Osteogaster
Osteogaster is a genus of catfish in the subfamily Corydoradinae, family Callichthyidae of the order Siluriformes. Before the recent resurrection of the genus, these species had been grouped in the genus Corydoras.
Taxonomy
Osteogaster was erected by Edward Drinker Cope in 1894. Before 2024, it was considered defunct by most scientific authorities, being considered as a junior synonym or subgenus of Corydoras. It was formally resurrected and revalidated in a phylogenomic analysis carried out in 2024.Etymology
The generic name, Osteogaster, is derived from the Greek ὀστέον, ostéon, meaning "bone:, and γαστήρ, gastḗr, meaning "belly", referring to the coracoid bones of O. eques which completely enclose the ventral region.Morphology
The basic color of species of the genus Osteogaster is yellowish-orange to reddish-orange, and there is a single large dark spot on the sides of the body. The fins are usually unspotted. Osteogaster species differ from all other armoured catfishes in the following characteristics, among others:- The mesethmoid, a skull bone, is small to medium-sized. In Gastrodermus, the mesethmoid is noticeably short. In Corydoras, it is large, and in Brochis, it is very large.
- The posterior edge of the pectoral fin spine is usually provided with serrations, which are perpendicular or arranged at right angles to the spine. In Brochis, Corydoras, Gastrodermus, and Scleromystax, these serrations are directed toward the base of the pectoral fin spine.
Species
, there are currently eight extant species in this genus :Osteogaster aenea Osteogaster eques Osteogaster hephaestus Osteogaster maclurei Osteogaster melanotaenia Osteogaster oharai Tencatt, Carvalho, Silva & Britto, 2025Osteogaster rabauti Osteogaster zygata;Incertae sedisOsteogaster macrosteus Osteogaster microps Osteogaster schultzei