Gross brain morphology of Hypoptopomatinae and Neoplecostominae (Siluriformes: Loricariidae): Comparative anatomy and phylogenetic implications

Abstract

Neoplecostominae sensu Pereira and Reis (2017) together include 250 valid species arranged in 33 genera (Fricke, Eschmeyer, & Van der Laan, 2020). The subfamilies comprise small to medium-sized loricariid catfishes, known commonly as cascudinhos, and which are widely distributed in small to moderate-sized streams and rivers in South America from Venezuela to Argentina (Ferraris, 2003; Schaefer, 2003).

A new species ofParotocinclus(Loricariidae: Hypoptopomatinae) from the rio Pardo basin, Bahia State, Brazil, with comments on the sexually dimorphic traits of the nares and olfactory lamellae

“…Recently, Rosa et al . (2020) registered sexual dimorphism in olfactory organ present, with larger and/or with more lamellae in males as occurring in 13 species of hypoptopomatines, along with Neoplecostomus microps . Only Parotocinclus maculicauda represented the genus on that study being coded as having a sexually dimorphic olfactory organ.…”

“…(2017) described the presence of wider nares in males of P. fluminense Roxo, Melo, Silva & Oliveira and, more recently, Rosa et al . (2020) registered larger and/or with more lamellae in males to 13 species of hypoptopomatines plus Neoplecostomus microps (Steindachner). Although the trait is newly described in hypoptopomatines, wider nares in males were first recorded in marine fishes (Bertelsen, 1951; Marshall, 1967) and posteriorly taken as a sexually dimorphic character in different species of fishes, including representatives of orders such as Siluriformes (Roxo et al ., 2017) and Characiformes (Abrahão et al ., 2019).…”

Gross morphology of the brain and some sense organs of subterranean pencil catfishes of the genus ItuglanisCosta and Bockmann, 1993 (Siluriformes, Trichomycteridae), with a discussion on sensory compensation versus preadaptation in subterranean fishes

“…The general pattern of the brain, which is the general condition found in all specimens analysed, is described before the comparisons are presented, and compared with data from literature (e.g., Kotrschal et al, 1998). Identification and nomenclature of the different brain regions were based on studies of the brain anatomy of different catfishes, including trichomycterids, available in the literature (Abrahão et al, 2018a; Abrahão et al, 2018b; Abrahão et al, 2021; Abrahão & Shibatta, 2015; Chamon et al, 2018; Espíndola et al, 2018; Kapoor et al, 2003; Langecker & Longley, 1993; Nalbant & Linares, 1987; Northcutt et al, 2000; Pouilly & Miranda, 2003; Pupo & Britto, 2018; Rosa et al, 2020; Trajano, 1994), to facilitate comparisons with other studies on catfish brain anatomy. Besides the different brain regions, we compared the following sense organs: olfactory organ (including the number of olfactory lamellae, which were counted on both sides of the specimens), eye, and semicircular canals of the inner ear, and the swim bladder.…”