Endless forms most beautiful: the evolution of ophidian oral glands, including the venom system, and the use of appropriate terminology for homologous structures

• DOI: 10.1007/s00435-016-0332-9
• Publication Date: 2016-12-15T08:43:11Z
• Authors: Timothy N. W. Jac...; Bruce Young; Garth Underwood; Colin J. McCarthy; Elazar Kochva; Nicolas Vidal; Louise van der Weerd; Rob Nabuurs; James Dobson; Daryl Whitehead; Freek J. Vonk; Iwan Hendrikx; Chris Hay; Bryan G. Fry
• Keywords: 1309 Developmental Biology; 0303 health sciences; 03 medical and health sciences; Snake; Evolution; 590; 1103 Animal Science and Zoology; Anatomy; Function; Terminology; Venom

The differentiated serous-secreting dental glands of caenophidian snakes are diverse in form despite their developmental homology. This variation makes the elucidation of their evolutionary history a complex task. In addition, some authors identify as many as ten discrete types/subtypes of ophidian oral gland. Over the past decade and a half, molecular systematics and toxinology have deepened our understanding of the evolution of these fascinating and occasionally enigmatic structures. This paper includes a comprehensive examination of ophidian oral gland structure and (where possible) function, as well as new data on rictal glands and their associated anatomy. Following this, appropriate use of terminology, especially that pertaining to homologous structures (including the controversial “venom gland” vs “Duvernoy’s gland” debate), is considered. An interpretation of the evolutionary history of the ophidian venom system, drawing on recent results from molecular systematics, toxinology and palaeontology, concludes the paper.