Gross brain morphology of the Loricariinae (Siluriformes: Loricariidae): comparative anatomy, ecological implications and phylogenetic analysis
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Data
2019-02-12
Autores
Angulo, Arturo
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Universidade Estadual Paulista (Unesp)
Resumo
A família Loricariidae é a mais diversa dentro do ordem Siluriformes, contendo cerca de 980 espécies válidas. Os membros da família são facilmente reconhecidos por possuírem corpos cobertos por placas dérmicas ossificadas, dentes tegumentares abundantes e um disco oral ventral que facilita a fixação á superfície e a alimentação. A subfamília Loricariinae é a segunda mais diversa dentro de Loricariidae, contendo 31 gêneros e cerca de 243 espécies válidas. Os membros da subfamília são facilmente reconhecidos por ter um pedúnculo caudal alongado e deprimido e por a falta de uma nadadeira adiposa. As espécies de Loricariinae estão amplamente distribuídas pelas principais drenagens da maioria dos rios da América Central e do Sul, sendo geralmente encontradas próximas ao substrato e apresentando uma extraordinária diversidade morfológica e funcional. Tradicionalmente, a maioria dos estudos morfológicos e ecomorfológicos em membros da subfamília e a família, seja sob uma abordagem descritiva/comparativa e/ou cladística, focalizou o uso de caracteres osteológicos. Este estudo descreve e compara a morfologia cerebral superficial dos membros da subfamília e família e explora seu significado ou valor ecológico e filogenético. Mais de 300 espécimes [incluindo representantes de quase todos os gêneros válidos de Loricariinae, bem como de outras sete subfamílias de Loricariidae (Delturinae, Hypoptopomatinae, Hypostominae, Lithogeninae, Neoplecostominae, “Otothyrinae” e Rhinelepinae)] e 89 caracteres foram examinados. Os resultados obtidos sugerem que o tamanho, volume e forma relativa das diferentes estruturas cerebrais examinadas varia principalmente com o comportamento alimentar e o ambiente preferido. Além disso, quando analisados e avaliados em conjunto com hipóteses de relacionamento filogenético, estes resultados podem ser considerados como evidência empírica apoiando o fato de que a diversidade cerebral nos membros atuais da subfamília e a família pode ser o resultado tanto do conservadorismo de nicho filogenético quanto da radiação adaptativa repetida. Finalmente, este trabalho fornece dados adicionais a serem considerados na árvore evolutiva da subfamília e a família, destacando a necessidade de mais estudos integrando informações de diferentes sistemas anatômicos em um contexto filogenético. Além disso, este trabalho representa uma base para futuras investigações sobre as relações entre a anatomia do cérebro e a ecologia dos membros da subfamília, família e ordem em um contexto filogenético.
The family Loricariidae is the most species-rich within the Siluriformes, containing about 980 valid species. Members of the family are easily recognized by having bodies covered by ossified dermal plates, abundant integumentary teeth and a ventral oral disk that facilitates surface attachment and feeding. The subfamily Loricariinae is the second most species rich within the Loricariidae containing 31 genera and about 243 valid species. Members of the subfamily are easily recognized by having an elongate and depressed caudal peduncle and by lacking of adipose fin. Species of the Loricariinae are widely distributed throughout the Central and South American major river drainages, being usually found near the substrate and showing an extraordinary morphological and functional diversity. Traditionally, most of the morphological, and ecomorphological, studies on members of the subfamily and the family, either under a descriptive/comparative and/or cladistic approach, have focused on the use of osteological characters. This study describes and compares the gross brain morphology of the members of the subfamily and the family and explores their ecological and phylogenetic significance. More than 300 specimens [including representatives of almost all valid genera of the Loricariinae, as well as of other seven subfamilies of the Loricariidae (Delturinae, Hypoptopomatinae, Hypostominae, Lithogeninae, Neoplecostominae, “Otothyrinae” and Rhinelepinae)] and 89 characters were examined. The results obtained suggest that the relative size, volume and shape of the different brain structures examined varies mostly with feeding behaviour and preferred environment. Furthermore, when analyzed and evaluated in conjunction with hypotheses of phylogenetic relationships, these results can be considered as empirical evidence supporting the fact that brain diversity in current members of the subfamily, and the family in general terms, could be the result of both phylogenetic niche conservatism and repeated adaptive radiation. Finally, this work provides considerable additional data to the evolutionary tree of the subfamily and the family, highlighting the needing of further studies integrating information from different anatomical systems in a phylogenetic context. Moreover, this work could be a basis for further investigations on the relationships between brain anatomy and the ecology of members of the subfamily, family and order in a phylogenetic frame.
The family Loricariidae is the most species-rich within the Siluriformes, containing about 980 valid species. Members of the family are easily recognized by having bodies covered by ossified dermal plates, abundant integumentary teeth and a ventral oral disk that facilitates surface attachment and feeding. The subfamily Loricariinae is the second most species rich within the Loricariidae containing 31 genera and about 243 valid species. Members of the subfamily are easily recognized by having an elongate and depressed caudal peduncle and by lacking of adipose fin. Species of the Loricariinae are widely distributed throughout the Central and South American major river drainages, being usually found near the substrate and showing an extraordinary morphological and functional diversity. Traditionally, most of the morphological, and ecomorphological, studies on members of the subfamily and the family, either under a descriptive/comparative and/or cladistic approach, have focused on the use of osteological characters. This study describes and compares the gross brain morphology of the members of the subfamily and the family and explores their ecological and phylogenetic significance. More than 300 specimens [including representatives of almost all valid genera of the Loricariinae, as well as of other seven subfamilies of the Loricariidae (Delturinae, Hypoptopomatinae, Hypostominae, Lithogeninae, Neoplecostominae, “Otothyrinae” and Rhinelepinae)] and 89 characters were examined. The results obtained suggest that the relative size, volume and shape of the different brain structures examined varies mostly with feeding behaviour and preferred environment. Furthermore, when analyzed and evaluated in conjunction with hypotheses of phylogenetic relationships, these results can be considered as empirical evidence supporting the fact that brain diversity in current members of the subfamily, and the family in general terms, could be the result of both phylogenetic niche conservatism and repeated adaptive radiation. Finally, this work provides considerable additional data to the evolutionary tree of the subfamily and the family, highlighting the needing of further studies integrating information from different anatomical systems in a phylogenetic context. Moreover, this work could be a basis for further investigations on the relationships between brain anatomy and the ecology of members of the subfamily, family and order in a phylogenetic frame.
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Cascudos, Ecomorfologia, Filogenia, Neuroanatomia, Ontogenia, Ecomorphology, Neuroanatomy, Ontogeny, Phylogeny, Suckermouth armoured catfishes