Composición comparativa de la fauna de serpientes (Reptilia, Squamata) de cuatro provincias biogeográficas del Dominio Chaqueño

Abstract

Comparative composition of snake faunas (Reptilia, Squamata) in four biogeographical provinces of the Chacoan Domain. The comparative composition of snake species in the Gran Chaco, Espinal, Pampa, and Monte biogeographical provinces was analyzed in order to determine shared taxa among them, endemic species, and faunal similarity by calculating the Coefficient of Biogeographic Resemblance (CBR). The richest province is the Gran Chaco (39 genera, 97 species and subspecies, 10 endemics), followed by Pampa (28 genera, 48 species, three endemics) and Espinal (25 genera, 47 species and subspecies, no endemics). The Monte province is the poorest (16 genera, 22 species, two endemics), however, this last formation has a floristic and faunistic definite physiognomy, different from its neighbouring provinces. Faunal similarity is highest between Espinal and Pampa (CBR = 0.67), followed by Gran Chaco and Espinal (CBR = 0.61). In all comparisons these three provinces are more similar among them than to the Monte. Analysis of published results on lizard, amphisbaenian, and turtle assemblages from these four provinces adds support to the hypothesis that the Espinal formation has not a characteristic reptile fauna, and that it is an ecotone between Gran Chaco and Pampa.