História natural e ecomorfologia de serpentes da tribo Xenodontini
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Data
2021-10-21
Autores
Batista, Silara Fatima
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A História Natural é uma das ciências mais antigas e é base para o entendimento da biologia dos organismos. Igualmente, investigar padrões ecomorfológicos entre espécies fornece importantes informações sobre o papel dos organismos no ambiente. Estudar tais aspectos em serpentes é especialmente interessante, pois são diversas morfológica e ecologicamente. Dessa forma, o objetivo geral desta tese foi investigar os padrões de História Natural e mais especificamente Ecomorfologia em um clado amplamente distribuído e diverso de serpentes Neotropicais, a tribo Xenodontini. Isso foi alcançado (1) pela coleta de dados sobre a História Natural das serpentes da tribo - incluindo tamanho do corpo, uso de habitat e substrato, comportamentos defensivos, padrões de atividade diária, dieta e reprodução - por meio da análise de espécimes de coleções científicas e revisão da literatura, com os dados sendo inventariados e resumidos; (2) o uso de Métodos Filogenéticos Comparativos, para estabelecer a relação entre dieta e micro-hábitat com a forma do corpo, além das taxas de mudança evolutiva neste traço; e, finalmente, (3) descrevendo padrões de dieta e uso do hábitat em Erythrolamprus frenatus. São fornecidos dados de História Natural para 74 das 75 espécies da tribo, embora para algumas, somente dados morfológicos ou observações anedóticas estavam disponíveis. Serpentes da tribo são morfologicamente diversas, com espécies que vão de 20 cm à mais de 1 metro de comprimento rostro-cloacal e são essencialmente batracófagas e terrestres, habitando tanto áreas abertas como florestadas. Entretanto, especializações alimentares como ofiofagia e piscivoria estão presentes, além do hábito aquático em algumas espécies. A maioria das espécies é diurna, e usa achatamento lateral e dorsal do corpo como estratégias defensivas. Fecundidade é positivamente associada com o tamanho, pois espécies maiores produzem ninhadas maiores. O ciclo reprodutivo é contínuo na maioria das espécies e o dimorfismo sexual é encontrado em 18 delas. O micro-hábitat influencia a forma do corpo e da cabeça, mas a dieta não. A posição das espécies nos filomorfoespaços sugere evolução direcional no gênero Xenodon, como resultado da exploração de oportunidades ecológicas, como o hábito criptozoico e de comer ovos de Squamata. Também há um aumento nas taxas de evolução morfológica no gênero. Adicionalmente, é relatado que E. frenatus preda peixes alongados, sendo aquática e encontrada dentro ou próximo de corpos d´água. De maneira geral, a História Natural das serpentes da tribo Xenodontini é diversa e revela que, mesmo para espécies relativamente conhecidas, pouco se sabe sobre como os padrões morfológicos e ecológicos evoluíram. Portanto, estudos em contexto ecológico e evolutivo, tanto inter e intraespecíficos, ainda são necessários. De forma geral, a presente tese evidencia a relevância de estudos de História Natural para as Ciências Biológicas, e enfatiza a importância das coleções científicas como fonte primária de dados.
Natural History is one of the oldest sciences, and is the basis for understanding the biology of the organisms. Likewise, investigating ecomorphological patterns between species provides important information on the role of organisms in the environment. Studying such aspects in snakes is especially interesting, because they are both morphologically and ecologically diverse. Thus, the general objective of this thesis was to investigate the patterns of Natural History, and more especifically Ecomorphology in a widely distributed and diverse clade of Neotropical snakes, the tribe Xenodontini. This was achieved by (1) gathering data on the Natural History of the snakes of the tribe - including body size, habitat and substrate use, defensive behaviors, daily activity patterns, diet and reproduction – by analyzing specimens from scientific collections and reviewing the literature, with data being inventoried and summarized; (2) using Phylogenetic Comparative Methods, for stabilishing the relationship between diet and microhabitat with body shape, as well as the evolutionary rates shifts in this trait, and, finally, (3) describing diet patterns and habitat use in Erythrolamprus frenatus. We provide Natural History data for 74 of the 75 species in the tribe, although for some, only morphological data or anecdotal observations were available. Snakes of the tribe are morphologically diverse, with species ranging from 20 cm to more than 1 meter in snout-vent length, and are essentially batracophagous and terrestrial, inhabiting both open and forested areas. However, dietary specializations such as ophiophagy and piscivory are also present, as is the aquatic habit in some species. Most species are diurnal, and use hooding and body flattening as defensive strategies. Fecundity is positively associated to size, as larger species produce larger offspring. Microhabitat influences the shape of the body and the head, but diet does not. The position of species in phylomorphospaces suggests directional evolution in the genus Xenodon, as a result of the exploration of ecological opportunities, such as the cryptozoic habit and feeding on Squamata eggs. There is ALSO an increase in morphological evolution rates in this genus. Additionally, is reported that E. frenatus preys on elongated fish, being aquatic and inhabiting waterbodies or surroundings. In general, the Natural History of snakes of the tribe Xenodontini is diverse, and reveals that, even for relatively well-known species, little is known about how morphological and ecological patterns evolved. Therefore, studies on ecological and evolutionary contexts, both interespecific and intraspecifically, are still needed. Overall, the present thesis evinces the importance of the Natural History for Biological Sciences, and emphasizes the importance of scientific collections as primary source of data.
Natural History is one of the oldest sciences, and is the basis for understanding the biology of the organisms. Likewise, investigating ecomorphological patterns between species provides important information on the role of organisms in the environment. Studying such aspects in snakes is especially interesting, because they are both morphologically and ecologically diverse. Thus, the general objective of this thesis was to investigate the patterns of Natural History, and more especifically Ecomorphology in a widely distributed and diverse clade of Neotropical snakes, the tribe Xenodontini. This was achieved by (1) gathering data on the Natural History of the snakes of the tribe - including body size, habitat and substrate use, defensive behaviors, daily activity patterns, diet and reproduction – by analyzing specimens from scientific collections and reviewing the literature, with data being inventoried and summarized; (2) using Phylogenetic Comparative Methods, for stabilishing the relationship between diet and microhabitat with body shape, as well as the evolutionary rates shifts in this trait, and, finally, (3) describing diet patterns and habitat use in Erythrolamprus frenatus. We provide Natural History data for 74 of the 75 species in the tribe, although for some, only morphological data or anecdotal observations were available. Snakes of the tribe are morphologically diverse, with species ranging from 20 cm to more than 1 meter in snout-vent length, and are essentially batracophagous and terrestrial, inhabiting both open and forested areas. However, dietary specializations such as ophiophagy and piscivory are also present, as is the aquatic habit in some species. Most species are diurnal, and use hooding and body flattening as defensive strategies. Fecundity is positively associated to size, as larger species produce larger offspring. Microhabitat influences the shape of the body and the head, but diet does not. The position of species in phylomorphospaces suggests directional evolution in the genus Xenodon, as a result of the exploration of ecological opportunities, such as the cryptozoic habit and feeding on Squamata eggs. There is ALSO an increase in morphological evolution rates in this genus. Additionally, is reported that E. frenatus preys on elongated fish, being aquatic and inhabiting waterbodies or surroundings. In general, the Natural History of snakes of the tribe Xenodontini is diverse, and reveals that, even for relatively well-known species, little is known about how morphological and ecological patterns evolved. Therefore, studies on ecological and evolutionary contexts, both interespecific and intraspecifically, are still needed. Overall, the present thesis evinces the importance of the Natural History for Biological Sciences, and emphasizes the importance of scientific collections as primary source of data.
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Palavras-chave
Serpentes, Dipsadidae, Dieta, Micro-hábitat, Evolução, Snakes, Dipsadidae, Diet, Microhabitat, Evolution