Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon

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  Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon Abstract Snakes exhibit extreme cranial kinesis that facilitates ingestion of prey with large cross-sectional area, but this ability is widely predicted to reduce bite performance due to decreased structural rigidity. Consequently, most large-bodied snakes rely on envenomation or constriction to subdue prey prior to ingestion. Species within the genus Drymarchon represent a notable exception: these large, non-venomous, non-constricting snakes routinely consume a wide range of prey, including large and potentially dangerous vertebrates, using only simple seizing and pinioning behaviors. Here, we quantify bite performance in three species of Drymarchon ( D. corais, D. couperi, and D. melanurus ), examine morphological predictors of biting performance, compare biting pressure to constriction pressure in similarly sized snakes, and synthesize dietary records across the genus. Our results sh...

A new species of Lychas C. L. Koch, 1845 from a cave in the Sai Yok National Parc in Thailand (Scorpiones: Buthidae)

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A new species of Lychas C. L. Koch, 1845 from a cave in the Sai Yok National Parc in Thailand (Scorpiones: Buthidae)

Abstract

A new species, Lychas saiyok sp. n., is described from a cave in the Sai Yok National Park in western
Thailand, on the basis of an adult male. The specimen was found in the walls of this karstic cave, approximately 50-60 meters from the entry. The new species is characterized by a moderate to small size with respect to the genus (42.9 mm in total length), a general coloration from yellow to pale yellow marked by a strong pigmentation over the body and appendages, which however shows a distinct pattern from the one commonly observed in L. mucronatus, the most common Lychas species found in Southeast Asia, chelicerae showing a peculiar pigmentation formed by marked blackish spots which do not form any type of reticular structure, and pectines moderately long with 22-21 teeth. This new taxon represents the 35th described species among the currently recognized species for the genus Lychas. The number of known Lychas species in Thailand is increased to six. The species status of L. kotao Lourenço, 2020 stat. n. from Ko Tao island (Thailand) is also revalidated.

Lourenço, Wilson & Ythier, Eric. (2026). A new species of Lychas C. L. Koch, 1845 from a cave in the Sai Yok National Parc in Thailand (Scorpiones: Buthidae). Revista Ibérica de Aracnología.