Genus Mesoamericus gen. nov.

Central American Forest Lizards

Fig. 27

Type species. Celestus bilobatus O’Shaughnessy, 1874:257 .

Diagnosis. Species of Mesoamericus gen. nov. have (1) claw sheath, present, (2) contact between the nasal and rostral scales, present, (3) scales in contact with the nasal scale, six, (4) postnasal scales, two, (5) position of the nostril in the nasal scale, posterior, (6) keels on dorsal body scales, absent, (7) digits per limb, five, (8) longest toe lamellae, 11–18, (9) dorsal scale rows, n/a (10) relative head width, 12.0–14.0, (11) relative rostral height, 65.0– 67.0, (12) relative frontonasal length, n/a, (13) relative interparietal distance, n/a, (14) relative axilla-groin distance, n/a.

From Siderolamprus, we distinguish Mesoamericus gen. nov. by the claw sheath (present versus absent in Siderolamprus) and relative rostral height (65.0–67.0 versus 44.7–63.9).

Content. One species (Table 3): Mesoamericus bilobatus .

Distribution. Mesoamericus gen. nov. occurs in Central America (Nicaragua, Costa Rica, and Panama) (Fig. 27).

Etymology. The generic name is a masculine noun derived from the name for the region (Mesoamerica) where it occurs.

Remarks. Mesoamericus gen. nov. is a monophyletic clade that has a support value of 100% in Bayesian and ML analyses (Fig. 2). The large molecular divergence among populations of M. bilobatus, with some splits as old as 5 Mya (Fig. 3), suggests the presence of three undefined species.