When destruction comes first: Two new species of Hypostomus Lacépède, 1803 (Siluriformes: Loricariidae) from a deeply‐impacted river in the Rio São Francisco basin in Brazil

Abstract

Environmental disasters affecting Brazilian rivers have been frequent recently, especially involving mining activities. Two recent dam-rupture events suddenly released millions of cubic meters of iron tailings downstream into two major Brazilian watersheds. These events generated major losses to the environment and human life.Additionally, the biodiversity in both watersheds was still incompletely known. Two new species of the armoured catfish genus Hypostomus were discovered in the Rio Paraopeba and surrounding rivers of the Rio São Francisco Basin. The species share some main characteristics including a depressed body, large dark spots on a clearer background and the absence of keels on flanks. However, while one species (Hypostomus freirei sp. n.) has a large mandibular ramus and numerous slender teeth, the other (Hypostomus guajupia sp. n.) has a shorter mandibular ramus and few robust teeth. The discovery of these two new mid-sized fish species emphasizes the presumption that the effects of major environmental disasters cannot be fully estimated as local biodiversity is not completely known. This discovery in a recently devastated area also shows that tough environmental laws for the protection, supervision and mitigation of major impacts are urgently needed in developing countries.

Catfishes: A global review of the literature

“… Cluster 5: Geographical Explorations - Moving away from species-centric studies, this cluster, with its spotlight on the “rio sao francisco basin”, emphasizes geographically oriented catfish research. The “southernmost record” theme further underscores regional significance, with most studies from around 2011 [ [59] , [60] , [61] , [62] ]. Cluster 6: Pathogenic Interactions - Rooted in “channel catfish”, this cluster introduces “E dwardsiella ictaluri ”, a known pathogen, hinting at studies concerning disease dynamics in aquaculture.…”

“…Cluster 5: Geographical Explorations - Moving away from species-centric studies, this cluster, with its spotlight on the “rio sao francisco basin”, emphasizes geographically oriented catfish research. The “southernmost record” theme further underscores regional significance, with most studies from around 2011 [ [59] , [60] , [61] , [62] ].…”

A taxonomically complex catfish group from an underrepresented geographic area: Systematics and species limits in Hypostomus Lacépède, 1803 (Siluriformes, Loricariidae) from Eastern South America

“…The species Hypostomus paulinus (Ihering 1905) and H. auroguttatus (Gosline 1947) described for the Upper Paraná ecoregion are also reported in SF and NMA, respectively. The four most recently described species in this group are Hypostomus freirei and Hypostomus guajupia (Penido, Pessali & Zawadzki, 2021), Hypostomus bimbai and Hypostomus pastinhai (Zawadzki & Penido, 2021) (from tributaries of the São Francisco river). In addition, some species described from the NMA and SF ecoregions still lack a precise distribution.…”

“…In general, the color pattern of species from the NMA is characterized by dark spots over a clear background, with variation in the size of spots along head and body (Zanata & Pitanga, 2016; Zanata et al, 2013). On the other hand, the SF ecoregion includes taxa with similar patterns in relation to the NMA and species with clear spots over a dark background (Penido et al, 2021; Ramos et al, 2017; Zawadzki et al, 2017). Nonetheless, morphological and genetic aspects of most representatives of Hypostomus from NMA and SF remain unknown, leading to uncertainties about the validity status of various species due to the lack of refined studies to define whether or not they belong to their scientific names.…”