly

posteriorly by the postorbital and the postfrontal.

The length of the orbit was measured as the greatest distance between lacrimal and postorbHalo The width was the greatest distance between jugal and frontal bones. These relationships are expressed in table 25 which shows the greatest length-vridth ratios (most circular opening) to be found in Conolophus (.969) and the smallest ratio (most eliptical opening) in Chalarodon ( .682).

Fenestr-a exonarina (Plates III, IV, V and VI) is the :r:aired prominent opening on the dorsal rostrum of the skull. It is bordered medially and anteroventrally by the premaxilla, laterally by the maxilla, and posterodorsally by the nasalso In life the fenestra exonarina provides the opening for the external nareso

The length of the fenestra exonarina 1tras considered to be the 49 internal distance between the suture of the lateral projection of the premaxilla and the maxi1.la and the suture between the nasal and maxillae

The width was considered to be the greatest inside distance between the lateral border of the prema.xilla and the anterior border of the maxilla.

Table 26 represents a tabulation of these values and shows the greatest ratio (most circular opening) to exist in Brachylophus (.872) and the lowest ratio (most eliptical opening) to be folmd in Cyclura ( .41+3).

The lower jaw consists of two paired rami which unite anteriorly in a mental symphysis and each articulates with the quadrate of the skull posteriorly. The dentary of each ramus bears a single row of pleurodont teeth, whereas the remaining bones (articular, surangular, angular, splenial and coronoid) are edentate.

Dentary (Plates V, VI and VII) is the largest bone of the lower jaw and bears teeth on its dorsonvsc'lial border. At its posterior rrargins the dentary interdigitates with the coronoid, splenial, angular, articular, and surangular. The ventral border provides the origin for the anterior fibers of the mandibulohyoideus I and III and the genioglossus muscles.

Measurements taken on the dentary included the length as the distance from the anterior tip of the bone to the posterior most projection on the lateral surface of the mandible. The width of the dentary was that vertical distance between the top and the bottom of the mandible immediately in front of the coronoid. An examination of table

27 reveals that the largest length width ratio (srrallest, widest bone) for the dentary is possessed by Arnblyrh;znchu,:2.(0297) and Conolophus

(.282). The smallest ratio (longest, narrowest bone) is that of Oplurus

( .11+7) and Cha.larodon ( ..174).

The relationship between the posterolateral border of the 50 dentary, the coronoid., the surangular ctLffers from genus to genuso In

Chalarodon and O_plurus the dentary is not overlapped by the coronoid on its posterodorsal. sur-faceo In BrachyloFhus, Ctenosaura, Dipsosaurus,

Igv_ana and Sauromalus, the dP-ntary is overlapped, dorsally by the coronoid and the ventral border of coronoid and its suture with the dentary is parallel to the ventral border of the nE.ndibleo The p::,sterior suture of the dentary in Brachylophus, Ctenosaura, Iguana and Sauro,,.. malus is concave in natureo In Dipsosaurus this suture is convexo

Jl.mblyrhyne:hus, ConoloDhus and Cyclura have complex rounded or slanting suture between the ventral border of the overlapping coronoid and its suture with the dentary o The posterolateral suture in these genera is complex with two posteriorly poinUng triangular projections being present in bmblyrhynchus and Conolophuso Cyclura p::,ssesses a smooth

Articular (Plates V, VI and VII) is that :r:art of the nandibles which articulates with the quadrate. of the skullo This bone with its retro-- articular process serves as the point for insertion for the depressor mandibularis, intermandibtlaris posterior., fibers of the pterJgomandi ... bularis, and adductor rnandibularis externus muscleso The medial border is sutured to the splen.ia.l boneo

The length of the articular bone was measured from its most anterior projection on the medial surface where it sutured to the coronoid, and splenial, to the most posterior tip of the retroarticula.r processo The width was taken from the most ventromedial projection of the angular process to the opposite border of the articular bone where it sutured with the surangular on the mandible 2 s lateral surface.

These measure:ments are imrrnriarized in table 28 which shows the greatest 51 length-width ratio (shortest, widest bones) to be .found in Conolophus

( .390) and the lowest ratio is possessed by Chalarodon ( .200).

The angular process of the articular bone differs in shape and size from genus to genus. This projection was also subjected to

length, width measurements. '.i'he length was taken as the greatest length of the mandible and was contrasted. with the width of the articular which is in a great part a resuJ_t of the size of the angular process.

The ratio between those measurements is expressed in table 29 which shows Conolophus (.219) to have the greatest ratio (shortest, wj_dest bones), while the smallest ratios (longest, narrowest bones) are those of Chalarodon (0105) and Oplurus (0120),,

As previously indicated the shape of the angular process

( Plate VII) differs from genus to genus. The projection which extends media,lly from the posterior ventromedial surface of the articular bone is either a small rounded bump as in Amblyrhvnchus, and 1£..~., o:::-a pointed spine like anteriorly pointing projection as in the remaining genera. The smallest projection is that of Amblyrhynchus. Of the pointed projections, that of Cyclura is the most massive and pronounced while the projection in Conol.ophus is a close second. The angular process of Ctenosaura and Sauromalus is less massive and projecting than U.a t of Cyclura and Conolophus. It is sirriilar in shape but less pointed in the last two generao In Brachylophus, Chalarodon, Dipso- saurus and Oplurus, the angular projection is more triangular shaped than hooklike. In al.l four genera the anterior face terminates as a sharp spine. The process of Brachylophus and Oplurus is more sharply curved and hooklike than that of Chalarodon and Dipsosaurus.

Surangular (Plates V, VI and VII) forms the lateral wall of the p:isterior 52

third of the mandible. The dorsal border serves as the area of inser-

tion for the adductor rr,andibularis externus muscle, and the intermandi-

bu.laris posterior muscle inserts on its lateral surface.

The surangular 1s length is taken as the longest anterior-

posterior axis on the lateral surface of the mandibleo The width is

considered to be t,he longest dorsal-ventral axis in the area of the

anterior sutures with the dentary and coronoid on the mandible 1s lateral

surface. Table 30 indicates the largest length-width ratio (shortest,

· widest bone) is found in Am.blyrhynchus ( 0425) and the sma.llest ratio

(longest, narrowest bone) in Sauromalus (.270) and Iguana (o278)o

Splenial_ (Plate VII) is found on the mesial side of the jaw where it

connects with the angular, articular, surangular, dentary and coronoid

bones. The interrnandibularis anterior profundus muscle has its origin

on this bone.

The splenia1 1s length was considered to be the longest

anterior-posterior a.xis and the longest dorsal-ventral axis was taken

as the width. Table 31 indicates the largest ratio (shortest: widest

bone) is found in Chalarodon (.405) and the smallest ratio (longest,

narrowest bone) is that of Cyclura ( 0149).

The. splenial bone is a fusiform splinter shape in all ten

genera but it is pierced by the anterior inferior alveolar foramen in

different places in different genera. This foramen is completely

enclosed within the bone in Arr.bly:i;:-h:ynchusand Oplurus. In Brachylophus

the anterior tip of the bone forms the posterior border of the foramen.

In Chalarodon, Conolophus, Ctenosaura, Cvclura, It;uana and Saurornalus,

the foramen is partially enclosed by the anterodorsal border of the

splenial. In Dipsosaurus the i'oramen is found in the dentary and is 53 separated from the splenial by a projection of the coronoid.

Angular (Plates V, VI and VII) is a fiat bone whose posterior part

.forms the ventral surface of the jaw between the articular and surangular. The anterior process of the angular attaches to the dentary.

Part of this bone serves as the Or'igin for the mandibulohyoideus I muscle.

The angular is roughly fusiform and its length was measured between the most anterior and most posterior projections. The width was the greatest distance between the opposite borders on an axis at right angles to the length. These measurements are summarized in table 32 which indicates the greatest ra~io (shortest, widest bone) to be that of Dipsosau.rus ( .223) and the shortest ratio (longest, narrowest bone) to be Sauromalus (.107).

Coror:oic ( Ple,tes VJ VI anc:1 VII) '."'traddlefl tt e otr, e".' bones of the ,iaw from a dorsal position. The two anterior extrernities articuJ.ate in most genera with the dentary and surangular laterally and the dentary, splenial and articular bone ventrally.

The posterior, lateral, apical surfaces give rise to the insertion of the adductor mandibularis externus and adductor medius muscles, and provides an attachment surface for the bodenaponeurosis.

The coronoid length was measured as the distance from the dorsa tip of the bore to the tip of the ventral most projection on the lateral surface of the mandible. The width war, the distance between anterior and posterior borders where they contact the dorsolateral surface of thE mandible. As table 33 shows the greatest ratio (shortest, widest bones) is found in ChaJ9-rodon (.941) and Amblyrhynchus (.935). The lowest ratio (longest., narrowest bones) is that ofConolophus (.571). 54

The shape of the bone differs greatly from genus to genuso

The anterolateral projection of the coronoid takes different shapes in different genera. In ChaJ.arodon and Oplurus this projection is missing and the dentary and surangular are not overlapped on the lateral surface. In Conolophus and Cyclura the projection overlaps the dentary and surangular ventrally and projects very little anteriorly on th8 lateral surface of the dentary. Amblyrhynchus has a similar condition, however, there is a small anterior projection extending forward over part of the dentary. In Brachylophus, Ctenosaura, Iguana and Sa.urcmalus the anterolateral projection overlapping the dentary and surangular is extended forward as an elongated triangular or rectangular process.

The sma.llest angles of triangulation occur in Ctenosa}.1ra and Brachylo- phus, in which the projection is elongated and splint likeo In Igl1.ana and Sauro:nalus the anterior apex of the projection is roundedo The conditions of Dipsosaurus is similar to that of Arnbl;y:rhynchus and

Conoloprns where the lateral projection of the coronoid bone is mostly ventral in natureo There is, however,. in Dipsosaurus, a small rounded anterior projection on the anterior border of the processo

TEETH

Teeth are pleurodont and are borne by the dentary in the lower jaw, the maxilla and prernaxilla of the upper jaw and the pterygoid of the palate. The possession of teeth and the numbers in each genus is summarized in table 34.

Pter.ygoid teeth a.re fOlmd in many genera on the pterygoid bones and their numbers are quite variable among individualso Of five skulls of

Ar:1blyrh;vnchus examined, only two had pterygoid teeth and these varied between 'J.-7 per side, very tiny or represented only by a few sockets. 55

In four skulls of Brachylophus, pter.1goid teeth ranged in number from

1-·8 per sideo Chalarodon had well developed teeth in all four skulls examined but they were .f'e11,in nwribcr) ranging from 2-4 per side. In five skulls of Conolophus only one had any remnant of teetho This remnant consisted of a few sockets on each pterygoid boneo In Ctenosaura all skulls had nwnerous well developed teeth numbering from .3-14 per side. A similar situation existed in Cyclura with 1-10 teeth per side,

Iguana with 8-27 teeth per side a~d Oplurus with 4-9 teeth per side.

In Saurorn.alu.s six skulls were examined and four had between 1-7 teeth per sideo Only in Dipsosaurus were no pterygoid teeth or their ventages found in the four skulls examined. Camp (1923:367) omits Dipsosaurus from his list of Iguanidae lacking pterygoid teethe This may be a mistake on his part or perhaps an examination of a larger series o.f skulls ma;y-reveal tm t some pterygoid teeth are present in some individuals of this genus.

Montanucci (1968:307-314) cow.ments on the pterygoid teeth of

IEuana and Ctenosaura and indicates that in 1guana the teeth have taken over the function of gripping as the lateral teeth are specialized for shearing. In Ctenosaura the pterygoid teeth share the gripping function with less specialized lateral teeth. He also indicates that there is a relationship between size of the skull and number of pterygoid teeth.

Prem.axillary teeth are found in aJ.l ten generao These are less cusped than the lateral teeth in Sauroma.lus (Avery and Tanner, 1964: 7-8) o

Observations on other genera indicates this is also the case for

Ctenosaura, Cyel£D'l, Iguana, Dipsosaurus and Opluruso In the other genera the premaxillary teeth bear secondary cuspso

Maxillary teeth are borne by the maxilla in all genera and number from 56

15 to 26 per side in skulls exa1Tl.ined. From my observations and those

of Montanucci (1968:307·-315)there appears to be a size, number

relationship in :i.guanids, with small er skulls always having less teeth

than larger skulls in the same genus.

The cusps of the teeth differ considerably between genera.

According to the system of Hotton (1955:91) the cuspate character- of

the teeth of all genera would fit the catagory 11high degree 11• The

cusp number and shape varies a great deal within this catagory.

Chalarodon, 1.g__™ and Oplurus have small cusps and are poorly definede

Brachylophus, Ctenosaura, Cyclura, Dipsosaurus and Sauromalus have

cusps well defined but not separated by deep indentions. In _;...... _ Ambly-,

rhynchus and Conologrns the lateral cusps are well defined and widely

separated from the central cusp of the tooth. The number of cusps per

tooth also varies from genus to genus. Amblyrhynchus, B~chylophm·~_.

Chalarodon, and Onlurus are all tricuspate. Conolophus, Ctenosaura and

Dipsosaurus are tricuspate with a few teeth bearing up to five cusps.

In Cyclura and Sauromalus teeth with up to seven cusps are common and

in Sauromalus, some with nine are seen. The most highly cusrate teeth belong to Iguana which exhibits up to 13 cusps per tooth in some individuals. Hotten (1955) and Montanucci (1968) attribute the number of cusps per tooth to the kind of diet and specialized functions (gripping, shearing, masticating) of the teeth., It appears that lizards with

-similar diet and eating habits have simiJ_ar dentition.

Dentary teeth are borne by the dentary in all ten generao The number

of teeth per bone is slightly larger than that for the maxilla of the

same lizardo This is because the upper teeth are found on the premaxilla as well. 'I'he sum of one half the teeth of the premaxilla and 57 all the maxillary teeth of one side should roughly equal the number of dentary teeth.

In general teeth o:f the dentary are similar to those of the maxilla and prema.Yilla and the size-number relationship exists :for them as wello

HYOID F.LEME.NTS

The hyoids of the iguanines (Plate VIII) are basically alike in structure. The hyoid is always cartilagenous in nature and consists of a central disc, the basihyal, to which is attached an anterior projection, the glossohyal or processes entoglossus; an anterolateral projection on each side, the hypohyal; and two ceratobranchials, pro-◄ jecting posteriorly on each side. The medial ceratobranchials (II) are pi.ired and extend posteriorlyo In Iguana these are involved in operating t.he dewlap. The lateral l.:eraGuln·a.rn;l1.i..c1.ls (l) .f.;.Lv.:jcct pJSt&..:0- laterally from the basihyal and articulate with the hypohyal by means of a lateral certohyal which extends between the lateral terminations of each cartilage.

Unfortunately hyoids are seldom preserved in museum collections.

As a result only one or two hyoids from each genus were examined, but some differences between genera can be noted. The shape of the hyoid corresponds to the shape of the animal. Iguanines that are dorsoventrally flattened normally have hyoids that are short and with a large lateral spread of the ceratohyals and ceratobranchial I 1s. Such a situation is found in Conolophus, .9.Y~l!!:{:);and Sauroma.lus. Most of the remainine genera are compressed laterally and the spread of the lateral elements of the hyoid in these organisms is less than in the dorsoventrally .flattened forms o 58

The basihyal is broader than long in some dorsoventrally flattened forms such as Sauromalus but is elongated in Conolophus,

Ctenosaura, Cyclura and the other genera. Sauroro.alus also differs from the other genera in that the ceratobranchial II 1s are spread apart in lifeo

Individual elements of the hyoid show some differences which may be'of phylogenetic importance. The dorsomedial portion of the ceratohyal is enlarged into a triangular to spoon shaped flange in

Ambly:rhynchus, Brachylonhus, Conolop}rns, Ctenosaura, Cyclura, Dipso- saurus, Iguana and Sauromalus. In Oplurus this flange is extremely small and is absent in ChaJ.arodon. All other elements of the hyoid differ in length but not in shape.

STERNUMAND RIBS

'l'he sterna and ribs of U1e iguanines nave been discussed by

Etheridge (1965) who examined the relationships of the abdominal skeleton of iguanids to the sternum and figured those of Arnblyrhynchus and

Chalarodon. Etheridge indicates that abdominal or inscriptional ribs are associated with the sternum in at least four different ways in the family Iguanidae. Three of Etheridge 1s four p:.i.tterns include iguanines.

In one type 11all of the inscriptional ribs posterior to the xiphi- sternum are attached to their corresponding dorsal ribs and end free without reaching the ventral midline 1r (Etheridge, 1965:163). Included in this group are Sauromalus and some :individuals of Conolophus,

Amblyrhynchus, Cyclura and Ctenosaura. A second type according to

Etheridge (1965:163), 11is similar to the preceeding except that one or two of the inscriptional rib pairs> either the first or second, or both may join one another at the ventral midline to form continuous 59

chevrons 11• Iguana, Brachylophus and some Conolophus, Amblyrhynchus,

Cyclura and Ctenosaura have this type of attachmento A third pattern involves Chalarodon and Oplur~~ a,nd according to Etheridge (1965:166) >

11consists entirely of paired elements that are free of attachment either to their corresponding dorsal ribe or to one another at the ventral rnidline. Members of the pair may approach one another very closely, touch, or even overlap midventrally, but never join one another to form a continuous chevron 11• It is perplexing to note that although

Etheridge mentions having exa:mined Dinsosaurus he fails to assign it an abdominal skeletal type. This may be an oversight on his part or the genus rray be variable. The one specimen of Dipsosaurus that I examined conformed to Etheridge 1 s second type.

The sternum of all iguanines examined (Plates IX and X) consists of a ste:rna1 cartilage wliich articllJ_ates laterally with four pairs of sternal ribs and posteriorly with two pairs of xiphoid ribs.

Anteriorly the sternal cartilage is attached to arid :r:artially surrounds a 11T11 shaped interclavicle. The arms of the 11T11 are of different lengths and leave the body of the interclavicle at different angles.

The clavicle articulates at the anterior junction of the arm and body of the interclavicle.

Sternal cartilage corresponds in shape to general shape of the lizards.

In dorsoventrally flattened forms the cartilage is wider than long.,

This situation exists in Sauromalus and frnbl.z.rhynchus and is about equally wide as long in Ctenosaura and .Q.I.£1~• All other genera ha.ve elongated sterna.

The sterna in some forms, is pierced by sternal fontanelles.

Camp (1923:409-410) reports fontanelles ta ba Jacking in Chalarodon and 60

Saurornalusa He found a single medial fontanelle in Iguana and Dipso- sauruso Two fontanelles were not recorded for any Iguanines. I have found fontanelles to be lacking in Amblyrhynchus, Chalarodon and Sauro- malus. A single central fontanelle exists in Brachylophus, Conolophus,

Ctenosaura, Cyclu.ra, Dipsosaurus and Iguana. These openings usually surround the terminal end of the body of the interclavicle. The one sternum of 0plurus examined has two small fontanelJ..es along the center line.

Interclavicle differs in size of the body, the angles of the anterior arms to the body, and the length of the armso The arms attach to the body at 90° angles in Amblyrhynchus, Brachylophus, Iguana and Saurom-:1,lus.

The arms are attached at 45° angles in Chalarodon, Conolophus, Cterco- saura, Cyclura and 0nluruso In Dipsosaurus the interclavicle arrns are in an intermediate position between the two preceeding groups. The arms are attached at approximately a 30° angle to the bodyo

The length of the interclavicle arws are also of interesto

They are very short in Brachylophus and Dipsosaurus being about one quarter the length of the bodyo The longest arms in relation to the body are those of Amblyrhynchus, Sauromalus and Iguana, being about equal to the length of the bodyo In 0plurus, Ctenosaura, Chalarodon,

Conolophus a..'1.dCycl ura the arms are two-thirds the length of the body o TABLE 1

SKULL LENC,THAND WIDTH

Length Width Width-Length Ratio Genus Min. Mean ¥..ax. Min. Mean Maxo M.i.n. Mean Ma.xo

Amblvrhynchus Uol+-4707-53.2 30 •.3-36.7-4301 .731-..789-0809 Brachylophus 2707-3007-.34.2 1608-19.8-24.9 .5.35-0644-0726 Chalarodon 12o5-13.,l-14ol 808- 9 ..2-10.0 .666-.705-.,792 Conolophus 85.0-79.1-8600 37.0-,54.1-6403 0618-..679-0747 Ctenosaura 30.1-40.5-54.l 17.6-24.0-32.l 0584-0593-.,605 Cyclura 45.7-73.3-97.1 2607-4306-56.6 • 582-..593-0623 Dipsosaurus 22o2-22o3-23o9 14.0-16.6-18.3 .,700-.745-.781 Iguana 4903... 60.0-.70.3 28.1-35.4-36.5 .519-.549-.590 Oplurus 18.1-21,,6-30.6 1L2-14.5-20.0 .608-..670-.729 Sa urornal us 23.4-3L~.4~•48 .1 1403-22.6-32.8 .6u-.653-.684

f!J' Tl-BLE 2

SKULLIBNGTH AND HEIGHT

Length Height Width-Length Ratio Genus Mino Mean Max. Mino Mean Maxo Min. Mean Max.a

Amblyrhynchus 41.4-4707-5302 2008-23.2-26.0 0 402-. 460-0 4-89

Brachylophus 27o7-30o7-34o2 11.2-12.0-13.8 o372Ao390-o404 Chalarodon , 1205-13.1- 4.1 4.4- 4.8- 5.1 .335-0368-.400 Conolophus 85.0-79.,1-86.. 0 2006-3005-34.3 .344-o379-o398 Ctenosaura 30.1-4005-5401 9.7-1208-16.4 a.303-o316-o331 Cyclura 4507-7303-97.1 15.2-2309-21+06 ~306-.326-0334 Di]2§_osaurU§_ 22.2-22.3-23.9 7.3- 806- 9o4 0365-.386-.400 Iguana 49.3-60.0-70.3 1706-20.6-22.6 .318-0344-.3 56

0 &_u_rtJ._s 18.1-21.6-30.6 6.4- 707-10.J .336-.357-0386 Sauromalus 23.4-3404-48.. 1 608- 9.9-14.1 .273-.286.--.308

~ TABLE3

BASISPHErOID BONE

Length Width Width-Length RaU_o Genus Min • Mean Max. Min. Mean Max. Min. Mean Max.

Ambl;zrh;zDch us 5.1- 6.0- 7.0 9.1-12.8-16.7 .419-.~82-.560 Brachylophus 4.1- 4-5:- 5.0 6.9- 7-9- 9.5 .526-.570-.594 Chalarodon 1.0- 1.1- 1.3 2 . 8- 2 •9- 3 •2 .333-.360-.406

Conolophus 7.5-10.5-12.1 13.2-19.9-23.9 .506-.533-.567 Ctenosaura J.9- 5.3- 7.4 6.7- 8.J-10 .•7 .549-.633-.691 Cyclura 6 .2-10.0-lle.4 1003-16.1-22.3 • 546-.619-. 685 Dipsosaurus 2.5- 2.9- 3.7 5.4- 6.3- 6.9 .412-.469-.536 Iguana 7.2- 7-9- 8.7 10.3-12.2-14.5 .600-.652-.699 0plurus 2.5- 3.4- 5.1 3 . Le- 4. 5- 6. 6 ,717-.755-.780 Sauromalus 3 • 8- 5 . 7- 8 .1 6.7- 9.6-12.2 • 500-. 589-. 669

~ TABLE4 BASIOCCIPITALBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

Amblyrhynchus 8. 7- 9. 8-11. 6 12.3-15.0-17.6 .573-.663-.739 Brachvlonhus 5.0- 6.2- 7-4 3.5- 4.2- 5.0 .648-.709-.781 Chalarodon 2.0- 2.1- 2.2 3.2- 3.4- 3.6 .600-.625-.656 Conolophus 8.5- 9.4-10.7 15.0-20.0-23.4 .420-.477-.580 Ctenosaura 4.2- 5.7- 6.7 6.2- 8.6-10.5 .650-.664-.677 Cyclura 6.2- 9.4-12.1 11.6-15.1-24.2 .500-.534-.596 Dipsosaurus 2.1- 2.2- 2.5 5.9- 6.1·- 6.7 .350- .369- .389 Iguana 6.6- 8.1- 9.8 11. 5-16.0-19. 6 .500-.513-.573 0plurus 3.1- 3.3- 4.0 5.4- 5.7- 6.4 • 534-. 583-. 625 Sauromalus 3.4- 5.8- 7.8 5.1- 9.8-13.0 .600-.649-.696

.i::-°' TAI'LE 5 EXOCCIPJTALBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

A!:lblyrhynchus 8. 9-11.0-13 .o 8.5-11.6-16.0 .762-.830-.861 Brachylophus 5.0- 5.5- 6.3 4.5- 4-7- 5.0 .793-.858-.900 Chalarodon 2.2- 2.2- 2.4 1.8- 1.8- 1.9 .782-.813-.863 Conolophus 8.5-12.4-14.2 13.0-20.0-23.8 .571-.626-.653 Ctenosaura 3.0- l.i.9- 6.9 4.5- 7.8-12.5 .552-.649-.724 Cvclura 6.2-11.3-15.8 8.5-17.1-25.8 .605-.661-.720 Dipsosaurus 2.8- 3.3- 3.6 5.4- 5.6- 5.8 .509-.594-.648 Iguana 7.0- 7-7- 8.2 9-4-11.2-11. 9 .606-.671-.744 Onlurus 3.3- 3.9- 5.0 4.2- 5.1- 6.8 -735-.774-.809 Sauromalus 4. 0- 5 • 6- 8. 2 5.3- 8.2-12.4 .602-.692-.759

\J1°' TAKE 6

S UPEAOCCI?ITAL BONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

Am2lyrhynchus 6.4- 6.8- 7.8 9 . 0- 9 • 8-11. 9 .655-.700---.755 Brachylophus 5.5- 5.9- 6.1 5.2- 5.4- 5.6 .852-.906-.982 Chalarodon 1.2- 1.5- 2.1 2.4- 3.0- 3.7 • 413-. 524-. 583 Conolonhus 11.4-14. 7-21.l 7-4-13.5-13.9 .748-.706-.793 CLenosaura 3.3- 4.7- 6.7 5.1- 6.9- 9.2 • 632-. 677-. 739 Cyclura 5.8-10.9-14.6 $.1-14.4-18.1 .700-.751-.806

Dipsosaurus 3.7- 4.0- 4.2 4 . 6- 4. 8- 5 . 2 .795-.820-.874 Iguana 7.9- 8.6- 9.6 7.6- 8.8- 9.4 .900-.949-.979 Oplurus 2.4- 3.2- 5.0 4.0- 5.2- 7-4 .521-.596-.675 Sauromalus 3.3- 4.6- 6.8 5.1- 7.2-10.0 • 538-. 632-. 680

o, °' TABLE7

· PTERYGOID BONES

Length Width Width-Length Ratio Genus

Min. Mean Max. Min. Mean Max. Min. Mean Max.

Ambl;yrhJJlchus 23.9-38.8-32.6 8.4-10.3-13.5 ,309-•.346-. 414

Brach;y].opl'l_u§_ 14.0-15.5-18.4 6.1- 7.0- 7.5 .380- .458-. 535

Chalarodon 5.6- 5.7- 5.7 2.4- 2.4- 2.6 .421-.435-,464

Conolophus 34.2-51.0-59. 5 11.8-18.8-22 .3 ,345-.367- .382

Ctenosaura 18,7-24.5-33.5 5.8- 7,5-10.8 .287-.311-.355

C,;z:,cJ_ur~ 29.1-39,0-63,1 7 •.3-13,5-20.6 ,250-.283-.326

Di£§_osau_rus 10.1-12.0-13.1 4.1- 4.2- 5,3 ,333- ,353- ,401+

Igu_c3,na 26,5-31,5-35.6 7,0- 9,5-11.1 .264-.309-,364

O.elur_u_s 8 .4-11.6-19. 6 2.9- 3,9- 6.2 .316-.347-.377

Sauromalus 13.0-19,8-30,0 3,9- 5,8- 9,1 .252-.293~.343

-.J°' TABLE8

ECTOPTERYCOIDBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

Amblyrhynchus 7.2- 8.9-10.4 1.8- 2.4- 3 .1 .250-.275-.303 Brachylophus 3.0- 4.0- 5.0 1.0- 1.5- 2.2 .333-.371-.4~-0 Chalarodon 1.4- 1.4- 1.5 o.6- o.6- 0.7 .400-.431-.466 Conolophus 10.9-15.J-17.5 5.0- 6.5- 7.5 .405-.429-.458 Ctenosaura 3.3- 5.6- 8.9 1.4- 2.3- 3.6 .404-.421-.444 Cyclura 6.1-10.8-15.2 2.2- 4.1- 6.3 .356-.377-.414 Di12.sosaurus 2.3- 2.6- 2.8 1.4- 1.5- 1.8 .551-.600-.642 Ig_u.a,rg 6.1- 7.9- 9.3 J.0- 3.5- 4.0 .415-.448-.491 0plurus 2.2- 2.6- 3.6 0.9- 1.1- 1.5 .409-.419-.434 Sauromalus 2.4- 5.4- 8.5 1.0- 2.0- 3.2 .323-.392-.457

°'(Xl TABIE 9

\TOMERBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. l'fi"J.n• Mean Max.

Amblyrh;z];chus 11.2-1.3.0-15.0 2 . 8- 3 •2- 4. O .200-.253-.294 Brachylop.11.us 6.5- 7.0- 7.6 2.4- 2.5- 2.7 •.315-.359-.380 Chalarodon 1.8- 1.9- 2.0 1.3- 1.3- 1.4 .700-.711-.722 Conolophus 12.2-13.6-17.1 4.1- 5,5- 7.0 .335-.372-.L.09 Ctenosaura 7 .2- 9. 7-11.1 2.0- 2.9- 4.2 .270-.278-.328 Cyclura 11.6-18.2-25.8 3.1- 5.5- 7.7 .235-.274-.335 Dipsosaurus 3,9- 4o2- 4,8 2.0- 2.1- 2 •.3 .479-.497-.512 Iguana 13.5-17.4-21.1 4.8- 5.5- 6.9 .265-.322-.389 Oplurus .3.1- 4.2- 6.0 1.4- 1.6- 2.2 .365-.399-.451 Sauro:malus 5.7- 7 .8-11.8 1.4- 2.6- .3.7 .245-.329-.390

'°°' TAB::.,E10 PALATINEBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

Ambl;yrhynchus 12.0-13.2-14.4 7,7- 8.6- 9.2 .604-.653-.721 Brachylophus 8.0- 8.2- 8.4 4.5- 4.9- 5,4 .560-.601-.658 Chalarodon 2.8- 2.8- 2.9 2.3- 2.4- 2.5 • 821-. 846-..862 Conolophus 14.2-23.1-28.4 9.1-14.4-17.7 .577-.627-.648 Ctenosaura 8.5-10.8-15 .1 5 •0- 6 ;0- 8. 2 .543-.565-.588 Cyclura 12.1-20.9-30.0 6.0- 9.9-13.9 .406-.466-.502

Di12sosaurus 5 . 6- 6 •l+- 7 •9 3.7- 4.1- 4.6 . 582-. 6~.4-.678 Iguana 11.2-15. 9-20 .1 7-4- 9.1-10.6 .432-.598-.671 0olurus 5.9- 7.5-12.0 3.4- 3.6- 5.3 .441-.532-.576 Sauromalus 5.8- 9.7-12.9 3.6- 5.3- 7.0 .542-.557-.620

.m:mm

--.:i 0 TABLE11

PREM.AXILLfl.RY BONES

Length Width Width-Length Ratio Genus Min. Mean Muc. Min. Mean Max. 11.in. Mean Max.

Amblyrh:ynch us 10.1-12.6-U .•4 6 .3- 7 .3- 8.2 .566-.585-.623 Brachylophus 7.5- 8.5- 9.8 4.2- 4.?- 5.6 .442-.558-.629

Chalarodon 2.5- 2.6- 2.9 1.4- 1.6- 2.0 .560-.611-.689

Conolophus 15.8-17.9-19.3 13.6-18.4-20.5 .860-.914-.963 Ctenosaura 8.0-11.0-15 .o 4.1- 5-7- 8.4 .464-.512-.560

Cyclura 11.7-21.6-29.1 5.1-10.7-15.0 .1435-.491-.566

Dipsosaurus 4.0- 4.9- 6.5 2.5- 3.1- 4.3 .607-.629-.661

Iguana 13.5-16.2-18.9 6.7- 8.4- 9.9 .485-.521-.581 0pl urus 4.4- 5.7- 9.1 2.5- 3.1- 5.1 .500-.542-.568 Sauromalus 4.7- 7-3-12.3 2.6- 4.3- 6.3 .509-.603-.676

--..:i I:-' TABL~ 12

MAXILLARY BONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. }tin. Mean }1a.x..

A.ublyrhynchus 21.7-25.3-28.8 13.5-15.4-17.5 .596-.619-.642

Brachylophus 15.0-17.4-18.9 6.0- 6.6- 7.5 •.346-.373-.400

Chalarodon 6.3- 6.7- 7.2 2.2- 2.2- 2.3 .319-.334-.349

ConolOFJ:lS 30.0-41.0-45.6 14 .3-19 .3-21. 5 •432-. 466-. h83 Ctenosaura 16.1-21.3-29.3 5 • 5- 8. 0-11. 7 .341-.371-.399

Cyclura 23.4-40.6-54.3 8.9-15.5-21.4 .359- .383- .402 Dipsosaurus 10.1-10.8-11.9 5,0- 5.5- 6.1 .495-.51.3-.564

I~ana 27.6-35.0-40.6 11.9-13.9-15.5 .381- .399-. 431

OE_luru~ 9 .4-11.4-15. 9 3.5- 4.1- 5.7 .346-.358-.372 Sauromalus 15.1-18.9-27.l 4-3- 7.2-10.8 .355-.377-.398

~ TABLE 13 NASALBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean :tviax. Min. !foan Max.

Amblyrh;ynchus 17.2-20.1-24.1 6.3- 7-5- 8.4 .348-.375-.416 Brachylophus 7.2- 8.7-12.4 3.9- 4.4- 5.3 .427-.522-.564 Chalarodon 2.3- 2.5- 2.7 1.1- 1.1- 1.3 .423-0455-.481 Conolophus 15.6-22.4-26.1 8.6-10.6-11.9 .409-.480-.551 Ctenosaura 8.1-11.5-14.8 4.2- 6.4- 8.6 .507-.555-.618 Cyclura 12.6-21.4-27.0 5.8-10.2-15.1 •428- .472-. 559 Dipsosaurus 6.8- 7.2- 7.5 2.9- 3.6- 3.9 • 426-. 500-. 541 Iguana 14.5-19.7-22.5 6.4- 8.9-10.5 .443-.449-.466 Oplurus 4.5- 5.3- 7.7 1.9...:2.4- 3. 7 .422-.448-.480 Sauromalus 5.1- 8.8-13.0 2.5- 4.3- 6.1 .434-.496-.583

~ TABLE14

PREFR0ilfrALBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max•

Amblyrhynchus 13.5-14.9-15.9 10.0-13.3-18.9 • 718-. 776-. 849 Brachylophus 8.4- 9.0-10.1 4.5- 5.1- 5.8 .535-.571-.619 Chalarodon 2.9- 2.9- 3.1 1.5- 1.5- 1.6 .500-.512-.517 Conolophus 17.5-22.7-25.7 10.9-14.6-17.3 • 595-. 636-. 676 Ctenosaura 8.0-10.5-13.4 5.0- 6.8- 9.1 .625-.645-.679 Cyclura 10.5-18.3-23.8 5-7-11.3-14. 9 .542-.603-.668 Di12sosaurus 6.3- 6.6- 6.8 4.2- 4.3- 4.5 .656-.662-.666 Iguana 12.4-16.0-20.3 8.2-10.7-13.9 .621-.672-.723 0plurus 4.4- 5 .4- 8.0 2.8- 3.4- 5.1 .612-.636-.676 Sauromalus 5 .3- 8.1-11.0 2.7- 4.6- 7.1 .500-.553-.645

--:i +:'" TABLE15

LACRIMA.1BONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Ytln. Mean Max.

Amblyrhynchus 3.2- 4.0- 5.0 1.5- 1.9- 2. 7 .405-.471-.540

Brachvlophus 2.4- 3.3- 4.3 1.L,- 1.6- 1.9 •428-. 523-. 61+0 Chalarodon 1.0- 1.0- 1.1 0.3- 0.3- 0.3 .272-.293-.300 Conolophus J.4- 6.1- 7.8 2.0- 3.3- 4.2 .507-.542-.588 Ctenosaura 2.4- 3.8- 6.0 1.2- 2.-0- 3.3 .500-.532-.555 Cyclura 3 -5- 8.3-13 .4 2.0- 4.2- 5.9 .506-.526-.588 Dipsosaurus 2.2- 2.6- 3.2 1.0- 1.0- 1.0 .Jl.2-.392-.454 Iguana 7.7- 9.L,-10.8 J.4- 4.2- 5.0 .441-.451-.462 Oplurus 1.7- 1.7- 1.8 o.6- o.6- 0.7 .352-.370-.388 Sauromalus 2.3- 3.9- 5.7 1.0- 1.5- 1.9 .333-.385-.463

-....1 V1 TABLE 16

FR0NTAI BC}NES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. :tvrin. Mean Max•

Amblyrhmchus 12.1-15.5-18.1 18.9-24.7-30 • .3 • 597-.629-.653 Brachylophus 11.0-12.6-14.2 12.6-13.8-14.8 .808-.907-.985 Chalarodon 5.9- 6.0- 6.2 4.8- 4.9- 5.0 .806-.840-.847

Conolophus 16.6-21.3-24.4 22.L+-31.2-36.3 • 631-. 689-. 746 Ctenosaura 11.6-14.2-16.6 11.1-14. 7-18. 7 .887-.936-.063

Cyclura 16.3-22.5-29.1 17.3-25.8-34.1 .839-.886-.942 Dipsosaurus 8.4- 9.5-10.3 7o5- 8.3- 9o2 • 838-. 873-. 910 Iguana 18.3-21.8-25. 9 15 .l+-22.1-24.1 .806-.894-.946

0£11=1-rus 7.3- 8.6-12.1 6.0- 7.0-10.0 .800-.815-.835 Sauromalus 11.0-13. 7-18 .1 9.6-12.0-17.4 .800-.873-.966

---:i °' TABJ,E 17

POSTFROW'i\LDON1.2S

Length Width Width-Length Ratio Genus 1J1"in• Mean Max. Min. Mean Max. JVfj_n.Mean Max.

Anbl;vrh;zg ch us 6.9- 8.7-10.3 3.8- 4.2- 4.6 .436-.489-.550 Brachylophus 4.0- 4.7- 6.2 1.1- 1.3- 1.8 .275-.286-.300

Chalarodon 0.5- 0.5- 0.5 0.1- 0.1- 0.1 .200-.200-.200

Conoloph_u~ 10.0-13.6-16.7 2.3- 3.5- 4.4 .230-.256-.269

C-Lenosaura 3.9- 4.8- 5.8 0.8- 1.1- 1.7 .207-.234-.293

Cyclura 6.5- 9.4-12.4 1.9- 2.7- 3.9 .219-.287-.326 Dipsosauru_s 2.4- 2.7- 3.0 o.5- o.6- o.8 .204-.235-.266

Iguan§l 4.6- 7.0- 8.4 2.0- 2.7- 3.2 .360-.394-.434 Oplurus 0.2- 0.2- 0.3 0.1- 0.1- 0.3 . 500-. 625-1.000 Sauro,nalus 2.1- 3.8- 5.6 o. 7- l.J- 1.9 .310- .380-.388

--..J --..J TABLE18

~TUGALBONES

Length VJidth Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max•

Amblyrhynch us 18.1-21.0-24.? 3.4- 4.3- 5.2 •169-.207-.236 Brachylophus 12.5-13.7-15.9 2.0- 2.7- 3.5 .160-.172-.220

Chalarodon 6.1- 6.4- 6.8 1.0- 1.1- 1.2 .163-.169-.176

Conolophus 26.2-34.2-38.2 5.4- 6.6- 7.2 .188-.195-.206 Ctenosaura 14.0-19.2-27.3 1.6- 2.6- 3.7 .114-.136-.155 Cyclura 24.0-38.5-50.8 3 .1- 7. 7-11. 8 .129-.191-.265

Dil?,sosaurus 11.6-12.1-12.8 1.7- 1.9- 2.2 .141-.161-.180

Iguana 20.0-26.8-31.9 3.2- 4.2- 5.0 .141-.156-.167 0£1U_l'.'US 9.4-10.7-13.9 1.3- 1.6- 2.1 .139- .148-.159 Saurornalus 11.9-15 .9-24.l 1.3- 2.4- 3.4 .109-.141-.196

.....::i 00. TABLF.19 PARIETALBONES

Ler,.gth Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean }f.ax.

Amblyrhynchus 9.9-12.2-16.1 19,4-24.2-29.2 .444-.502-.551 Brachyloohus 5.9- 6.5- 7.4 12.8-14.7-18.7 .395-.448-.496 Chalarodon 2.6- 2.8- 3.1 4.9- 5.2- 5.5 .530-.550-.563 Conolophus 16.3-24.9-29.3 24.7-32.5-37.1 .659--751-.789

Ctenosaura 7 .1- 9 •0-11. O 11.6-13 .4-21.0 .522-.552-.612 Cyclura 10.3-19.2--32.9 18.1-28. 8-41. 7 .515-.640-.788 Dipsosaurus 3.4- 3.9- 4.3 8.1- 9.1- 9.7 .419-.431-.443 Iguana 10.9-12.8-14.7 18.4-21.8-24.5 .566-.585-.600 Oplurus 3.9- 4.4- 5.5 7. 8- 8. 7-11.3 .486-.510-.555 Sauromalus 5.0- 7.6-10.0 10.l-lJ.2-19.3 .495-.566-.646

---:J '° TABLE20

PARIET1,LWINGS

Length Width Width-Length Ratio Genus lJin. Mean Max. Min. Mean Max. Min. Mean :rv:ax•

Ambl~chus 28.1-33.1-38.1 24.4-29.1-33.5 • 868-.878-.891 Brachylophus 13.4-14.3-16.1 17 •.3-18.3-20.5 .734-.765-.785 Chalarodon 7.0- 7-4- 7.7 6.3- 6.5- 6.7 .840-.880-.957 Conolophus 34.1-50.8-58.5 27.4-40.6-48.4 -771-.802-.827 Ctenosaura 15.7-25.4-30.9 12.5-18.9-25.8 -747-.781-.802 .Q,yclura 25.0-42.4-58.1 19 •.3-.35.0-48.8 .772-.817-.839

Dipsosaurus 12.6-13.6-14.4 12.4-12.8-1.3.2 .916-.945-.984

Iguana 23.2-29.3-JJ.4 19.6-25.5-28.7 .814-.870-.925

Oplurus 11.0-12. 7-18.0 9.0-10.5-15.1 • 810-. 824-. 83.3

Sauromalus 12.9-19-7-29.0 11. 9-19 .1-28.0 .897-.926-.980

co 0 TAB-SE21 POSTORBITALBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

Amblyrhynchus 9.l-JJ.5-17.5 8. 5-11. 8-15 .3 .850-.882-.934 Brachylophus 5.5- 6.4- 7.8 4.1- 4.9- 6.0 .745--771-.800 Chalarodon 3.1- 3.3- 3.7 2.4- 2.4- 2.6 .702-.734-.774 Conolophus 16.0-25.7-30.4 14.3-23.1-27.4 • 824-. 876-. 901 Ctenosaura 8.0-11.3-15 .o 4.2- 6.9- 9.1 .525-.607-.690 Gyclura 14.0-22.1-35.3 7-5-15.2-21.6 .535-.585-.614 Di12sosaurus 5 .4- 6.4-_ 7 .1 4.0- 4.9- 5.9 -740-.789-.835 Iguana 9.8-14.1-16.7 9.0-12.4-15.4 .842-.886-.922 Op:::..urus 5.0- 5.8'"'."8.2 J.6- 4.3- 5.9 .704-.719-.760 Sauromalus 7-3-10.0-15.5 3.7- 5-7- 9.2 ._500-0556-.605

CX). f-' TABLE22

SQUAMOSLLBONES

Length Width Width-Length Ratio Genus Min. Mean J.'fJ.BJC. Min. Mean Max. Min. Mean Ma."'C•

Amblyrhynchus 7.1-10.2-12.9 5-7- 7.4- 9.5 • 606-.736-.802 Brachylophus 6.1- 7.1- 8.5 2.0- 2.2- 2.6 .280-.304-.327 Chalarodon 3.0- 3.1- 3.5 0.2- 0.2- 0.2 .057-.063-.066 Conolophus 13.0-20.6-24 •.3 5.2-10.0-13.4 .400-.476-.551 Ctenosaura 5.9- 9.1-1_3.0 1..3- 2. 6- 5 .2 .202-.2.34-.268 Cyclura 9.8-18.1-2.3.1 2.4- 4.9- 8.0 .244-.297--346 Dipsosaurus 6.0- 6.4- 7.1 1.5- 1.5- 1.7 .245-.268-.309 Iguana 9 .8-11.2-12 .2 3.0- 4.1- 5.0 .306-.369-.434 Oplurus 4.1- 5.4- 8.6 1.3- 1.5- 2.2 .244-.296-.369

Sauromalus 4.6-- ?.9-10.1 1.0- 2.4- 4.3 .217-.299-.373

co 1v TAR~E23

QUADRA'l'EBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean l•fax. Min. Mean Max. - Amblyrhynchus 9 .8-11. 6-13 .5 '/.0- 8.0- 9.3 .614-.690-.718 Brachylophus 7.0- 7-4- 8.0 4.1- 4.3- 4.5 .537-.549-.642 Chalarodon 2.7- 2.9- 3.2 J..8- 1.8- 1.9 .593-.628-.666 Conolcphus 13.4-19.7-24.9 8.3-13.7-17.0 • 619-. 69.3-.774 Ctenosaura 7 •0- 8. 9-11. 0 4.4- 5.8- 8.1 .625-.653-.736 Cyclur a 10.0-17.9-24.2 5.0- 8.9-15.0 .500-.557-.615 Dipsosaurus 6. 0- 6 . 2-. 6 •8 3.1- 3.3- 3.7 .516-.531-.544 Iguana 10.5-12.7-13.6 4.9- .6.9- 7.9 .457-.537-.580 Oplurus 4.0- 4.7-c 6.7 2.4- 3.1- 4.1 .600-.662-.731 Saurorrialus 5.0- 7.0-10.0 3.2- 5.2- 7.1 .640-.737-.887

~ TABJ,E24 SUPRATEMPCRA.LFOSSA

Length Width Width-Length R.atio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

Ambl;yrhynchus 12.5-15.2-18.3 6.3- 9 .4-11.9 .504-.616-.781 B:".''3.chylonhus 8.0- 9.4-12.l 4.3- 5.4- 6.9 .524-.577-.637 Ghalarodon 3.4- 3.6- 4.3 1.5- 1.6- 1.9 • 428-. 443-. 462 Conolophus 18.0-28.8-34.0 12 •0-1 7 • 4-21. 2 .560-.609-.666

Ctenosaura 8.1-11.0-13.9 4.9- 8.t5- 9.1 .589-.615-.654 Cyclura 12.0-21.2-28.0 5.1-11.3-19.1 • 425-. 515-. 682 Di12sosaurus 4.2- 5.0- 5.7 2.6- 3.2- 3.7 .619-.647-.687 Ig'J.ana 10.9-14.2-16.8 4.6- 7.1- 8.3 .422-.499-.567

Oplurus 4 •2- 5 •3- 8. O 2.1- 2.8- 4,1 .500-.524-.586

Sauromalus 5.0- 8.0-12.6 2.4- 5.0- 8.1 .1+80-. 620-. 672

~ TABLE25

OR.FIT

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Ma.x.

Ambl;zrhynchus 12.4-14.3-16.3 10.9-15.8-19.5 .802-.827-.866 Brachylophus 11.3-11. 9_-13.2 9.0- 9.7-10.9 • 796-. 811-. 825 Chalarodon 5.2- 6.2- 7.3 3.9- 4.2- 4.5 .611-.682-.769 Conolophus 17. 8-23 • 9--26. 6 17.2-23.3-26.9 .958-.969-.988 Ctenosaura 12.1-15.3-18.3 7 .6-12.(')-14_.l .770-.782-.793 Cyclura 16.8-25.6-33.1 12.8-20.7-27.5 .760-.803-.830 Di12sosaurus 8.6- 9.5-10.l 7.0- 7.5- 7.9 -770-.790-.813 Iguana 19 .0-21.3-24. 9 15.3-17.5-19.3 .775-.825-.867 Oplurus 7.6- 8.J-12.1 5.9- 7.0- 9.2 .760-.795-.839 Sauromalus 9.6-13.1-17.9 7.1- 9.9-13.5 .711-.741-.776

C) V, TABIE26 FENESTRAEX0NARINA

Length Width Width-Length Ratio Genus Min. Mean Max. Mino Mean Max. Min. Mean Max. -- Amblyrhynchus 8.1- 9.1-10 • .3 5.8- 7.0- 8.0 .716-.764-.817 Brachyloph"'J.s 4.0- 4.2- 4.8 3.3- 3.7- 4.0 .804-.872-.951 Chalarodon 1.4- 1.5- 1.8 1.0- 1.0- 1.1 .611-.664--714

Conolophus 11.7-15.4-17.5 8. 5-11. 9-13. 6 .726-.767-.803 Ctenosaura 4.1- 5.5- 6.8 3.0- 4.1- 5.0 ,700-.743-.806 Cyclura 7.3-20.4-32.1 5.3- 9.0-14.5 ,428-.443-.452 Dipsosaurld§ 3.2- J.8- 4.2 2.0- 2oJ- 2,5 .571-.590-.606

' Ig_uan0_ 8.2-11.7-14.3 515- 7.8- 8,7 .608-.669-.714 0plurus 1.9- 2.5- 4.2 1.4- 1.8- 3.1 .700-.718-.738 Sauromalus J.0- 4.6- 6.8 2.1- 4.1- 5.0 .600-.751-.833

00. °' TABIE27 DENTARYBONES

Length Width Width-Length Ratio Genus Min. Mean lvlax. Min. Mean Max. Min. Mean Ma..-sc.

Amblyrhynshus 20.3-28.3-34.3 7.5- 8.3-10.2 .271-.297-.320 Brachylophus · 19 .8-21.4-23 .1 4.0- 4.5- 5.0 .202-.209-.216 Chalarodon 8.1- 9.2-10.0 1.3- 1.5- 2.0 .142-.17li,-.209 Conolophus 40.4-51.2-55 .6 8.7-14.7-17.4 .215-.282-.319 Ctenosaura 19.2-26.7-35.6 3.4- 5.2- 7.5 .171-.190-.210 Cyclura 29. 5-51.3-72 .3 6.5-10.9-15.0 .202-.214-.228 Dipsosaurus 12.9-14.7-15.9 3.1- 3.6- 3.9 .240-.243-.246 Iguana 30.0-40.3-47.5 6.7- 9.3-10.8 .213-.225-.239 0plurus 13.2-17.1-24.0 2.1- 2.4- 3.1 .129-.147-.159 Saurornalus 13.6-20.0-28.4 2.5- 3.6- 5.5 .143- .181- .203

00 -..J TABLE28

.A..RTIClJV1.RBO:t-.'"ES

Length Width Width-Length Ratio Genus Min• Mean }'!"...ax. Min. Mean Max. Min. Mean Max.

Amblyrhynchus 18.4-25.0-30.0 5.9- 8.1-10.8 .258-.320-.360 Brachylophus 16.0-17.4-18.4 4.3- 5.3- 6.4 .240-.309-.400 Chalarodon 6.1- 6.3- 6.7 1.2- 1.2- 1.4 .193-.200-.208

Conolophus 34~2-52 .8-61. 5 11. 7-21.1-27 .2 .342-.394-.457 Ctenosaura 14.1-21.4-21.2 4.6- 6."4-10.6 .238-.297-.349 Cyclura 24.2-42.4-57.8 4.7-12.0-20.3 .182-.264-.351 Dipsosaurus 8. 9-11.3-12. 6 3.0- 3.6- 4.1 .298-.320-.337 Iguana 23.4-31.9-38.7 7.4- 8.6- 9.1 .227-.271-.316 Oplurus 8 .3-11.3-15. 8 1.9- 3.0- 4.9 .228-.257-.310

Sauromalus 14.8-20.?-25.5 2.8- 5.5- 9.3 .185-.253-.325

ro co TAKE 29

ANGULAR?R.OCESS

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean :Max.

Ambly:rh;ynchus 35.0-48.4-57.1 6.4- 9.5-11.5 .182-.196-.203 Brachylophus 32.2-33.6-35.6 4.2- 5.4- 6.6 .130-.157-.185 Chalarodon 12.0-12.6-13.4 1.0- 1.3- 1.8 .081-.105-.134 Conole~ 66.6-95.1-107.6 11.6-21.3-27.2 .174-.219-.256 Ctenosaura 30.2-43.1-60.4 3.9-6 .3-10.6 .123-.141-.174 C;yslura 48.7-84.7-117.3 7 .9-14.5-21.1 .162-.169-.179 Dinsosaurus-; 19~9-23.2-25.4 3.5- 4.1- 4.4 .169-.174-.175

Igsam 50.0-65.4-77.2 7-5- 8.6- 9.2 .112-.134-.150 0£}._u_r_us 18.2-24.3-34.7 1.9- 3.0- 4.9 .104-.120-.141 Saurorr.alus 22 .L,,-33.4-43 .1 2.8- 5.5- 9.3 .113-.138-.167

00 '° TABLSJO SUP.ANGULARBONES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. 1JT...in.Mean Max.

Ambl;y:rh;y:nchus - 11. 9-16.6-21.6 5.8- 6.9- 8.9 .365-.425-.487 Brach;ylo12hus 9.2- 9.6-10.4 J.4- J.6- J.9 .J69- 0377-.389 Chalarodon 2.9- 2.9- J.l 1.0- 1.0- 1.1 .344- .352- .J66 Conolo12hus 25.5-4503-62.1 9.0-15.2-18.0 0289-.343-.365 Ctenosaura 11.4-16.8-25.4 J.1- 4.7- 6.6 .271-.296-.309 Cyclura 20.1-24.0-44.J 5.0-10.2-15.1 •248-. 296-. 340 Dipsosaurus 6.5- 7-7-_8.7 2.4- 2.7- J.O .J44-.356-.J69 lguana 20.0-25.2-30.4 5 .4- 7 .O- 8.5 .270-.278-.299 OI?,lur:g,_~ 5 • 0- 6 .1-. 8. 2 1.4- 1.8- 2.6 .280-.293-.316 Sauromalus 8.8-13 •.3-19.6 2.1- J.6- 6.0 .229-.270-.306

'°0 TABLE31

SPLENIJi.. BOI\1ES

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Ma.."'C. Min • Mean Max.

Amblyrhy:nchus 8.0-10.8-14.3 2.1- 3.1- 4.1 .230-.296-.425 Br::i,chyloohus 6 • 5- 6. 8_-7 •2 2.0- 2.4- 3.4 .263- .361-. 513 Chalarodon 4.3- 4.3- 4.5 1.7- 1.7- 1.9 .395-.405-.422 Conolophus 13.4-20.0-24.4 4.2- 6.3- 7.9 .252-.317-.393 Ctenosaura 7.7- 9.7-12.4 1.3- 2 .2- 3_.o .186-.230--.300 Cyclura 12 •0-21. 8-3O. 0 1.9- 3.3- 5.3 .120-.149-.176 Dipsosaurus 3.7- 4.4- 5.3 1.3- 1.4- 1. 7 .283-.334- .378 Iguana 14.7-20.6-24.6 4.7- 6.2- 7.7 .255-.301-.319 Oplurus 8.4-10.9-15.3 1.5- 1.8- 2.4 .156--.166- .178 Sauromalus 5.0- 9.0-12.1 1.0- 1.8- 2.8 .151-.199-.231

-.D I-' TABi,E 32 ANGULARBONES

Length Width Width-Length Ratio Genus Min. Mean Ma."'C. Min. Mean Max. Min. Mean Max.

Amblyrhynchus 12.4-16.4-19.5 2.8- 3.5- 4.1 .202-.214-.225 Brachylophus 9.2-10.5-12.l 1.4- 2.0- 2.5 .152-.189-.211 Chalarodon J.0- ,3.5- t..4 0.5- 0.5- 0.7 .156-.160-.166

Conolonhus 24.1-37.4-46.7 4.9- 7.1- 8.8 .155-.193-.226 Ctenosaura 10.2-16.5-23.1 2.1- 2.7- 3 • .3 .1.34-.171-.204 Cyclura 16.4-31.8-43.1 2.5- 4.3- 5.6 .129-.139-.152 Dipsosaurus 7.6- 8.0- 8.3 1.6- 1.8- 1.9 .227-.223-.230 Iguana 19.2-24.5-30.4 3.2- 4.1- 4.8 .157-.170-.193 Oplurus 4-7- 6.1- 9.4 0.9- 1.1- 1.5 .159-.189-.204 Sauro:malus 6.5-10.1-14,5 0.5- 1.3- 2.4 .076-.107-.165

'°iv TAELE33 CORONCIDBONE

Length Width Width-Length Ratio Genus Min. Mean Max. Min. Mean Max. Min. Mean Max.

Ambl:zrhynchus 6.4- 9.7-12.0 6.9- 9.3-11.4 .900-.935-.968 Brachylophus 6.4- 6.7- 6.0 5.0- 5.8- 6.5 -746-.857-.969 Chalarodon 1.4- 1.6- 1.9 1.5- 1.6- 1.8 .933-.941-.947 Conolophus 15 .1-21. 8-25 .o 9.0-12.4-14.3 .521-.571-.596 Ctenosaura 4.3- 6.6- 9.5 3.0- 4.8- 7.4 .684-.717-.778 Cyclura 5.8- 9.7-13.6 7.3-10.7-14.4 -794-.883-.943 Di12sosaurus 3.2- 3.6- 4-3 4.2- 4.4- 4.9 • 761-. 798-. 873 Iguana 5.3- 7-5- 9.0 7.0-.9.0-10.7 .662-.733-.794 0plurus 2.3- 3.0-:-4.1 2.1- 2.8- 3.8 .916-.922-.926 Sauromalus 3.0- 5.2- 8.1 2.7- 4.5- 6.9 -771-.875-.936

'vJ'° TABLE34

TEE'IH

Pterygoid :V..axilla cy Dentary Genus per slde Premaxilla per side per side

Amblyrhynchus 0-7 7 17- 21 17- 24

Brachylophus 1- 8 6-7 16-19 18-21

Chalarodon 2- 4 6 16-18 19- 21

Conol.ophus None 7- 8 15- 20 17- 21

Ctenosaura .3-14 7- 8 20-26 20-33

C_yclura 0-10 6- 10 19- 2.3 22- 28

Di12_sosaurus None 7- B 16-19 20- 2.3

Iguana 8- 52 6- 7 20- 26 19-~30

0_£lurus 4- 9 6 15-19 16-2.3 Sauromalus 0-7 5- 6 16- 20 15- 25

'°+""" 95

MYOLOGY

In order to avoid confusion, the terminology used for the

following description of the muscles is that of Robison and Tanner

(1962), Avery and Tan11er (1964) and Jenkins and Tanner (1968). !Any

deviations will be noted in the text.

THROATMUSCUI.ATURE

,MoIntermandibularis anterior superficialis (Plates XI and XII), is a

short strap like muscle connecting the rami of the mandibles, in the

area between the origin of the genioglossus and the first mandibulo-

hyoideus muscle. The body lies superficial to the interrrandibularis

anterior prol'undus, mandibulohyoideus II and the genioglossus muscle.

It is overlain superficially by the skin.

It arises from the oral membrane, the a.nterior fibers of the

intermandibularis anterior profundus, and the crista dentalis ligament.

The fibers o.f this muscle insert on the fibers of its opposite equivalent along the mid-line ra:rne.

This muscle is constant in all genera examined with the

following exception5. It was .found to be absent in one juvenile

12.iJ2sosaurus exarrd..i"1edand narrrn,,i and reduced in adults. The muscle was also found reduced and narro',,,; in ~§J}§. where it contributes to the

anterior margin of the muscular contents o.f the dewlap. In the remain-

ing genera the muscle is sheet like with the width at least hal.f the length. 96

!1• InterrnandibuJ.aris anterior profundus (Plates XI and XII) is a

continuous sheet of muscle lying superficial to the majority of throat musculature and just deep to the skin. The muscle arises from the mesial surface of the splenial and coronoid bones and from the crista

dentalis,- by a tendon. The anterior fibers extend anteriomesi.ally

across the throat to insert on the ventral mid-line raphe. The poster-

ior fibers also insert on the mid-line raphe after arising vi.a several interdigitations with the first mandibulohyoideus muscle.

The muscle is relatively consistant in the iguanines exarrined.

In Igua,na the intermandibularis anterior profundus extends deep into the dewlap with the fibers ending about one-third the distance from the ventral bo.rder. It also forms the bulk of the muscular contents

of the dewlap.

Ji. Intermandibu..larJ§_ rosterioz: ( Plates XI., XII., XZ.I:v and Y:lV) is a thin sheet overlying the angle of the jaw and covering superficially, the posterior fibers of the intermandibularis anterior profundus. The muscle sheet is extremely thin in the posterior extremities and thickens towards its anterior extremes. The posterior origin of this muscle is .from the lateral surface of the mandible beginning at the midpoint

of the ret:roarticular process. Anteriorly the muscle originates as the last two or three interdigitations of the anterior profundus muscle with which it is continuous. Its insertion on the mid-line raphe is characterized by a wide aponeurosis which leaves both sets of fibers from each side separated in some specimens.

Posted orly the inter:mandibularis posterior is continuous with the constrictor colli from v.rhich it can be deliniated by a natural separation o.f the muscle fiber bundles. The possession of this separa- 97

tion is quite variable in the genera eJO.rrd.ned. In Arrblyrh;ynchus,

Brachylophus, Chalarodon, Dipsosaurus, Ig™ and Opluru.s the constrictor colli and jr,terrr~ndibularis p::;sterior are closely associated along

their entire corrnnon bord.erso In Conolophus and Ctenosaura the two muscles are sepa,rated laterally at the angle of the jaw with :r:art of the

pterygomandibularis being visible between them. In Cycl ura and Sauro- malus the borders of the two muscles become more separated towards the midline raphe. In lg_'.:§:!§. the intermandibularis p:i sterior extends deep into the dewlap endj.ng about a third of the way to the ventral borde.:.:' o

It also forms the p:isterj_or p:irtion of the dewlap 1s muscular cmtento

N• Mandibulohvoideus I (Plates XI and XII) is a long triangular muscle which extendt, two-thirds of the length of the mandible, and lies lateral to the second mandibulohyoideus, mesial to the mandibular rami, and

anterior to the insertion of the sternohyoideus. Thif> muf>cle lies

dorsal to the intermandibularis muscle and ventral to the genioglossus, hyoglossus, mand.ibulohyoid.eus III, and the pterygomandibularis muscleso

At its anterior end, the rnandibulohyoideus I interdigitates at right

angles vd. th the fibers of the intermandibularis anterior profunduso

The mandibulohyoideus I originates along the ventromesial

surface of tl:e dentary and a srri.all :r:art of the angular, from the

posterior border of the intermandibularis anterior superficialis,

posteriorly to the mass of the pterygomandibula ris. It inserts just

posterolateral to the insertion of the mandibulohyoideus II along the anterolateral border of the distal three-fourths of the first cerato-

branchial.

There is no deviation from this :r:attern in the genera examined.

,M. Mand-ibulohyo::..d.en~ 11 (Plates XI and XII) is a small, pointed 98

elongated muscle tapering at both ends and lying mesial to the mandi--

bulohyoideus I, and inserting alongside its opposite equivalent on the

rr~dventral rapheo It lies deep to the intermandibularis muscle and

superficial to the tongue, the genioglossus, and the hyoglossuso

The origin of the mandibulohyoidous muscle is a narrow tendon,

an anterior extension of the rr~d-line raphe, from the capsule of

cartilage overlying the rrandibular symphysis. The muscle inserts on

the anterior border of the pro.:xirral end of the first ceratobranchial,

anteromesial to the insertion of the first mandibulohyoideus. A

similar situation exists in all the genera exanrined.

11•Mandibulohyoideus ]II (Plates XIII and XIV) is a thick strap like

muscle running over the pterygornandibu1aris with attachments to it by

connective tissue. The course of this muscle is nearly parallel to the

mandibu.13.r c:>aiilUS on e-ach side. It lies between the ceratohyal and the

pterygoJr,andibul ari s.

In all genera this muscle arises from the ventromesip.l sur-

face of the dentary and angular bones between the anterior and posterior myohyoid foramina. The narr~1 insertion of this muscle is on the lateral surface of the ceratohyal, distal to its midpoint.

,N. Gen;10glos-rns (Plates XI, XII, XIII and XIV) in all genera, is a thick band-like muscle which, with its partner on the opposite side,

occupies a large area between the mandibular rami. Its position is ventral to the tongue and anterior to the basihyal. The first, second and third mandibulohyoideus muscles and the intermandibularis muscle all lie ventral to it.

The genioglossus originates along the ventral and mesial

surfaces of the anterior one-sixth of the mandibular ramus, and dorsal 99

to Meckel 1s canal. The mesial fibers run JX)Steriorly, while the

lateral fibers turn dorsally and laterally before passing posteriorly.

]1. Hyoglossus (Plates XIII and XIV) in the genera examined, is a thick

broad muscle lying lateral to the basihya.l and the second ceratobranchial

and basial to the rn&nd.iblc, the m.andibulohyoideus III and the pterygo-

mandibularis. The mandibulohyoideus I and II muscles and the anterior

portion of the mandibuJ.ohyoideus III lies superficial to it. The

hyoglossus muscle lies ventral to the ceratohyal and the oral membranes.

The origin of this muscle is along the anterolateral face

of the distal two-thirds of the first ceratobranchial and dorsal to the insertion of the mandibulohyoideus I muscle. The muscle traverses an anterior path to interdigitate with the genioglossus near the proximal

end of the hypohyal and to form the main body of the tongue.

,M, Branchiohyo:ideus (Plates XIII and XIV) lies dorsal to the hyoglossus, between the ceratohyal and the first ceratobranchial of the hyoid bone, This muscle lies just ventral to the oral membrane which in turn lies ventral to the massive pterygomandibularis muscle.

The branchiohyoideus has its origin from the posteromesial

surface of the posterior t{'[o-thirds of the ceratohyal. Its path passes

parallel to the two hyoid limbs, and inserts near the distal end of the. first ceratobranchial.

Iri Sauromalus the insertion on the first ceratobranchial is narrow while the insertion in the other genera covers over half the

distal portion of the first ceratobranchial.

!:J:.Sternohyoideus ( Plates XI., XII, XIII, XIV, XXV and XXIJI) is an exten-

sive muscle sheet, occupying a large area posterior to the first ceratoO branchial cartilage and 2.nt erior to the stem um and clavicle. Its 100

position is deep to the intermandibularis and the constrictor colli,

anteriorly, and to the episternocleidomastoideus, the trapezius and a

small µi.rt of the levator scapulae profundus, the pharyngeal membranes,

the trachea, the clavicle, and the clavodeltoideus.

There has been considerable confusion in the literature over

the limits of this muscle. Davis (1934:19) considers the superficial

layer to be divisible into three parts in Crotaphytus., One of these

muscles he calls the omohyoideus. Robison and Tanner (1962:6) consider

this muscle continuous in the same genus. Oelrich (1956:51-52) treats

this muscle in Ctenosaura as being continuous but owing to the different

origin and direction of the fibers, he separates the layers into

ornohyoideus and sternohyoideus. Kestevenfs studies (191+4:245-246)

on the agamid, Physignathus, suggests a separation in young specirri£ns a.:1d treats these layers as consJsting of three parts which he considers to represent the similar, though distinct division present in Varanu3.

In the iguanines it has been decided to treat the sternohyoideus con~

plex as three seµi.rate muscles: sternohyoideus, sternothyroideus, and omohyoideus.

The sternohyoideus originates via several heads from the clavicle. Its oblique fibers run anteriorty to insert on the posterior surface of the first ceratobranchial. In all the genera examined, the sternohyoideus forms a broad elongated sheet of muscle with the exception of Oplurus where its appearance is narrow and cord like.

11· Omohyoideus (Plates XI., XII., XV., XVI., XXV and XXVI) is sheet like, and forms the lateral eA'tension of the sternohyoideus complex. In all of the genera examined i.t originates, mesially, from the lateral tip of the transverse process of the interclavicle with some fibers of the 101 episternocleidomastoideuso Laterally, the omohyoideus takes its origin

.from the anterolateral surface of the clavicle and anterior border of the suprascapula.

The fibers of the omohyoideus pass obliquely anterior to insert on the posterior rrargin of the first ceratobranchial cartilage to the proximal end of the second ceratobranchial cartilage.

In all of the iguanines examined except Chalarodon, the medial border is difficult to separate from the lateral border of the sternohyoideus. The delineation of both muscles must be made by comparing the origins and insertions. In Chalarodon the omohyoideus is easily separated as the fibers of this muscle pass oblique to those of the sternohyoideus.

,MaSternothvroideus (Plates XI and XII) is the most medial extension of the sternohyoideus comn1ex and c;.,,n b0 sepc.r':'ted froJ:1 the other members of this muscle group by its different origin and insertion. The name sternothyroideus is used as in. Camp (1923:451) who figured this muscle as the deep member of the complex in Brachylophus.

The o:dgin of this muscle is considered to be those fibers that arise from the interclavicle and sternumo These fibers fB.SS anteriorly and parallel to the trachea to insert on the hyoid at the point of union between the basihyal and the hypohyal.

In the genera examined the lateral border of the sternothyroideus and the medial border of the sternohyoideus are difficult to deter- r mine except in Oplurus and Chalarodon where the borders of both muscles are separated in situ~

NECKMUSCULATURE

11• Constrictor colli (Plates XI, XII, XVII, XVIII, XXIII, and XXIV), the 102 most superficial muscle of the cervical region) is overlain by the

connective tissue of the skin and a few scattered fat pads. The con-

strictor colli lies superficial to parts of the depressor ~andibularis

and episternocleidomastoideus, and is from one to two fibers thick.

The main origin of this muscle is on the superficial dorso~

lateral fascia of the neck which extends almost as far as the posterior margin of the depressor ma.ndibularis. The muscle passes verrtrolaterally

posterior to the retroarticular process of the articular bone J and

inserts on the extensive ventral aponeurosis at the midline, which

also serves as the point of insertion for the intermandibularis posteriore

The relationships between the anterior border of the constrictor colli and the posterior border of the intermandibul.aris posterior have previously been described. The width of the constrictor colli

is variable in the iguanines o 'I'he muscle is widest, covering most of the lateral surface of the neckJ in Amblyrhynchus, Chalarodon, Cyclura,

Iguana, and Sauromaluso A narrow constrictor colli is found in

Brachylophus, Conolor±rns, Ctenosaura, Dipsosaurus and Oplurus.

~• Episternocleidomasto~deus ( Plates XI, XII, XIX, XX, XXIII, XXIV,

XXV, XXVI, XXVII and XXVIII) is a neck muscle crossing at an oblique

angle from tl:e sh01Jlder to the heado It is overlain by the depressor mandibularis which covers its anterior end. The episternocleidomastoideus lies superficial to the omohyoideus, the tympanic meFbrane,

the distal ends of the ceratohyal, the ceratobranchial rones and the

two levator scapulae muscleso

The origin is a single head arising from the lateral process

of the interclavicleo The insertion occurs on the distal half of the

pg.rietal crest, the lateral surface of the pg.raoccipital process of 103

the exoccipital bone and with some connec:ti on to the fascia of the

dorsolateral engle of the neck.

This muscle was not found to deviate from this P3,ttern in any

of the specimens examined.

]1. Depres..5..2r,mndib1.,Llaris (Plates 1.'VII, XVIII, XXIII, XXIV, X1.v and

XXVI) is situated laterally with its anterior edge bordering the

auditory meatus posteriorlyo It is overlain by the constrictor colliv

The anterior part of the depressor mandibularis is superficial to part

of the post,erior fibers of the adductor .rrandibularis externus medius

and the posterior border of the tympanic membraneo Its JX)Sterior parts pass superficially to the anterior fibers of the trapezius and the

episternocleidomastoideus, with some lying superficial to the distal

ends of the ceratohyal and ceratobranchial bones, and the tympanium.

The

bundles. The origin of the anterior bundle is from the anterolateral

surface of the posterolateral parietal wing and parietal crest. This bundle makes up the major part of the depressor mandibularis muscle

and passes posteroventrally with a tendonous insertion on the retroarticular process of the articular bone.

The intermediate bundle, in its .posterior region, takes origin

from the fascia along the dorsolateral angle of the neck, in the region

of the first certical vertebras, and ventral to the constrictor collL

'rhis bundle has a common origin with the posterior bundle ( cervicomandibularis) and a common insertion, ventrally, with fibers of the anterior bundle on the retroarticular process. The intermediate bundle is sheet like rather than forming a thick mass as does the anterior and posterior bundleo 104

The posterior bundle is considered as a separate muscle, the cervicomandibularis (Plates XVII, XVIII XXIII, XXIV, XXVand XXVI), when distincto It is separable from the other two bundles at its insertion and throughout most of its length. It takes its origin from the superficial fascia of the dorsal mid-line of the neck in common with the posterior fibers of the intermediate bundle, and ventral to the origin of the constrictor colli. It extends anteroventrally along the posterior border o.f the intermediate bundle and continues past the insertion of the anterior and intermediate bundles to insert on the superficial fascia of the intermandibularis and the skino

Some variations in the width of the anterior bundles occur in Igu~ and C<2nolophus where the bundle is very narrow and in Ambly- rhynchus where the bundle is very thick and wide.

The cervico:m.anrlibu.laris also shows considerable variation in distinctness and relationship to the origin of the constrictor colli.

Robison and Tanner (1962:8) indicate that this posterior bundle became indistinct in old forms of Crotaphytus. This problem of distinctness may be a function of age. Unfortunately the sirall sample sizes used in this study can lend no support to that theoryo

In Brachylophus, Chalarodon and Di nsosaurus, the cervico- rm=mdibul::i,ris is extensive and its rosterior border at the origin extends posteriorly beyond the p:isterior border of the origin of the constrictor colli, thereby making the cervicomandibularis the most superficial muscle, at its origin in that area of the necko In all other genera examined, the cervicomandibularis is completely obscured by the more superficial constrictor colli.

£1. Levator scapulae superficialis (Plates XVII., XVIII, XIX, XX, m., 105

XXVI, XXVII, XXVIII., XXIX and XXX) is normally considered to be a musc:le of' the pectoral girdle. As it originates on the neck, deep to the neck musculature it will be included with these muscles.

The levator scapuiae superficialis is a broad fan-shaped muscle, lying mostly anterior, but IB,rtly superficial to the suprascapula bone. It is superficial to the levator scapulae profundus, the axial musculature and the posterodorsal fibers of the origin of the omohyoideus.

The constrictor colli, trapezius, episternocleidorrastoideus, depressor rnandibularis, tymIB,nic membrane, distal ends of the ceratohyal and the first ceratobranchial all contribute to the superficial layer over this muscle.

The origin of the levator scaplLlae profundus is a tendon,

(•ornmcn, t,o i ➔. nrirl t'be 1evator scanuJc1e profund1.1s; from the diapophysis of the atlas. The muscle extends posterodorsally and inserts on the anterior half of the lateral surface of the scapular bone~ There is little deviatiori in this pattern in the genera examined.

N• Levator scapulae profundus (Plates XIX, XX, XXVII., XXVIII, XXIX and

XY.X)is the deep P3,rtner of the levator scapulae superficialis, and has a similar position with relation to the surrounding muscles, with the exception that the posterior fibers of insertion pass deep to those of the omohyoideus muscleo

The origin is by a common tendon with the levator scapulae superficialis, from the diapophysis of the atlas. Muscle fibers pass posterodorsally to insert along the naterior margin of the suprascapula just ventral to the insertion of the levator ~capulae superficialis, and to the anterior surface of the acrornial snd of the clavicle. 106

TEMPORALMUSCULATURE

_M. fterygomandibuJ.aris ( Plates XI, XII, XIII, XIV, "X"V,and XVI) is a

large muscle at the angle of the jaw covering a large part of the

posterior half of the mandible. It reaches its largest size between

the mandibular rami and lateral to t.he trachea. The interma.ndibularis

posterior lies superficial to it laterally with the oral n1embrane

bordering it ventromesially. The third :rns.ndibulohyoideus and the hyo--

glossus muscles lie ventral to it.

The origin of the pterygomandibularis is a heavy tendon

arising from the ventral projection of the e~tcpterygoid, and the trans-

verse process of the pterJgoid. Some fibers also originate as a

tendonous sheath from the re:maining part of the transverse process,

and the ventrolateral border of the quadrate process of the pterygoid with pg.rt from the ventral border of the basiptorygoid process of the

basisphenoid bone where this bone articulates vJith the pterygoid.

The main fibers of this muscle extend posteriorly and poste~•

cJ.orsally, to obscure the ventral and lateral surfaces of the angular,

articular, and supra-angular bones of the mandible. The fibers insert

on the dorsal, mesial and ventral surfaces of the articular bone,

including the retroarticular and angular processes. Some fibers form

a line across t.he lateral surface of the angular and the supra-angular

fora.men. Between the foramen and the adductor :mandibuJ_ar:Ls externus

superficialis, a tendonous insertion extends lengthwise through the muscle mass in a posterior direction and attaches to the angular

process of the articul.ar~

_M. Leva tor _§,ngularis ori~ ( pl.ates :XXIII a.nd XXIV), the most superficial muscle of the infra.temporal fossa, is overlain by the infra.temporal 107 fascia and the skin. It covers part of the surface of the adductor mandibularis externus superfici.alis.

It is this mw::,cle which arises from the mesial surfaces of the su erficial infratemporal fascia, the ventrolateral surfaces of the squamosal, the posterior r,art of the jugal and the anterodorsal angle of the tympanic crest. The fibers pass anteroventrally to insert near the posterior border of the coronoid.

The size of the levator angularis oris differs in the genera examined. In all of the genera except Brachy1ophus and Dipsosaurus, the muscle covers over half the infratemporal fossa. In Brachylophus and

Dipsosaurus the muscle is very small and narrow, covering less than a third of the anterior ps,rt of the infratemporal fossa. lJ. Adductor rrandibuJ_aris extern us superficialis ( Plates XXIII, XXIV,

XY.Vand XX1IT) _. of the :infr3,tsr::por3,l fossa_. is 2n extensive Emscle r-2.ss which mesially is scarcely distinguishable from the adductor mandibularis externus medius. It lies beneath the levator angularis oris at its anterior border and beneath the superficial infratemporal fossa at its posterior border.

The superficialis originates from the ventral surface of the postorbital, squamosal, jugal and quadrate bones, and from the lateral surfaces of the tympanic crest. The fibers, which extend anteroventrally, are more ventrally oriented than those of the levator angularis oris.

They insert along the dorsolateral surface of the supra-angular bone, with fibers passing dorsal to the posterior supra-angular foramen and covering the anterior supra-angular foramen. The most anterior of these fibers insert on the lateral and posterolateral surface of the coronoid with parts inserting on the lateral surfaces of the bodenaponeurosis. 108

_M. Adductor ma.ndi buJ_aris extern us medius ( Plates XVII, XVIII, XXIII,

:xxrv,XY:V, XXVI, XXVII and XXVIII) is a large muscle, faintly separated from and mesial to the adductor mandibularis externus superficialis and dorsolateral to the adductor mandibularis externus profunduso It is also posterolateral to the pseudotemporalis superficialis with the exception of its anteromesia1 fibers which are dorsal to that muscleo

The origin of this muscle is from the mesial surface of the squamosal, the anterola teral surfaces of the supra temporal and the posterola teral ving of the }'.Brietal, the dorsolaterally beveled surface of the parietal, and from the anterior and dorsal surfaces of the quadrate bone. Fibers extend anteroventrally with the dorsal ones being more anteriorly oriented than the ventral. These insert along the dorsomesial surf2.ce of the supra-ang1Jlar, the posterior surface of the coronoid_, and the lateral~ posterior, and mesial sides of the bodenaponeurosis.

_NoAdductor mandibularis extemus proflmdus (Plates XXIX and XXX), 2, massive muscle, not clearly separable from the adductor mandibularis externus medius, is located ventrolaterally to the pseudotemporalis superficialis, dorsal to the prootic, and lateral to the braincase and the supra.occipital.

This muscle 1s origin arises from the entire posteromesial border of the posterolateral wing of the parietal, from the paraoccipital process of the exoccipital, and from the dorsolateral surface of the posterior process of the prootic bone. From its parietal origin this muscle turns ventrally and anteroventrally to enter the infratemporal fossa where it passes ventral to t:ie t""mpratemporal and the posterolateral pc1,rietal wing and dorsal to the exoccipital and the posterior process of the prootic bone. At this point it joins with 109

another head from the prootic and continues·ant.eroventrally to insert

by the bodenaponeurosis to the posterior surface and base of the

coronoid. The adductor mandibularis externus group has been considered

as a single rnass (Adams, 1919) Hith sepa.rate slips as described above.

According to Oelrich (1956~41) thfo group is divided into three muscles

on the basis of its relations to the three ra.'Di of the trigeminal

nerve. This system has been followed here for the sake of convenience

and clarity. No special differern:es were noted in the genera examined.

£1. Pseudotemporalis supcrfj_cialis (Plates )."VII., XVIII., XXIX and XXX) is

a divergent, massive muscle with a complex placement. It lies ventro-

mesial to the adductor mandibularis externus medius, posterior to the

orbit, anterolateral to the cranial cavity, lateral to the epipterygoid,

and lateral to the pseudotemporalis profundus. The posterior fibers

are trapped between the adductor mandibularis externus profu,'1.dus and the

adductor mandibularis externus mediuso

The origin of the pseudotemporalis superficialis is from the

dorsolaterally beveled lateral margin oft.he parietal, :r:art of the

anterolateral surface of the parietal wing, the lateral surfaces of

the anterio:t:.' semicircular canal, and the alar process of the prootic,

and the internal surface of the dorsal one-third of the epipterygoid.

Fibers of the anterior :p3,rt pass ventrally whHe posterior fibers

extend anteroventrally. The insertion is with the pseudotemporalis

profundus, on the mesial surface of the bodenaponeurosis, the postero-

mesial border of the coronoid to its base and the dorsal border of the

articular to its rrLid-point.

_N. Pseudotemporalis prof~ridus (Plates XXXI and YJCXII), a pyramid shaped 110 muscle, lies ju.st posteromesial to the pseudotemporalis superficialis., lateral to the epipterygoid bone and the levator pterygoideus muscle.

This muscle arises from the anterior, lateral and posterior sides of the ventral two-thirds of the epipterygoid bonoo These fibers extend ventrally to :Lnse.ct, with the pseudotemporalis superficialis muscle, on the posteromesial border of the coronoid bone and on tho dorsal surface of the articular bone to its mid-point~

]1. Adductor mandibularis posterior (Plates XXXI and XY..XII) is a w:Lde straplike muscle, lying lateral to the tympanic cavity, the protractor pterygoideus muscle, and mesial to the mandible and to the adductor mandibular:Ls externus muscles.

A few fibers arise from the lateral and mesial surfaces of an aponeurosis running between the rEes:Lal crest of the quadrate and

Meckel rs cartilage. Other .fibers take their origin from the pnc,ter:ior process of the prootic bone. All fibers pass anteroventraU.,y to insert on the dorsal surface of the articular bone with some fibers of the pseudotempora,lis muscles, and on Meckel I s cartilageo

_N. Levator :eterygoideus (Plates XXXI., XXXII., XXXIII and XXXIV), a triangular shaped muscle, lies posteromesial to the epipter-y-goid bone and the pseucfotemporalis profundus muscle. It lies anterolateral to the protractor pterygoideus and lateral to the prootic membrane of the cranial cavityo

The origin is by a flat tendon from the ventral surface of the parietal bone, mesial to the epipterygoid, and posteriorly along the parietal bone, rnesial to the epipterygoid, and posteriorly along the lateral margin of the parietal to its midpoint. Some fibers fan out posteroventrally to insert, with anterior fibers of the protractor 111 pterygoideus, on the proyJ..rr.al dorsal surface of the quadrate process of the pterygoid bone, beginning posterolateral to the fossa columella and extending anterorne2ially, to end mesial to the epipterygoido

_N. Protracto;i:_: J?_l:,erygoideus (Plates XX.XI XX.XII, XXXIII and XXXIV), a broad, short muscle, fcrn:s the antc:tolateral wall of the tyrnpanic cavity. This muscle lies posteromesial to the levator pterygoideus and lateral to the basisphenoid bone, and the anterior p:i.rts of the prootic bone.

The origin of this muscle is from the lateral surface of the anterior inferior process of the prootic bone, the posteroventral end of the pila antotica, and from a tendon which comes from the anterior inferior proc:es.3 of the prootic to the region of the condyle on the anterior tip of the basipterygoid process of the basisphenoid bone.

Most fibers of the protractor pterygoideus fan out, posteroventrally, to insert on the dorsal and mesial surfaces of the quadrate process of the pterygoid. The muscle insertion extends from posteromesial to the fossa colwr:ella, posteriorly, to the mesial crest of the quadrateo

Some anterior fibers insert with those of the levator pterygoideus.

The majority remain posteromesial to this muscle. TABLE35

SUMW1.RYOF IMI-ORTANT}fiOLOGICAL DIFFERENCES

Sternothyroideus Levator Angularis lateral border Cervicomandibularis Oris

Genus Se:p3.rate Attached Visible Hidden Large Sma.12. h.rnblyrq;ynchu~s X X X

Brachylophus X X X

Chalarodon X X X

Conol :>phus X X X

Cten.os3.u.ra X X X

.Q,vclura X X X

Di£SOS_?-Urus X X X

Iguana X X X

Oplurus X X X

Sauromalus X X X

1-J I-' N 11.3

OTHERCHARACTERS

Besides the osteology and myology; the structure of the

tongue and hemipenes of iguanine lizards has been investigated.

TONGUE

Only one tor,gue from each genus was examined with the exception of Dipsosaurus_, where three tongues were utilizedo Measurenents were taken of total length, measured from the anterior tip to the most

posterior extension of the tongue. Width was recorded as the greatest

distance, at a right angle, to the length. Width in all cases was taken

at the mo::;t J:Y)sterior extremities of the tongue which is the widest

region. The depth of uoth anterior and posterior indentation or

clefts were also measuredo Ratios were computed between length and width, length and depth of anterior cleft, and length and depth of

posterior clefto

The tongues (Plate Y.Y:J:!v)in all the iguanines are fleshy and

protrusible with an arrowhead shape with a slight cleft anteriorly and

a deeper cleft JX)steriorly, which surrounds the glottis laterally. The tongue is covered with 11 ••• velvety filamentous papillaeo••" (Oelrich,

1956:5.3) which are missing or very small at the most anterior tip and

become increasingly larger posteriorly until, at the posterior extremity

of the tongue., the papillae are fleshy and pointed rather than blunt.

As table .36 shows, the most elongated a.rd narrow tongues are those o.f Ctenosaura (length times width ratio ol+91), Sauromalus ( .5.30) 114

and Cyclura (.539)0 The fattest tongues are found in Chalarodon ( ..705),

Dipsosaurus ( .698), and Qplurus ( 0691) c The other genera show an

intermediate situation for this character.

The deepest anterior cleft is found in Dipsosaurus (length

times depth of anterior cleft .l~-7), Onlurus ( 0119) and Ctenosaura

( .118). The shallowest clefts are those possessed by Cyclura ( o0.36),

Brachylophus ( .039), and Arnblyrhynchl~S ( .044).

The JX)Sterior cleft is deepest in Cyclura (length times depth

of posterior cleft ratio .369) and Ctenosaura ( 0368). The shallowest

posterior cleft is found in Conolophus ( 0239), Oplurus ( .245) and

Chalarodon (.279). All other genera are intermediate between these

two extremes.

The anterior tip of the tongue is free of papillae in all

genera ex2,nd'-1'2d exc,:,rr 1- C+,en1.:>sc11n·a,, Oelr1ch (1956: 53) also found the

dorsun1 of the tongue in Ctenosaura to be completely coveredo

The developrBnt of the fleshy pointed P3-pillae at the

posterior of the tongue is extensive in all of the genera except

Chalarodon and Oplurus where the 1)3.pillae are poorly deveoped and few in number.

HEMIPENF...S

1he vocabulary for descriptions of the hemipenes will

follow that of Cope (1896) and Dowling and Savage (1960). Only the hemipenes (Plate XY.XVI) of Amblyrhynchus, Bra,chylophus, Ctenosaura,

Dipsosaurus, Iguana and Sauromalus were available for study.,

Cope (1896) found the hemipenes to be lmdivided in Cyclura and lg™, and bilobate jn Ctenosaura, Dipsosaurus and Sauromalus., 115

He also noted calyces covering the distal ends of all the above generao

In my investigations, I have found the hernipenes of all the genera to be bulbous rather than bilobate jn Sauromalus, Dipsosaurus,

Amblyrhynchus and Iguan'!. Ctenosaura and Brachylophus are more bilobate than the above genera with Brachylophus having the most bilobate hemipenes of the group.

The sulcus spermaticus forms a broad, open curving groove on the posterior surface of the hernipenis in all genera except Brachylo- phus, where the sulcus is narrow and tightly closed forming a tube rather than a groove. In Ctenosaura, Sauromalus and Dipsosaurus, a fold exists on the lateral border of the sulcus forming a small diverti- ctllu.m in that area.

The distal half of the hemipenis is calyculate on the surface, while the base and proximal half is covered with irregular creases in all genera. All hernipenes lack spines or spinose structures. TAK..E36 TONGUE:MEASUREMENTS

Anterior Posterior Length Width Length Ant. Length Post. Genus Length Width cleft cLeft ratio oleft ratio cleft ratio

Arnblyrhynchus 33o7 19o3 1.5 9~8 .572 .044 .290 Brachyl ophus 20.1 1L5 0.8 5 .3 .572 .039 .288 Chalarodon 6.8 4.8 0.4 1.9 .705 .058 .279 Conolophus 37.1 22.4 2.4 8.9 .604 .064 .239

Ctenosaura 24.4 12.0 2.8 9,.0 .491 .118 •.368 C.yclura 16.5 8.9 o.6 6.1 .539 .OJ6 .369 Dipsosaurus 11.5 8.0 1.7 J,.6 .698 .147 .318 Iguana 28.6 16.0 1.4 8~4 .559 .049 ~293 Oplurus 15.9 11.0 1.9 3,,9 .691 .119 .245 Sa urornal us 19.8 10.5 1.4 5.8 .530 .070 0291

I-' I-' °' 117

DISCUSSION

The phylogenetic relat,ionships between ths genera of iguaninE

lizards have never been analyzed. Boul.enger (1890) outlined some

osteological characteristics for most of the genera but made no attempt at defining relationships. Cope, in 1892) discussed Dipsosaurus and

indicated it to be related to Crotn.-~hytus by general appearance but

different from it osteologically. Cope also analyzed Sauromalus and by virtue of the zygosphenal articulation) allied 11 ••• it to Dipso-

saurus and the larger Iguanidae> but the separated ceratobranchials) and wide sternwn are like that of the Phrynosomas, with the exception

of the fonta.nelles 11 (Cope; 1892:205). Camp (1923) in his monumental work on the classification of l:izards indicated .:I,g}!:;.fil§, Cyclura,

Sauromalus, )J.ipsosaurm and Ambl;y:rhynchus to be related and intermediai in primitiveness. He also allied Brachylophus to Ctenosaurus and

11 Cyclura ••• on the basis of details of the throat musculature, and number of abdom5.. nal parasterna 11 (Camp, 192.3:416).

In 1942 Yiittleman considered the relationships between Uta,

Urosaurus and the iguanines Sauromalus, Dipsosaurus and Ctenosaura.

He indicated that these latter three herbivores were a primitive ances• tral stock closely related to ~celoporw, and Crotaph:ytus. Savage (1951 outlined the igu.anine characteristics and included Crotaphytus in that

evolutionary line. Avery and Tanner (1964) we1·e able to show several myological differences betwe.en SauromaJ..us and Crota)2hytus and indicate( these two genera were not in the same evoluticnary line. Etheridge, 118 in 1964, also exarnined the iguanines and separated the genus Crota-

phytus from them, based on osteological differenceso

As a result of the previous work, the existence of an iguanine evolutionary line has been well established but no conclusions have been made concerning the phylogenies within the iguanine lineo

OSTEOLOGY

As previously indicated, length-width measurements of bones and bone shapes were utilized to analyze the osteological relationships between the iguanines. The ratio means of tables 1 ...34 were used to make clear these relationshipso It has been assumed that a difference of forty or less points between means of the same bone indicates a close relationship. The possession of bones with similar shape is also an indicator of close relationship. Those genera sharing the most

I, characters in common are considereu to uso G11sorno~)'t, clvocly .relatcc.o .n. summary of the number of characters shared between genera is found in table 37. Etheridge (1965:166) commented on the uniqueness of the abdominal skeleton of Chalarodon and Opluruso These organisms, by virtue of this abdominal skeleton are either more primitive than, or as primitive as any member of the iguanine line. Because these two genera are isolated on Madagascar, one would assume that they are closely related.

Oplurus and Chalarodon share 24 characters in common. 'I'his degree of relationship is higher than that of Oplurun or Chalarodon with any other genus. Oplurus also shares a number of close relationships with other genera. There are 19 characters shared in common between

Oplurus and Ctenosaura, 18 between Oplurus and Cyclura, and 17 between 119

Oplurus and Brachylophuso On the other hand, Chalarodon shows no close

relationships vri th any genus except Oplurus. The only other high

number of shared characters is that of Chalarodon vtlth Ctenosaura (15).

It is obvious from the above that Ool urus is more closely

related to the iguanines than Chalarodon. Chalarodon shows so few

characters in com,'!lonwith the iguanines that it may be more closely

related to some other line of iguanid evolnt:lon. The high number of

characters shared in common between Chalarodon and Oplur1Js are probably

the result of a distant common ancestry between the two genera and

common adaptations needed to meet the environmental demands of Madagc1scar.

In regards to the iguanine line, the primitive Oplurus is

more closely related to Ctenosaura, with 19 characters shared, and

Cyclura, with 18 shared characters. This suggests that Ctenosaura. is

the li,ost pril"Jitive of the Western Hemisphere iguanines. The prjmi_t,jve-

ness of Ctenosaura has been previously suggested by Mittleman (191+2:llJ) who placed it as ancestral to all North American Iguanidae. This

form nay not be ancestral to all North American iguanids but is cer-

tainly ancestral to the Western Hemisphere iguanines. Besides possess-

ing more characters in corrunonwith Oplurus than any other iguanine,

Ctenosaura also shares characters in common with Conolophus (22),

Cyclura (Jl), Iguana (32) and Sauromalus (27). If Ctenosaura is not

primitive, it is at least in the center of the evolution of the terres-

trial Western Hemisphere iguanines~

Cyclura is very close to Ctenosaura in structure and in the number of osteological characters shared (31). Cyclura is also closely

related to Iguana with which it shares 28 characters. Cyclura is an

island form, probably evolved from the Ctenosaura line by isolation. 120

Lg~ c1ppear;3 to have much in common with both C_yclura (28 characters charcd) and. Ctenosaura (J2 characters shared). 'l'oo-ether,.,

Ctenosaura, Jg~f".12§:.a.nd C:[slura .form a closely related natural group and probably repreiJent, a prima.ry radiation in the Central American area. of' the 1rfostern Hem:isphereo

Sauronn.lus is a. northern extension of the Ctenosaura type,

Sauromalus showG 2? characters in conm1on with _gterlosaura while 26 charact0rs are shared w.ith Cyclura and 2/+ with J~.ricl,. It is logical to assume that §,9.::'-!;~omalv..s,a desert form, has evolved from a Ctenosaura type organisn, a more tropical form, rather than a Cyclura typs,,

Cteno:::,aura ar,d @:1:pmal_S§. are both continental rather than island forms, such &.s .Qyclura, and Ctenosaura and Sauromalus overlap ranges in Mexico and Baja California.

Ctenos~ura, c-vclura, and Ip-u~t]§l,_o This is an indication that this representative of the Galapagos Island fauna is derived from the Central

American radiation rather than elsewhere.

After eliJrj_nating all characters shared in common between aJ_l five genera, one finds more are shared with Ctenosaura than Cvclura:

Iguana and ALbl_;zrbynchus. The size of the interc1avicle anm:;, the placement of the anterior inferior alveolar foran:en in the splenial bone, the size and sh;:i,pe of the lacrimal bone, size and shape of the postfrontal, size and shape of the angular process in the lower jaw, size of the supraoccipital, size of the fener,tra exonarina, size and shape of the angular bone anc'l size of the suprQtemfflral fossa all link Conolopr1 1 1s with _Ctenoc;aura. rather than lJith either of the other three genera. Amblvrh:tnC:J:0.~~ ~i_s clo:~rnly related to Conolophus vlith 22 characten, shared., and to Ig_U§:,1}2:.vtith 17 characters shared" An analysis of these shared characters t,hovJS that ArnbJvrhvnchus is more closely rela.ted to ConoJ cohus than to Ir,:uana. After eliminating the charar;- ters shared in co;Y"mon oy all tl:ree genera one finds that Ar:1bJ~).2.j1~zncl1_~~- shares 12 characters with Conolophus as opposed to 6 for Iguana.

Among the characters shared in common with Conolouhus are the si.z e of the supraoccipital, JP.latine, jugal, quadratc, supratemy.Dral .fossa; fenestra exonarina, dentary and size of angular process" Also the posterior bo1°der of the dentary for11,s a complex j_nterfingering suture with the surangular boneo The frontal bone, in both is wider than long, and the pyriform recess widens posteriorly at a sharp angle in botl1 genera. A.rnbl:yrhypchus shares Hi.th ~.ll§. the size of the lacrimal.

similar shape in both genera and the interclavicles are the same r,hape with arms equal in lengU1 to the body and attached to the body at a 90° angle.. Conolo.2:1us and Ai~]-.}'l'hvnchus are more closely related. to each other than to any other iguanines. Arcbl,.crhvnc}rns is pTobably derived from a Conolophm~-~Ctenos_§,ura~ ancester the.t invaded the Gala}Y:J,gos

Islands from the main.land"

FlrachzJ.or:J1w_;; fro:1-:. Fiji and Tor2ga Islands, is the most geogr2.ph:i.cal1y iso}ated iguanine. This genus shares a large number

,.. 7 r"l) .:::iauroma.J_u§.\.. ,!, , • Obviously tli:i.,3 close relat:\onship to aJ.l these gem.ora indicate~, c:,, point of origin ~,omeµ1ace in the primacy Central American rJ,diationo Sauro:G°;alus being a Northern representative of this group is the least likely re1a:Uv1:; of F::rJ,chylophus. \'!hen all common 122

characters between the five genera are eliminated we find the three

characters, the size of the postfrontals, prefrontals and articular

bones are shared between Brachylophus and C;yclura. Brachylophus and

Ctenosaura share nasals, parietal wings, orbits, and articulars of

similar size and shape. Iguana and Brach;ylophus have similar palatines,

premaxillas, quadrates and vomerso Bra.chylophus, as with Conolophus, with which it shares 19 characters, is probably evolved from the pre-

Ctenosaura-Iguana ancestral stocko

Dipsosaurus is the most problematical genus in the iguanine line. Osteologically, as pointed out by Cope (1892:201), Dipsosaurus is different from the other Iguanidae. This genus differs from all

other iguanines in lacking pterygoid teeth, having a convex dentary

suture with the surangular, interclavicle arms that attach to the inter•~

clavicle body at a 30° angle, and an anterior inferior alveolar fora..-r::er.. found in the dentary instead of the splenial bone. A SlLTIBlB,ryof the

characters shared with other genera shows that Dipsosaurus shares more

characters in common with Brachylophus (27), than with any other genus.

No other genus is even close in its relationship to Dipsosaurus. The

size ratios of the frontals, parietals, ju.gals, nasals, squamosals, quadrates, postorbitals, orbits, dentarys, surangulars, splenials, articulars, angulars, angular processes are similar. Also the inter-

clavicle arms are' one quarter the length of the interclavicle body, the sternal cartilage possess one fontanelle, the angular process is triangular and the squa1nosals are splint like in both genera. It

seems obvious that Dipsosaurus and Brachylophus were derived from a conunon ancestry.

In s1.;nm1:1ry,the osteological characters of the iguanine 12_3

lizards indicate that Oplurus and Chalarodon are more closely related

to each other than to the iguanines, and Oplurus is the Madagascarian

genus most closely ralated to the Western Hemisphere iguaninesa Of

the iguanines, Ctenosaura represents the ancestral stock from which

Cyclura, -_Iguana and Sauromalus were evolveda Conolophus and Brachy-

lophus are both early derivatives of this stock as well, with Ambly-

rhynchus having been derived from the Conolophus_ line, and Dipsosaurus

and Brachylophus having a common ancestryo

MYOLOGY

An examination of the muscles has revealed that the iguanines

and the Madagascarian genera exhibit two. basic patterns of muscle arrangement. In Arnblyrhynchus, Conolophus, Ctenosaura, Cvclura,

Iguana, Oplurus and SauromaJ.us, the cervicomandibularis is hidden beneath the posterior orlgln ui' Vu1;:;GOnst:clcl.,or c;cllio Thi:::; sc..n.8 grc;c1p

o.f genera, plus Chalarodon, have a large levator angularis oris muscle.

The remaining genera, Brachylophus and Dipsosaurus, appear to form a

second natural group with the cervicomandibularis muscle extending beyond the posterior margin of the constrictor colli and with a small levator angularis oris muscle present. The fact that Oplurus shares both characters with the larger group is an ind:ication of its close

relationship to the central iguanine stocko Chalarodon possess only

one of the characters and is probably the most distantly related of

all the genera studied.

A few other myological characters are useful in determining

relationships. The position of the adjoining borders of the intermandibularis posterior and the constrictor colli indicate a natural

grouping between Conolophus, Ctenosaura, Cyclura, and Sauromaluso In 124

these genera. the borders are not conn0cted along part of their lenc;U1.,

these muscles are connected for th'.:', ,,mt ire length. These genera

appear to have divcrsed away f:corc, th0 central stock. It is interesting

to note that both Chalarodon and Q..pl..uruf:.have the border of the inter- mandib1iLaris posterior and the constrictc:>r colli connected for the

entire len 6tll. These two gener&, are not ig:J.anine but may represent the

primitive condition in the farnilyo

The Branchiohyoj_deus has a wide insertion on the distal end

of the first ceratobranchial in al1 of the gei1era except Saurornalus.

'I'his deviation from the iguaninc :p3,tte1'n is pr-obably due to the unique

shape of the hyoid in Sauro:malus. Such a d.evL,,tion probably represe~1ts a highly specialized condition rath2r than a pri:miti\'8 one o

border, from the medial border o.f the sternohyoideus in all genera. except

Oplurus and Chalarodon, where the two muscles are quite dL stinc;t o This

character indicates a relationship between the two Hadagascarian genera that is lacking in the iguanines.

In surrrrrcry the musculature shows the iguanines to be separated into an Arnbl;yrh;vnchus, ConoJJ:.?_glus, Ctenosaura, .Qvclura, Igl~'lf@:. and

Sauro:malus group, and a BrachyloCJhW3 and Dipsosaurus tsroup as determined by the position o.f the cervicomandibuJ_aris and levator a:ngularis eris.

The muscnla.ture further shows that Opllll'US and Cha1arodcm form a natural grouping as indicated ;_;y the free lateral border of the Sterno- thyro:i..d.

Within the 1aTr;cst iguunine group of genera Conolophrn,,

Ctenosaurc!:: _Qyc1ur2. a,1d SaurcnnJ rn, appear to bE, the most closely related 125 members of the ancestral stock as indicated by each having incompletely connected borders between the constrictor colli and intermandibularis posterior muscle.

TONGUE

Camp (1923:374) states, 11The broad, fleshy, partly smooth, partly papillate tongue of geckos and iguanids would seem hj_stologi- cally the least specialized and probably the more ancient type."

Unfortunately this primitive tongue does not show any clear evo1ution- ary trends between the genera of iguanines. This :rray be because of the low sample size used in this study.

It may be noted, however, that the poorest development of pointed papillae at the posterior end of the tongue is found in

Chalarodon and Onlurus. The depth of the posterior cleft is also more shallow in the above two genera. This is another indication of the uniqueness of the two Nadgascarian genera.

One specimen of a tongue from Dipsosaurus showed a small pointed tip at the anterior extremity of the tongue. This was not seen in larger individuals in any other genus and it may be that such a structure is a function of age and use. Older individuals may have owrn this tip away leaving the rounded tip found in the other iguanines.

HEMIPENIS

The study of the he:nipenis was hampered by a lack of material with four genera not being represented in the series.

The hemipenis of Brach;vlophus is unique among the six:- genera examined as the structure is bifid rather than bulbous. The sulcus spermaticus is tightly closed and tube like rather than an open groove a,; found in Ambly:rbynchu2, Ctc11cc::;:;,ur~;.,JJj psosa.urus, Iguana and S2:;_s:ro•- lTB+.}f~• These cl.if.fercncc3 may f:a:t';gest a more distant relationship between l3:r,~.c_hyloph1!,:2.ar:.d the re:r:ia.i::;inr-; continental iguanines.

A phylogenetic eLart representing the relationships between the ten gen ere,> 2.s deter:rn.bc~d by the above morphological c11aracte1'i" j .s seen in Plate :X::X::1.'VII.

IGUANINE DISTRIBUTION

Explainic.g t]1e dif.,tribuUon of the :i..gi.;.a~rines has been e::s,-• pecially perplexing for zoogeog:cE~phci'c, ments on the subject is that of Carl.cfuist (196.Jd95-396) who s;:i.;/::., ttEsp2cially annoying to biogr2.p}1ers if; t 1·rn pret;eY.:.ce of iguan,:i,;::;.

Iguanas are inescap<..1bly a chai',1.c:tcri::,t:i.calJ.y Amer·ican farril;y- of 1iz2.rd,:;.

has myc,teriously ree..c:hed F:Lji arid 'l'o:nga; on which i::;la,nds the gem:.f3 is cn~lemic a But ho,·, to e:xpL:d.n.

The 1)est explar1ation sce~TtS to Of;

them and c,ther c~ree,t.L;r:.:;s, f.'iji ,:1.:nd1''1-:1,iaga13car) before they dj_od out on the ms :inla.n.d. i.:

(192/..,.), and Camp (19L.5) :i.nd.i.cai.,e,:; tliat liz.s,r·cl::, probably origh1c,tcu. in 126 as found in Amblyrhynchuz, Ctenosaur~, !)j..J?sosaurus, Iguan.~ and Sauro- malus. These differences may suggest a mora distant relationship between Brachylophus and the remaining continental iguanines.

A phylogenetic chart representing the relationships between the ten genera, cJS determined by the above morphological characters is

seen in Plate XXXVII.

IGUANINEDISTRIBUTION

Explaining the distribution of the iguan:i.nes has been especially perplexing for zoogeographcrs. One of the most recent state- ments on the subject is that of Carlquist (1965:395-396) who says,

"Especially annoying to biogeographers is the presence of iguanas.

Iguanas are inescapnbly a characteristically An:erican family of lizards.

To be sure, an iguanid (Brachylophus) has mysteriously reached Fiji and Tonga, on which islands the genus is endemic. But how to explain. that two iguanid genera exist on 1/eclagasc3r? Chalarodon, from the dry

Southwest of th,~ island and Oplm:~, with six species are living evidence

that iguanids did reach Madagascar. The best explanation seems to be that iguanas are a very anclent group of reptiles which have been extinguished on the African and Eurasian mainland, but managed, during their tenure there, to reach what were to become refuge islands for them and other creatures, Fiji and Madagascar, before they died out on

the II'.liinlann." Beaufort (1951: 132) and Darlington (1957: 212) also consider the Iguanidae to have evolved in the Old World.

The literature on fossi.1 lizards such as Broom (1903), Broom

(1924), and Camp (1945) indicates that lizards probably originated in

Africa in Triassic tim::!S. By the beginning of the Cenozoic Era, the 127

Family Iguanidae was well established in North America (Gilmore 1928,

Gilmore 1941, and Estes 1964).

The family Iguanidae may also have originated in the Old

World Tropics. The presence of Chalarodon and OJ?lurus on Madagascar is

evidence of a long history in the African area. Current theory indi-

cates that the ancestral iguanids spread to Europe and Asia and even-

tually to the Western Hemisphere. Fossils should mark the existence

of iguanids on the Eurasian land mass. Some iguanids from Europe have

been described by Hoffstetter (1942, 1955). However, according to

Romer (1968:121) these arc more likely agarnids. There is no fossU

record for igua.nids from Asia.

Regardless of the fossil record, iguanids had to reach the

Western Henrrsphere from the Old World tropics, One of the more logical

explanations of s,1ch a migration would be for the iguanids to spread

northward through Europe, invade North America via the Bering Straits

land.bridge and U..'1dergo a radiation in the Western· Hemisphere. The

development of better adapted families of lizards in the Old World

tropics could have caused the extinction of the farnUy Iguanidae in

all areas where the families competed" Only in refugia, where the

iguanids were isolated from these more successful families, wo1J.ld the

iguanids survive. Members of the family Agamidae are ecological

equivalents for many iguanids and are widespread in the Old ·world

tropics. They may have caused the elimination of the Iguanidae where

the two families overlapped. It is interesting to note that there

are no agamids on Madagascar where iguanids still existo Nowhere in

the world except on Fiji do iguanids and agaJnids live side by sideo

There is an alternative method by wl,ich the Iguanidae could 128

have reached the New World tropics. The publicatior.. of several recent

papers, such as Hurley, Almeida, et al 1967, Heirtzler 1968, Hurley

1968, Via.xwell 1968, Hurley and Rand 1969, Kurten 1969, and McElhinny

and Luck 1970 lend new credence to the oJ_d theory of continental drift.

All the above papers indicate the existence of a large pre-Cretaceous

land mass, Gondwanaland, which fractured in Cretaceous times to form

Africa, South America, Australia_, Antarctica, Southern India &"ld Mada-

gascar.

If the Iguanidae were widespread over Gondwanaland when this

continental mass fractured in the Cretaceous, they would have been

separated into separate popuJ.ations on each of the above land rnasseso

Of these continental areas only the Americas and Madagascar have not

been invaded by Agamidaeo These two areas are also the only areas that

h.a,re iguanid lizards fl

Conti,1ental drift would explain why the :Madagascar genera are

considered primitive to the rest of the familyo They are closest to

the family 1 s center of origin, and are relicts of Cretaceous times.

The drift theory would also explain why the iguanine line is mostly

southern and equatoriaL They originated in that area in Gondwanaland

and have spread little from their center of origin.

Regardless of the method of iguanine migration to the New

World, be it land bridge or continental drift, we are still faced with

explaining the distribution of iguanines on the oceanic islands of the

Western Hemisphereo

Cvclura is found in the Antilles and the Bahamas. This

Ctenosaura derivative is widespread on the islands and is endemic to the area, having migrated and evolved there whE:m these islands were connected 129 to the mainland.

The origin of the Galapagos Islands has been debated for many years. Arnbl;vrhynchus a.rid Conolophus, which are endemic to the

Galapagos Islands have been separated from the mainland genera for a long time, as indicated by their high degree of differences. If the islands are continental these iguanids cold rave easily reached themo

If the islands are oceanic Amblyrhynchus and Conoloph~~ must have

:migrated by rafting on logs or some other floating debriso

Baur (1891:310) considered the islands to have been connected to the mainland as late as Eocene times. Heller (1903:43-44) considered the islands to be volcanic and oceanic in nature. Chubb (1933:

1-25) commented extensively on the volcanic nature of the Galapagos

Islands and indicated a close affinity, geologically, to Cocos Island off Costa Rica. Svenson (191...8:496-498)studied the plants of the

Galapagos Islands and indicated a close affinity with South America.

Finally, Vinton (1951:356-376) proposed a partial or complete land bridge from Costa Rica, through Cocos Island to either a connection with the islands or terminating in a close proximity to the Galapagos land mass, that later sank forming the present islands. This land bridge would have bee,1 developed in Mid-Tertiary time and would have provided means whereby turtles and iguanids could have gotten close enough to the islands to raft successfully. As the land bridge never attached to the Galapagos Islands, these oceanic islands would have retained a considerable degree of uniqueness. Only the hardiest of roi-• grants could have made the trip across the gap of water between the land bridge and the islands. Regardless of land connection or not, a pre-

Ctenosaura-J,guana ancester apparently did make the trip and later 130

diverged into modern day Ambl,y7b-ynchus and Conolophus.

The problem of Brachylophus on Fiji and Tonga Islands is the most perplexing problem in iguanine d.istributiono If the iguanines were widespread in the world during late Mesozoic-early Cenozoic times

and were widely scattered on the Gondwanaland continental nucleus, they

should have occurred in Australia and Asia after the fracturing of that nucleus. From Australia or Southeast Asia it is a short trip by

rafting to the Fiji and Tonga Island groups. If such a trip were accom-

panied by iguanid elimination on the Asian and Australian land masses by agarnids, Brachylophus would be left isolated on Fiji and Tonga.

Two factors disrupt the plausibility of this theory, however.

If iguanines were wide~pread and gave rise to the Fiji and Tonga populations of Brachylo~ via Asia and/or .Australia, one would expect to find 0U1.tr relic µop.1lat:lo,1s on other Pacific Islands such as New

Zealand, New Guinea, the Solomons, the Philippines and Indonesia.

These islands are all inhabited by agaJ11ids which could have eliminated

Brachylophus and other iguanines. Unfortunately the fossil record does not provide evidence of any Far Eastern Iguanidae, and we find toda,y that agamids and Brachylophus do exist together on Fiji. This modern coexistance may be the result of Brachylophus or the aga.mids being recent invaders of the islands rather than long term residents.

A second fact disrupting the Far Eastern Theory for the origin of Brachylophus is the relationship of Brachylophus to Dipso- saurus, the North American iguanine. Did Dipsosalirus also raft from the Far East to North America? It seems highly unlikely. A more plausible explanation for the problem is that a Brachylor:hus-Dipsosaur"Js complex existed in the Western Hemisphere, close]y related to the 131 existing igu.anine complex. BrachvloDhus in the South Pacific is probably the result of a few individuals that accidently rafted on floating debris to the Fiji and Tonga Island groups and a Northern survivor of this complex has eyolved into the modern Dipsosaurus. Such a hazardous journey b;,r log raft needs to occur only once with a gravid female to produce a viable island population.

Sauromalus represents the most northward extension of the iguanine line. Gilmore (1928:27-28) described the teeth of Par.§:- sauromalus olseni from the Middle :Eocene, Wind River Formation of

Fremont County, ..Wyoming. This form may represent the ancestral stock of Sauro:rnalus and indicates the ½'ithdrawl of the modern Sanromalus frorL what once was a more extensive and northern range. According to

Savage (1966:722-723) North and South America were connected in

Paleocene and Pliocene times. The pre-Sauromal1J~. stock may have 5n- vaded North America in Paleocene times before the land bridge was broken. This Sauromalus stock may have been separated from the Cteno- saura stock from Eocene to Pliocene times and had evolved and diverged far enough from the parent stock to allow Ctenosaura to reinvade southern North America in Late Pliocene times and overlap the SaurorrB7 us range without competing ecologically. TAE~ 37

THE NUMBEROF OSTEOLOGIC.t1LSINILA.RITIES BETWEENGENERA

0 0 0 t:J CJ) 0 c+ I-'· a., ::; (D f3'p J _) ;:: f 0 ""' ~ (ll c; f-;i ~ r.) f-1 0 c; 0 0 ' rj 0 [Jl f-J rn 8 Genus ~ 0 Ill [ l.\l [JJ ~ I ~ c; r::; I f-' g, ,:; 1--j f-;i ,:; " (Jl [ ~ l.\l g m II[ ff

Ambl;yrhynchus X 12 8 22 8 10 13 17 10 13 Brachylo12hus 12 X 14 19 21 24 27 22 17 21 Chalarodon 8 14 X 11 15 10 13 ll 24 10 -, -, Gonolophus 22 19 j_J_ X 22 ·22 20 22 14 12 Ctenosaura 8 21 15 22 X 31 17 32 19 27 Cyclura 10 24 lO 22 31 X 16 28 18 26 Di12sosaurus 13 27 13 20 17 16 X 17 15 15 Iguana 17 22 11 22 32 28 17 X 15 24 Onlurus 10 17 24 U- 19 18 15 15 X 16 7 ~ Sauromalus 13 21 10 ..J..,:'. 27 26 15 24 16 X

I-' \.0 1\) 133

CONCLUSIONS

The examination of the anterior osteology, 111.yology, tongue and hernipenes of the members of the iguanine phy1etic line, exclusive of

Enyaliosaurus, and a comparison with the Madagascar iguanids indicates

the following. (1.) The Madagascar genera Chalarodon and Oplurus appear

to be more closely related to each other than to other iguanid genera.

(2) Of the Ivladagascar genera, Oplurus is most closely related to the

iguanine line of evolutiono (3) Ctenosaura, Cyclura and Igua.r~ repre-

sent the main ancestral stock of iguanines in the Western Herrisphereo

(4) Cyclura is probably an early descendent of the Ctenosaura ancestral

line. (5) Iguana and Ctenosaura evolved from a common ancestral stocko

( 6) bauromalus is a northern deriva1:,ive of the Ct,er,osaura ancestral

line. ( 7) Conolovhus is probably an early invader of the Galapagos

Islands and is derived from the pre-Ctenosaura-Iguana iguanine ances-

tral stock. (8) Ambl,r.chynchus is a close relative of Conolophus and

may be derived directly from a Conolophus ancestor. (9) Brachvlophus

is a derivative of the pre-Ctenosaura-Iguan§l: ancestral stock and has

probably rafted to Fiji and Tonga Islands from tropical America. (10)

Dipsosaurus is more closely related to Brachylophus than any other

iguanine and represents the northern extension of that generic complex.

(11) The Madagascar Iguanidae and the Western Hemisphere iguanines were

probably separated in post-Cretaceous times by Continental Drift which

is thought to have resulted in a fracturing of Gondwanaland and the for-

mation of Australia, Southern India, Antarctica, Africa, Madagascar, and

South America. SU11MJ\.RY

The problem of phylogenic relationships within the iguanine phyletic line and the Madagascar iguanids has been investigated in order to explain the discontinuous distribution exhibited by the members of the family Iguanidaeo Due to inconclusive results from cytology and histological methods, the comparative morphology of the anterior osteology, myology, tongues and hemipenes were used to determi..11.erela- tionships o

It has been found that the Madagascar genera Chalarodon and

Oplurus are more closely related to each other than to the other iguanid genera. Oplurus is also closely related to the Ctenosaura-

Iguana ancestral stock of the iguanine phyletic line • .Qyclura and

Sauromalus are derivatives of a Cten.osaura like ancestor with the former being an island form and the latter a specialized desert dwellero

Iguana is a highly specialized and isolated member of the iguanine group. Conolophus and its derivative Amblyrhynchus are also related to the ptenosaura~Iguana ancestral stock and probably rafted the

Galapagos Islandso Brachylophus and Dipsosaurus are closely related and the former probably invaded its present range of Fiji and Tonga

Islands by rafting from the Western Hemisphere. Dipsosaurus is a northern representative of this generic complex in North Americao

It is probable that the Madagascar Iguanidae and the Western

Hemisphere iguanine lizards v.rere separated in post-Cretaceous times by Continenta.l Drift which resulted in the fracturing of Gondwanaland. 135

LITERATUR.ECITED

Ad,9,ms, L.A. 1919. A memoir on the phylogeny of the jaw muscles in recent and fossil vertebrateso Ann. N. Y. Acad. Scio 28: 51-166.

Angel, F. 1942. Les Lezards de Madagascar" Memoires de L 1Acadernie Malgache. 193 p.

Avery, D. F., and W. W. Tanner. 1961, The osteology and myology oi' the head and thora.x regions of the obesus group of the genus Sauromalus Dumeril (IguMidae). Brigham Young Univo Sci. Bullo, Bio. Ser., 5(3):1-30.

Axelrod, D .. I. 1948. Climate and evolution in 1,1estern North America during lf.:iddle Pliocene time. Evolution 2(2) :127-11+4. ,

Bahl, K. N. 1937. Skull of Varanus monitor (Lir1n.). Rec. Ind. Mus. Calcutta. 39:133-174~

Bailsy, Jo 1,J. 1928. A revision of the lizards of the genus Ctenos2.ura. Proc. U.S. Nat. Mus.·No. 2733, 73(12)~1--58.

Baird, I. L. 19600 A survey. of the periotic labyrinth in some representative recent reptiles. Univ. Kansas ScL Bullo 41:891-98L

Barbour, T. and G. K. Noble. 1916. A revision of the lizards o.f the genus Cycluraa Bullo Musa Compo Zool. Cambridge. 66:140-164.

Barry, T. H. 1953~ Contribution to the cranial morphology of Ag~ h:ispida (Linna). Ann. Univ. Stellenbosch. 29A(2):55-??.

Baur, G. 189L On the origin of the Galapagos Islandso Amer. Nat. 2): 217-229, J0?•-326.

Beaufort, L D. de. 1951. Zoogeography of the land and inland waters~ Sedgwich and .,_'!Jacksonlimited, London. 208 p.

Beddard, F. E. l905ao Some notes on the cranial osteology of the mastigure lizard-Uromast:i.xo Proc. Zool~ Soco Londono 1905:1~·90

Beddard, Fo EQ 1905b. A contribution to the anatomy of the frilled lizard ( ChJ_am,ydosa.urns .!s.ir:pj) and some otb er Agamidae. Proc. Zool. Soco Londono 1905;9,-220 136

Beddard, F. E. 1907. Contributions to the knowledge of the systematic arrangement and anatomy of certain genera and species of Squarnatao Proco Zoolo Soc., Londono 1907:35-680

Bellairs, A. dlA. 1950. Observations on the cranial aratomy of Anniella and a comJXJ,rison with that of other burrowing lizards. Proco Zoolo Soc~ London. ll9:887-904Q

Blanc, C. Po 1965. Etudes sur les Iguanidae de Mad.agascar. I. Le squellette de ChaJ.arodon JIB,dagascariensis Peters 18540 Memo Muso Na.tr. Histo Nat., Series JA, ZooL 3.3(3) :93-1460

Boulenger, G., Ao 1885-87 o Catalogue of the lizards in the British Museum (Natural History). 2nda Editiono 3 voL Taylor and Francis, Londono

Boulenger, G., A,. 1890e On the distinctive cranial characters of the iguanoid lizards allied to Jguanae Anno Mago Nat. Histo VI(6):412-414.

Boulenger, Go A. 1891a Notes on the osteology of Heloderrra horridum and li• suspectum, with remarks on the systematic position of the Helcderrnidae, and on the vertebrae of the Lacerti.lia .. Proco Zoolo Soco Londono 1891:109-ll8.

Bradley, Oo Co 1903 o The muscles of mastication and the movem2nt of the skull ir.. Lacertil1ia. ZooL J2.hrb"' Ar.at. Abth . .L8:4l-.?0.

Brattstrom, B. Ho 19530 Records of Pleistocene reptiles from Cali- fornia.o Copeia 1953(2):174~1790

Brattstrom, Bo Ho 1958ao New Records of Cenozoic amphibians and Reptiles from California.. Bull. Southern Califo Acado Sci. 57(1):5-130

Brattstrom, B. H. 1958bo Two Oligocene lizardso Herpetologica 14: 43-44.

Brattstrom, B. IL 1964. Amphibians and reptiles from ca-re deposits in SouLhcentral New Mexico. Bull .. Southern Califo Aca.do Scio 16: 50-510

Brock, G. To 19.'32o Some developnental stages in the skulls of the Geckos, Lygodactylu,5 _capensis and Pachydactylus maculosa and their bearing on certain important problems in Lacertilian cranialogy. South African Journ~ Scio 29:508-532.

Brock, G. To 1935., The temporal bones in lizanls, birds and mammals o Ant. Anze 80:27-31.

Brock, Go T. 19.380 The r::ranial muscles cf the Gecko, a general account, with a c:orrq:urison of the mw.;cles in other Gnatho ... stomsso Proc. ZooL, Soco London .. Series B, 108:735-761. 137

Brock, G. T. 1941. The skull of Acontias meleagris, with a study of the affinities between lizards and snakes. Journo Linno Soc. l1-l:?l~-880

Brock, Go T., 1941. The skull of the charnaeleon Lophosaura ventralis (Gray); some developrnentai stages. Proc. Zool. Soco London. ll0~219-24L Broom., R; 1903. On the skull of a true lizard (Paligmna whitei) from the Triassic beds of South Africao Rec. Albany Mus. 1(1):1-3. Broom, R. 1925. On the origin of Lizardsa Proc. Zoolo Soc. Londono 1925:1-160

Broom, R. 1935. On the structure of the temporal region in lizard skullso Ann. Transvo Mus. 18:13-22.

Broom, R. 19480 Note on the skull of the American horned lizard, Phrynosoma. Ann. Transv. Mus. 21(1):43-45.

Brown, Wo 1956. The distribution o.f terrestrial reptiles in the islands of the Pacific Basin. Proco 8th. Pacific Scio Congress. JA:1479-J.1~91.

Bryant, H. C. 1911. The horned lizards of California and Nevada of the genera Phrvnoscrrg1 and Anota o Univ. Calif. Pub o Zool. 9(1) :1-840

Camp., C. Lo 19230 Classification of the lizards. Bull. Amer. Mus. Nat. Hist. 48(11):289-481.

Camp., C. L. 19450 Prolacerta and the Protosaurian reptiles. Amer. Journ. Scio New Haven. 2h.3:17~32.

Carlquist, SQ 19650 Island Life. The Natural History Press, Garden City, New York. 45lp.

Chaine, Jo 1902. Considerations sur la constitution musculaire de la region sus-hyoidienne chez les vertebres en general., Annales des Sciences Natu.relleso 16:375-393.

Charles, So 1953. On the morphology of the nale generative organ of the spiny tailed lizard, Uror:nasti.x hardwicldi (Gray). Proco 40tho Indian Scio Congress, Lucknowo 111:205-206.

Chubb, L. J. 19330 Geologv of GalaP3,gos, Cocos, and Easter Island" Bernice P. Bishop Hus. Bull. 110:1--4-4.

Colbert, E. H. 1961., Evolution of the vertebrateso Science Editions, Inc. New York. 479 Po

Cope, E. Do 1892a. On the homologies of the posterior cranial arches in the reptiles. Amer. Phil. Soc. XVII(l) :ll-26. 1.38

Cope, E. D. 1892b. The osteology of the Lacertilia. Proc. Amer. Philos. Soc. 30(138):185-221.

Cope., Eo D. 1896. On the hemipenes of the Sauria. Proc. Acad. Nato Sci. Phila. XLVIII:461-4670

Cope, Ee D. 19000 The Crocodilians, Lizards and Snakes of North America., In Annual Eept. U. So Nat. Museum. 1898(2) :151-1294.

Cornig, H. K~ 1895. Ueber die Entwicldung der Zungenmuskulatur bei Reptilieno Verhandlungen der Anat. Gesellschaft in Basel., 1895:165-1750

Criley, B. Be 1968. The cranial osteology of the Gerrhonotiform lizards. Amer. Midland Nat. 80(1):199-219.

Darlington, P. Jo 1957. Zoogeography. JohnWileyandSons., Inc • ., New York. 675 p.

Davis., D. D. 1934. The collard lizard, a laboratory guide. ¥.acmillan, New Yorko 57 p. Davis, D. D. 1936. The terminology of reptilian musculature. Herpetologica 1(1):12-170

Detrie, Ao J. 1950. Osteology of the skull of Phrynosoma cornutum ( Harh.r:). Ji'j eld 2•,d Lab, DelJc1s,, 18(4) :lh6-:J 55.

De Vis, C. W. 1883. Morphology of Chlarnydosaurus kingi. Proc. Linn. Soc. New South Wales. 1883:1-320.

Dowling, H. G. and ,T. M. Savage. 1.960. A guide to the snake hemipenis; a survey of basic structure and systematic characteristics. Zoologica 45~17-27.

Dubecq, J. 1925. La musculative elevative de la mandibule chez quelgue reptiles. Proco Verb. Soc. Scio Phys. Nat. Bordeauz, 1922-23:S.....lJ.

Duda., 1tJ. 1965. On the cranial osteology of Agama tuberculata with a note on the comps,rative study of skulls in the family Agamidae. Vestn. Ceshoslo Zool. Spalco 29:156-1.740

Dunn, E. R. 1931. The herpetological faunas of the .Americas. Copeia 1931:106-119Q

Durham, Jo W. and E. Ca Allisono 1960. The geologic history of Baja California and its narj_ne fauna. Systematic Zoology 9(2): 47-910

Edgeworth., F o H. 1931a. On the muscles used in shutting and opening the mouth. Proco Zool. Soc. Londono 1931:817-818. 139

Edgeworth, Fo Ho 1931b. On the developmE:nt of the external ocular masticatory and hyoid muscles of §_ohenodon punctatus. Proc. ZooL Soc. London. 1931:803-808, 817-8180

Edgeworth, Fo H. 1935. The cranial muscles of vertebrates. Univ. Cambridge press. Cambridge, Eng.land" 494 p.

Edinger, T. 1955. The size of the :r:arietal foramen and organ in reptiles. Bulla Mus. Comp. Zoolo 114:1-34.

Eibl-Eibesfeldt, I,, 1956. Eine neue rasse der meerechse, _11JUQ1,yrhynchus cristatus venustissimus, nebst einigen bemerkungen uber Amblyrh;ynchus cristatus cristatuso Senchenbergiana Biolo 37:87-100.,

El Toubi, M. R. 19.38. The osteology of the lizard Scincus scincus (Linn.). Bullo F'aca Sci. Cairo, Fouad I Univo l4(l938)~5-38o

El Toubi, M. R. 1947a. Some observations on the osteology of the lizard Agarr§_ stellio (Linno)o Journ. Morpho Phila. 81.:135-149.

El Toubi, Mo R. 19Le7b. Notes on the cranial osteology of Uromastix aegyptia (Fo:rskal) o Bii12. Fae. Scio :Fouad I Univo 25(191}7): 1-13.

El Toubi, Mo R. 191.i.9.· The post cranial osteology of the lizard lJ.t

El Toubi, M. Ro and Ao Mo Kan1:1-L 1959 o The de,:eJ.opment of the skull in Chalcicles ocellatus~ Journ. Morph. Phila. 105:55-10L1-.

El Toubi, Mo R. and A. M. Khalil. 1952. The cranial osteology of Egyptian geckos. Bull. de L 1Institut Fouad Ier du Desert. 11(1952):84-llOo

Estes, R. 19630 Early Miocene salamanders and lizards from Florida. Quart. Southern Fla" .Acad. Sci. 26:234-256.

Estes, Ro 1964. Fossil vertebrates from the Late Cretaceous Lance Formation Eastern Wyoming. Univo Cal:i.i'. Publ. Geol. Scio 49:1-180.

Estes, R. and J. A. Tihen. 19640 Lower vertebrates from the Valentine Formation of Nebraska. Amere Mid.lo Nato 72:45.3-4720

Etheridge, H., 1962. Skeletal variation in the iguanid lizard Sator grandaerus. Copeia 1962( 4-): 613-619.

Etheridge, R., 1964ao The skeletal morphology and systematic relationships of Sceloporine liz2.rds. Copeia 1964 (4) :610-631.

Etheridge, R~ 1964b. L2.te Pleistocene lizards from Barbuda, British West Indies o Bull. Floride. State Huseum. 9(2) :43-75 o 140

Etheridge., R. 1965a. Fossil lizards from the Dominican Republic. Quart. Journ. Florida Acad. Sciences. 28(1):83-105.

Etheridge., R. 1965b. The abdominal skeleton of lizards in the family Iguanidae. Herpetologica 21(3) :161~.167.

Etheridge, R. 1966. The systematic relationships o.f West Indian and South American lizards referred to the iguanid genus Leiocepha1us. Copeia 1966(1) :79-91. Etheridge., n. 1967. Lizard caudal vertebrae& Copeia 1967(4):699-721. Eyal-Giladi, H. 1964. The development o.f the chondrocranium of .Aga~ stelli~. Acta Zool. Stockh. 45:139~165.

Evans, F. G. 1939. The morphology and functional e-volution of the atlas-axis complex from fish to ma.mn1a.ls. Ann. N. Y. Acad. Sci. 39(2):29-104.

Gambino, Jo J. 1957. Relationships of North American Iguanidae as suggested by an analysis of their pimrnrm pa,rasites., C;z:rto- somum spp. Anat. Reco 128: 553-554. (Abstro)

Gambino, J. J. and D. Heynemann. 1960. Specificity and speciation in the genus Cyrtosomu..]. Amer. Ylidl .. Nat. 63:365-382.

GandoJ. .fi, H. 1908. w.e zun:1.e der Agarn:idae lmd Ig:uanidae. Zool" 1rn~. XKXII:569-580.

Gase, J. P,. 1968. Contribution a L 10steo1ogie et a La Myologie de Dibamus novaeguineae Gra,y (Sauria, Reptilia), Discussion Systematique. Ann. Sci. Nat. Zool. Biol. Ani.m. 10:127~·1500

Gehlbach, F~ R. 1965. Amphibians and reptiles from the Pliocene and Pleistocene of North America. A chronological sun:um,ry and selected bibliography., Texas Journ. Sci. 17(1): 56-70.

George, J. C. 1948. The muscular system of Uromastix hardwickii (Gray). Journ., Univ. Bombay. 17(3) ~1-17.

George, Jo Co 1954. On the cranial osteology of Uromastix hardwickii (Gray). Journ. Anim. Morph. and Phys. 1(2)~23-29.

George, J. Co 1955. The post cranial osteology of Uromastix hard- v1icld.:L (Gray). Journo .Anim. Morph~ and Physo 2(.3):25-35.

Gervais, P. 1873. Remarks on skull and teeth of Molock. Journ~ of 'Zool. 1873: 45L

Gill, T. 1886. The classification of the lizards. Ann. Rept. Smithsonian Inst. 1885 ...1886(1):?9?-801. 141

Gilmore, C. W. 1928. Fossil lizards of North America. Memoirs Nato Acad. Sci. Washington. 22(3):1-201. Gilmore, C. W. 19410 Some little known fossil lizards from the Oligocene of Wyoming. Proc. U. S. Nat. Museum. 91(3124): 71-76.

Gladstone, Ro ,J. and C. P. G., Wakeley. 1932. The morphology of the sternum and its relation to the ribs. Journ. of Anat. London. 66:508-564.

Gnanarnthu, Co P. 1937. Comparative study of the hyoid and tongue of some typical genera of reptiles. Proc. Zool~ Soc. London. 107(B) :l-_63a

Goin, Co J. and C. B. Goin. 1962. Introduction to herpetologyo W. H. Freeman and Coo San Francisco, 341 p. Goodrich, Edwin s. 1930. Studies on the structures and development of vertebTates. Dover Press, New York. 837 p.

Gorman, G. C., L. Atkins and T. Holzinger. 1967. New karyotypic data on 15 genera of lizards in the family Igua::iidae with discussion of taxonomic and cytological implications. C;ytogenetics 6(3) :286-299.

Haas, G. 1960. On the tr:i.1:;ernirn1smuscles of the lizards X~[l~_3_c},}~I.~ grandis and Shinisaurus crocodilurus. Amer. Hus. Novitates. 2017: l•-54. Haines, R. W. 1950. The flexor muscles of the forearm and hand in lizards and mammals. Journ. Anato 84:13-29. Hamilton, D. W. 1964. The inner ear of lizards. I. Gross structure, Journo of Morph. 115:255-271.

Hanson, F. B. 1919. The ontology and phylogeny of the sternumo Amer. Journ. Anat, XX:VI:41-91.

Harris, V, A. 196 3 • The a.nat omy of the rai,----ibow lizard, AgarnB:§gaIIla: (Lim1.), with a glossary of anatomical terms. Hutchison Tropical Monographs, (Anchor Press Ed.) 104 p.

Hebard, Wo B. and H. iA. Charipper. 1955. Histological evidence of saurian phylogeny., Copeia 1955:.305-307.

Heirtzler, J. R. 1968. Sea-floor spreading. Scientific American 219(6):60-70.

Heller, E. 1903. Papers from the Hopkins Stanford Galapagos Expedi~• tion, 1898-1899. XIV Reptileso Proc. Wash. Acad. Sci. 5:39-98. Hoffstetter, Ro 1942. Surles restes de sauria du Nurrnnulitique Europeen rapportes a la famille des Iguanidae. Bull. Muso Hist. Nat. Paris o 14( 2) : 2.33-240.

Hoffstetter, R. 1955. Squamates de type moderne. In: Traite de Paleontologie (ed. J. Piveteau). 5:606-662. Paris.

Hollman, J. A. 1964, Pleistocene amphibians and reptiles from Texas. Herpetologica 20(1) :'(3-830

Hotton, N. 1955. A slU'vey of adaptive relationships of dentition to diet in the North American Iguanidae. Amer. Midl. Nato 53(1):88-114.

Howell., H. B. 1936. Morphogenesis of the shoulder architecture, Part rv. Reptilia. Quart. Rev. BioL 11:183-200. Howes, G. B. 1891. The morphology of the sternum. Nature. 43:269 ..

Hurley, P. M., F. F. M. de Almeida~ G. C. Melcher, U. G. Cordani, J. R. Rand, K. Kawashita, P. Vandoros, W. H. Pinson, Jr., and H. W. Fairbairn. 1967. Test of continental drift by comp:i.rison of radiometric ages. Science 157(3788):495-500.

Hurley, P. M. 1968. The confirmation of continental drift .. Scienti- fic American 218(4):52-64.

Hurley, P. M. and J. R. Rand. 1969. P:ce-drift continental nuc..Leig Science 164(3885):1229-1242. lordansky, N. N. 1968a. Muscles of the external ear in some lizards. Zool. Zh. 47(11):1703-1732. Iordansky, N. N. 1968b. Cranial kinesis in lizards. Contribution to the problem of the adaptive significance of skull kinesis. Zool. Zho 49(9):1398-1410. Islam, A. 1955. The skull of Uromastix hardwickii (Gray)a Biologica LahoreQ 1(2):141-196.

Islam; A. 19560 The postcranial skeleton of Urornastix hardwickii (Gray). Biologia Lahore., 2(2):231-246.

Iyer> M. Mo N. 191;.2. The habits, external features and skeletal system of Calotes yersicolor. Part Io Journ. Mysore Univ. Seco B • .3(19h2):l5J~l70.

Iyer, M. M. N. 19/+3. The habits, external features and skeletal system of Calotes versicolor (Daud). Part II. The skulla Journ. Mysore Univ. Sec. B. 4(1943) :115-1510 143

Jenkins, R~ Lo and W. We Tannero 1968. Osteology -3.DdMyology of Phrynosom 12• Dlatvrhinus Giraxd and Phr 1osorna 12· hsrnandesi Girard. Brigham Young Univ. Sc~. Bullo Biol. Ser.). 9{4):1-34.

M. J. 1960. The head skeleton of the lizard. Acta Zool. Stockh. 41: 1..-64. Kesteven, H. L. 1941+. The evolution o.f the skull and the cephalic muscles. A compg,rative study o.f their development and adult morphologyo Memoir Australian Mus. Sydney. 8(3): 237-264.

Kingman, Ro H. 1932. A Compg,rative study of the skull in the genus Eumec~ of the family Scincidae. Bullo Univo Kansas.

33{ 1932) ~ 273-2.95 0

Kluge, A. 19620 The comµ3,rative osteology of the Eublepharid .lizard genus Coleonyx Gray. Journ. Morph. 110:299-3320

Kuroda, R. 1923. Studies of audition in reptileso Journo of Comp. Phys., 3~27-360 Kurten, B.. 1969. Continental drift and evolution. Scientific American 220( 3) : 54-64.

Lasana., M. 18340 Essai sur L I os hyoido de guelgues reptiles~ l-1err1vi:cc..Doll.a. 1~" .l~cc:.G.dcriQ.Della Scisr..~c C:~ Tc1~i;:10. 37!1•~?5w

Lundel:i.us, E. L. 1957. Skeletal adaptations in two species of Scelouorus. Evolution 11: 65-83.

Lynn, G. W., M. C, 0 1Brien and P. Herhenreader. 19660 Thyroid morphology in lizards of the families Iguanidae and Agamidae. Herpetologica 22(2):90-94.

Mahenclra, B. Co 19490 The skull of the Indian house-gecko Hemi- dactylus fluriviridus Ruppel. P:coc. Zool. Soc. Calcutta. 2(1949):29-42.

Malam, Mo E. 19l+1. Cranial anatomy of the genus Gerrhosaurus~ South African Journ~ ScL 37:192-217.

MaJupuria., T. 1957. On the m;yology, blood, vascular and nervous supply of the cloaca and hemi_renes in Urornastix hardwickii (Gray). Proc. Indian Sci. Co11gress. l+4:J?6-J77.

Maxvrnll, J. Co 19681, Continental drift and a dynamic earth. American Scientist 56(1) :J5·-5L

McCann, C. l9l+6o The hemipen:i.s in rept-Ues., Journ. Bombay Nato Hist. Soc. 46(2):348--3730 McDowell, S. B. and C. :M. Bogert. 1954. The systematic position of Lanthanotus and the affinities of the Anguinomorphan lizards. Bu]_l. Amer. Mus. Nato Hist. 105(1):1-142<

McElhinny, M. W. and G. R. Luck. 1970. Paleomagnetism and Gondwana- land. Science 168(39Jh) :8.30-832.

Minot, C. S. 1880. Studies on the tongue of reptiles and birdso Anniv. Jviem. Boston Soco Nat. Hist. 20 p.

Mittleman, M. Be 19li2. A s-wmnary of the iglianid genus Urosaurus. Bull. Mus. Comp. Zool. Harvard. 91(2) :106-181.

Mivart, St. George. 1867., Notes on the myology of Iq;uana tuberculata.. Proco Zool. Soc. London. 1867: 766-787.

:VJ.ivart., Ste George. 1870. On the m;yology of .Qba'l!aelon parsonii. Proc. Zool. Soc. London. 1870:850-890.

Montanucci, R.R. 19680 Comparative dentition in four iguanid lizards. Herpetologica 24(4):305-315"

Nopcsa, Fe 1928. The genera of reptiles. Palaeobiologicao 1(1): 163-188.

Norris, K. S. 1958. The evolution and systematics of the iguanid genus Urn2. and its relation to the evoll;.tion of other North American desert reptiles. BuJ_L Amer~ Mu.s. Nat. Histo 11/+ (3):247-326.

Norris, K. S. and C. H. Lowe. 19 51.., A study of the osteology and musculature of Phrynosoma mtcallii pertinant to its systematic status. Bull. Chicago Acad. Sci. 9:117-125.

Oelrich, T. M. 1956. The anatomy of the head of Ctenosaur~ pectinata ( Iguanidae). Misc • Pu bl o Mus . Zool. UrLi.v. }'.I:i chigan. 94: 1-122.

Ortenburger., A. I. 19230 A method of preparing reptile penes. Copeia 119:71-73~

Ostrmn, J. H. 1963. Further comments on herbivorous lizardso Evolution 17(3):368-369.

Parker., We K. l880., On the fftructure and development of the skull in the La.certilia, Part I,; on the skull of the common lizards La~_ a,rriJis, 1• viridis, and _Zootoca Yivip.1.ra. Phil. Trans. Royal Soco London., 170(1880):595-640.

Parker, T. J. 1891. On the origin of the sternum. Trans. and Proco of New Zealand Institute. 23:119-123. 145

Fing, Chi. 1932. Anatomy of the tongue and its adjacent muscles of Hemidactvlus bouris:-rJi. Nat. ScL 8:98-110.

PJ.etzen, R. Van. 1946. The cranial morphology of Cordylus, with special reference to the cranial kinesis. Ann. Univo Stellenbosch. (Sec., A. No. 3) 24:42-68.

Potter, G. E. 196L Vertebr-ate Zoology,. John Swift Co. pp. 190-205~

Pres ch. W. 1969. Evolutionary 0steology and relationships of the horned lizard gem:.s Phrvnosoma (Fam.Uy Iguanidae). Copeia 1969(2):250-275.

Ray, C., EG 1965. Variation in the number of lllarginal tooth positions in three species of iguanid lizards. Breviora, Mus. Compo Zoolo Harvard. 236:1-15.

Reese, H. M. 1923. The osteology of the 'l'egu, Tubinambis nJ;:i:ro1:u_nctatus., Journ. Morph. 38:1-17.

Rice, Eo L. 1920.. The development of the skull in the skink, Eumeces fil)-ingialineatus. Journ. Morph. 34:119-220.

Robison, W. G. and W. W. Tanner. 1962. A comparative study of the species of the ge:r~is Crotaphytus Holbrook ( Iguanidae). Brigham Young Univ. Science Bull., Biol. Series. 2(1) :1-31.

Romer, Ac S.. 1956a. OsteolOf::Y of the reptileso Univ. Chicago Press. Chicago. 772 p.

Romer, A. S,, 1956b. The vertebrate body., Wo B. Saunders Co. Phila. 486 Po

Romer, A. S. 1966. Vertebrate Paleontology. 3rd Ed. Univ. Chicago Press. Chicago. 1+68 p.

Romer, A. S. 1968. Notes and comments on vertebrate paleontology. Univo Chicago Press, Chicago. 304 p.

Rosenberg, H., I. 1967. Hemipenial morphology of some A.mphisbaenids (Amphisbaenidae; Reptilia). Copeia 1967(2):349-361.

Sabatier, A. 1897. Morphologie du sternum et des clavicules. C. R. Acad. Sci. Paris. 124( 15) : 61-69 a

Saksena, Ro D., 1942a The bony palate of Uromastix Merremo Proc. Indian Acado Scio 16(1942):107-119.

Sanders, A 0 1870. Notes on the rnyology o.f Platydactylus ~nicus. Proc. Zool. Soc. London. 18?0:413-426.

Sanders, Ao 1872. Notes on the rnyology of Liolepis belli. Proc. Zool. Soc. LondoE. 1872:154•~183. Sanders, A. 1871+. Notes on the myology of Phrvnosoma coronatum. Proc. Zool. Soc. Londono 187 i+: 71-89.

Savage., J .. M. 1958. The igu.anid li.z ard genera Urosaurus and Uta with remarks on related groups. Zoologica 4.3(2):41-54. -

Savage, ~T. M. 1963. Development of the herpeto.fauna. 16th. Interncttional Congress o.f Zoology. Proc. Int. Congress ZooL 16(4) :12-lL~.

Savage, J., M. 1966. The origins and history of the Central American herpeto.fauna. Copeia 1966(4):719-766.

Schmidt-Nielson, Ko 1959. Salt Glands. Scientific American. 200(4): 107-116.

Schmidt=Nielson, K. and R. Fangeo 1959. Salt Glands in marine reptiles. Nature, London. 182:78.3-785.

Scrnnidt., R. s. 1964. Phylogenetic significance of the lizard cochlea. Copeia 1964(L1-): 542-549.

Secoy, D. M. 1968. The myology of Sceloporus clarki clarki Baird and Girard (Reptilia: Iguanidae). Ph.D. Thesis. Univ. Colorado. Univ. Microfilms, Ann Arbor, Micho 68-14,399. (Diss. Abstr. B 29(4):1242).

Sewertzoff, S. 1929. Zur Entwicklungsgeschichte der Zu.ng bie dem Reptilien. Acta Zool. Stockholm .. 10:231-3~1.

Shaw, C. E. 1945. The chuchwallas, genus Sauromalus. Trans. San Diego Soc. Nat. Hist. 10(15):269-306e

Siebenrock.9 F. 1892a. Das skelet von Uroplatcs fimbriatus Schncid, Ann. Naturhist Nus. Wien. 8: 517-536.

Siebenrock, F. 1892b. Zur kenntniss des kapf'skeletteE der Scincoiden, Angviden und Gerrhosaursiden. Ann. Naturhist Hus. 'Wien. 7:163-·195.

S:Lebenrock, F. 1893. Das skelet von Brookes:i.a suDerciliaris KuhL Sitzungebar Aka.d. Wiss. Wien. 102:71-llSa

Siebenrock, F. 1894. Skel t der J;;..~C;.2,ttasimonyi Steind. Sitz Bero Akad. Wiss. Wien. cijj_. l(J,3:205•-292.

Siebenrock, F. 1895. Daf, skelt der Agamidenp Sitz Ber. Akad. Wiss. Wien. Civ. 104:1089-lJ.960

Sinitsin, D. T. 1928. The types o.f skulls in the family Teiidae. Zool. Anz. Leipzig. 76:232-236. 147

Smith, M. Ao 19.38. Evolutionary c.:hanges in the middle ear of' certain agamid and iguanid lizards. Proc. ZooL Soc. London. 19.38:

543--5490

Smith, Ho M. 1960. Evolution of' chordate structure. Holt, Rinehart and Winston, Inc. I'fow Yorko 529 p.

Sondhi, D. Co 19580 The hyoid and associated structures in some Indian reptiles. Ann. Zoolo Agrao 2(11):155-240.

Stephenson, N. G. and E. M. Stephenson. 19560 The osteology of the New Zealand gecko and its bearing on their morphological statuso Transo Royal Soc. New Zealand. 84(2):.341-.358.

Stokely, P. S. 1950. The occurance of an intermedium in lizards. Amer. Midl. Nat. 4.3:179-182.

Sukhanov, V. B. 1961. Nekotorye vorposy filogenii i sisteny Lacer- tilia (seu Sauria). Zool. 7..huro 40(1):73-83.

Svenson, H. K. 1946. Vegetation of the coast of Ecuador and Peru and its relation to the Galapagos Islands. Arner. Journ. of Botany • .3.3:394-498.

Tilak, Ro 1964a. The osteology of Uromastix hardwickii (Gray). Zool. Anz. 173:403-426.

Tilak, Ro 1964b. The hyoid apparatus or Uroma,stix hardwickii (Gr-a.;y). Sci. Culto 30(5):244-245.

Toerien, M. J. 1950. The cranial morphology of the Californian lizard Anniella pulchra Gray. South African Journ. Sci. 46~321-342.

Van Denburg_, J. and J. R. Sleven. 1913. The Galapagos lizards of the genus Tropidurus with notes on the iguanas of the genus Conolophu§_ and Air:blyrhynchus. Calif. Acad. Sci. Proco 4th. Series. 2(1):133-202.

Vinton, K. W. 195l. Origin of life on the Galapagos Islandso Amer. Journ. Sci. 249:356-376.

Webb, M. 195lo The cranial anatomy of the South African geckos Palmatogeclrn ram:E,i (Anderson) and Oedura karroica (Hewitt). Annals of the Uni-v. of Stellenbosch. 47A(5):1JJ-165.

Weiner, N. J. and H. Mo Smith. 1965. Comparative osteology and classification of the Crotaphytiform lizards. Amer. Midl. Nat. 73(1) :170-187.

Williston, S. W. 1925. Osteology of the reptiles. Harvard Univ. Press. Cambridge. 300 p. J.48

Young, Eo H. E. 1942. The cranial morphology of the Californian lizard )'",.antuf;ia vigilis. South African Journ. Med. Scio 7th. Supplement. 191+2:19-32..

Zangeri, R. 191;.l+. Contribution to the osteology of the skull of the Amphisbaenidae. Amer. Midl. Nat. 31(4):417-l;.54.

Zangeri, R. 192+5. Contribution to the osteology of the post-cranial skeleton of the Arnphisbacnidae, Amer. Midl. Nata 33: 764-780. PLATES 149

Plate Io Dorsal view of skull.

Ao Amblyrhynch~ .f.~o BYU 22810., x 1.25 B. Brachylophus fasciatuso JvlCZ15009. x 2.0 C. Chalarodon mada,F!ascariensis o HCZ 1153le x 4.,0 Do Conolophus pa1.1:_;~dU§.oMCZ 79772G X LO E., Ctenosaura pectinat:3.. MC'.Z 2176., x 1. 5

Key to s;nnbols used in Plate Io ec-ectopterygoid fe-fenestra exonarina fr-frontal ju-jugal mx-maxilla na-nasal ob-orbit pal-palatine p:3.r-pa. rie t al pf-pineal fora:nen pm-pr emaxtlla pot-postorbital prf-.prefrontal pt-pterygoid ptf'-postfrontal qu-quadrate stf-supratemporal f'ossa so,.,supraocdpi tal sq-squamosal 150

Plate I

-l, ----ob

~~_::.;;::.au_:~~-j---..Ptf ---pf ---pot ---stf ---par ----pt ----sq - --qu --so

B C

D E 151

Plate IIo Dorsal view of skullo

Ao .Q;_yclu@ rr@-..£~le;yt_. MCZ 6915. x O. 75 Bo Dipsosaurus dorsalis,., BYU 21726., x 2o0 c. lg~al},§: .ig_~o BYLT 22795 .. x LO D. Oplurus sebae,. NCZ .37191. x .3o0 E. Sauromalus obesuso BYU 21728. x 2.0

Key to symbols used in Plate II., ec-ect opt erygcid fe-fenestra exonarina .fr-frontal ju-jugal mx~•:maz::illa na-nascJ.l ob-,orbit pal-palatine par-parietal pf-pineal f oraEen pm-prerra..,dlla pot-postorbital prf-prefrontal pt-pterygoid ptf-postfrontal qu-quadrate stf-supraten:poral fossa so-supraoccipital sq-squamosal 152

Plate II

---so ---pt --sq ._..___,,---qu

D E 153

Plate III. Ventral view of skull.

A. Amblyrhynchu.s .£_ri.,2ta_t~us,. BYU 22810& x: 1.25 Bo Brachylophus fasciatuso MCZ15009. x 2o0 C. Chalarodon madaaascarierisiso r,ICZ 11513~ x 4o0 D. Conoloohus P§:lliciuso MCZ 79772. x LO Eo Ctenosaura oectinatao HCZ 2176. x lo5

Key to symbols used in Plate IIIo bo-basioccipital bp-basipterygoid p:cocess bs-basisphenoid ec-ectopt er;ygoi d ju-jugal mx-maxill~ pa.J_-J:-B_Latine pm--•prema:x:il.la po-post orbital pp-parasphenoid process pr-pyriform recess pt-pterygoid ptt-pterygoid teeth qu-quadrate sq-squamosal vo-vomer 154

Plate III ------pm

------nix ------pal

-----PP -----ju -----ptt -----po -----bs '"1~-+ -----bp ,-----~, --"'l'.... -----sq ------pt -il!Ii,\4:~=,.-•- -- -bo ----qu A

B C

D E 155

Plate llT. Ventral view of skull.,

!Ac _Cyclura. m@:_CCJ~yL MCZ 6915. x 0., 75 B. Dip;:;osaurus dorsalis. BYU 217260 :x. 2.,0 C. }f~c1ana _it~U§,l}.§:" BYU 227950 x 1.0 D. .Ql:1.~l~ _sebae,, r•iCZ 37191c, x J.O E. Sauroma.lus obesus. BYU217280 x 2.0

Key to symbols used in Plate IV. bo-basioc d.p:Ltal bp-basiptory goj_c; process br,•-ba.sis pheno:'._d ec-ectopterygoici ju ...jugal :m_x... ma,"-2..J.la p:3.l-•paJ.atino pm-premaxilla po--postorbi taJ. pp-parasphenoid p:coc:ess pr-pyrif orm proc~ss pt-pterygoid ptt-pterygoid teeth qu ...quadrate sq-squamosal vo-vomer 156

Plate IV ------pm

-----ec -----Pr ----ptt ----PP ~--1_,,_----ju .._:_,•t.' :;r ----po .:•.. -----bp '-!:', -----bs ...... -·---sq ----bo ---qu A

D E 157

Plate V. Lateral vi8v of skullo

!A. Amblyrhynchus _fristatuso BYU 22810. x lo25 B. BrachyloDhus fa,sciatus o MCZ 15009 c x 2o0 C. Chalarodon ma.dagasca.riensis. MCZ1153lo x 4.0 D. Conolophus f:Blliduso ECZ 79772. x 1.0 E. Ctenosai;_ra pectinatao MCZ 2176. x lo 5

Key to syriliols used in Plate Vo an-angular ar-articular co-coronoid de-dentary ec-ecto pt erygoid ep-epipterygoid fe-fcnestra exonarina fr-fronte,l JU-juga:i. la-lacrirnal mx-ma.-x:illa na-nasal ob-orbit pm-premaxilla po-postorbital pp-pa,rasphenoid process prf-prefrontal pr-pa,rietal pt-pterygoid pt.f-postfrontal qu-quadra.te . sq-squamosal sr-surangular 158

Plat,, V

------pm --==------fe ------de -----nix

()

B C 159

Plate VI. Lateral view of sln1llo

.A. Cyclura IIBccleYin MCZ 69150 X 0 ..75 B. Dipsosaurus dorEalis .. BYU 21726, X 2,,0 c. Iguana iguana. BYU 22795. X LO D. 012lurus sebae. HCZ 271910 X 3o0 E. Saurorral us obeSUE:io BYU 21728., X 2~0

Key to symbols used in Plate VIo ar-articular co-coronoid de~dentary ec-ectopterygoid ep-epipterygoid fe-fenestra exonarina ju-jugal la-la cri.,yial mx-maxilla na-nasal ob-orbit pm-prernaxiJ.la po-post orbital pp-J::e,rasphenoid process prf-prefrontal pr-parietal pt-pter.1goid ptf-postfrorrtal qu-quadrate sq-squamosal s:r--surangular 160

Plate VI

----.prf ----la ----ju ----ob. ---PP ---ec ---co ---ptf --pt ---ep --PO --pr --sr _..qu --sq ----a.r A

B C

D E 161

Plate VII. Medial view of mandibleo

Ao Amblyrh;ynchus cristatuso BYU 22810 .. x 1~75 B. Brachvlophus fasciatus. MCZ15009. x 2o0 Co Chalarodon r&1.da2acc:carien:3is o HCZ 11531. x 4o0 D., Conolophus palliJu2,o HCZ 79772., x LO E. Ctenosaura _pect:.na1,aG MC'Z 21'/6,, x 1 ..5 Fo Cycll.ld:§:.macclev:h_o ECZ 6915. x 0.75 G. Dipsosat~~ dors;:~lis. BYU 217260 x 2e0 H. Ig-c1a122:iguana. BYU 22795 o x l.G Io Oplurus sebae. I·ICZ37191. x 3 .O J. Sauroma1us ob_S:_;;,s9.~BYU 21728. x 2.0

Key to symbols used in Plate VII. aif.,..anterior ini'eri.or alveoler foramen an-angular anp-angular process ar-articular condyle co-coronoid de-dentary sp-splenial sr-surangular Plate VII

H J 163

Plate VIII. Ventral viei.,,- of Hyoid Boneso

A. Amblyrhynchus cristatus. BYU 228105 x O. 75 B. Bra.chvlophus fasciatus. BYU 237430 x LO C. Chalarodo:i:--1 rna~2.sca1·iensiso MCZ lJ.522. x 4a0 D. ConoloDhus subcrista.tut>. NCZ 202?~ x 0o75 Eo Ctenosaura pectinataQ BYU 22?96. x 0.75 F. Cyclura carin2,ta. :M:CZ59255 ~ x LO Go Dipsosaunis dorsc1,lis. BYU 21726., x l,;5 H. _Iguana igua.n.£1::. BYU -228520 x J.QO I. Oplurus _seba~o MCZ 271880 x .3.0 Jo SAY.:-t~rr_igJy,~obe::;u_e. HCZ 389,'... x L5

Key to symbols used in Plate VIIIo bh-basihyaJ_ cb I-cera.tobranchial I cb II- ceratobranchj_al II ch-ceratohyal. gh-gloesohyal hh-hypohyal Plate VIII ------gh

------Cb II A B

C D E

F G H

J Plate IX., Ventral view of sternumo

A. Amblyrh;ynchus £Tistatus. MC'Z 2006. X 1.0 B. l3rach;ylo.1huQ fasciatUSo MCZ 15008. X 2.0 c. Chalarodon rriadaR;as cariensis. MCZ11531. X 4.0 D. .Q.,onolo12rrns_g,llicius. HCZ 79772. X 1.0 E. Ctenosaura r,2ctj_natc1:. MCZ21760 X 1.5

Key to s;ymbols used in Plate IX .. cl-clavicle ic~,interclavic:le sc-sternal ca:r-tilage sf-sternal fontanelle sr-sternal ribs xr-xiphisternal ribs 166

Plate IX

E Plate Xo Ventral view of sternurn.

A. .Qyclura maccleyl. imz 6915• X 1.0 B. Di2sosaurus dorsalis. BYU 21726. X 2o0 c. Jguana l:g~. lrfCZ 549890 X 1.0 DG 02luru_s sebae. NCZ 37191. X J.O E. Sauromalus obe~. MC'Z8894. X 2.0 -~· WIX-. Key to symbols used in Plate X. cl ...clavicle ic~interclavicle sc•◄ sterna.l cartilage sf-sternal fontanelle sr-sternal ribs xr-xiphisternal ribs 168

PlateX

------ic

j .,/.-\ I ✓---• C I, . y\_ ~- B. ~vJ''c,.- 4 ~ Plate n~ Ventral view of throat musculature; superficial layer shown at left and nrst deptli at righto

Ao kblyrhynchus er"' stat~§.. BYU 22806. x 0.35 B. Brach7lophus fasci2.tc1sQ BYU :319550 x lo0 Co Chalar·odon :mada,1::a.scar·iensis. BYU 22801, 22803. x J.0 D. Conolochu~ subseristatus. BYU 22311. x 0.35 E. Ctenosaura pectinata. BYU 228500 x 0.5

Key to symbols used in Plate XI. cc-constrictor colli ep-episternocleidor::astoideus ge-genioglossus iap-interrn~ndibularis anterior profu.ndus ir~s~,..i~t cr:m.andi[y;J_a.~·i~3aP.t e~it,.r· f;u,r>"?r.ricia,l1s ip-interrnandibularis posterior rrbIP•m~nd:i..bulohyoicie,1s I mhII-mandibulohyoideus II orr!'"4omohyoideus pe-pectoralis pt-ptecygomandibularis sh-sternohyoideus st-sternothyroideus 170

Plate XI

------ias

~~l-i.JJIIA.-~4------mhII ------iap

Superficial Depth

D E 171

Plate XII. Ventral view of throat musculature; superficial layer shown a left and first depth at right.

Ac Cyclura nuchal_i§.Q BYU 22799. X 1 ..0 Bo Dipsosaurus dorsaJ.is. BYU 31954. X 1 ..5 c. Iguana _iguana.. BYD 2~2851.X 0"75 D. OJ2lurus seb.~~• BYU11504. X 1.25 E., Sauromalus ob~!-...s• BYU31953. X 1.5

Key to sy1r.bols used in Plate XII. cc ...constricto:;_~ co:.Lli ep-episternodcidorr0.stoideus go-r,er 1:.LO?lo~,~:\Ji, iap-intermandib,u.aris anterior proi'undus ias•~intermamUhula:c·is anterior superfid.alis ip~intermandibuh.ris posterfor mhI-mandibulohyoidel:cs I mhII-mand ..ibulohyoidsus II om---omohyoideus pe-pectoralis pt-pterygomandibu.laris sh-sternoh;yoideus st-sternothyroideus 172

Plate XII

R~,.:,ill.\llll+l,'..J~•-11------iap ------mhll -~~~~~~------~p ------pt

D 173

Plate XIII. Ventral vie,-; of throat musculature; second depth at left and third depth at right~

A. Amblyrh;ynchus _cr:i.sta.tl_l;~. BYU 22806. x Oo35 B. Brachylor:;hus fas£_ia:~,u~. BYU 319550 x LO Co Chalaroclcn .[§,S:3,/7asg_a1'icmsis. BYU 22801, 2280Jo x 3.0 Do ConoloDhus subcrist2.t1.:s. BYU 22811. x 0.35 E. Ctenosaura pec1,inata. BYU 22850. x 0,,5

Key to symbols used in Plate XIII., hh• ◄ brc=mch~ oh:nl-id,~u,; ge-genioglossus hg-hyoglC1ssus mhIII-mandibulohyoideus III prrr--pharyngeal membrane pt-pt erygomandi bu1aris sh-sternohyoideus 174

Plate XIII

------ge ------mhIII ------pm

------pt

B C

D E 175

Plate XIV. Ventral vie11 of thl'oat muscuJae,ure; second depth at left and third depth at right.

Ao Cyclura nuchalis. 1-:lYU227990 x LO B. Dipsosau_rus dorsab s. BYU 31951-1-ox L'..i C ., I guana J.2'.'iana,· --BY. .u1-;-')28'51 ,.,~ • x (',. ""1 J D. Oplurus sebaE::, BYU11504. x la25 E. Sauromalus ~.2.ld..~• BYU31953c x 1.5

Key to symbols used in Plate X..W.

bh-brancniohyoicieus ge-genioglossus hg-hyoglossus w.hIII-rr:andibuJ.ohyoideus III pm-pharyngeal membrane pt-pterygomandibulad s sh ....sternohyoideus 176

Plate XIV

------ge

------pt

D E 177

Plate 'KV. Ventral vie.-..r of tbroat musculature,; fourth depth at left and fifth depth at right.

A. Amblyrhynchus _gristatus 0 BYU 22806. x 0.35 B. Brachylophus fa2cia,t1.;5. BYU 319550 x LO C. Chalarodon rrada2asc2arierisis. BYU 22801, 22803. x 3.0 Do Conolonhus subcrista-'.-,us. BYU 228110 x 0.,35 E. Ctenosaura ~:J-nata. BYU 22850. x 0,5

Key to symbols -:1sed :i_n Plate YS. clcl:.,... _ri_cl0 ic•-interclavicle lx-larynx orri-omohyoideus pm-pharyngeal mernbrar,e pt-pter-Jgomandibularis tr-trachea 178

Plate XV

Fourth Depth Fifth Depth

B C

D E 179

Plate XVI. Ventral view of throat musculature; fourth depth at left and fifth depth at right•o

A. C_yclura nuchaliso BYU 22799. X loO B. Di_Qeosaurus do.rsc:..lis o BYU 3l95l+. X L5 c. ,Iguana iguapa. BYU22851. X 0.75 Do 912lurus sebae. BYU11504. X 1..25 E. Sauromalus obesuso BY1J 31953. X L5

Key to symbols used in Plate X\TL cl-•clav:i c1e ic-interclavicle lx-larynx on::-omohyoide11s prrr--pharyngeal membrane pt-pterygomandibularis tr-trachea 180

Plate XVI

D E 181

Plate XVII. Dorsal view of head and neck musculature; superficial depth at left and first depth at rigrit.

A. AmblY.:rhvnchus c:'.'istc3:tuso DYU 228060 x 0.35 Bo Brachyloohus faE,G:Ls,t,;s o BYU 31955 c x LO C. Chalarodon mari1;;;:a,scariensis. BYU 22801, 228030 x 3o0 D. Conolophv_s subcristatus. BYU 2281L x 0.35 E. Ctenosaura E.S:!-ina~.ac BYU 22850. x 0.5

Key to symbols used in Elate XVII. am-adductor randibularjs externus medius cc-constrictor colli cm--cervicorr,andib1__1l<:tris d.i"11-depressor rg,ndi.bularis ld---latissimus dorsi ls-levator scaplllae superficialis ps-pseudotemporalis superficialis tr-trapzius 182

Plate XVII

Superficial Depth First Depth

D E 183

Plate XVIII.. Dorsal vie1·r of head and neck musculature; superficial depth at left and first depth at right.

A. C;yclura nuchalif?., BYU 22799. X 1.0 B. Di:12sosaurus dors?Jis. BYU31951+. X 1 ..5 c. Iguana iguana. BYU 228510 X 0.75 Do Oplurus sebae. I:YU 11504 .. X L25 E. Sauromalus obesus, BYU3195JQ .x 1.5

Key to symbols usec'.. in Plate XVIIL am-adductor mandi·o-,1laris externus medius cc•-eonstdct,or cclJ.i crn-cervicornandilmlaris d.m-depressor m.a:ndibul.aris ld-latissirnus dorsi ls-levator scapulae superficialis ps-pseudotempralis superfieialis tr ....trapezius 184

Plate XVIII

D E 185

Plate XIX. Dorsal view of head and neck musculature; second depth at the left and third depth at the right.

A. funblyrhynchus cristatus. BYU 22806. x 0o35 B. Brachylophus fasciatus~ BYU 319550 x LO C. Chalarodon rrcad_2:_ga,sc2,riensis ~ BYU 22801, 22803. x J .,0 Do Conolophus subc:.'istatus. BYU 2281l. x 0o35 E. Ctenosaura pectinat3:. BYU 228500 x 0.5

K0y 1:ri syirhnl::, 1.Jc.ed in PJ ate YJ7., ep-episternocleidoITastoideus lp-levator scapulae profundus ~ ls~levator scapulae superficialis sd-serratus (dorsal part). sl-sacrolurrbalis 186

Plate XIX

Th.irdDepth

D E l87

Plate XX. Dors2J.. view of head and neck musculature; second depth at the left and third depth at the righto

A. Cyclura nuchali~~ BYU 22799. x LO B. Dipsosaurus dOf.:§..§:lis. BYU .31954, x L5 Co Iguana j..guan2 • BYU 2~2.8:51.x Oo75 Do O_plurus sebae. BYU 115Ch. x l..25 E. Sauromalus obesus. BYU.3195.3. x 1.5

Key to SJTJn·nols used in Pl.o,tc XX" ep-episternocJ.eiciomastoideus lp-levator scapuJ_ae profundus ls-levator scapulae superficialis sd-serratus (d;rsal part) sl-sacrolumbaLLs 188

Plate XX

A SecondDepth Third Depth

D E 189

Plate XXI. Dorsal view of head and neck musculature; fourth depth at left and fifth depth at rigr11t.

A. Arrblyrh;wnchus cristatus. BYU 22806Q x 0.35 B. B,...achylophus fasciatus. BYU .31955. x 1.0 C. Chalarodon J11adag~scariensis. BYU ;?2801, 2280.3. x 3 oO Do Conolop~·rns trnbcristatu.s. BYU 22811. x 0.35 E. Ctenosaura pectlnata. BYU 22850 • .x 0.5

Key to symbols used in Plate XXI.. ie-intercostales extsrni sd•-serr;:it.11s ( cl0rs,;._I f,a:rt) sp-spinus dorsi ss-subscapularis II 190

PlateXXI

B C

D E 191

Plate XXII. Dorsal view of head and neck musculature; fourth depth at left and fifth depth at rj_ghto

Ao Cyclura nucha1is. BYU 22799. x LO B~ Dipsosaurus do:rsali::;. BYU JJ.954. x. 1.5 C. :J:guana iguana~ BYU 2285L x Oo75 D. Oplu:rus sebae. BYU ll504. x 1.25 E. Saur-t2m-3,lus obesur;. BYU 31953. x 1.5

Key to symbols used in Plate XYJL ie-intercostales ez.terni sd-serratus ( dorsal r.,s.rt) sp-spinus dorsi ss-subscapularis II 192 PlateXXII

------sp

D E 193

Plate X:X:IIIo Lateral view of head and neck musculature; superficial depth.

A. Amblyrhynchus cristatus. BYU 22806. x 0.35 B. Brachylonhu~ fasciatus. BYU 31955. x 1.0 C. Chalarodon mad~g§,~ttiensis. BYU 22801, 22803. x 3.0 D. Conolophus subcris::,atus. BYU 2.2811,, x 0c35 Eo Ctenosaura pectfoata. BYU 22E'.~50. x 0o5

Key to symbols used in Plate XXIII.:, a~adductor mandihtLlaris esternus medius as-adductor mandibll-1.aris externus superficialis au-auditory me2.tus cc-constrictor co ..L.1i cm-cervicomandibularis dm-:-depressor mandibularis ep--episternocleidorrastoideus ip--intermandibularis posterior la-levator angularis oris tr-trapezius 194

PlateXXIII

D E 195

Plate XXIV. Lateral view of head and neck musculature; superficial depth

Ao Cyclura nuchali:?.• BYU22799. X 1.0 c: B. Di12sosaurus dors2lis~ BYU.3195i+o X l ._) c. Iguan 2 iguana •. BYU22851. X Oo75 Do 012lurus sebae. BYD11504. X L25 Eo Sauromalus obesus. BY-U3195.3. X 1.5

Key to symbols used in Plate 7:LF/,. am-addueto.r rr,c1xtd2.b'JJ_aris externus medius as-adductor rrcs.ndibularis externus superficialis r.:t1J~a,1J.dl_tor:rme~t ~, u~~ cc-constrictor colli cm-c ervicomandi bu.laris dJn-depressor mandi.bularis ep-episternoclei doi11astoide.us ip-intermandibularis rosterior la-levator angularis oris tr-trapezius 196

PlateXXIV

D E 197

Plate Ilv. Lateral view of her.cl and neck mwJc1.Jlature; first depth.

A. Ar;ib1vrhvnchus cristatu::. BYU 22806. x Oo35 B. Brachylophus fasciatus. BYU .31955. x LO C. Chalarodon rnadagascariern,is. BYU 22801, 22803. x .3.0 D. Conolophus subc~ 0 istatm,. BYU 22811.. x 0.35 E. Ctenosaura pectina;:,a. BYU 22850. x 0~5

Key to symbols used i:.1 Plate XXVI. am-adductor IT1andibu.laris externus medius as-adductor mandibul.aris externus superficialis cm-cervicomandibularis dm-depressor r.,anc.~,_b,J.1aris ep-episi:, erno c:i.eiciom.ac; t u..i.deu.::; i p-int ermaridi bu.lad.s f.D~,t erior ls-levator scapulae superficialis om-omohyoideus sh-sternohyoideus 198

PlateXXV

D E 199

Plate XXVI. Lateral view of hec.d and neck nn.:i.scu.lature; first depth.

A. Cvclura nuchalis~ BYlf 22799,, x 1.0 Bo Dipsosaurus dorsalis. BYU 3195li-,, x 1.5 c. Iguana iguana. BYll 2;28510 X Oo75 D. Oplurus _§ebae. BYU 11504. x L25 E. Sauromalus o'oesus. BYD31953~ x lo5

Key to symbols used in Pl.ate XXVI .. am.-adductor mandibularis exte:mus rr:.edius as-adductor mand:Lbul.aris extenrns su.perficia:lis crr~cerviconiandibularis dir,.-dep~esf~nr r,'".::..nd~I l,11}.,s Y':is ep-episternocleidornastoideus ip-intermandibularis posterior ls-levator scapulae superficialis om-omohyoideus sh ...sternohyoideus 200

PlateXXVI

D E 201

Plate XXVII. Lateral vj_ew of head and neck musculature; second depth.

A. Ambl;yrhynchus c:r:i.l3tat us_. BYU 22806. X Oo35 B. Brachylop:ius fasciatus" BYU31955. X LO c. Chalarodon ma.daco:asca~iensis. BYU22801) 22303. X 3.0 D. Conolo1:2hus subcristatus. BYU22811. X 0,,35 E. Ctenosaura 1:2ectinat~. BYU 22850. X 0.5

Key to syrr.bols used in Pld,e XXVII. am-aa.ductor mand:1bu_l_ar.is externus medius ep-episternocleidomastoideus lp-levator scaplilae profundus ls-levator scapuls,e superficialis pm-pharyngeal meillbrane 202

PlateXXVII

B C

D E 203

Plate XXVIIJ::. Lateral view of head and neck musculature; second depth.

A. Cvclura nuchalJ_~• EYU 22799. x 1.0 B. Dinsosaurus dors2.J.t.E.• BYU 31952.. x 1.5 C. L;,\:.an~ iguar:a. BYU ?2851. x 0.75 D. Onl1,1rus sebae. BYU 11504. x L25 E. SaurQrr::>lu::; obes;_1s. BYiJ 31953.. .x L5

Key to symbols used in Plate Y,.XVIJL arn-adciuctor ni..and:i.b"i.u..ari s exterT1 us neu.LLtt> ep-episternocle:Ldor:-1as'c.oideus lp-levator scapulae profur1dus ls-levator scapulae superficialis pn-pharyngeal membrane 204

Plate XXVIII

D E 205

Plate XXIX. Lateral view of head and neck musculature; third depth.

Ao Ambl;z:rhynchus cristatus. BYU22806. X 0 •.35 B. Brachvlophus fasciatus. BYU319:)5. x.1.0 c. Chalarodon madagascari.ensis. BYU22801, 22803. X 3.0 D. Conolonhus subcri2te,tus. BYU22811. ~'( 0 •.35 E. Ctenosaura :eectin~ta. BYU22850. X 0.5

KP-y to symhols used :in Plate XXIX~ cl.p-aUUU.C\.,Ol' manu.i.uuJ.ct.::·.i.:::-t::.X.l-el"llU.b JJ.L"U.Lt:wuuc:i lp-levator scapulae profun.dus ls-levator scap.:i.lae superficialis ps-pseudotemporalis superi'icialis 2ch

PlateXXIX

B C

D E 207

Plate :XXX. Lateral view of hec.d and neck musculature; third depth.

A., Cyclura rn1chalis. BYU 22799. x LO B. Dipsosaurus dorsalis. BYU 3195~-o x L5

C. _Iguana iguana. BYU 22851 Q x 0.75 Do OJ2lurus sebae. BYU 115D4o x L25 Eo Sauromalus ob~~• BYU 31953. x 1.5

Ke;y to syrnboJ;.:, l,sed in PJ;:,te XYX. ap-adductor mandioularis externus profundus l:p-levator scapu_lae profundus ls-levator scapulae superficiali[➔ ps-pseudotemporalis superficialis 208

PlateXXX

D 209

Plate X.UI.. Lateral view of head and neck musculature; fourth deptho

A. Ambl vrhynchus cristatus. BYU 22806. x. 0o35 B. Brachy.l.9.n~ _fasciatm,. BYU 31955. x 1.0 C. Chalarod0n rrcadapd.sc;U':i.ensis. BYU 22801, 22803. x 3.0 D. Conolophus su!Jcri,:.tatw:.. BYU 22811. x 0o35 E.. Ctenosa11ra rechnEJ.ta. ·-BYU22850. x 0.5

Key to r;ymbols used iY1 Pl,:;.to XXXI~ am-adductor rnand·ibularis posterior -. '1 . ' . -- J.._1,)-.l.t::Vd,l.,UJ: }JL-t~:.·,y /c',U..L.Ut::Ll.~, pp--protractor pt ery go::.clcus pt-ps eudotem1nrcclis pro fun,5.us sc.:-scapuJ.a sd-spinus dorsi ss-suprascapul.a 210

PlateXXXI 211

Plate XXXII. Lateral view of head and neck musculature; fourth deptho

A. Cyclura nucha-iis. BYU 22799., x LO B. Dipsosaurus ao:rsalis. BYU31954. x 1.5 Co Iguana i.g~mr1;2:. BYU 22851. x L25 D. Oplurus sebae. BY~J11504. x L25 E. Sauromalus obesc:.s. BYU 3195J. x 1.5

Key to syni~ols used in Plate XXXII. am-adductor rns:·1chb;JJar:l.s poste::::'ior lp-levator pterygoidcu.s pp-protractor ptcrygoideus pt-pseudotemporalis prof'undus sc-scapula sd-spinus dorsi ss-suprascapula 212

PlateXXXII

D 213

Plate XXXIII. Lateral view of head and neck musculature; fifth depth.

A. Amblyrhvnchus cristatuso BYU 22806. x 0.35 Bo Brachylophus .fasci.atus. BYU 31955. x 1.0 C. Chalarodon n3.dagascariensis. BYU22801, 22803. x 3.0 D. Conolophus s-c.bcrista.tus. BYU 22811. x 0.35 E. Ctenosaura pectinata. BYU 22850. x 0.5

Key to syrnbols 1.;.sed in Plate XX.XIII. cl-clavicle ic-interclavicle lp-levator pterygoideu.s pp-protractor pLerygoideus sd-spinus dorsi se-serratus ( dorsal part) · sl-sacrolumbalis 214

Plate XXXIII 215

Plate XXXIV. Lateral vie.,, of head and neck musculature; fifth depth.

A. Cyclura nuchaLJ:.~o BYU22799. x LO B. Dipsosaurus do:csalis. :SYU 3195L+. x 1.5 C. Iguana igua~~ BYU 228510 x 1.25 D. Oplurus sebae. BYU 11504o x 1.25 E. Sauromalus obe~o BYU 31953. x L5

Key to symbols used in Plate -XX.XIV..

ic-interclavicle lp--levator pter;y-gojdeus pp-protractor pterygoideus sd-spinus dorsi se-serratus (dorsal part) sl-sacrolurnbalis 216

PlateXXXIV

e C

D E 217

Plate Y:XXV• Dorsal view of the tonguec

A. Amblyrh;vnc~.:.:0:§ cristatus. BYU 22£!10~ x 1.25 B. Br:~chyloph1;,3 fascia~_,ut:o o BYU 2371-iJ.x 1.5 C. ChalarodoH I.i}?-..'..-~-.:~£ascariensiso BYU 22801. x 6.0 D. Cono2-ophus ,mbcrhctatuso BYU 22E)ll. x LO E. Cter~osau~-:£::_pectinata. BYU 22796. x 1.5

F'. .Qy~l~~ r!.ttc:!1alis $ 53YU 22799. x ;2. 5 G.. Dip2osaurus dorsalis. BYU 23761. x J.O H. lg-c.ana _;i.p~us,ll~• BYU 22852. x 1.25 I. Qr.ill~ sel:E.':!'_"2.•BYU 11504. x 2o5 .1, S.:11)t'O"'::il-,;s cboi::us. HYU 23762. x L 5

Ke;y to s;ymbols used in Plate XXXV•. ac-anteylor cleft f:p-filamentous pap:i_llae gl•-glottis pc-posterior cleft p:rrpointed papillae PlateX:XXV

_g1 •PP B

J 219

Plate XXVI. Hemipenes

A. Amblyrhynchus cristatus~ BYU 22806. x L5o Left hemipenis. B. Br&c;hylophus fasciatus~ BYU 2371~3. x 2.0. Left hemipenis. C. Cteno~:am~a, oectinata. BYU 22796. x 2~0. Left hernipeniso D. J2_jJJsosaur 1.1s dorE;alig_. BYU 23760. x /hOa Le.ft hernipenis. E. l>;uana j_;;:~~Q:I§.• BYU 2285L x 2.,0. Left he:mipenis. F. Saurom.3,luc obe_sus. BYD 23762 .. x 3~0. Right hernipenis.

Key to symbols used in Plate x:t::J.VL. er-crease cs-calyculate surface ss-sulcus sperma.ticus 220

PlateXXXVI

E F 221

Plate XXXVII. Phylogenetic relationships of the Madagascar Iguanidae and the genera of iguanine lizards. 222

PlateXXXVII

Ctenosaura

Sauromalus

Cyclura

Conolophus

Amblyrhynchus

Iguana ...... ~

Pre-Ctenosaura-lguana Stock

Dipsosaurus

Oplurus

Chalarodon

lguanid Ancester VITA

David F. Avery EVOLUTION OF '.!:'HE IGUA1JINE Lib'l.HDS

(SAlJHIA., IGUANIDAE) AS DE'TEPJHNED BY

OSTEOLOGICAL AND :MYOLOGICAL CHA..�ACTERS

David F. A very

Department of Zoo.logy

Ph. D. Degree, August 1970

ABSTRACT

From -':i detailed study of the anterior osteology, myology, tong11es a:·,.d he:1.ri.penes of A:mbl,rrhv,1ch�, Bracr.vloDr;u!:', Cha1E:.:�odon, (.,;,:i11olOJ2hl1s, .Qtenosam-a, Cvcll:..ra, pipsosa:.,rus_, J.2�, 012._�1:.�rui and �3a�_'.9II§:h'.-..� ar.. interpretation of the phylogenet:.c relationships of the ig_tt.anine li11e in tl1e F'arn_ily Iguanidae is n61.i1 possiCle. It :ts cl ec:1.r that the Nadagascarian ge'1€ra Cha1arodcn Q.nd .Q..pJ.urur3 a,re iwst closely related to each othcJ.� 1:Jit11 0nl1:r-u_s also being closel:l relctLecl t:.) _Qj,_ES-2..�§:-'.c.£.c,�, p�,7c.;..ura £,Ed I.rc:a2.!·,a, ·v,hich represent the r;:ain igua.nine aT1cestraJ stock in t}v:- 11fostern He1:1isphere. Cvc:1J.1'8: is 2.n early island de�Jcer1dant c�f· .!;t�,r�0s2.:.:�-� arid. Saur�orn3.lus is c:. r:crtJ-1ern deri·vative of th.?.,,,t g�;:111-ls. Co�::)��-0Dhl1s is ap1=ars11tly an -2..nvader of the G·aJ_c�1=acos J Tc-?_ y1/") r-,-,- "· ,. _ .• •::'J.. ��-- -=�: .::. l-::_•,:._ ·:.:� -:.;_� ��:,� y1::-�2� .. :2 :;.��•-:_•c�-=·-:-.�[-:_ ::,:_ �,_::•, _;�•= .. �IQ.b.J.2l12YJlCJ-1t1�j CtfJpe8.. rs to Le derived fro�n ConoJ JEii�. Br�;:-h-1 lo"(;iYc.s ., an ,";ar1y der.:i:vat��vc, of' the ig1,.r,.rii.ne stock, was probf-;.. b1y rafted to tn8 Fi.1.i aJ1d Tcr1gc1 ls1a.r.icls fr·o1� t:r·opical A1neri..:!a. ��1n�11s� :represent3 th s nor-the.rn exteEsion of that generic complex. The l•la.da6ascar· Iglmnid.?;,e and the Western Herdsp�iere igua::iines were probably ;3eprated. in post Crot.2.ceou�; i.,ir,1es vb; Continental Drift.

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