Caracterização Morfológica de Eunectes deschauenseei Dunn & Conant, 1936 e Comparação com Eunectes murinus (LINNAEUS, 1758) (Serpentes, Boidae)

Abstract

The genus Eunectes (W AGLER, 1830), with four semi-aquatic species, is distributed in different environments of South America. Eunectes murinus (LINNAEUS, 1758) occurs from Venezue1a to Bolivia; whereas Eunectes deschauenseei Dunn & Conant, 1936 can be found only in Brazil (Pará and Amapá) and French Guiana. The objective of this work is to morphologically characterize E. deschauenseei and compare it with the Brazilian Amazonian populations of E. murinus, based on meristic, morphometric and morphological characters (drawing and coloration, hemipennis and skull). For this, 45 specimens of E. murinus (26 females and 19 males) and 16 of E. deschauenseei (11 females and 5 males), from the Herpetological Collection of the Museu Paraense Emílio Goe1di, Be1ém, Pará, Brazil, were analyzed. Fourteen meristic and 10 morphometric characters were used. Drawing pattern and coloration were described from fixed specimens. Hemipennis and skulls were drawn and described comparatively. Regarding external characters E. deschauenseei differs from E. rnurinus by having a smaller number of dorsal, ventral, subcaudal, supralabial, infralabial postocular and sub-ocular scales. In the analysis, neither of the two species showed significant sexual dimorphism in relation to meristic characters. As for the morphometric characters, females showed greater rostro-doacal length than males, while males showed greater caudal length than females. The pattern of drawing and coloration is different in the two species. E. deschauenseei shows brown coloration with only one row of black dorsal spots in a zig-zag pattern, black, irregular, solid lateral spots, and five longitudinal black stripes on the head. E. murinus has greenish coloration with paired rows of black dorsal blotches, black, oval lateral blotches, but the center is clear. The hemipennis of E. deschauenseei has eight transverse folds in the distal half of the body and only papillae in the lobes, while that of E. murinus has nine folds in the distal half of the body and the proximal half of the lobes have folds and papillae in the distal half of them. We emphasize the importance of herpetofaunal surveys for a more detailed analysis of this taxa.