L I B R.AR.Y

OF THE

UNIVERSITY Of ILL1 NOI5

THE MEXICAN AND CENTRAL AMERICAN LIZARDS OF THE GENUS SCELOPORUS

BY

HOBART M. SMITH

W XLTKU RATHBONE BACON SCHOLAR SMITHSONIAN INSTITUTION

IHE LIBRARY OF THE UNIVERSITY OF ILLINOIS

ZOOLOGICAL SERIES

FIELD MUSEUM OF NATURAL HISTORY

VOLUME 26

JULY 27, 1939 PUBLICATION 445

Natural Htstorv

THE MEXICAN AND CENTRAL AMERICAN LIZARDS OF THE GENUS SCELOPORUS

BY

HOBART M. SMITH

WALTER RATHBONE BACON SCHOLAR SMITHSONIAN INSTITUTION

LIBRARY OF THE

/U/G 15 1939

ZOOLOGICAL SERIES

FIELD MUSEUM OF NATURAL HISTORY

VOLUME 26

JULY 27, 1939 PUBLICATION 445 &

IN THE UNITED STATES OF AMERICA BY FIELD MUSEUM PRESS

CONTENTS

PAOB

List of Illustrations 5

Introduction 9

Geographical Trends in Variation 12

Biotic Provinces of Mexico 14

Regional Lists 19

Method of Treatment 23

Definition of the Genus 28

Arrangement of the Species in Groups 29

Key to the Groups of SceZoporws 30

Systematic List 32

Forraosus Group £ 32

Spinosus Group 59

Undulatus Group 172

Graciosus Group 176

Grammicus Group 177

Megalepidurus Group 199

Poinsettii Group 209

Variabilis Group 236

Merriami Group 284

Maculosus Group 290

Chrysostictus Group 294

Siniferus Group 300

Utiformis Group 324

Scalaris Group 330

Pyrocephalus Group 361

Bibliography 378

Index . 395

LIST OF ILLUSTRATIONS

PLATES

1. Sceloporus formosus formosus, Chilpancingo, Guerrero. Sceloporus merriami annulatus, Glenn Spring, Texas.

2. Sceloporus asper, Uruapan, Michoacan.

3. Sceloporus salvini, Jalapa, Vera Cruz. Sceloporus formosus malachiticus, Boquete, Panama.

4. Sceloporus lundelli lundelli, Hacienda Balchacaj, Campeche. Sceloporus orcutti licki, San Bartolo, Lower California.

5. Sceloporus lunaei, Guatemala.

Sceloporus lundelli gaigeae, Merida, Yucatan.

6. Sceloporus acanthinus, type of S. guentheri.

1. Head scales of Sceloporus acanthinus (from type of S. guentheri).

8. Sceloporus edwardtaylori, Tehuantepec, Oaxaca.

9. Sceloporus melanorhinus, Hacienda El Sabino, Michoacan.

10. Sceloporus melanorhinus, ventral views of specimens on Plate 9.

11. Sceloporus spinosus spinosus, Maravatio, Michoacan. Sceloporus spinosus spinosus, El Salado, San Luis Potosi. Sceloporus spinosus spinosus, Alseseca, Puebla. Sceloporus horridus horridus, Chilpancingo, Guerrero.

12. Sceloporus horridus albiventris, Tepic, Nayarit. Sceloporus horridus horridus, Cuernavaca, Morelos.

13. Sceloporus olivaceus, Rio Grande City, Texas.

14. Sceloporus olivaceus, Huasteca Canon, near Monterrey, Nuevo Le6n.

15. Sceloporus magister magister, Kanab, Utah. Sceloporus clarkii boulengeri, Presidio, Sinaloa.

16. Sceloporus heterolepis (from Boulenger), Jalisco. Sceloporus microlepidotus disparilis, Rio Grande City, Texas.

17. Sceloporus pictus, Acultzingo, Puebla. Sceloporus pictus, Puebla.

Sceloporus megalepidurus, Totalco, Vera Cruz.

18. Sceloporus ferrariperezi binocularis, between Pablillo and Alamar, Nuevo Le6n. Sceloporus serrifer plioporus, Lim6n, Tamaulipas.

19. Sceloporus couchii, Huasteca Canon, near Monterrey, Nuevo Le6n. Sceloporus couchii, Sabinas Hidalgo, Nuevo Le6n.

20. Sceloporus cozumelae, Cozumel Island, Yucatan. Sceloporus aeneus bicanthalis, Cruz Blanca, Vera Cruz. Sceloporus scalaris scalaris, Mexico City.

21. Sceloporus teapensis, San Agustin, British Honduras.

22. Sceloporus variabilis variabilis, Tierra Colorado, Vera Cruz. Sceloporus variabilis variabilis, Las Vigas, Vera Cruz.

23. Sceloporus variabilis smithi, Quiengola Mountains, near Tehuantepec, Oaxaca.

24. Sceloporus chrysostictus, Yucatan. Sceloporus squamosus, Tapachula, Chiapas.

25. Sceloporus siniferus, between Rincon and Cajones, Guerrero. Sceloporus siniferus, El Treinte, Guerrero.

5

6 LIST OF ILLUSTRATIONS

26. Sceloporus utiformis, Hacienda El Sabino, Michoacan. Sceloporus utiformis, Uruapan, Michoacan.

27. Sceloporus jalapae, Chazumba, Oaxaca. Sceloporus jalapae, Canada de Morelos, Puebla.

28. Sceloporus nelsoni, Mazatlan, Sinaloa.

29. Sceloporus pyrocephalus, Hacienda El Sabino, Michoacan. Sceloporus pyrocephalus, north of Rio Balsas, Guerrero.

30. Sceloporus pyrocephalus, ventral surfaces of specimens shown in Plate 29.

31. Sceloporus gadoviae, Hacienda El Sabino, Michoacan.

TEXT FIGURES

PAGE

1. The biotic provinces of Mexico 15

2. Nomenclature of head scales of Sceloporus employed in the present paper . 23

3. Phylogeny of the groups of Sceloporus 28

4. Phylogeny of the formosus group 33

5. Distribution of Sceloporus asper, S. salvini, and S. formosus formosus. . . 36

6. Distribution of Sceloporus formosus smaragdinus and S. f. malachiticus

in Central America 42

7. Phylogeny of the spinosus group 59

8. Distribution of the primitive forms of the spinosus group 67

. 9. Head scales of the type of Sceloporus edwardtaylori 79

10. Distribution of Sceloporus melanorhinus, S. spinosus spinosus, and

S. s. caeruleopunctatus 88

11. Distribution of the subspecies of Sceloporus horridus and S. olivaceus ... 99

12. Distribution of the subspecies of Sceloporus clarkii and S. orcutti . . . .120

13. Distribution of the subspecies of Sceloporus magister in Mexico 148

14. Variation in number of femoral pores in the subspecies of Sceloporus

magister 167

15. Phylogeny of the grammicus and megalepidurus groups 178

16. Lateral nuchal scales of Sceloporus grammicus 181

17. Lateral nuchal scales of Sceloporus microlepidotus microlepidotus .... 185

18. Distribution of the forms of the grammicus group 197

19. Distribution of Sceloporus megalepidurus and S. pictus 200

20. Head scales of Sceloporus megalepidurus 205

21. Phylogeny of the poinsettii group 209

22. Head scales of Sceloporus serrifer serrifer 211

23. Distribution of Sceloporus serrifer, S. ferrariperezi, and S. bulleri .... 213

24. Head scales of Sceloporus ferrariperezi ferrariperezi 215

25. Head scales of Sceloporus bulleri 217

26. Head scales of Sceloporus mucronatus mucronatus 218

27. Distribution of Sceloporus mucronatus, S. cyanogenys, and S. poinsettii . .219

28. Head scales of Sceloporus mucronatus omiltemanus 220

29. Head scales of Sceloporus cyanogenys 222

30. Head scales of Sceloporus poinsettii 223

31. Head scales of Sceloporus lineolateralis 225

32. Head scales of Sceloporus jarrovii jarrovii 226

33. Distribution of Sceloporus lineolateralis and S. jarrovii 228

34. Head scales of Sceloporus jarrovii minor 229

35. Head scales of Sceloporus jarrovii immucronatus 231

LIST OF ILLUSTRATIONS 7

PAGE

36. Head scales of Sceloporus ornatus ornatus 232

37. Distribution of Sceloporus ornatus and S. dugesii 233

38. Head scales of Sceloporus ornatus caeruleus 233

39. Head scales of Sceloporus dugesii dugesii 234

40. Head scales of Sceloporus dugesii intermedius 235

41. The postfemoral dermal pocket of Sceloporus variabilis marmoratus . . . 237

42. Phylogeny of the variabilis, maculosus, and merriami groups 238

43. Distribution of Sceloporus couchii, S. teapensis, and S. cozumelae .... 241

44. Head scales of Sceloporus parvus parvus 252

45. Distribution of Sceloporus variabilis 264

46. Distribution of Sceloporus maculosus, S. parvus, and S. merriami .... 284

47. Head scales of Sceloporus maculosus 292

48. Phylogeny of the siniferus group 300

49. Distribution of Sceloporus carinatus and S. siniferus 302

50. Distribution of Sceloporus ochoterenae and S. cupreus 306

51. Head scales of Sceloporus ochoterenae 309

52. Distribution of Sceloporus squamosus 320

53. Distribution of Sceloporus utiformis and S. gadoviae 326

54. Phylogeny of the scalaris group 331

55. Head scales of Sceloporus jalapae 334

56. Distribution of Sceloporus jalapae, S. goldmani, S. scalaris, and S.

chrysostictus 335

57. Distribution of Sceloporus aeneus aeneus and S. a. bicanthalis 357

58. Phylogeny of the pyrocephalus group 362

59. Distribution of Sceloporus nelsoni and S. pyrocephalus 369

THE MEXICAN AND CENTRAL AMERICAN LIZARDS OF THE GENUS SCELOPORUS

BY HOBART M. SMITH1

INTRODUCTION

The lizards of the iguanid genus Sceloporus form one of the largest, most progressive, and most recent groups among the reptiles of the New World. Their evolutionary success is accompanied by great variability, and since distribution is continuous, with frequent inter- gradation through chains of subspecies, and with the further diffi- culty that aberration is sometimes difficult to distinguish from geographic variation, the taxonomy of the genus is especially difficult. Attractive problems in species formation and geographical distri- bution are presented, and their solution is brought within reach by the fact that these lizards are frequently abundant and relatively easy to observe and collect. The problems in this genus were recommended by Cope "as an excellent piece de resistance for those persons who do not believe in the doctrine of derivation of species."

Authors who have dealt with the genus as a whole have disagreed to a surprising extent in their arrangement and evaluation of the species. They tend to extremes, either recognizing individual variants as named forms, or lumping distinct forms under a single name. Boulenger's "Revision of the lizards of the genus Sceloporus" of 1897 may be cited as an example of the lumping tendency and Cope's treatment in "The Crocodilians, Lizards, and Snakes of North America" tends toward splitting. More recently, C. E. Burt has combined under single names species which are here regarded as distinct.

Conditions for a detailed study of the genus are now more propitious than at any previous time; the collections now available far more nearly approach adequacy for the solution of the main problems; and the application of the modern concept of geographic races solves many of the difficulties which perplexed the students of the past century.

The importance of familiarity with the creatures in life, of seeing them in their natural environments, and of having fresh material to study in the laboratory can scarcely be overemphasized. In the course of my own field experience in Mexico, I have had the

1 Walter Rathbone Bacon Scholar, Smithsonian Institution.

9

10 FIELD MUSEUM OF NATURAL HISTORY— ZOOLOGY, VOL. 26

advantage of observing and collecting 69 of the 95 recognized forms in their natural surroundings. Material from certain critical areas is still lacking, and more direct evidence of relationships is frequently to be desired. The conclusions now presented are accordingly tentative.

My studies on the genus Sceloporus began in the fall of 1932, and have been pursued throughout the subsequent years as time per- mitted. Beginning in the attempt to identify specimens collected in Mexico during the summer of 1932, the studies were expanded in following years. With renewed expeditions to Mexico, emphasis has been placed on the Mexican and Central American groups of species within the genus. The subgroups found north of the Mexican border in the United States are being studied in detail by Dr. Clinton V. MacCoy and Dr. Charles E. Burt. Hence the synopsis given here of the undulatus and graciosus groups, which fall mainly within the borders of the United States, is brief.

The Graduate Research Council of Kansas University gave financial aid during the scholastic years of 1934 and 1935, materially contributing to the progress of these studies, and making possible the preparation of many of the drawings. The greater part of the work, however, was completed in 1936 and 1937 during tenure of a National Research Fellowship and while laboratory space in an environment favorable for herpetological research was supplied by the Museum of Zoology of the University of Michigan.

The considerable collections of Mexican reptiles in Field Museum obtained by the Museum's expeditions in 1901, 1903, and 1904 include numerous specimens of various species of Sceloporus. This material was examined at Field Museum in the course of repeated visits. The fresh Mexican collections of this genus made by Dr. E. H. Taylor and myself since 1932 amount to 2,996 specimens. Half of this collection, representing 57 species, and including nine of the types of the new forms described, has been deposited in the reference collections of Field Museum of Natural History.

While not yet as complete as might be desired, this study would never have progressed thus far without the opportunities, aid, and encouragement afforded by the tutor under whose direction the problem was originally undertaken, and who has my deepest appreci- ation— Dr. Edward H. Taylor. I am especially indebted also to Mrs. Helen T. Gaige and Mr. Karl P. Schmidt for many favors and for kindly interest which have been of very material aid.

Numerous other individuals have afforded valuable aid in many ways. I wish to thank in particular Mr. Joseph R. Bailey, Mr.

1939 MEXICAN LIZARDS SMITH 11

Reeve Bailey, Dr. Thomas Barbour, Mr. Charles E. Bogert, Sr. Julio Raymond Bresson, Mr. C. D. Bunker, Dr. Doris Cochran, Mr. David H. Dunkle, Dr. E. R. Dunn, Sr. Emilio del Rio, Dr. H. W. Fowler, Mr. F. M. Gaige, Sr. Pedro Gal van, Dr. Howard K. Gloyd, Dr. Joseph Grinnell, Dr. Norman Hartweg, Mr. C. W. Hibbard, Dr. Howard R. Hill, Dr. Carl L. Hubbs, Mr. C. F. Kauffeld, Mr. L. M. Klauber, Dr. H. H. Lane, Dr. Jean M. Linsdale, Mr. Arthur Loveridge, Mr. John T. Martin, Sr. Rafael Martin del Campo, Mr. and Mrs. Robert Miller, Sr. Adolfo Morales, Dr. Walter Mosauer, Dr. George S. Myers, Mr. Walter L. Necker, Mr. M. Graham Netting, Dr. G. K. Noble, Dr. Isaac Ochoterena, Mr. James A. Oliver, Dr. R. H. Painter, Mr. Benjamin Shreve, Mr. Joseph R. Slevin, Dr. Leonhard Stejneger, Dr. L. C. Stuart, Dr. Vasco M. Tanner, Mr. H. Devlin Thomas, Dr. C. F. Walker, Dr. A. H. Wright, and Dr. A. M. Woodbury.

The drawings have been made by Miss Myra Wildish, Mr. Carol Johnson, Mr. Russell Chezem, and Mr. Maxim Eliashevich, all of the University of Kansas, and by Miss Grace Eager of the University of Michigan. Most of the photographs were taken by Mr. Oren Bingham of the University of Kansas and by Mr. F. W. Ouradnick of Ann Arbor, Michigan. The photographs of preserved specimens were taken by immersing the specimens in water between glass plates. Text figure 55 is reproduced through the courtesy of the Biological Society of Washington; text figures 20, 44, 47, and 51 through the courtesy of the Kansas Academy of Science; and text figures 2, 24, 26, 28-32, 34-36, and 38-40 through the courtesy of the University of Kansas.

Material in the following collections has been examined:

KU Dyche Natural History Museum, University of Kansas.

EHT Collection of Edward H. Taylor.

ERD Collection of Emmett R. Dunn.

KSC Kansas State College, Manhattan.

USNM United States National Museum.

AMNH American Museum of Natural History.

MCZ Museum of Comparative Zoology.

ANSP Academy of Natural Sciences of Philadelphia.

CM Carnegie Museum, Pittsburgh.

UMMZ University of Michigan Museum of Zoology.

FMNH Field Museum of Natural History.

CHS Chicago Academy of Sciences.

UU University of Utah.

12 FIELD MUSEUM OF NATURAL HISTORY— ZOOLOGY, VOL. 26

BYU Brigham Young University.

MVZ Museum of Vertebrate Zoology.

CAS California Academy of Sciences.

LSJU Leland Stanford University.

LAM Los Angeles Museum of Natural History.

LMK Collection of L. M. Klauber.

WM Collection of Walter Mosauer.

SDSNH San Diego Society of Natural History.

The number of specimens included in the scope of this study, in these collections, totals approximately 17,500.

My first opportunity to collect specimens of this genus occurred in the summer of 1929, when I accompanied Dr. and Mrs. Howard K. Gloyd on a brief collecting trip through Kansas, Colorado, and Utah. In the summer of 1930, I again collected with Dr. and Mrs. Gloyd in Texas, New Mexico, Arizona, and California, and in 1931 I accompanied Dr. and Mrs. R. H. Painter in Texas and New Mexico. Introduction to the Mexican forms was made possible by Dr. Edward H. Taylor, whom I accompanied during the summer of 1932 on an expedition covering seventeen central and northern Mexican states. In the summer of 1934 Mr. David H. Dunkle and I again ventured into Mexico, collecting in the northern states. A third trip, which covered most of the other states of Mexico, was undertaken during the summer of 1935. In 1936 Mr. H. Devlin Thomas and I spent several months in Yucatan and Campeche.

GEOGRAPHICAL TRENDS IN VARIATION

Body size and size of scales. In some groups of reptiles there is an apparent decrease in size of scales from the southern part of the range to the northern. Data derived from the present study of Sceloporus do not support this generalization. The forms in which a definite trend toward decrease in size of scales is discernible from south to north are:

Southern Northern

formosus malachiticus /. smaragdinus

acanthinus (southern) acanthinus (northern)

occidentalis biseriatus o. occidentalis

undulatus undulatus u. fasciatus

undulatus tristichus u. elongatus

graciosus vandenburgianus g. gracilis

variabilis variabilis variabilis marmoratus

pictus megalepidurus

There are practically as many cases in which decrease in size of scales takes place in the opposite direction.

1939 MEXICAN LIZARDS SMITH 13

Southern Northern

formosus smaragdimis /. formosus

orcutti licki o. orcutti

spinosus caeruleopunctatus s. spinosus

microlepidotus microlepidotus m. disparilis

parvus scutulatus parvus parvus

pyrocephalus nelsoni

mucronatus omiltemanus m. mucronatus

squamosus (southern) squamosus (northern)

It has also been suggested that scales tend to decrease in size with increase in altitude. While this seems to be true in some cases, there are as many in which it is not true.

No clear examples of reduction of body size from the southern part of the range to the north, or with increasing altitude, can be discerned in the Mexican forms.

In two groups (undulatus and graciosus) progressive decrease in size of scales toward the north and with increase of elevation, and decrease in body size from south to north do seem to be demonstra- ble. These general trends are evidently much more clearly defined in forms occurring north of the 30th parallel. Some members of the poinsettii and spinosus groups, which fail to show this trend, range northward beyond this limit, but they may be disregarded as belong- ing to groups with their principal concentration of species and sub- species farther south. Selection of single factors for such correlations is, of course, inherently erroneous, for it is certain that more than one factor is correlated with scale and body size. In Mexico and Central America, where environmental conditions are relatively stable only over small areas, such correlations are bound to be obscure. In the United States, where large areas have relatively uniform environ- mental conditions, or where changes tend to be more gradual in any given direction, generalizations tend to be more significant.

Trends in breeding habits. All members of the poinsettii, micro- lepidotus, and formosus groups, as well as some (perhaps all) members of the scalaris group, are ovoviviparous. Schmidt (in Hesse, Allee, and Schmidt, 1937) states that microlepidotus is oviparous at the base of Mount Orizaba in Mexico, and viviparous at high levels. This I am inclined to doubt, and Mr. Schmidt and I have searched the literature for the authority for this statement without success.

The species of Sceloporus occurring at high altitudes in Mexico and the southern United States are ovoviviparous, oviparous species being entirely excluded, so far as known. All species occurring at elevations above approximately 10,000 feet belong to one of the three groups of ovoviviparous species. As the elevation is decreased,

14 FIELD MUSEUM OF NATURAL HISTORY— ZOOLOGY, VOL. 26

oviparous species gradually replace the ovoviviparous species in abundance, until at elevations of 1,000 feet or lower, only a few ovoviviparous species occur (e.g., serrifer, poinsettii, cyanogenys, microlepidotus disparilis). It is of interest that Sceloporus parallels in this respect the condition discovered by Weekes (1933) in Australian lizards of the family Scincidae at high altitudes.

BIOTIC PROVINCES OF MEXICO

The position of Mexico is, as generally recognized, intermediate between the Nearctic and Neotropical regions. The Nearctic region includes the plateau and adjacent mountain ranges, Lower California, and the coasts of Mexico southward approximately to the Tropic of Cancer. The Neotropical region extends northward through Central America to the Isthmus of Tehuantepec, and north- ward along both coasts. On the Pacific side, the Neotropical region extends nearly to Mazatlan, and up the Rio Balsas basin to southern Puebla; on the east, it extends well north of Tampico, almost exactly to the Tropic of Cancer.

Two of the generally recognized subregions of the Nearctic occur in Mexico: the Rocky Mountain and the Calif ornian. The Cali- fornian subregion, however, enters Mexico only in extreme north- western Lower California. The Neotropical part of Mexico falls entirely within the "Mexican subregion."

Eighty forms of Sceloporus occur in Mexico. Fifty-six of these are confined to the Nearctic region, and 18 to the Neotropical. Five, which occur in both regions, seem to be essentially Neotropical; two of these enter the Nearctic through the Balsas basin (gadoviae, h. horridus), two over the mountain range south of Lake Chapala (utiformis, horridus oligoporus), and one over the middle of the isthmus of Tehuantepec (variabilis variabilis).

THE NEOTROPICAL PROVINCES

The Mexican subregion is composed of at least seven provinces which are defined by physiographic, climatic, and faunal character- istics. In this summary they are defined largely on the basis of physiography and of data afforded by the distribution of Sceloporus. Climatic data and information on the distribution of other land vertebrates in Mexico, which would be of especial interest for com- parison with the system here proposed, are as yet quite inadequate for this purpose. The provinces of the Mexican subregion (in Mexico) thus defined are as follows: Chiapan Plateau (CP), Lower Balsan (LB), Pete"n (P), Tapachulan (TAP), Tehuantepecan (TEH),

1939

MEXICAN LIZARDS SMITH

15

Vera Cruzian (VC), and Yucatecan (YUC). Definition of these provinces with the scelopori occurring in them follow.

Chiapan Plateau. An elevated region extending westward to the isthmus of Tehuantepec and eastward into Guatemala; its southern edge is marked a few miles inland by a very abrupt, high escarp- ment which increases in elevation toward the Guatemalan border;

FIG. 1. The biotic provinces of Mexico. Boundary of Nearctic and Neo-trop- ical regions shown in red. Abbreviations for the provinces: A, Guerreran; AC^ Austrocentral; AOC, Austro-occidental; AOR, Austro-oriental; AP, A'j^ala^k^n; ^*tf>* ARIZ, Arizonian; CHI, Chihuahuan; CP, Chiapan Plateau; D, Durangan; LB, (J Lower Balsan; OH, Oaxacan Highland; PETEN, PetSn; SIN, Sinaloan; TAM, Tamaulipan; TAP, Tapachulan; TEH, Tehuantepecan; UB, Upper Balsan; VC, Vera Cruzian; YUC, Yucatecan.

the northern boundary is irregular, much excavated by rivers and valleys.1

carinatus formosus smaragdinus variabilis variabilis (VC, AOR)

Tapachulan. A coastal region south of the Chiapan Plateau province, extending from a region just west of the western Chiapas border into Guatemala.

acanthinus squamosus siniferus (TEH, LB)

1 Abbreviations in parentheses refer to other provinces in which the species or subspecies occurs. If no abbreviation is given, the form is restricted to the province for which it is listed.

16 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. 26

Peten. An area north of the Chiapan Plateau province and on the Atlantic drainage of the isthmus, extending northwest along the coast about to the Rio Papaloapam; on the north, approximately to the 20th parallel; on the west, into Guatemala and British Hon- duras.

lundelli lundelli chrysostictus (YUC)

teapensis serrifer plioporus (VC)

Yucatecan. The Yucatan Peninsula north of approximately the 20th parallel.

cozumelae serrifer serrifer

lundelli gaigeae chrysostictus (P)

Vera Cruzian. The coastal region north of Rio Papaloapam approximately to the Tropic of Cancer. The region is defined by the absence of certain species of Sceloporus as much as by the presence of others.

variabilis variabilis (AOR, CP) serrifer plioporus (P)

Tehuantepecan. A semiarid region in Oaxaca, extending south- ward from the Oaxacan Highland and Austroral provinces to the coast, eastward nearly to the Chiapas border, and westward approxi- mately to the Rio Verde.

edwardtaylori siniferus (TAP, LB)

melanorhinus (LB) variabilis smithi

Lower Balsan. An irregularly outlined area, extending along the coast from the Rio Verde in Oaxaca to a region just south of Mazatlan in Sinaloa; the province extends up the Rio Balsas to northern Oaxaca and southwestern Puebla.

horridus albiventris horridus horridus (UB, A)

ochoterenae horridus oligoporus (AOC, AC)

pyrocephalus melanorhinus (TEH)

gadoriae (UB) siniferus (TEH, TAP)

utiformis (AOC)

THE NEARCTIC PROVINCES

The Rocky Mountain subregion of the Nearctic is composed (in Mexico, excluding Lower California) of twelve provinces: Oaxa- can Highland (OH), Guerreran (A), Upper Balsan (UB), Austro- central (AC), Austro-occidental (AOC), Austro-oriental (AOR), Chi- huahuan (CHI), Sinaloan (SIN), Tamaulipan (TAM), Arizonan (ARIZ), Apachian (AP), and Durangan (D).

The Apachian, Durangan, and Sinaloan provinces were proposed by William H. Burt (1938, 39, pp. 1-77, maps 1-26). The Tamauli- pan province is that proposed by J. A. Allen (1892, 4, pp. 241-243)

1939 MEXICAN LIZARDS— SMITH 17

and redefined by Dice1 (1937, 12, pp. 265-268). The Austro-oriental, Austrocentral and Austro-occidental provinces were defined by Cope (1896, 30, pp. 1020-25).

Oaxacan Highland. A small, elevated tract, mostly grassy plains, south of the upper Rio Balsas and the Sierra Oriental ; extend- ing southward approximately to San Pedro El Alto, and to the Rio Tehuantepec on the east.

cupreus jalapae (UB)

spinosus caeruleopunctatus microlepidotus microlepidotus (AC,

formosus formosus (A) AOC, AOR, A)

mucronalus omiltemanus (A)

Guerreran. The southern edge of the plateau south of the Rio Balsas in Guerrero and Oaxaca, northward on the east side along the narrow mountain chain to approximately Mirador, Vera Cruz; southward along the eastern mountain ridge to the isthmus of Tehuantepec.

salvini horridus horridus (UB, LB)

aeneus bicanlhalis (AOR) m. microlepidotus (AC, AOC, AOR,

formosus formosus (OH) OH)

mucronalus omiltemanus (OH)

Upper Balsan. A desert or semiarid region at the upper limits of the Rio Balsas and near the lower end of the interior plateau (Austrocentral) province. This district occupies a definite path of communication between the Neotropical and Nearctic regions.

pictus horridus horridus (LB, A)

gadoviae (LB) jalapae (OH)

spinosus spinosus (AC)

Austrocentral. A broad area on the interior of the Mexican plateau, bordered on the east, south (except the interval noted above), and west by the peripheral mountain ranges; on the north, the district extends nearly to Saltillo on the east, and beyond Dur- ango (city) on the west. The Upper Austrocentral province en- croaches upon the Chihuahuan in the region of northwestern and central Zacatecas.

caulus aeneus aeneus (AOC)

dugesii intermedius horridus oligoporus (LB, AOC)

ferrariperezi melanogasier microlepidotus disparilis (TAM,

goldmani D, AOR)

jarrovii minor m. microlepidotus (AOC, AOR, A,

parvus parvus OH)

scalaris scalaris spinosus spinosus (UB)

Austro-occidental. An area of mountain ridges on the southwest edge of the plateau, extending from northern Nayarit, south of Lake

1 The Potosian province proposed by Dice is apparently the same as that here called the Austro-oriental.

18 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. 26

Chapala, eastward south of Lake Cuitzeo, through the southern part of the Distrito Federal to northwestern Puebla.

asper aeneus aeneus (AC)

bulleri ferrariperezi ferrariperezi (AOR)

dugesii dugesii horridus oligoporus (LB, AC)

heterolepis m. microlepidotus (AC, AOR, A, OH)

scalaris unicanthalis utiformis (LB)

Austro-oriental. Mountainous ridges on the eastern edge of the plateau approximately from Mirador northward to Monterrey.

ferrariperezi binocularis ferrariperezi ferrariperezi (AOC)

jarrovii immucronatus microlepidotus disparilis (TAM, D,

megalepidurus AC)

mucronatus mucronatus m. microlepidotus (AC, AOC, A,

parvus scutulatus OH)

aeneus bicanthalis (A) variabilis variabilis (VC, CP)

Apachian. The mountains on the western edge of the plateau northward from central Chihuahua to southeastern Arizona.

undulatus virgatus jarrovii jarrovii (D)

scalaris slevini (D)

Sinaloan. Coastal region from a short distance south of Mazat- lan to southern Sonora.

clarkii boulengeri nelsoni

Durangan. Mountains northward from central Chihuahua southward to northern Nayarit.

jarrovii jarrovii (AP) microlepidotus disparilis (TAM,

scalaris slevini (AP) AC, AOR)

Tamaulipan. A broad coastal area southward from the Rio Grande approximately to the Tropic of Cancer.

cyanogenys microlepidotus disparilis (D, AC,

olivaceus AOR)

variabilis marmoratus undulatus consobrinus (CHI)

Chihuahuan. The central area north of the Austrocentral province, east of the western mountain ridges, west of the Tamauli- pan province.

couchii ornatus ornatus

lineolateralis ornatus caeruleus

maculosus poinsettii

merriami annulatus undulatus consobrinus (TAM)

magister magister (ARIZ)

Arizonan. Eastern Sonora, southward approximately to the Rio Mayo; northeastern Lower California.

clarkii clarkii magister magister (CHI)

The biotic provinces of Lower California, as supported by data on distribution of Sceloporus, appear to be correctly analyzed by

1939 MEXICAN LIZARDS— SMITH 19

Grinnell (1928). The data furnished by Sceloporus do not, however, add to that already available concerning the island faunas, as Sceloporus does not seem to have developed island species. The only exception is S. m. lineatulus, on Santa Catalina Island, in the Gulf of California. Forms of Sceloporus in the peninsular provinces are as follows: Colorado Desert (m. magister); San Pedro Martir (o. orcutti, graciosus vandenburgianus) ; San Diegan (o. orcutti, o. biseri- atus); Vizcaino Desert (o. orcutti, m. rufidorsum)', San Ignacio (m. lineatulus, m. monserratensis, o. orcutti) ; Cape (m. zosteromus, o. licki).

REGIONAL LISTS

The species and subspecies known to occur in each of the various states of Mexico and in the countries of Central America may be listed, as an aid in the identification of small collections.

AGUASCALIENTES ferrariperezi melanogaster spinosus spinosus

LOWER CALIFORNIA

graciosus vandenburgianus magister rufidorsum

magister lineatulus magister zosteromus

magister magister occidentalis biseriatus

magister monserratensis orcutti licki

orcutti orcutti

CAMPECHE

chrysostictus serrifer serrifer

lundelli lundelli teapensis

CHIAPAS

aeanthinus siniferus

carinatus squamosus

formosus smaragdinus teapensis

mucronatus omiltemanus variabilis variabilis

CHIHUAHUA

clarkii clarkii(l) nelsoni

jarrovii jarrovii poinsettii

magister magister scalaris slevini

microlepidotus disparilis undulatus consobrinus

COAHUILA

cautus olivaceus

couchii ornatus caeruleus

goldmani ornatus ornatus

jarrovii minor poinsettii

merriami annulatus scalaris slevini

microlepidotus disparilis undulatus consobrinus

variabilis marmoratus

COLIMA

dugesii dugesii melanorhinus

formosus formosus microlepidotus microlepidotusCi)

horridus oligoporus pyrocephalus

utiformis

20 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. 26

DISTRITO FEDERAL

aeneus aeneus ocholerenae(l)

ferrariperezi ferrariperezi scalaris scalaris

microlepidolus microlepidotus spinosus spinosus

DURANGO

horridus oligoporus poinsettii

jarrovii jarrovii scalaris scalaris

lineolateralis scalaris slevini

magister magister spinosus spinosus

microlepidotus disparilis undulatus consobrinus

GUANAJUATO

aeneus aeneus microlepidotus disparilis

dugesii intermedius microlepidotus microlepidotus

ferrariperezi ferrariperezi scalaris scalaris

jarrovii minor spinosus spinosus

variabilis variabilis

GUERRERO

aeneus aeneus melanorhinus

asper microlepidotus microlepidolus

formosus formosus mucronatus omiltemanus

gadoviae ochoterenae

horridus horridus pyrocephalus

horridus oligoporus siniferus

utiformis

HIDALGO

aeneus bicanthalis mucronatus mucronatus

ferrariperezi ferrariperezi parvus scutulatus

jarrovii immucronatus scalaris scalaris

microlepidotus disparilis spinosus spinosus

microlepidotus microlepidolus variabilis variabilis

JALISCO

aeneus aeneus horridus albiventris

asper horridus oligoporus

bulleri melanorhinus

clarkii boulengeri microlepidotus microlepidolus

dugesii dugesii nelsoni

dugesii intermedius pyrocephalus

ferrariperezi melanogaster scalaris scalaris

formosus formosus(l) scalaris unicanthalis

heterolepis spinosus spinosus

utiformis

MEXICO

aeneus aeneus microlepidotus microlepidotus

ferrariperezi ferrariperezi mucronatus mucronatus

jarrovii minor scalaris scalaris

spinosus spinosus

MICHOACAN

aeneus aeneus horridus oligoporus

asper melanorhinus

dugesii intermedius microlepidotus microlepidotus

ferrariperezi ferrariperezi pyrocephalus

ferrariperezi melanogaster scalaris scalaris

gadoviae spinosus spinosus

utiformis

1939 MEXICAN LIZARDS— SMITH 21

MORELOS

aeneus aeneus horridus horridus

ferrariperezi ferrariperezi microlepidotus microlepidotus

gadoviae ochoterenae

siniferus

NAYARIT

asper jarrovii jarrovii

clarkii boulengeri melanorhinus

dugesii dugesii nelsoni

horridus albiventris scalaris unicanthalis

utiformis

NUEVO LEON

couchii olivaceus

cyanogenys parvus parvus

ferrariperezi binocularis poinsettii

jarrovii minor scalaris slevini

microlepidotus disparilis undulatus consobrinus variabilis marmoratus

OAXACA

aeneus bicanttialis melanorhinus

cupreus microlepidotus microlepidotus

edwardtaylori mucronatus omiltemanus

formosus formosus salvini

gadoviae siniferus

grammicus spinosus caeruleopunctatus

horridus horridus teapensis

jalapae variabilis smithi

variabilis variabilis

PUEBLA

aeneus aeneus microlepidotus microlepidotus

aeneus bicanthalis mucronatus mucronatus

ferrariperezi ferrariperezi mucronatus omiltemanus

gadoviae pictus

horridus horridus scalaris scalaris

jalapae spinosus spinosus

megalepidurus variabilis variabilis

QUERETARO jarrovii immucronatus variabilis variabilis

SAN LUIS POTOSI

cautus microlepidotus disparilis

ferrariperezi melanogaster parvus parvus

goldmani parvus scutulatus

jarrovii minor spinosus spinosus

variabilis variabilis

SINALOA

clarkii boulengeri nelsoni

horridus albiventris utiformis

SONORA

clarkii boulengeri magister magister

clarkii clarkii nelsoni

jarrovii jarrovii scalaris slevini

undulatus virgatus

22 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. 26

cyanogenys

microlepidotus disparilis olivaceus

aeneus bicanthalis

ferrariperezi ferrariperezi

formosus formosus

jalapae

jarrovii immucronalus

megalepidurus

TABASCO

teapensis

TAMAULIPAS

serrifer plioporus spinosus spinosus variabilis marmoratus variabilis variabilis

VERA CRUZ

mucronatus mucronatus

mucronatus omiltemanus

pictus

salvini

serrifer plioporus

spinosus spinosus

microlepidotus microlepidotus teapensis

variabilis variabilis

YUCATAN

chrysostictus cozumelae

cautus

ferrariperezi melanogaster horridus oligoporus jarrovii jarrovii

lundelli gaigeae serrifer serrifer

ZACATECAS

jarrovii minor microlepidotus disparili scalaris scalaris spinosus spinosus

chrysostictus

acanthinus

formosus smaragdinus

lunaei

lundelli lundelli

serrifer plioporus

acanthinus formosus malachiticus

formosus malachiticus formosus smaragdinus

formosus malachiticus

formosus malachiticus

undulatus consobrinus

BRITISH HONDURAS

lundelli lundelli teapensis

GUATEMALA

siniferus squamosus teapensis

variabilis olloporus variabilis variabilis

SALVADOR

squamosus variabilis olloporus

HONDURAS

squamosus variabilis olloporus

NICARAGUA

squamosus variabilis olloporus

COSTA RICA

squamosus variabilis olloporus

PANAMA

formosus malachiticus

1939

MEXICAN LIZARDS SMITH

23

METHOD OF TREATMENT

The detailed description of each species is drawn up on a definite plan, from which there is little departure. The descriptions of scutellation are arranged in seven paragraphs, each of which con- siders a certain set of characters. The general plan, with an evalu- ation of the characters, follows.

Rugosity and pitting of head scales. Of varying importance.

Frontal ridges. Two distinct, rounded ridges originating on the frontal and diverging anteriorly, enclosing between them a distinct depression in the median prefrontal area. Members of the formosus group exhibit these structures most clearly.

toculars

superciliaries

preocular

canth -loreal /nasal

',supralabials '/astral

nfralabials

mental

labiomentals (outir TOD) •-posbmentals

_ labiomanta!s(mniriou)

lorilobioh

- suboculor

infralabials

'---&• postmental s " ^' ,-tabiom«ntals (outer rouj •'^tobiomcntals^mntr rouj

rostral internasals

; - subnasal

7.7--— -nasal feVLl!"'- canbhols "~ frontonasals '-"•pref rentals frontal, ant. part supardliarica - frontal, post.part frontoparicbal parietal interpari«tal

FIG. 2. Nomenclature of head scales of Sceloporus employed in the present paper (based on S. ferrariperezi melanogaster).

Interparietal (occipital). A large median scale at the posterior edge of the head, always single, with a spot marking the position of the parietal foramen. The scale is usually subquadrate, and its rela- tive size is of some importance. The interparietal is relatively quite large at birth, and gradually decreases in proportionate size as the animal attains greater age. In species which attain greatest size, the interparietal is relatively the smallest.

Parietals. A single, subtriangular parietal usually borders the interparietal on each side. Occasionally in some species, regularly in others, a second, enlarged, convex parietal occurs posterior to the first.

24 FIELD MUSEUM OF NATURAL HISTORY— ZOOLOGY, VOL. 26

Frontoparietals. A single pair of small, rectangular fronto- parietals normally precedes the parietals, separating the interparietal from the row of scales about the supraoculars. The frontoparietals may contact each other medially, or may be separated either by an azygous scale or by contact of the frontal with the interparietal. In some species the frontoparietals are usually divided into four scales.

Frontal. A large scale between the orbits, normally trans- versely divided into two sections, the anterior somewhat larger than the posterior. In ornatus the tendency is to lose the posterior portion of the frontal, probably by fusion with adjacent scales. In poinsettii the frontal is usually broken irregularly into several scales. It is significant that in species of the poinsettii group in which the supraoculars are in two rows, the frontal rarely touches the interparietal. The reverse is the case in species having a single row of supraoculars. Some species are characterized by having the anterior section or the entire frontal longitudinally divided.

Supraoculars. A series of enlarged scales above the orbit, in some species divided irregularly, in others in two regular rows, and in still other species quite large and entire. Between them and the median head scales there is usually a single row of small scales which may or may not be complete; the number of supraoculars in con- tact with the median head scales is of great importance in certain groups, particularly the spinosus group. Between the supraoculars and superciliaries there may be one, two, or three complete or incom- plete rows of small scales. The number of rows is of importance; in edwardtaylori, for instance, there is but one, nearly obsolete row.

Superciliaries. Six superciliaries are always present, the first four imbricating posteriorly, the fifth completely hidden below the' fourth, and the sixth overlapping the posterior part of the fourth. They are occasionally subdivided.

Prefrontals. Two rather large scales preceding the frontal, in contact medially, or separated either by contact of the median frontonasal with the frontal or by an azygous scale.

Internasals. Two or four pairs of internasals is apparently the normal condition, but this arrangement is seldom realized. The scales are usually irregularly divided.

Postrostrals. A row of two to six scales between the rostral and the nasals and internasals; sometimes further subdivided. The num- ber, whether two or more, may be significant. Some species have none, the nasals and internasals being in contact with the rostral.

1939 MEXICAN LIZARDS— SMITH 25

Subnasal. A relatively large scale immediately below the nasal, in contact with the anterior can thai and loreal. It is regularly absent in some species.

Canthals. One or two scales on the canthus rostralis. The number is of taxonomic importance. In some species the anterior is frequently forced above the canthal ridge by contact of the subnasal and posterior canthal.

Loreal. A small scale below the canthals, in contact anteriorly with the subnasal and posteriorly with the preocular. It may rarely be divided into two or three scales. The first canthal occasionally separates the loreal from the subnasal and contacts the rows of scales above the supralabials.

Preocular. A small scale, with a heavy keel near its upper pos- terior edge, split off from the anterior end of the subocular. The preocular is, in some species, divided longitudinally.

Subocular. A large, curved, elongate scale immediately below the eye, with a heavy keel near its upper edge.

Postoculars. Variable, usually two. They follow the subocular, curving posteriorly and upward at the edge of the orbit, and are usually distinguished from the adjacent temporal scales by being keeled and somewhat larger.

Lorilabials. The small scales above the supralabials. They are in one or two rows; if the latter, they may be reduced to one at some point below the subocular. One of these rows continues about the snout as the postrostrals in most species.

Supralabials. The scales on the upper labial border, excluding the scale at the tip of the snout. The scales of this series are smooth and as a rule nonimbricate, but in certain species are rather strongly imbricate and may be rugose or keeled.

Infralabials. The scales on the lower labial border, excluding the scale at the mandibular symphysis. The scales of this series are similar in character to the supralabials.

Mental. A median anterior pentagonal or triangular scale bordering the lip.

Postmentals. A series of enlarged scales on each side posterior to the mental. The scales are paired; those of the anterior pair are separated from each other by a varying number of scales. The number of postmentals is irregular and of little taxonomic significance.

26 FIELD MUSEUM OF NATURAL HISTORY— ZOOLOGY, VOL. 26

Labiomentals. Usually two, sometimes one, series of scales on each side between the postmentals and infralabials. In some species the anterior scale of the outer row may contact the mental, and this condition is of some taxonomic significance. Whei*»the anterior scale of the outer row is separated from the mental, it is only by narrow contact of the first infralabial with the first postmental. The inner row of labiomentals, when present, never extends as far forward as the outer row, and the position at which it terminates, in relation to the infralabials, is of considerable taxonomic significance.

Gular scales. The modifications such as carination, mucrona- tion, and denticulation of these scales, as well as their relative size, are important.

Auricular lobules. These are the scales on the anterior border of the ear. Their number and relative size are important in some species.

Temporals. The modifications and relative size of these scales are important.

Lateral nuchal pocket. A dermal pocket between the