The Amphibians and Reptiles of Sinaloa, Mexico - Smithsonian ...

138 UNIVERSITY OF KANSAS PUBLS,, MUS. NAT. HIST.
have less maculation on the chest than those previously discussed.
These color patterns indicate a clinal loss of black or blue ventral
pigmentation in S. nelsoni from north to south.
Based on the evidence that the geographic variation involving
ventral coloration is continuous, and that there are no consistent
differences in numbers of dorsal scales and postrostrals, we conclude
that S. nelsoni barrancorum should be allocated to the
synonymy of S. nelsoni.
Sceloponts nelsoni is found at moderate to high elevations in the
foothills and on the western slope of the Sierra Madre Occidental
in western Mexico. Lizards also have been taken in suitable habitat
at a few isolated localities on the coastal plain. Specimens were
collected on rocky outcroppings, along arroyos and rocky streams,
usually in heavily shaded areas. All adult females collected in
July and August were gravid.
Distribution in Sinaloa.—Most of the state except in the northwestern
lowlands. See Fig. 51.
Specimen* examined.—21 km. ESE Badiraguato, 210 m. (• KU 83400); 1.5
km. SE Camino Real, Rio Piaxtla, 120 m.