Gross morphology of the brain of Pseudopimelodus bufonius (Valenciennes, 1840) (Siluriformes: Pseudopimelodidae)

Abstract

The gross morphology of the brain of the pseudopimelodid Pseudopimelodus bufonius is described and compared with congeners. Observations were made on removed brains after elimination of bones from the top of the skull and severing of the cranial nerves and the spinal cord. Nine morphometric characters associated with the major subdivisions of the brain were identified, seven of which revealed significant differences among the species examined. The corpus cerebelli in all examined species of the genus is the largest structure of the brain. The behavior of the species of Pseudopimelodus is still unknown, but in other teleosts that condition is typically correlated with a higher degree of motor coordination. Relative size proportions of the tectum opticum, eminentia granularis, lobus facialis and lobus vagi, might be related to carnivory and an enhanced capacity for food selection.A morfologia externa do encéfalo de Pseudopimelodus bufonius é descrita e comparada com seus congêneres. As análises foram feitas no cérebro removido após a eliminação dos ossos do topo da cabeça e secção dos nervos cranianos e cordão espinhal. Nove caracteres morfométricos foram obtidos das principais subdivisões do encéfalo, dos quais em sete ocorreram diferenças significativas entre as espécies. Em todas as espécies examinadas do gênero o corpus cerebelli é a maior estrutura do encéfalo. O comportamento das espécies de Pseudopimelodus ainda é desconhecido, mas em outros teleósteos esta característica é normalmente correlacionada com uma boa coordenação motora. Além disso, as proporções relativas do tectum opticum, eminentia granularis, lobus facialis e lobus vagi podem ser relacionadas a hábitos carnívoros e boa capacidade de selecionar alimentos.

New species of the genus Spectracanthicus (Loricariidae, Hypostominae, Ancistrini) from the Rio Javaés (Rio Araguaia basin), with a description of gross brain morphology

“…Abrahão & Shibatta () suggested that the corpus cerebelli is relatively large in all Pseudopimelodus Bleeker 1858 species when compared with species of Characiformes ( c.f . Pereira & Castro, ).…”

“…The brain of Spectracanthicus javae is similar to the brains of other siluriform species (Abrahão & Shibatta, ; Rosa, ; Angulo & Langeani, ). Pereira & Castro () described six putative synapomorphies for Siluriformes, all of them are present in the new species: the area postrema is almost as wide as long throughout its length; the rhombencephalon is well developed when compared to the size of the midbrain; the lobus vagi is developed; the lobus fascialis is present, although it is reduced in S. javae; the corpus cerebelli is horizontally developed; the tectum opticum is relatively smaller than the corpus cerebelli.…”

From the inside out: a new species of armoured catfish Corydoras with the description of poorly‐explored character sources (Teleostei, Siluriformes, Callichthyidae)

“…Datovo & Vari (), summarizing Wiley & Johnson (), revealed that within 180 major groups of Teleostei, 6% of synapomorphies are based on myology, 5% on splanchnology and 1% on neurology. Of the last, the first attempts to understand the neural‐complex date back to the beginning of the 20th century, but only from the mid‐1990s has neuroanatomy been used in systematic works on Antarctic fishes (Eastman & Lannoo, , , , , ) and more recently on Neotropical groups (Albert, ; Pupo, ; Abrahão & Shibatta, ; Pupo, ; Pereira & Castro, ). Likewise with other structures, such as the swimbladder capsule and Weberian apparatus, many studies were provided in the 19th century (Birindelli et al, ) and there has more recently been renewed interested in describing them (Birindelli et al, , ; Birindelli & Shibatta, ).…”

The brain of Brycon orbignyanus (Valenciennes, 1850) (Teleostei: Characiformes: Bryconidae): gross morphology and phylogenetic considerations

“…Among the Otophysi (composed by the Orders Cypriniformes, Characiformes, Siluriformes and Gymnotiformes), the study of the brain gross morphology has recently been addressed for gymnotiforms (Albert et al, 1998;Albert, 2001), in addition to the siluriforms Callichthyidae and Pseudopimelodidae (Abrahão & Shibatta, 2015), the Callichthyidae which was the subject of a Master's dissertation (Pupo, 2011) and the Characiformes studied in a Doctoral thesis (Pereira, 2014), both unpublished at this moment. These Otophysi brain studies have unequivocally shown that the central nervous system can be an important source of phylogenetically informative morphological characters, although relatively unexplored.…”