Pattern and processes of cichlid speciation along a geographical gradient in the Lower Congo River: Are species complex genomic networks?
Final Report Abstract
The cichlid (Teleostei: Ovalentaria) fauna along the rapids of the lower Congo river had been established as a potential model-system to study patterns of parapatric and hybrid speciation in a riverine species-flock. As the river section around Inga had been identified in the preceding project as a border for cichlid species composition and as a potential contact zone for secondary hybridisation, a refined sampling of cichlids of different evolutionary lineages belonging to the genus Steatocranus, Lamprologus and Haplochromis was conducted in summer July/August 2013 across this section for this project. With a focus on the key genus Steatocranus, 234 samples were successfully genotyped using the NGS technique ddRADseq method, phenotypically characterised using geometric morphometry and 692 stable-isotope data to obtain a complementary dataset that would allow for hypothesis testing alternative hypotheses regarding alternative parapatric speciation scenarios. Genome-wide patterns of allopatric and parapatric divergence of Steatocranus populations belonging to the lineages GGM (S. gibbiceps, S. glaber, S. mpozoensis) and TIN (S. cf. tinanti) could be explored. Although patterns of gene flow and connectivity between the different Steatocranus populations were investigated using genome-wide SNP data, the planned in-depth analysis of genetic variation across genomes to infer patterns of introgression and hybridisation had to remained incomplete with regard to testing for the (1) relative importance of “hybrid trait speciation” versus “mosaic genome hybrid speciation”, (2) the role of transgressive segregation in the rapid build-up of local adaption and reproductive isolation, and (3) differential genomic architecture of putative homoploid hybrid species look like.
Publications
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(2015) Lake Tanganyika—A 'Melting Pot' of Ancient and Young Cichlid Lineages (Teleostei: Cichlidae)? PLoS One: e0125043
Weiss JD. Cotterill FPD & Schliewen UK
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(2019) Paragobiocichla, a new genus name for Gobiochromis irvinei Trewavas, 1943 (Teleostei, Cichlidae). Spixiana 42 (1) 133-139
Weiss JD, Schedel FDB, Ibala Zamba, A, Vreven JWMN & Schliewen UK
