Ontogeny of the brain of Microglanis garavelloi Shibatta and Benine 2005 (Teleostei: Siluriformes: Pseudopimelodidae).

The gross brain morphology and the peripheral olfactory organ of Microglanis garavelloi are described throughout development, and the relationship of these organs to the general behaviour of the species is discussed. During the development, the main brain subdivisions undergo a series of morphological changes keeping a relatively constant volume increase. However, we observed different growth rates in the brains of males and females when these were compared. During the maturation process, a series of hormonal events result in the development of some secondary sexual traits in the brain of male specimens, like faster growth rate of brain areas linked to motor control, olfactory and visual responses. The number of olfactory-organ lamellae increases continuously in both males and females, during their maturation period. These results suggest that changes may be caused by cognitive demands that this species is exposed to throughout its lifespan. The gross morphological arrangement of the central nervous system indicates shared patterns with other members of the family Pseudopimelodidae.

Phylogeny of the Neotropical Pacman catfish genus Lophiosilurus (Siluriformes: Pseudopimelodidae)

Lophiosilurus is a monotypic genus represented by L. alexandri, a species endemic to the São Francisco river basin, Brazil. In previous phylogenetic analyses, the genus has been recovered as the sister group of Cephalosilurus. However, few species of Cephalosilurus or few characters were included in those studies. Thus, the current study aims to test the monophyletic hypothesis of the genera Lophiosilurus and Cephalosilurus with a more comprehensive phylogenetic analysis, including all Cephalosilurus species and a representative number of characters. Phylogenetic analyses of 18 terminal taxa (15 ingroups and three outgroups) were conducted based on a combined 75 character matrix, including 70 discrete morphological characters concerning osteology and neuroanatomy, four continuous characters, and the geometric morphometry of the head. The monophyly of the family Pseudopimelodidae was highly supported, and Cephalosilurus is synonymized with Lophiosilurus. The recovered phylogeny of the genus was (L. albomarginatus (L. nigricaudus (L. apurensis (L. fowleri, L. alexandri)))).(AU)

Lophiosilurus é um gênero monotípico representado por L. alexandri, uma espécie endêmica da bacia do rio São Francisco, Brasil. Em análises filogenéticas anteriores, o gênero foi recuperado como grupo irmão de Cephalosilurus. No entanto, poucas espécies de Cephalosilurus ou poucos caracteres foram incluídos nesses estudos. Assim, este estudo tem como objetivo testar a hipótese de monofilia dos gêneros Lophiosilurus e Cephalosilurus, com uma análise filogenética mais abrangente, incluindo todas as espécies de Cephalosilurus e um número representativo de caracteres. As análises filogenéticas de 18 táxons terminais (15 do grupo interno e três grupos externos) foram realizadas com base em uma matriz combinada de 75 caracteres, incluindo 70 caracteres morfológicos discretos de osteologia e neuroanatomia, quatro caracteres contínuos e um de morfometria geométrica da cabeça. A monofilia da família Pseudopimelodidae foi altamente apoiada e Cephalosilurus foi sinonimizado como Lophiosilurus. A filogenia recuperada do gênero foi (L. albomarginatus (L. nigricaudus (L. apurensis (L. fowleri, L. alexandri))).(AU)

Reappraisal of the systematics of Microglanis cottoides (Siluriformes, Pseudopimelodidae), a catfish from southern Brazil.

The southern region of Brazil is characterized by high species diversity and endemism of freshwater fishes distributed across geographically isolated river basins. Microglanis cottoides has a widespread range across these river basins and occurs in sympatry with other endemic species of the genus (e.g. M. cibelae, M. eurystoma, and M. malabarbai). Herein we tested the monophyly of M. cottoides and presented for the first time information about the molecular phylogeny of species in the genus. The results suggest that M. cottoides currently forms a non-monophyletic group which includes populations endemic to the Uruguay River basin that are more closely related to M. malabarbai, and excludes M. cibelae, found to be nested within M. cottoides. Based on an integrative approach using morphological and molecular data, we propose M. cibelae as a junior synonym of M. cottoides, and the populations of the Uruguay River basin previously assigned to M. cottoides in fact belong to M. malabarbai. Our molecular phylogeny shows that M. cottoides is sister to M. parahybae, which is also a coastal species, and M. malabarbai is sister of M. garavelloi, both endemic to inland river basins. The time-calibrated phylogeny indicates that the separation between inland and the coastal clades occurred in the Tertiary period, and that the species within the coastal basins diverged in the Pliocene, which overlaps with the diversification times estimated for the two inland species as well. This pattern of diversification corroborates some previous studies with other fishes from the same region.