Notes on defensive behaviors in the Dipsadini

47 p. : ill. (2 col.), 3 maps ; 26 cm.Includes bibliographical references (p. 44-47).The name Dipsas variegata (Duméril, Bibron, and Duméril) has been applied to snakes disjunctively distributed in northeastern South America and in Panama and western South America. The specific name variegata is here restricted to populations occurring from Venezuela to Trinidad and French Guiana, and seemingly to the mouth of the Amazon in Brazil. Records from Colombia are unsubstantiated. The name Dipsas nicholsi (Dunn) is revalidated for a Central American endemic with an exceptionally small range in central Panama. Specimens from western Ecuador previously assigned to "Dipsas variegata nicholsi" represent a different species--Dipsas andiana (Boulenger), which is resurrected from the synonymy of Dipsas oreas (Cope). Other records of Dipsas variegata from western Ecuador and southeastern Peru are based on misidentifications of species well known from those areas. Dipsas nicholsi and D. andiana differ in some scutellation, hemipenial, and color pattern characters. The two species share an unusual head pattern, but data are insufficient to conclude that they are sister species, although their disjunct distribution pattern (Panama and Chocoan South America) is one shared by many other organisms thought to be phylogenetically related. Hemipenes of Dipsas nicholsi and D. andiana are slightly bilobed and fully capitate; the sulcus spermaticus divides within the capitulum and has centrolineal branches. The capitulum is ornamented with papillate calyces. A battery of enlarged spines encircles the organ below the capitulum (with more spines in nicholsi than in andiana). There is an elongated basal nude pocket positioned laterally on the organ. Overall hemipenial morphology is similar to other species of the tribe Dipsadini (Dipsas, Sibon, Sibynomorphus, Tropidodipsas) for which organs have been described. The Dipsadini are docile snakes that, in the authors' experience, never defend themselves by biting or even striking with mouth closed. Defensive positional deportment is nonetheless widespread and varied, most commonly including acquisition of a triangular head shape in at least three genera of Dipsadini (and other snakes as well), which is brought about by dorsolateral spreading of the quadratomandibular articulations. Either asymmetrical or symmetrical coiling and head-hiding also occur in diverse species; there is evident individual variability in some species, whereas others possibly lack specialized behavior. A specimen of Dipsas nicholsi did not show the common head triangulation, but repeatedly exhibited stereotypic stages of defensive positioning that resulted in it taking the shape of a raised spiral coil

Exploring non-invasive sampling of parasites by metabarcoding gastrointestinal nematodes in Madagascar frog species

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Rare Panamanian snake

18 p. : ill. (some col.), maps ; 26 cm.Includes bibliographical references (p. 16-17).Dipsas nicholsi has been known from a handful of specimens collected during the final three-quarters of the 20th century. All came from a restricted lowland area (60-150 m) in central Panama, in the upper drainage of the Río Chagres. A recently identified specimen, the first known juvenile and only the second female, was found in 1997 in the Darién highlands (Serranía de Jingurudó, 855 m) of extreme eastern Panama, about 250 km from the clustered lowland localities in central Panama. It differs from central Panamanian specimens in some scutellation characters and especially in details of dorsal color pattern. The species' rarity makes it impossible to determine whether differences reflect geographic isolation or unknown aspects of ontogenetic, sexual, or individual variation. Distributional disruptions are commonplace in the Panamanian herpetofauna, although difficult to verify in the case of rare species. However, in the absence of a present-day habitat corridor, the Darién specimen of Dipsas nicholsi clearly represents a population widely separated and discontinuous from the one in central Panama. The Serranía de Jingurudó population, apparently a distributional relict, slightly closes the wide geographic gap between Dipsas nicholsi and its likely sister species, D. andiana, of western Ecuador. Commentary is provided on the cartographic names of several eastern Panamanian highlands. The Serranía de Jingurudó takes its name from a river, as shown by the Emberá suffix -dó. This highland was known for nearly half a century as the Sierra or Serranía de "Jungurudó", probably a confused combination of a still-older map name (Sierra de "Jungururo") and the Río Jingurudo

Phylogenetic relationships and molecular evolution in uropeltid snakes (Serpentes: Uropeltidae): allozymes and albumin immunology

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The dentition, systematics, and phylogeny of Pseudoxyrhopus and related genera from Madagascar (Serpentes: Colubridae), with descriptions of a new species and a new genus

Volume: 155Start Page: 381End Page: 44