ISSN 0327-9375 COMPARATIVE STUDIES OF SUPRAOCULAR LEPIDOSIS IN SQUAMATA (REPTILIA) AND ITS RELATIONSHIPS WITH AN EVOLUTIONARY TAXONOMY ESTUDIOS COMPARATIVOS DE LA LEPIDOSIS SUPRA-OCULAR EN SQUAMATA (REPTILIA) Y SU RELACIÓN CON LA TAXONOMÍA EVOLUCIONARIA JOSÉ M. CEI † las subfamilias Leiosaurinae y RESUMEN Enyaliinae. Siempre en Iguania Observaciones morfológicas Pleurodonta se evidencian ejemplos previas sobre un gran número de como los inconfundibles patrones de especies permiten establecer una escamas supraoculares de correspondencia entre la Opluridae, Leucocephalidae, peculiaridad de los patrones Polychrotidae, Tropiduridae. A nivel sistemáticos de las escamas específico la interdependencia en supraoculares de Squamata y la Iguanidae de los géneros Iguana, posición evolutiva de cada taxón Cercosaura, Brachylophus, considerado en los cladogramas Conolophus, puede llevar a propuestos por Estes et al. (1988). postular pretéritos acontecimientos Aparte del significado biológico paleogeográficos. También amerita general de estos hallazgos, incluso énfasis la llamativa separación, para discutidas orientaciones según este criterio morfológico, en- taxonómicas, la lepidosis tre Iguania y Scleroglossa, la supraocular llega a refrendar una uniforme lepidosis de centenares de decisión sistemática con su Gekkota, o la excepcional fisonomía evidencia. Así, en Iguania, la familia de Autarchoglossa, en sus ramas tan Leiosauridae, propuesta por Frost individualizadas de Scincomorpha et al. (2001), aparece sostenida (Lacertoidea; Teiioidea; hasta en el detalle de su división en Scincoidea) o Anguimorpha. MULTEQUINA 16: 1-52, 2007 1 Palabras clave: diagnosis, INTRODUCTION escamas supraoculares, pa- The selection of significant somatic trón específico lepidosis, morphological characters (shape, Pleurodonta, Squamata, size, structure) will play an essential taxonomía role in providing a systematic herpetological arrangement, at least SUMMARY to species level: furthermore it can Former observations on apply also to more elevated ranks characteristic patterns of supraocular of the herpetological classification. scutellation in different specific or We are pointing out here some supraspecific taxa of Squamata are interesting aspects of the so-called extended and analyzed in this general lepidosis, or cutaneous scale critical review. A relationship covering of Reptilia, mainly in between a defined morphological Lacertilian lizards. More exactly, supraocular lepidosis in a particular the differentiated scales bilaterally taxon and its evolutionary position located in the supraocular region of in a classificatory system, such as the the head, bounded inside by the cladograms obtained by Estes et al. orbital semicircles, and by the (1988), was tested and confirmed. ciliary eye border outside (Figure Supraocular scales of Squamata are 1). Given the noticeable position of not morphological elements at these supraocular scales in the head random, but can be assumed as scutellation of Squamata, their morphological scale characters, presence has generally been useful in systematic comparative reported in many diagnostic examinations and able to strengthen descriptions of species. some discussed new systematic Nevertheless, no true emphasis was assessments, such as the family status ever placed on their peculiar of Leiosauridae and its subfamilies taxonomic significance: either as in Pleurodont Iguanians, proposed an important generic characteristic by Frost et al. (2001), as well as in structure of the dorsal head several other cases. lepidosis, or as distinctive supraocular patterns in separated systematic groups, from different Key words: Squamata, genera to families and higher supraocular scutellation, categories. A preliminary paper was specific lepidosis pattern, provided on this matter (Cei, 2003), diagnosis, Pleurodonta, dealing with supraocular scales in taxonomy species and genera of Iguania, as 2 José M. Cei 1 2 4 3 Figure 1. Sketched fundamental morphology of supraocular scutellation in Squamata, Pleurodonta: 1. supraorbital semicircles, 2. supraocular scales, 3. intermediate supraorbital scales and 4. superimposed superciliaries Figura 1. Esquema fundamental de la morfología de la escutelación supraocular en Squamata, Pleurodonta: 1. semicírculos supraorbitales, 2. escalas supraoculares, 3. escalas supraorbitales interme- dias y 4. superciliares superimpuestos well as in some far-away taxonomic Reptiles, besides a preliminary categories, such as Scleroglossa paper (Cei, 2003), deal with Teiid lizards. Thus, considering the circumorbitals in one row or in two remarkable number of past and rows between supraoculars and recent species descriptions, a median head shields, as emphasized detailed review and discussion of in Frost‘s (1992) taxonomic such a noticeable but still revision of Tropidurus groups of disregarded anatomical peculiarity lizards that points out could be a very interesting job, discrimination among the genera postulating a distribution pattern Uranoscodon, Microlophus, not at random but in agreement Plesiomicrolophus and Tropidurus. with the phylogenetic subdivisions Likely in Etheridge‘s (1970) of well-known modern comparative research the classificatory essays. systematic differences in supraciliaries were suitably applied Some isolated reports about to discriminate Plica and specific supraocular scutellation in Uranoscodon from other members MULTEQUINA 16: 1-52, 2007 3 of the Tropidurus groups. However, Museo de Zoologia, Universidade apart from these interesting but de São Paulo, Brasil; MCZ: limited citations, a whole zoological Museum of Comparative Zoology, discussion and critical valuation of Harvard University, Cambridge, lacertilian supraocular scutellation USA; NMNH: National Museum is yet wanting to our knowledge. of Natural History, Smithsonian The present work will attempt to Institution, Washington, USA; reach better and conclusive FMNH: Field Museum of Natural information on such a suggestive History, Chicago, USA; MNHN and little analyzed subject. Paris: Museum Nationale Histoire Naturelle, Paris; UNNE: MATERIAL AND METHOD Universidad Nacional del Nordeste, Corrientes, Argentina. Given the aim of this work, its outcome is a detailed representation Given the Figures including the of the postulated relationships total samples drawn that support our between the supraocular present report and discussion, a scutellation patterns and the separated list of the examined taxonomic categories of Squamata. specimens would be prolix and Our comparative graphic unnecessary. Moreover the general documentation, exposed in Figures, localities of samples were was mainly obtained from careful opportunely indicated in the Figures. observations and drawings of When it was necessary, preserved specimens, or in some morphological details of the lizards case from careful adaptations of were drawn under a dissecting controlled reproductions by reliable microscope. Peter‘s Dictionary authors. The available materials (1964) was a reference for above all have been the specimens morphological and anatomical of a personal collection (JMC-DC: nomenclature, as well as the several José M. Cei Diagnostic Collection), Etheridge‘s papers, i.e. his occasionally complemented by past Ctenoblepharis adspersa studies of species from the redescription (1995). The drawings Herpetological Collections of some of the Figures have been all more or Museums or Scientific Institutions less slightly magnified: we believe whose list and acronyms are that individual magnification of following. IBA-UNC: Collections symbols in every identified drawing of the Instituto de Biología Animal, scale is useless to our purposes. Universidad Nacional de Cuyo, Besides the specimens documented Mendoza, Argentina; MZUSP: in the Figures, hundreds of specimens 4 José M. Cei corresponding to the patterns have phylogenetic indented taxonomy been observed and compared, for exhibited in the valuable conclusive improving the truthfulness and statements by Estes et al. (1988) significance of our samples. was considered as a suitable model Among the most important (Figure 2), together with the literature supporting the harvesting, reassessment of Iguania by Frost et arranging and discussion of our al. (2001). Such taxonomy has been representative samples, we wish to followed here for comparison with highlight the useful, good or our detailed morphological outstanding papers or reviews by observations, far away from any Anderson (1999), Angel (1942), aprioristic personal opinion. Then, Blarc (1977), Brygoo (1971, 1978), without disregarding other Dixon (1973), Donnelly and Myers interesting systematic contributions, (1991), Greer (1970), Grismer et as the recent paper by Schulte et al. al. (1994), Haas and Werner (1969), (2003), in full agreement with our Halliday and Adler (2002), findings, we recognize the taxon Hoogmoed (1973), Kluge (1974), Pleurodonta and its included Leviton et al. (1992), Mertens families as in the mentioned Frost (1958, 1959), Pregill (1992), Ruibal et al.’s (2001) arrangement. On the (1964), Savage (1963), Tayer contrary, the opposite general taxon (1956), Van Demburg (1978), Iguanidae (sensu Boulenger, 1895) Vanzolini et al. (1965, 1980) and postulated in the paper by Schulte Wiens (1993). et al., based on bio-molecular and morphological researchs, is fully discordant with our results. RESULTS In the following 27 Figures, Analytical review of comparative specific supraocular scutellation reports on supraocular lepidosis in patterns belonging to genera