Gerrhonotus cf. liocephalus Wiegmann

Castiglia, Riccardo, Annesi, Flavia, Bezerra, Alexandra M. R., García, Andrés & Flores-Villela, Oscar, 2010, Cytotaxonomy and DNA taxonomy of lizards (Squamata, Sauria) from a tropical dry forest in the Chamela-Cuixmala Biosphere Reserve on the coast of Jalisco, Mexico, Zootaxa 2508, pp. 1-29 : 8-9

Gerrhonotus cf. liocephalus Wiegmann (Texas alligator lizard)

Specimens analysed: one male (CEAC7).

Distribution: uncertain limits. Maybe limited to Jalisco and Colima. Subspecies: Good (1994) did not recognize subspecies.

Good (1994) studied only two specimens belonging to coastal Jalisco. Here we report a morphological description of the male specimen that we studied. In particular, we report the characters that are significant for the morphological diagnosis of Gerrhonotus species following Good (1994). Canthal/loreal series: 3 canthals, 3 loreals; supralabial number: 28; preocular number: 1; number of transverse dorsal scales rows: 48; number of longitudinal dorsal scales: 16; number of dorsal crossbands: 9; ventral pattern: mottled; lateral fold bars: present; limb length: not measured; tail whorl number: tail incomplete. The pattern of coloration shows 9 evident “V” shaped cross-bands. Each of these bands has a width of 2–3 white scales, flanked by darker scales. The ventral pattern is immaculate. The morphological characters of this specimen collected by us are similar to the other three specimens from Jalisco and Colima reported by Good (1994).

Karyotype: Gerrhonotus cf. liocephalus showed 2n = 38 composed by 14 macrochromosomes and 24 microcromosomes (not shown). All macrochromosomes seem biarmed but, for the smallest ones, some doubt exists on their morphology. The karyotype of this species shares with E. coerulea the same diploid number but it has only 12 machrochromosomes.

DNA taxonomy: the phylogenetic position of species of Gerrhonotus was recently addressed by Conroy et al. (2005). A fragment of the NADH dehydrogenase 2 gene and flanking regions (511bp) was sequenced and aligned with published sequences of G. liocephalus , G. infernalis and G. parvus . The sequences of the specimen analysed here clustered with the two sequences belonging to G. infernalis (bootstrap values 70– 75%) ( Fig. 3 ). However, the sequence divergence with this species is high (9.6%). A similar divergence was found between G. liocephalus and G. infernalis (10%). These findings, together with the distinct morphological characteristics of the specimens in the area of Chamela (present work and Good 1994), support its identity as a taxon different from the two mentioned above (Nieto Montes de Oca, unpublished).

Figures

FIGURE 3. Neighbour-Joining tree of 16 S rDNA haplotypes (511 bp) of Gerrhonotus species. Bootstrap values (%) obtained by the NJ, ML and MP are shown. The substitution model selected for ML was the Hasegawa, Kishino, Yano (HKY) model (Hasegawa et al. 1985) with rate variation among sites (+ G), and a gamma distribution shape parameter of 0.2997.