title: Discovery of a novel accessory structure of the pitviper infrared receptor organ (serpentes: viperidae).
abstract: The facial pits of rattlesnakes, copperheads, lanceheads, bushmasters and other American and Asian pitvipers (Crotalinae) are highly innervated and densely vascularized infrared (IR) receptor organs. For over a century, studies have focused on a small sample of model species from North America and Asia. Based on an expanded survey of Central and South American crotalines, we report a conspicuous accessory structure composed of well-defined papillae that project from the anterior orbital adnexa. The papillae are continuous with the inner chamber of the IR receptor organ and our histological and ultrastructural data suggest that they possess a well-developed nervous network and extensive vascularization; however, they lack the characteristic IR-sensitive terminal nerve masses found in the IR-receptive pit membrane. The function of the IR receptor organ papillae is unknown.
authors.affiliation: Departamento de Biología, Programa de Posgrado y Grupo de Investigación en Ecología Animal, Universidad del Valle, Cali, Valle del Cauca, Colombia.
authors.forename: Wilmar
authors.initials: W
authors.lastname: Bolívar-G
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, São Paulo, São Paulo, Brazil.
authors.forename: Marta M
authors.initials: MM
authors.lastname: Antoniazzi
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Taran
authors.initials: T
authors.lastname: Grant
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, São Paulo, São Paulo, Brazil.
authors.forename: Carlos
authors.initials: C
authors.lastname: Jared
mesh_terms: D000569:Americas; D000818:Animals; D001208:Asia; D007259:Infrared Rays; D010802:Phylogeny; D011984:Sensory Receptor Cells / Q000648:ultrastructure*; D017819:Viperidae / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics