Taxonomy of the lizard genus Cercosaura Wagler, 1830, Gymnophthalmidae,
has recently changed to incorporate the former genera Pantodactylus and
Prionodactylus. As currently recognized the genus contains 11 species.
However, divergences in the literature indicate that the name Cercosaura
argulus may encompass a group of species. The present study investigates the
Cercosaura with divided frontonasal, here called “argulus group”, that includes
the nominal species Cercosaura argulus Peters, 1863 and Prionodactylus
oshaughnessyi Boulenger, 1885. A total of 151 specimens of 41 localities were
studied on basis of five morphometric and 22 meristic characters. Specimens
were divided into three groups, according to characters previously considered
diagnostic of the two nominal species, further dividing ‘C. oshaughnessyi’ into a
western and a Guianan group. A Discriminant Function Analysis (DFA) was
used to compare these three groups. Previously, Principal Component
Analyses (PCA) were performed to (1) eliminate the influence of size in the
comparisons (residuals of morphometric data with the first axis of a PCA were
calculated and used in all subsequent statistical analyses); and (2) to select a
smaller number of meristic variables to be used in the DFA. Results indicate
that C. argulus and C. oshaughnessyi differ mainly by the presence of preanal
pores, body length, and number of scales around midbody. Cercosaura
oshaughnessyi is considered a valid species, restricted to western Amazonia,
while a third, undescribed species of Cercosaura with divided frontonasal
occurs in French Guiana and Amapá (Brazil).
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