Browsing by Author "Duellman, William Edward, 1930-"
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Item A monographic study of the colubrid snake genus Leptodeira. Bulletin of the AMNH ; v. 114, article 1(New York : [American Museum of Natural History], 1958) Duellman, William Edward, 1930-"The genus Leptodeira Fitzinger, 1843, includes as absolute synonyms the generic names Megalops Hallowell, 1861, Anoplophallus Cope, 1893, and Pseudoleptodeira Taylor, 1938. Nine species comprise the genus; five of these are monotypic; one embraces five subspecies, one includes four subspecies, and two others each contain three subspecies, making a total of 20 forms. Two subspecies are described as new in this paper. The genus is characterized by maxillary teeth that increase in size posteriorly followed by a diastema and two enlarged, grooved fangs. There are two apical pits, elliptical pupil, divided anal, smooth dorsal scales, normal complement of colubrid head shields, and a capitate hemipenis with many large spines. Four species groups are separated on the nature of the hemipenes, the dentition and certain skull elements, particularly the quadrates, vomers, and maxillaries. Analysis of the characters shows that the most useful in a systematic study of the snakes are the numbers of ventrals, caudals, and dorsal scale rows, the numbers of upper labials and preocular scales, the number, shape, and size of the body blotches, and the nature of the dorsal head pattern. Analysis of numerous character clines shows that parallel clines may exist in two or more species in certain characters, but that in others the clines may diverge. Discontinuous clines are common. In some cases these are correlated with striking morphological changes between populations and become incorporated in the characteristics of subspecies. Studies of the skull of Leptodeira indicate that the skull is a normal colubrid type without striking specializations. Certain skeletal elements readily identify it from related genera. The poison glands (modified posterior portions of parotid glands) are large and produce a venom of sufficient strength to kill small frogs and lizards. The distribution of the genus is essentially throughout the American tropics to elevations of about 2000 meters. Some forms are restricted to semi-arid habitats; others live in tropical rain forest. Two species range from semi-arid to wet forest environments; each has a subspecies adapted to arboreal life in the forest by having a reduced number of dorsal scale rows, enlarged vertebral and paravertebral scale rows, and a laterally compressed body. Snakes of this genus feed primarily on frogs and toads; some lizards are included in the diet. The snakes are nocturnal and appear to reach their greatest abundance at times of congregations of breeding frogs. So far as is known, all species are oviparous and may lay as many as 13 eggs. On penial characters Leptodeira may be placed with Hypsiglena and Trimorphodon as a subgroup of colubrine snakes. If Leptodeira is related to Trimorphodon, they must have diverged early in their evolutionary history. Hypsiglena and Leptodeira are closely related and evolved from a common ancestral stock. The African snakes of the genus Crotaphopeltis that have been placed in the genus Leptodeira represent a separate evolutionary line of colubrine snakes. Based on the Cenozoic history of tropical America, studies of the morphology and distribution of the snakes, and the fossil record of other animals, the evolutionary history of Leptodeira has been reconstructed. This shows that Leptodeira and Hypsiglena underwent generic differentiation from a common ancestral stock in southern México during the early Miocene. By middle Miocene time the groups of Leptodeira had diverged. The present distribution and differentiation are a result of the effects of sea portals across Middle America that isolated populations often for long periods of time, and the Cenozoic orogenies that changed the uniform climatic conditions of Middle America and produced arid as well as humid habitats"--P. 143.Item A new genus and species of colubrid snake from the Mexican state of Oaxaca. American Museum novitates ; no. 2162(New York, N.Y. : American Museum of Natural History, 1963) Bogert, Charles M. (Charles Mitchill), 1908-1992.; Duellman, William Edward, 1930-; Hallberg, Boone.Item A new species of Hyla from Cerro Colorado, and other tree frog records and geographical notes from western Panama. American Museum novitates ; no. 2752(New York, N.Y. : American Museum of Natural History, 1982) Myers, Charles W.; Duellman, William Edward, 1930-Item A synopsis of the lizards of the sexlineatus group (genus Cnemidophorus). Bulletin of the AMNH ; v. 123, article 3(New York : [American Museum of Natural History], 1962) Duellman, William Edward, 1930-; Zweifel, Richard George, 1926-"The lizards of the sexlineatus species group constitute the largest group within the genus Cnemidophorus and occupy the greatest geographic area, from Honduras to Maryland and westward to Arizona and northern Baja California. The taxonomic arrangement of the lizards of this group that has been developing over the 30 years since Burt (1931a) placed all forms described in two species (one with three subspecies) reveals a far more complicated situation than earlier authors appreciated. Within approximately the last decade, the application of more refined methods of study, together with a knowledge of the appearance of the animals in life and of their ecology, has greatly increased the understanding of variation and distribution. In the present report we recognize 17 species and 31 forms. The impetus for the preparation of the present report was provided by the discovery that one of the oldest, hence taxonomically most important, names in the genus, sackii Wiegmann, 1834, was misapplied. A simple shift of names or an application to the International Commission for conservation of names would scarcely remedy the situation satisfactorily, for a number of distinct species and subspecies would still remain buried in synonymy. This report, then, establishes the true identity of Cnemidophorus sacki as the form previously called C. sacki australis and redistributes the forms recently assigned to C. sacki among seven species. The arrangement given is assuredly not final, but it provides a working basis for future studies. With future workers in mind, we draw attention throughout this paper to the outstanding problems and point out where, particularly in the field, effort most profitably can be expended. We realize, however, that our colleagues may come, with Shakespeare, to feel that ''Tis the times' plague, when madmen lead the blind' (King Lear)"--P. 207.