Plestiodon parvulus Taylor

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 : 18-19

Plestiodon parvulus Taylor (Southern pigmy skink)

Specimens analysed: two males (CEAC23, CEAC24)

Distribution: Mexican endemic. The species occurs along Pacific coast from Sinaloa to Colima.

Subspecies: no subspecies have been described.

Karyotype: the karyotype is here described for the first time in this species. The karyotype shows 2n = 26, with 12 macro- and 14 microchromosomes ( Fig. 10 ). All the macro-chromosomes are biarmed as are four pairs of the microchromosomes. The other microchromosomes are telocentric. This karyotype differs in the morphology of the microchromosomes from other karyotypes of Plestiodon species. For example, the microchromosomes seem all biarmed in P. inexpectatus and P. obsoletus ( Caputo et al. 1994) .

DNA taxonomy: neither gene sequence of P. parvulus is present in GenBank. Therefore, the fragment of the 16S rRNA sequenced for this study was aligned with available sequences of other congeners ( Schmitz et al. 2004) to assess the phylogenetic affinities and genetic distance of this species within the genus. The obtained tree is shown in Figure 11 . The results suggest that E. parvulus is the sister species of another Mexican endemic species, P. l y n x e (bootstrap values 71% with NJ and 58% with ML). The genetic distance between the two species is 4.5–5.0% and is among the lowest interspecific genetic distance of the analysed dataset. This is the first report of a relationship between these two species ( Griffith et al. 2000; Schmitz et al. 2004).

Figures

FIGURE 10. Karyotype of Plestiodon parvulus male (2 n = 26).

FIGURE 11. Neighbour-Joining tree of 16 S rDNA haplotypes (518 bp) of Plestiodon species. Bootstrap values (%) obtained by the NJ, ML and MP are shown. The substitution model selected for ML was the Generalised time reversible (GTR) model with rate variation among sites (+ G), a proportion of invariable sites I = 0.5020 and a gamma distribution shape parameter of 0.3681.