https://www.researchgate.net/publication...ge_system_Kenya

Evolution of African barbs from the Lake Victoria drainage system, Kenya

Authors:

Violet M. Ndeda1,2, Mariana Mateos1 and Luis A. Hurtado1

1 Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, United States of America
2 Department of Zoology, Maseno University, Maseno, Kenya

October 2018 PeerJ 6(Suppl. 1):e5762
DOI:10.7717/peerj.5762
LicenseCC BY

Abstrakt:

The Lake Victoria drainage basin (LVD) in Kenya is home to ten nominal species of small barbs (Enteromius) and one of large barbs (Labeobarbus altianalis). A recent molecular study genetically characterized small barbs in this region and found evidence of introgression between certain species, complicating the taxonomy and species identification of these fishes. This study aimed to extend our understanding on the evolution of these fishes by: (1) determining whether putatively pure individuals of Enteromius cercops are found in the Kenyan LVD, as the previous study only found hybrid individuals of this species in this region; (2) testing the sister relationship between Enteromius profundus, endemic to Lake Victoria, and Enteromius radiatus, also found in Lake Victoria, which had been previously synonymized; (3) examining the phylogenetic relationships of small barbs of the Kenyan LVD with those reported from other ichthyological provinces of Africa; and (4) examining the phylogenetic relationships of Labeobarbus altianalis with other Labeobarbus species. To this end, we obtained mitochondrial Cytochrome b and nuclear Growth Hormone (GH) intron 2 gene sequences of nine Enteromius species from the LVD in Kenya, as well as cytochrome b sequences for L. altianalis. We conducted Maximum likelihood and Bayesian phylogenetic analyses to establish their evolutionary relationships in relation to many other barbs specimens from Africa. Phylogenetic analyses did not reveal instances ofhybridization/introgression amongthe individuals sequenced byus. Asister relationship between E. profundus and E. radiatus was not found. This latter species shows instead a sister relationship with a lineage comprised of two species from West Africa. Other sister relationships between taxa from the East coast and other ecoregions fromAfrica are observed, suggesting that past drainage connections and vicariant events contributed to the diversification of Enteromius. Finally, only a single haplotype was recovered among the L. altianalis individuals examined, which is most similar to a specimen from Lake Edward in Uganda.



Figure 1 Localities of specimens sampled in this study (triangles). Circles represent localities within theLake Victoria Drainage (LVD) sampled by Schmidt, Bart & Nyingi (2017) that were not sampled in ourstudy (locations are approximate based on their description of locality, as coordinates were not reported).The map was developed with ArcMap version 10.3—a part of the ESRI ArcGIS RDesktop suite. Localitieswhere each species was sampled for our study are as follows: Enteromius apleurogramma (2); Enteromius cercops (1, 5, 7, 9); Enteromius cf. paludinosus (13); E. jacksoni (7); E. kerstenii (1, 6, 14); E. neumayeri (3);E. nyanzae (7, 10); E. profundus (8); and L. altianalis (4, 5, 10, 11, 12).

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