The systematic relationships of Dravidogecko anamallensis (GÃ¼nther 1875)

I June 1995 Asiatic Herpetological Research Vol. 6, pp. 30-35 The Systematic Relationships of Dravidogecko anamallensis (Gunther 1875) AARON M. BAUER 1 AND ANTHONY P. RUSSELL 2 1 Biology Department, Villanova University, Villanova, Pennsylvania 19085, USA 2 Vertebrate Morphology Research Group, Department of Biological Sciences, University of Calgary, 2500 University Drive N.W., Calgary, Alberta, Canada T2N 1N4 Abstract. -The relationships of the monotypic gekkonine genus Dravidogecko are assessed by comparative evaluation of its external and internal morphology. A suite of shared-derived features is possessed by Hemidactylus and a variety of satellite genera, including Dravidogecko. These similarities are advocated as being so compelling, and the ostensible defining features of Dravidogecko to be so weak that the latter is subsumed as a junior synonym of Hemidactylus. The biogeographic consequences of this taxonomic shift are considered. Key words: Dravidogecko, Hemidactylus, Teratolepis, digits, scansors, phalanges, paraphalangeal elements, muscles, biogeography, India. Introduction Dravidogecko is a monotypic genus of gekkonid lizards endemic to south India. The single species, D. anamallensis, was originally described as a member of the genus Hoplodactylus (Gunther, 1875; Strauch, 1887), but following the work of Smith (1933), it was assigned to a new genus, primarily on the basis of differences in the distal scansors and in preanal pore arrangement. Subsequently it has been demonstrated that Dravidogecko is a gekkonine gecko, whereas Hoplodactylus sensu stricto is a diplodactyline (Underwood, 1954; Kluge, 1967). The relationships of Dravidogecko have remained obscure, and the systematic status of the species has never been investigated adequately. It is known from only a few specimens from the Anaimalais, Palnis and Tirunelveli Hills (Satyamurti, 1962; Murthy, 1985) but is reportedly widely distributed throughout forested areas of southern peninsular India (Daniel, 1983). Russell (1972) considered Dravidogecko to belong, on morpho-functional grounds, in the Hemidactylus group, along with Hemidactylus, Briba, Teratolepis and Cosymbotus. Kluge (1983) placed it, along with the other gekkonine genera previously mentioned, in the tribe Gekkonini on the basis of the absence of the second ceratobranchial arch. Russell (1976: 238; Fig. 14) suggested that Dravidogecko had a digital structure that was most closely approached by that of Hemidactylus and its close allies. While external form of the digits is particularly sensitive to functional demands and thus prone to exhibiting convergence and parallelism (Russell, 1979), details of the internal anatomy are much more helpful at indicating true homology and, therefore, affinity (Russell, 1976, 1979; Russell and Bauer, 1990). We herein present the results of a comparative survey of both the external and internal anatomy of the feet and digits in Hemidactylus (and its close relatives) and use these to demonstrate both the wide range of variation present and the shared derived features that circumscribe this cluster and help clarify the relationships of the enigmatic Dravidogecko. We further relegate the generic name Dravidogecko into the synonymy of Hemidactylus as there are no derived features of Dravidogecko that are not also shared by at least some Hemidactylus. It is probable that H . anamallensis is a primitive hemidactyl. Materials and Methods Specimens of Dravidogecko were examined or borrowed from the collections of The Natural History Museum, London (BMNH) and the Institute Royal des Sciences Naturelles de Belgique, Brussels © 1995 by Asiatic Herpetological Research

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The systematic relationships of Dravidogecko anamallensis (Günther 1875)

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