Integrative approach reveals a new species of Nematocharax (Teleostei: Characidae)

Unraveling the systematics and evolution of the 'Geophagus' brasiliensis (Cichliformes: Cichlidae) species complex

The 'Geophagus' brasiliensis complex is one of the most abundant groups of cichlids from eastern coastal basins in South America. Traditionally, this fish group has been recognized as incertae sedis because of phylogenetic uncertainties and unclear taxonomy. In addition, the remarkable morphological, chromosomal, and DNA variation reported over recent years in several populations of these cichlids has increased the debate about their species richness and their distributional range. Here, we tested the presence of independent evolutionary lineages within the 'G.' brasiliensis complex, addressing their taxonomic status and evolutionary relationships, including a comparative analysis of genetic and morphological patterns, based on an extensive dataset, comprising 172 sampling sites along most of their known range using a mitochondrial marker, RADseq data and geometric morphometrics. The number of putative species in the present study varied from 9 to 11 depending on the molecular species delimitation methods used. Our results revealed at least two putative new taxa ('Geophagus' sp. Doce and 'Geophagus' sp. Upper Contas). Morphometric analyses, particularly those based on Canonical Variate Analysis (CVA), revealed significant morphological differentiation between species within the main clades. On the other hand, analyses of morphological phylogenetic signal and phylomorphospace provided no evidence of adaptive differentiation among these species. Thus, diversification in the 'G.' brasiliensis complex seems to have been influenced by hydrogeological events that promoted allopatry, such as the presence of paleodrainages and distributional reconfiguration through river captures. We propose major changes in the known distribution of some species within the complex and conservatively suggest the recognition of 10 species within the 'Geophagus' brasiliensis complex, with the potential for further dividing 'G.' rufomarginatus after additional taxonomic evaluation.

Freshwater fishes of the Bahia State, Northeastern Brazil

Abstract: This work was carried out from the assessment of the conservation status of the freshwater ichthyofauna from Bahia State. The inventory data and species distribution were obtained from the specialized scientific literature and representative ichthyological collections. A total of 281 native species was recorded in Bahia State, distributed in the Northeastern Mata Atlantica (NMA) and São Francisco (SFR) freshwater ecoregions. There was a larger number of species in the NMA (187 spp.), composed by several coastal basins, than in the SFR (134 spp.), composed by São Francisco river basin. Among the 30 families recorded, Characidae and Rivulidae were the most representative, with 53 and 48 species, respectively. The conservation status of 214 species was assessed and 33 of them (15%) were included in the IUCN threat categories. Of these, 11 species were classified as vulnerable (VU), 12 as endangered (EN), and 10 as critically endangered (CR). Most threatened species (n = 14) belongs to the family Rivulidae. The larger number of threatened species in the NMA: (n = 23) is mainly related to the high endemism of restricted-range species associated with the human occupation impacts along the coastal regions. In the SFR, most of threatened species are annual killifishes, which are locally disappearing due to increasing degradation of their temporary habitats.

Integrative systematics unveils the controversial identity of Engraulidae fishing stocks in a Neotropical estuary, northeast Brazil

ABSTRACT In Brazil, the use and diversity of the common names of fish species, coupled with taxonomic uncertainties, hinder the reliability of fishing statistical data. In this scenario, there are the so-called pilombetas of the São Francisco River, an important fishing resource in region. Despite its importance, the real diversity of species identified in the area remains obscure. In order to properly identify and delimit the species popularly known as pilombetas, an integrative approach involving traditional taxonomy, geometric morphometrics and molecular systematics was applied. Results from geometric morphometrics and molecular analyses were consistent with the results of the traditional morphological analysis, also indicating the delimitation of six taxa belonging to Engraulidae in the lower São Francisco River. In addition, species delimitation methods revealed an intrapopulation genetic divergence of 1.7% for Lycengraulis grossidens. The results revealed that the currently known richness species of Engraulidae in the studied area has been underestimated. Thus, an updated taxonomic key is herein proposed for the Engraulidae species from the lower São Francisco River and estuary. The integrative analysis approach revealed to be effective to address taxonomic questions and help the management of stocks, ensuring the maintenance of local diversity of fishes in the Neotropical region.

A new species of Astyanax (Characiformes: Characidae) from the rio de Contas basin, Bahia, Brazil

ABSTRACT A new species of Astyanax from tributaries of the rio de Contas, Bahia, Brazil, is described. The new species differs from congeners by having three horizontal series of scales from lateral line to pelvic-fin origin and the distal margin of third infraorbital distinctly separated from vertical and horizontal limbs of preopercle, leaving a broad area not covered by superficial bones. The new species further differs from most congeners by the presence of bony hooks on all fins of mature males. Particularly from congeners occurring in rivers of the Northeastern Mata Atlântica freshwater ecoregion, it further differs by having the highest body depth just anterior to the dorsal-fin origin, 34-37 pored lateral line scales, a vertically elongated conspicuous dark humeral blotch reaching below the lateral line and a conspicuous dark wide midlateral stripe extending from the clear area on the rear of the humeral blotch to the end of middle caudal-fin rays and forming an inconspicuous blotch on caudal peduncle.