JOURNALOF PALEONTOLOGY,V. 39, NO. 3, P. 379-382, PL. 54, MAY 1965

AN ANOLIS (SAURIA, IGUANIDAE) IN AMBER JAMES D. LAZELL, JR. The Museum of Comparative Zoology Cambridge 38, Massachusetts

ABSTRACT-Anoliselectrum sp. nov.-described on the basis of two partial specimens in amber from Chiapas, Mexico-is believed to be Oligocene or Miocene in age. It is thus the earliest record of this lizard genus. The new species has the characteristic digital pads of Anolis very well developed and is unique in combining small, uniform middorsals, smooth, subimbricate ventrals, and small scales around the interparietal with unicarinate limb scales.

INTRODUCTION a general survey of what is known about Chiapas amber here. The two cited how- OME time ago Robert C. Stebbins, of the papers above, are to such a to Museum of Vertebrate Zoology, brought to ever, precedent general survey be undertaken to the detailed the attention of Ernest E. Williams, of the Mu- subsequent reports of on the various and animal seum of Comparative Zoology, the occurrence of specialists plant remains of the lizard Anolis in two blocks of inclusions, of which the present paper is an Chiapas amber. This discovery is believed to example. constitute the first authentic record of reptilian SYSTEMATIC DESCRIPTION remains in amber. The specimens were sub- ANOLIS ELECTRUM1sp. nov. sequently loaned to the Museum of Compara- P1. 54, figs. A,B tive Zoology through the kindness of Paul D. loc. the en- -Hurd, Jr., of the Department of Entomology, Type.-UCMP 648496, B-7047-1, tire hind and of the left hind Museum of Paleontology, University of Cali- right limb, portions limb and imbedded in amber fornia, Berkeley (UCMP). trunk, (see pi. 54, Langenheim (1964, p. 259-276) has sum- fig. B) the Chi- marized present information and thought on Type locality.-"From Simojovel, Mexico Chiapas amber from a botanical viewpoint, and apas, area; precise locality unknown, but in view of known occurrences in the Hurd, Smith, and Durham (1962) have done area, of latest Miocene the same from a zoological viewpoint. At present probably Oligocene-early age, but as as mid-Miocene." there is little that can be said in a general and possibly young (fide Museum of synthetic way about Chiapas amber that clari- J. Wyatt Durham, Paleontology, of fies the situation of the new species. Hurd (pers. University California, Berkeley.) loc. comm.) reports that the fossils were recovered Paratype.-UCMP 68497, B-7047-3, por- tions of the and forelimbs imbedded from a lot of amber purchased from local people head, trunk, in amber. Same data as the at Simojovel; for this reason I am unable to type. provide precise details on the type locality of 1 Electrum, Latin for amber, is here used as a the new species, and certainly I cannot attempt noun in apposition to the generic name Anolis

EXPLANATION OF PLATE 54 FIGS. A,B-Anolis electrumsp. nov. A, Portions of head, trunk, and forelimbs (paratype, UCMP B-7047-3). B, Portions of posterior trunk and hind limbs (type, UCMP B-7047-1). Parts of the photographsof the amber blocks not containing Anolis have been trimmed from the photographs. Photos by Frank White, Department of Biology, Harvard University. 379 JOURNALOF PALEONTOLOGY,VOL. 39 PLATE54 J. D. Lazell, Jr.

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Diagnosis.-Interparietal scale bordered pos- surface of the forearm are largest, being but teriorly by small scales blending into dorsal slightly smaller than the ventrals. granules; no enlargement or other modification The head, at the level of the interparietal, of the middorsal scales; dorsal granules uniform measures ca. 4.8 mm.; the upper arm ca. 3.9 from nape to rump; ventrals smooth, swollen, mm.; the forearm ca. 3.2 mm.; the foot ca. subimbricate, arranged in transverse rows, and 3.6 mm. twice as large as dorsals; limb scales unicarinate; Size.-From the measurements obtained from those of anterior surface of forearm nearly as the type the proportions can be reasonably large as the ventrals, those of anterior surface of judged; it seems evident that the paratype hind limb smaller than ventrals, but larger than represents an individual of the same size as the dorsal granules; digital pad and dilation pro- type, and it may be the same individual (see nounced; 21 or 22 lamellae under second and below). Anolis electrum seems to have been an third phalanges of fourth toe. anole of unspecialized proportions; the type, Description on the type.-The thigh is ca. a hatchling, probably measured between 26 mm. 5.2 mm., the lower leg ca. 4.1 mm., the distance and 31 mm. in snout-vent length. Comparison from the heel to the tip of the fourth toe ca. to modern forms whose juveniles show a similar 7.0 mm. The digital dilation is ca. 0.9 mm. at degree of yolk-sac scarring at comparable size the widest part. The trunk, at the level of the (e.g. A. fuscoauratus or A. chloris) indicates that hind limbs, is ca. 3.0 mm. in diameter. Anolis electrum probably did not grow larger The dorsal granules extend onto the dorsal than 70 mm. This is not a large Anolis. surface of the hind limb and become gradually Comparisons.-Anolis is perhaps the largest flattened and subquadrangular. These scales genus of living reptiles and is certainly one of become larger and subimbricate anteriorly and the largest living amniote genera. However, distally, those along the tibia being distinctly since the vast majority of known species in this larger than the dorsals, imbricate, and unicari- extremely diversified group show some sort of nate. The supradigital scales are imbricate and modification of middorsal, ventral, interparietal, multicarinate. The digital dilations are of the or limb squamation, identification and com- "raised" type of Boulenger (1885) and Williams parison of the fossils is greatly facilitated. Mid- (1963); that is, the digital pad and its lamellae dorsals may be in an enlarged zone of many extends beyond and "above" the proximal scales, a double row of aligned scales, or a scales of the fourth phalanx. single row. They may be flattened, tectiform, Precise determination of the number of sub- carinate, or spike-like. Ventrals may be flat- digital lamellae under the second and third tened, tectiform, or carinate. The scales around phalanges is difficult without being able to the interparietal may be variously enlarged, move the toe. Nevertheless, there are at least plate-like, swollen, tectiform, or carinate. Limb 21 and perhaps 22 under these phalanges of the scales are often multicarinate. Many modern fourth toe. species of Anolis combine modifications in each The ventrals are smooth, subimbricate, swol- of these areas of squamation. len, and arranged in transverse rows. There is a There are, therefore, few living forms in which distinct yolk-sac scar at the midline of the ab- the combination of characters seen in Anolis domen, indicating that this individual was a electrum is at all closely approached. For ex- hatchling. ample, living species like tigrinus, solitarius, and The ventrals are abruptly distinct from the nasofrontalis, though they have middorsals, dorsal granules, which are uniform and one ventrals, and limb scales basically similar to half the size of the ventrals. those of electrum, possess strikingly enlarged The paratype.-The anterior portions in and otherwise modified scales around the inter- 68497, here designated as paratype, add con- parietal. Species like limifrons, polylepis, ortoni, siderable useful information. The complete antoni, and leptoscelis, though they resemble the absence of modified middorsals is confirmed by fossils in the scales around the interparietal, ven- examination of the shoulder and nape regions. trals, and limb scales, possess distinctly enlarged Although the scales bordering the interparietal and otherwise modified middorsals. Some, like posteriorly are larger and flatter than the dorsal leptoscelis, differ as well in having narrow digital granules, they are still quite small; there is a dilations and low lamellae counts. gradual transition from them into the dorsal Both Anolis fuscoauratus and A. maculiventris granules, rather than any sharp demarcation are very close to A. electrum. There is virtual between occipital plates and dorsal granules. agreement with respect to middorsals, ventrals, The forelimb scales become immediately large, scales around the interparietal, and limb scales. imbricate, and unicarinate. Those on the radial Each of these, however, differs from A. electrum AN ANOLIS IN AMBER 381

in having comparatively narrow digital dilations the penultimate phalanx, and actually overlies and consistently less than 19 lamellae under the the proximal squamation of the terminal pha- second and third phalanges of the fourth toe. lanx. This is the "raised" condition mentioned Anolis chloris, on the other hand, resembles above, and the condition demonstrated defini- A. electrum in ventrals, scales around the inter- tively in Anolis electrum. parietal, limb scales, digital dilations, and num- It is unusual in vertebrate paleontology ber of subdigital lamellae. As in the fossil, the when structures other than bones can be com- middorsals of A. chloris are not notably enlarged; pared. In this case, however, only the skin and these middorsals are, however, aligned in a its squamation remain; the fossils were pre- distinct double row. Despite this difference, it served in amber, and apparently initially im- is entirely possible that Anolis chloris is the bedded in such a way so that there was access closest living relative of Anolis electrum. to the internal structures for decay and other degenerating agents. If vertebrae or portions DISCUSSION of the skull were available, it would be much Whether or not we are dealing with two indi- easier to relate this fossil form more precisely viduals, or merely two portions of the same to species of living Anolis. individual, is debatable. Not only do the type Anolis electrum gives every indication of being and paratype indicate similar size and propor- a thoroughly arboricolous form; well developed tions, but the two blocks would seem to fit digital dilations and comparatively high la- rather closely together. In both blocks the mellae counts, for a rather small species, are trunk shows evidence of twisting, so that if excellent evidence of arboreal habits. This inter. they do in fact represent a single individual it pretation is corroborated by the very fact that is not remarkable that the right side posteriorly this hatchling became entrapped in an amber- and the left side anteriorly are the best pre- forming tree resin (Langenheim, 1964). served. Thus the evidence is not inconsistent Anolis today is not only a very large and di- with the opinion that a single individual is verse genus, but a widely distributed one as represented. well. Anoles occur throughout most of tropical It is evident from degree of the differences and coastal Mexico, all of Central America and noted that, insofar as it can be compared, Anolis the West Indies, over most of tropical South electrum is not remarkably different from some America, the southern United States, and even - species of Anolis living today despite the on such eastern Pacific islands as Malpelo and fact that it may be as much as 28 million years Coco. Of the three forms apparently closest to old. Auffenberg (1957), Tihen (1962), and Estes Anolis electrum, however, none occurs in south- (1962) have all noted the presence of reptile or ern Mexico or Central America today. A. fusco- amphibian forms in the Miocene, or even earlier, auratus is widely distributed over northern that belong to recent species groups. In the South America east of the Andes. A. maculi- case of Anolis, however, it should be noted that ventris and A. chloris are both forms from the this genus, and its close allies, represent a Choco region of coastal Colombia, though the specialized and homogeneous subgroup of the latter occurs southward into Ecuador. Of all family Iguanidae, and that this family is not the anoles closely comparable to electrum, only known prior to the Upper Cretaceous (see one, A. limifrons, occurs in southern Mexico Romer, 1956, p. 534). today; it is very close to A. fuscoauratus and Some of the external generic characters of extends southward to Panama. In this form the Anolis have been discussed by Williams (1963). dorsals enlarge gradually towards the midline, Regrettably, the paratype of A. electrum ap- where they are aligned to form a noticeable, parently represents a hatchling, and therefore double, middorsal row. All other species of the absence of a throat fan, or dewlap, is to be Anolis currently known from Mexico differ so expected. The condition of the digital pad, markedly from A. electrum that comparison is however, is worthy of comment. not called for. Among living lizards only geckos and anoles show dilations under the penultimate phalanges ACKNOWLEDGMENTS that form pads. These pads show various ar- Thanks are due to Dr. Stebbins for the first rangements in geckos, but anoles consistently intimation of this remarkable discovery; to Dr. possess a single series of overlapping, trans- Hurd for the generous loan of the specimens; versely arranged scales-the subdigital lamellae. to Dr. J. Wyatt Durham for detailed informa- It is common among anoles for this pad, with tion on the horizon and preparation of the its lamellae, to be sufficiently well developed fossils; to Dr. Jean Langenheim for comments so that it protrudes beyond the distal end of on the amber itself; and to Dr. E. E. Williams 382 JAMES D. LAZELL, JR. for advice and for permission to examine com- of Kenya (Reptilia: Cordylidae): Breviora (Mus. v. 1-10. material. The photographs of the type Comp. Zool.) 158, p. parative HURD, P. D., R. F. SMITH, and J. W. DURHAM, and paratype were prepared by Frank White. 1962, The fossiliferous amber of Chiapas, Mexico: This work was supported by National Science Ciencia, v. 12, p. 161-163. Foundation Grant G 16066. LANGENHEIM, J., 1964, Present status of botanical studies of ambers: Bot. Mus. Leaflets Harvard Univ., v. 20, p. 225-287. Tx- - _ A c, Irx ,r r' x - 1 - ,- f - , REFERENCES KOMER, A. '., 19Y0, usteoiogy ot tne Keptiles: University of Chicago Press, xxi +772 p AUFFENBERG, W., 1957, Notes on fossil crocodilians TIHEN, J. A., 1962, A review of new w orld fossil from the southeastern United States: Quart. Journ. bufonids: The American Midland Nat uralist, v. Florida Acad. Sci., v. 20 (2), p. 107-113. 68, p. 1-50. BOULENGER,G. A., 1885, Catalogue of the lizards in WILLIAMS, E. E., 1963, Studies on South American the British Museum (Natural History): v. 2, 497 p., anoles: Bull. Mus. Comp. Zool., v. 129, p . 463-480. London. ESTES, R. 1962, A fossil gerrhosaur from the Miocene MANUSCRIPTRECEIVED JANUARY 21, 1964