Gerrhonotus Wiegmann

The genus Gerrhonotus has a very problematic taxonomy, both at an intra- and interspecific levels. Good (1994) recognized three species, without subspecies, namely, G. infernalis, G. liocephalus and G. ophiurus (sometimes reported as subspecies of G. liocephalus). Recently Elgaria parva was included in a molecular phylogenetic analysis with other Gerrhonotus species, and it resulted in belonging to this genus (= Gerrhonotus parvus) (Conroy et al. 2005). The populations from Jalisco-Colima are reported as G. liocephalus (García & Ceballos 1994; Ramírez-Bautista 1994) but they are studied from two specimens only. Their morphological characters are intermediate among G. liocephalus, G. infernalis and G. ophiurus and therefore they remained of uncertain identity and referred to G. cf. liocephalus by Good (1994). Individuals possibly belonging to this taxon were also found in Colima, Durango and Sinaloa.

No species of this genus has been karyotyped. The karyotype is known only for three species of Elgaria and one species of Mesaspis, which also belongs to the subfamily Gerrhonotinae (Bury et al. 1969). These species show inter and intraspecific chromosomal variability. Elgaria coerulea has 2n = 38 (12 macro- and 26 microchromosomes); Elgaria multicarinata has 2n = 47–48 (21–22 macro- and 26 microchromosomes); Elgaria paucicarinata has 2n = 46 (20 macro- and 26 microchromosomes); Mesaspis monticola has 2n = 30 (18 macro- and 12 microchromosomes).