Multi-locus phylogeny reveals instances of mitochondrial introgression and unrecognized diversity in Kenyan barbs (Cyprininae: Smiliogastrini)

Abstract

The phylogenetics and taxonomic status of small African barbs (Cyprininae: Smiliogastrini) remains unresolved despite the recent decision to elevate the genus name Enteromius for the group. The main barrier to understanding the origin of African small barbs and evolutionary relationships within the group is the poor resolution of phylogenies published to date. These phylogenies usually rely on mitochondrial markers and have limited taxon sampling. Here we investigate the phylogenetic relationships of small barbs of Kenya utilizing cytochrome b, Growth Hormone (GH) intron 2, and RAG1 markers from multiple populations of many species in the region. This multi-locus study produced well-supported phylogenies and revealed additional issues that complicate understanding the relationships among East African barbs. We observed widespread mtDNA introgression within the Kenyan barbs, highlighting the need to include nuclear markers in phylogenetic studies of the group. The GH intron 2 resolved heterospecific individuals and aided in inferring the species level phylogeny. The study reveals unrecognized diversity within the group, including within species reported to occur throughout East Africa, and it provides the groundwork for future taxonomic work in the region and across Africa.

Where ichthyofaunal provinces meet: the fish fauna of the Lake Edward system, East Africa

“…Enteromius apleurogramma , E. kerstenii and E. pellegrini were described from localities in the East Coast Province, respectively Lake Victoria, a coastal river in Tanzania and Lake Kivu, while E. perince and E. stigmatopygus were described from and widely distributed in the River Nile system (Table ). Genetic studies already revealed that widespread species of Enteromius often represent complexes of species that are actually confined to smaller distribution areas (Schmidt et al ., ; Van Ginneken et al ., ). Therefore, it is possible that some of these species may not correspond to the species that they are currently attributed to.…”

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

“…(Schmidt unpublished). Similar patterns of divergences occur in the coastal rivers of the Upper Guinean forests (Schmidt et al 2016), Kenya and Tanzania (Schmidt et al 2017a), and South Africa (Chakona et al 2013). Published barcodes from C. mongoensis (GenBank accession numbers MN015674 and MN015675) are now available and should advance studies on the freshwater diversity in the region.…”

A new species of cyprinoid fish from the Tana River, Kenya (Actinopterygii: Danionidae)

“…Sister relationships between Athi River and Tana River populations have been observed in three other groups of fishes: the Enteromius kerstenii complex (Schmidt et al 2017), the Chiloglanis brevibarbus species complex (Schmidt et al 2014), and mountain catfishes, Amphilius (Thomson & Page 2013). There have likely been numerous instances of headwater capture within the upper Athi and Tana River drainages that could have facilitated biotic dispersal and subsequent divergence.…”