Dryadosaura, Rodrigues & Freire & Pellegrino & Sites Jr, 2005

Rodrigues, Miguel Trefaut, Freire, Eliza Maria Xavier, Pellegrino, Katia Cristina Machado & Sites Jr, Jack W., 2005, Phylogenetic relationships of a new genus and species of microteiid lizard from the Atlantic forest of north-eastern Brazil (Squamata, Gymnophthalmidae), Zoological Journal of the Linnean Society 144 (4), pp. 543-557 : 545-546

DRYADOSAURA GEN. NOV.

Definition: Small gymnophthalmid with a robust and short head, elongate body and short, stout, pentadactyl limbs. Collar fold, ear opening and eyelid present. Frontonasal single; prefrontals, parietals and interparietals present; frontoparietals absent. Two pairs of chin shields and three supraoculars. Dorsal scales in transverse rows; anteriorly smooth, imbricate, rounded in the occipital region, becoming narrower, elongate and rectangular at the arm level; posterior to the arm, dorsal scales become progressively and irregularly mucronate, with lateral sides almost juxtaposed, keeled. Lateral scales of body about the same size as dorsals, smooth, rectangular, and laterally imbricate. Ventral scales smooth, juxtaposed or slightly imbricate, rectangular. Males with preanal and femoral pores; only preanal pores in females.

Content: Dryadosaura nordestina sp. nov.; monotypic.

Etymology: From the Greek Dryades , meaning ‘woodland nymph’. This was the first name proposed (by Carl Philipp von Martius) for the biogeographical province of the Atlantic Forest.

Considering the multiple origins of character complexes related to fossoriality in gymnophthalmid lizards and their chaotic taxonomy, until recently based only on external attributes, we emphasize morphological comparisons of Dryadosaura with Anotosaura and Colobosauroides , their closest relatives according to the molecular phylogenetic analyses of Pellegrino et al. (2001) and Castoe et al. (2004). In those papers, Dryadosaura (referred to as Anotosaura spn.), Anotosaura vanzolinia , and Colobosauroides cearensis were recovered as a strongly supported monophyletic group. However, Pellegrino et al. (2001) emphasized that the status of Anotosaura spn. was tentative, pending correct generic allocation. The pronounced morphological gap between Dryadosaura and its close relatives, in characters as number of sternal ribs, presence of an external ear opening, body shape and pholidosis, among other characters presented below, support the generic status here proposed.

Only two species ( Anotosaura vanzolinia and A. collaris ) are currently recognized in the genus Anotosaura . Anotosaura brachylepis , formerly included in Anotosaura due to the absence of an external ear opening, is now allocated to Rhachisaurus , a monotypic genus of the new subfamily Rhachisaurinae ( Pellegrino et al., 2001) . Rhachisaurus is characterized by the absence of an external ear opening, the presence of four digits on the front and hind limbs, a high number of short, narrow and smooth dorsal scales (57–60), absence of collar, a tail that is more than twice body length, a large number of temporals, ten rows of gulars, three pairs of chinshields, four supraoculars, six superciliaries, squared ventrals and rounded scales in the lateral sides of the neck.

Dryadosaura differs from Anotosaura and Colobosauroides by its larger size (maximum SVL, respectively: 57 mm, 43 mm, and 35 mm), robust body and massive fore limbs (more slender in both of the other genera). Dryadosaura also differs from Anotosaura by the presence of an external ear opening (absent in Anotosaura ), two pairs of chinshields (three in all other Ecpleopini) and dorsal scales keeled posteriorly (vs. smooth in the others). It further differs from A. vanzolinia by the presence of a pair of prefrontals (vs. absence); prefrontals are present in A. collaris . Two very similar species of Colobosauroides are currently recognized: C. cearensis and C. carvalhoi . From them Dryadosaura can be externally distinguished by the absence of frontoparietals (present in Colobosauroides ), by having only two pairs of chinshields (vs. three), an interparietal scale shorter than parietal (vs. longer), and four temporal scales (vs. six). Dryadosaura further differs from Colobosauroides by the presence of two pairs of sternal ribs (vs. three).

Other Gymnophthalmidae having two pairs of genials are the clades Gymnophthalmini ( Gymnophthalmus , Psilophthalmus , Nothobachia , Calyptommatus ), Heterodactylini ( Colobosaura , Stenolepis , Colobodactylus , Heterodactylus ), and some species of the Cercosaurini ( Bachia ). Among other characters, Dryadosaura differs from the first group by having an eyelid (absent in the referred Gymnophthalmini), from the Heterodactylini by having small and superficial preanal and femoral pores separated by a gap (large, prominent, and continuous), and short and stout fore limbs (vs. long and slender), and from Bachia by the presence of a distinctive ear opening (absent). As discussed below, the sister group of Dryadosaura is Anotosaura . The absence of an external ear opening and a longer body in Anotosaura , compared to the shorter and stout body and the presence of a distinct ear opening in Dryadosaura suggest different adaptation processes for these two radiations.