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

AMPHIBIANS AND REPTILES OF SINALOA, MEXICO 59
Quercus pallescens, Q. durifolia, and Q. candicans are other common
species in the oak-pine forest. Arbutus xtdapensis is found with
pines and oaks in some places in northern Sinaloa. No specific
information is available concerning the pine and oak forests in
the southern highlands of Sinaloa.
COMPOSITION OF THE HERPETOFAUNA
As presently understood, the herpetofauna of Sinaloa includes
131 species: 32 frogs (24.4£ of the total number of species, 10 turtles
(7.6%), 33 lizards (25.2$), 55 snakes (42.0%), and one crocodilian
(0.8%). Although no salamanders have been reported from Sinaloa,
additional collecting in the Lower Montane Dry Forest in the
eastern part of the state will probably reveal their presence.
A comparison of the herpetofaunal diversity of Sinaloa with that
of Michoacan and of Arizona is presented in Table 1. The data
TABLE 1.—Comparison of the Herpetofaunas of Arizona, Sinaloa, and
Michoacan by Major Components.
Arizona
(295,024 sq. km.)
Sinaloa
(58,092 aq. km.)
Michoacan
(60,093 sq. km.)
Number Percent Number Percent Number Percent
Anurous 20
1 0.9 0 0.0 6 3.7
17.5 31 25.6 38 23.4
Turtles 4 3.5 5 4.1 3 1.8
Crocodffians 0 0.0
1 0.8
1 0 6
Lizards
41 36.0 31 25.6 46 28.2
Snakes
48 42.1 53 43.9 69 42.3
Totals 114 100.0 121 100.0 163 100.0
for Michoacan are from Duellman (1965); those for Arizona are
from Lowe (1964). Only the native terrestrial species are pertinent
to the discussion. The marine turtles, the sea snake, and those
forms which are known to be introduced are excluded.
There is an increase in the number of species of amphibians and
reptiles from Arizona (114 species) through Sinaloa (121 species)
to Michoacan (154 species) independent of total area. This cline
in herpetofaunal diversity along a latitudinal gradient generally
conforms to the results expected in moving from temperate to
tropical environments. However, it should be noted that not all
components conform to the north-south increase in diversity. The