Unrecognized and imperilled diversity in an endemic barb (Smiliogastrini, Enteromius) from the Fouta Djallon highlands

Abstract

The Upper Guinean Forests of Guinea, Sierra Leone and Liberia contain high levels of freshwater biodiversity. The Guinean Range and associated Fouta Djallon highlands separate two biogeographical provinces in the region and served as a refugium during past climatic fluctuations. While many species of freshwater fishes are restricted to one biogeographical province or the other, some are reported to occur on both sides of the divide. Here, we examine the molecular and morphological diversity of an endemic small African barb, Enteromius foutensis, reported to occur in both provinces. This integrative analysis revealed unrecognized diversity and suggests recent, or ongoing, events that facilitated geodispersal and subsequent divergence in the region. The molecular analysis revealed three divergent and well‐supported populations within E. foutensis. Accounting for allometric shape variation allowed us to observe diagnostic morphological differences among the populations. Enteromius foutensis sensu stricto is restricted to the Little Scarcies drainage in Guinea and northern Sierra Leone. Our study revealed two candidate species distinct from E. foutensis. One is likely a narrow endemic restricted to a small area in the Konkouré River basin; the other candidate species inhabits the upper Senegal and Gambie River drainages. How these patterns of diversity compare with other freshwater species from the Fouta Djallon highlands and the conservation status of these candidate species are also discussed.

Revalidation of Enteromius alberti and presence of Enteromius cf. mimus (Cypriniformes: Cyprinidae) in the Lake Edward system, East Africa

“…The unrecognised diversity found within species complexes in various systems (e.g., Schmidt et al 2017Schmidt et al , 2019Van Ginneken et al 2017), the revalidation of species as found in our study and the study of Schmidt et al (2018), and the description of new species, such as E. pinnimaculatus from Gabon (Mipounga et al 2019) and E. thespesios from the Upper Congo River (Katemo Manda et al 2019) all suggest that the species richness of Enteromius is much larger than currently thought. Hence, the present number of 211 valid species of Enteromius (Froese & Pauly 2019), is certainly a considerable underestimation of the real species diversity.…”

“…Hence, although, a priori, we failed to distinguish the two species from each other, the concept of cryptic species is not applicable here. Another study (Schmidt et al 2019) also revealed unrecognised diversity in E. foutensis from the Fouta Djallon (Upper Guinea region) highlands, both genetically (Cytb) and morphologically. Schmidt et al (2017) also found evidence of high levels of genetic divergence and unrecognized diversity (Cytb) in specimens identified as E. kerstenii, E. apleurogramma and E. cf.…”

Allopatric differentiation in the Enteromius anoplus complex in South Africa, with the revalidation of Enteromius cernuus and Enteromius oraniensis, and description of a new species, Enteromius mandelai (Teleostei: Cyprinidae)

“…The small African barbs are abundant across Africa. With nearly 350 recognised species in the genus Enteromius (Eschmeyer, 2019), the recent works suggest that the actual number of species is higher (Mipounga et al ., 2019; Schmidt et al ., 2018, 2019). Taxonomic revision is needed for a number of species in the genus Enteromius .…”

A new species of suckermouth catfish (Mochokidae: Chiloglanis) from the Rio Mongo in Equatorial Guinea

“…Additionally, performing an allometric correction with the RMA regression in SMATR improves the resolution of this analysis, and while the elevations of PC1 were not significantly different between C. mongoensis and C. harbinger it seems likely that these results would change with the addition of more specimens. This allometric correction allows one to observe and test intergroup differences that may be overlooked by removing PC1 from the analysis and can aid in the delineation of morphologically cryptic species (Sidlauskas et al 2011;Bart et al 2019;Schmidt et al 2019). This study also shows the utility of RMA regression for determining the diagnostic value of size-correlated meristic variables.…”