Toxicocalamus, a New Guinea genus of snakes of the family Elapidae

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Abstract

Toxicocalamus is expanded to include Apistocalamus and Ultrocalamus as subgenera. Pseudapistocalamus nymani, Apistocalamus pratti, A. loennbergi, and A. lamingtoni are considered geographic variations of Toxicocalamus (Apistocalamus) loriae. Toxicocalamus (Ultrocalamus) buergersi, synonymized with T. (U.) preussi by previous workers, is recognized as a distinct species because of many structural peculiarities (most notably, extension of the venom gland back within the body cavity nearly to the heart, as in Maticora). Three species are described as new: T. (Apistocalamus) spiblepidotus, characterized by large size and peculiar colouration; T. (A.) holopelturus, characterized by entire subcaudals and hemi-penial structure; and T. (Toxicocalamus) misimae, differing from the related T. longissimus in much lower ventral count and in having only 15 scale rows. A population from Garaina (Morobe Division) is believed to be of recent origin from hybridization between T. (A.) loriae and T. (T.) stanleyanus. Toxicocalamus is most closely related to the Australian genera called Brachyurophis, Melwardia, Narophis, Rhinelaps, and Rhynchoelaps by Worrell, but here all grouped in the genus Rhynchoelaps. This Australian genus and Toxicocalamus make up the Rhynchoelaps group, which does not include the genera Vermicella (for V. annulata only), Ogmodon, or Parapistocalamus. The lack of a diastema behind the fang in the elapid genera Kerilia, Ogmodon, and Toxicocalamus is not a primitive, but a specialized, feature, probably developed independently in each of these genera as a mechanism for coordinating the replacement rhythm of the fangs with that of solid teeth behind. It is suggested that the solid maxillary teeth of Toxicocalamus are neomorphs, formed by backward extension of the fang-forming portion of the dental lamina.

Ancillary