Plesiodipsas perijanensis

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Herpetological Monographs, 22, 2008, 106–132 E 2008 by The Herpetologists’ League, Inc.

SYSTEMATICS OF THE ENIGMATIC DIPSADINE SNAKE TROPIDODIPSAS PERIJANENSIS ALEMA´N (SERPENTES: COLUBRIDAE) AND REVIEW OF MORPHOLOGICAL CHARACTERS OF DIPSADINI MICHAEL B. HARVEY1,5, GILSON RIVAS FUENMAYOR2, JOSE´ RANCES CAICEDO PORTILLA3, JOSE´ VICENTE RUEDA-ALMONACID4

AND

1

Department of Biological Sciences, Broward Community College, 3501 S.W. Davie Road, Davie, FL 33314, USA 2 Museo de Biologı´a, Facultad Experimental de Ciencias, La Universidad del Zulia, Apartado Postal 526, Maracaibo 4011, Estado Zulia, Venezuela 3 Laboratorio de Anfibios, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogota´, DC, Colombia 4 Coordinador Programa Biodiversidad y Especies Amenazadas, Conservacio´n Internacional Colombia, Bogota´, DC, Colombia, e-mail: jvrueda@yahoo.com ABSTRACT: On the basis of new material from Colombia, we describe external morphology, the hemipenis, osteology, musculature, and visceral morphology of Tropidodipsas perijanensis, a species previously known from the unique holotype and long assigned to Dipsas. Tropidodipsas perijanensis may be the sister species of all other Dipsadini or the sister species of a clade formed by Dipsas and Sibynomorphus. This distinctive South American species cannot be assigned to Tropidodipsas or to any other genus, and we erect a new genus for it. Our study of cephalic musculature identified a previously unreported division of the m. levator anguli oris and new insertion of the m. intermandibularis posterior superficialis. New characteristics of dipsadine hemipenes were visualized by Alizarin staining. Some osteological characters of Dipsadini support synonymization of Sibon and most species of Tropidodipsas, whereas visceral characters and published molecular data suggest that Dipsas, Sibon, and Sibynomorphus form a clade. RESUMEN: Con base en nuevos ejemplares de Colombia, se describe la morfologı´a externa y visceral, hemipenes, musculatura y osteologı´a de Tropidodipsas perijanensis. Esta especie conocida previamente solo por el holotipo fue por mucho tiempo asignada al ge´nero Dipsas. Posee caracteres especiales que la diferencian de todos los ge´neros descritos, por lo que se describe uno nuevo para la ubicacio´n de esta especie. El estudio sobre su musculatura cefa´lica identifico´ una divisio´n del m. levator anguli oris y una nueva insercio´n del m. intermandibularis posterior superficiales, no indicados previamente para la familia Colubridae. Nuevas caracterı´sticas de los hemipenes de Dipsadini fueron visualizadas por medio de tincio´n con Alizarina. Algunos caracteres osteolo´gicos soportan la sinonimia de Sibon y la mayorı´a de las especies de Tropidodipsas, mientras que los caracteres de la morfologia visceral y datos moleculares ya publicados sugieren que Dipsas, Sibon y Sibynomorphus forman un clado. Key words: Dipsas perijanensis; Dipsas sanctijoannis; Lung morphology; Musculature; Osteology; Plesiodipsas new genus; Sibon; Sibynomorphus; Tropidodipsas.

IN RECENT years, several careful studies have revisited the systematics of Dipsas. Herpetologists discovered two new species (MacCulloch and Lathrop, 2004; Reynolds and Foster, 1992) and redescribed poorly known species such as D. neivai (Porto and Fernandes, 1996), D. alternans (Passos et al., 2004), and D. albifrons (Passos et al., 2005). Several species were revalidated in the D. oreas (Cadle, 2005), D. pratti (Harvey and Embert, 2008), and D. variegata (Cadle and Myers, 2003) groups. Perhaps most importantly, these studies defined a suite of new morpho5

CORRESPONDENCE: e-mail, mharvey@broward.edu

logical characters that can reliably establish species boundaries and be used to infer relationships within Dipsas and other Dipsadini. Alema´n (1953) described Tropidodipsas perijanensis on the basis of a single female from 1700 m on the Venezuelan slopes of the Serranı´a de Perija´. When Peters (1960) reviewed the Dipsadini, he did not consider T. perijanensis. Later, Peters (1970) verified Alema´n’s report of 19–17 dorsal scale rows and referred this species to the D. polylepis group. As Peters (1970) acknowledged, the members of the D. polylepis group were a heterogenous assemblage of seemingly unrelated snakes sharing 17 or more scale rows at 106


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Plesiodipsas perijanensis by Luis Alejandro Rodriguez J. - Issuu