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

Abstract

The brain of Brycon orbignyanus is described as a model for future studies of the gross morphology of the central nervous system in Characiformes. The study of brain gross morphology of 48 distinct taxa of Characiformes, one of Cypriniformes, two of Siluriformes and two of Gymnotiformes, allowed us to propose, for the first time, six putative brain synapomorphies for the Characiformes and also two possibly unique gross brain morphology characters for the Siluriformes. A detailed protocol for the extraction of the brain in Characiformes is also provided.O encéfalo de Brycon orbignyanus é descrito como um modelo para futuros estudos da anatomia externa do Sistema Nervoso Central de Characiformes. O estudo da morfologia externa de 48 táxons distintos de Characiformes, um de Cypriniformes, dois de Siluriformes e dois de Gymnotiformes, permitiu-nos propor, pela primeira vez, seis prováveis sinapomorfias encefálicas e também duas possíveis características encefálicas para Siluriformes. Um protocolo detalhado para a dissecção e extração do encéfalo de Characiformes é também apresentado.

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

“…The brain limits established herein for S. javae follow Pereira & Castro () with some modifications, i.e . the anterior portions of the bulbus olfactorius anteriorly, usually ending at the semi‐oval olfactory epithelium (Fig.…”

“…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, ). In S. javae , the corpus cerebelli is very conspicuous and larger than in Pseudopimelodus .…”

“…Even though Pereira & Castro (2016) and Abrahão & Shibatta (2015) described the brain gross anatomy of Brycon orbignyanus (Valenciennes 1850) (Characiformes) and Pseudopimelodus bufonius (Valenciennes 1840) (Siluriformes), respectively, there are fewer studies in the current literature that examined the brains of loricariid species (Rosa et al, 2014;Rosa, 2015;Angulo & Langeani, 2017). Thus, the description proposed here may contribute to further studies in this area.…”

“…All specimens were previously stained using the technique of Datovo & Bockmann (2010) that allows a better visualization of neurocranial bones and its sutures in prepared specimens without any undesirable changes caused to the brain. Procedures for brain dissection and description follow Pereira & Castro (2016), with a few modifications related to the anatomical structure of the siluriform head as described by Abrahão & Shibatta (2015). Brain images were captured with a camera attached to a stereomicroscope and edited through software editors.…”

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, ).…”