A dune with a view: the eyes of a neotropical fossorial lizard

Autor(es)

Yovanovich, Carola A. M. ^[1] ; Pierotti, Michele E. R. ^{[1, 2]} ; Rodrigues, Miguel Trefaut ^[1] ; Grant, Taran ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biosci, Dept Zool, Sao Paulo - Brazil

^[2] Smithsonian Trop Res Inst, Naos Marine Labs, Panama City - Panama

• Tipo de documento: Artigo Científico
• Fonte: Frontiers in Zoology; v. 16, JUN 10 2019.
• Citações Web of Science: 0

Resumo

BackgroundLizards are excellent models to study the adaptations of the visual system to different scenarios, and surface-dwelling representatives have been relatively well studied. In contrast, very little is known about the functional anatomy of the eyes of fossorial lineages, and properties such as the light transmission by the ocular media have never been characterised in any fossorial species. Some lizards in the family Gymnophthalmidae endemic to the sand dunes of North Eastern Brazil have evolved sand-burrowing habits and nocturnal activity. Lizards in the sister group to Gymnophthalmidae, the family Teiidae, have decidedly diurnal and epigeal lifestyles, yet they are equally poorly known in terms of visual systems. We focussed on the eye anatomy, photoreceptor morphology and light transmittance properties of the ocular media and oil droplets in the gymnophthalmid Calyptommatus nicterus and the teiid Ameivula ocellifera.ResultsThe general organisation of the eyes of the fossorial nocturnal C. nicterus and the epigeal diurnal A. ocellifera is remarkably similar. The lenses are highly transmissive to light well into the ultraviolet part of the spectrum. The photoreceptors have the typical cone morphology, with narrow short outer segments and oil droplets. The main difference between the two species is that C. nicterus has only colourless oil droplets, whereas A. ocellifera has colourless as well as green-yellow and pale-orange droplets.ConclusionsOur results challenge the assumption that fossorial lizards undergo loss of visual function, a claim that is usually guided by the reduced size and external morphology of their eyes. In the case of C. nicterus, the visual system is well suited for vision in bright light and shows specialisations that improve sensitivity in dim light, suggesting that they might perform some visually-guided behaviour above the surface at the beginning or the end of their daily activity period, when light levels are relatively high in their open dunes habitat. This work highlights how studies on the functional anatomy of sensory systems can provide insights into the habits of secretive species. (AU)

• Processo FAPESP: 15/14857-6 - Estudo sistemático dos sistemas visuais dos anfíbios: da evolução de padrões de atividade dial aos limites fisiológicos para a visão colorida
• Beneficiário: Carola Anabel Mariana Yovanovich
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 18/11502-0 - A hiperdiversa fauna anfíbia do Brasil como um sistema de modelo para a ecofisiologia comparativa a genômica da visão
• Beneficiário: Taran Grant
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional
• Processo FAPESP: 11/50146-6 - Filogeografia comparada, filogenia, modelagem paleoclimática e taxonomia de répteis e anfíbios neotropicais
• Beneficiário: Miguel Trefaut Urbano Rodrigues
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático
• Processo FAPESP: 12/10000-5 - Uma abordagem multidisciplinar para o estudo da diversificação de anfíbios
• Beneficiário: Taran Grant
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores