Genetic diversity of a widespread annual killifish from coastal Tanzania

Abstract

Background: African annual killifishes (Nothobranchius spp.) are adapted to seasonally desiccating habitats (ephemeral pools), surviving dry periods as dormant eggs. Given their peculiar life history, geographic aspects of their diversity uniquely combine patterns typical for freshwater taxa (river basin structure and elevation gradient) and terrestrial animals (rivers acting as major dispersal barriers). However, our current knowledge on fine-scale interspecific and intra-specific genetic diversity of African annual fish is limited to a single, particularly dry region of their distribution (subtropical Mozambique). Using a widespread annual killifish from coastal Tanzania and Kenya, we tested whether the same pattern of genetic divergence pertains to a wet equatorial region in the centre of Nothobranchius distribution. Results: In populations of Nothobranchius melanospilus species group across its range, we genotyped a part of mitochondrial cytochrome oxidase subunit 1 (COI) gene (83 individuals from 22 populations) and 10 nuclear microsatellite markers (251 individuals from 16 populations). We found five lineages with a clear phylogeographic structure but frequent secondary contact. Mitochondrial lineages were largely congruent with main population genetic clusters identified on microsatellite markers. In the upper Wami basin, populations are isolated as a putative Nothobranchius prognathus, but include also a population from a periphery of the middle Ruvu basin. Other four lineages (including putative Nothobranchius kwalensis) coexisted in secondary contact zones, but possessed clear spatial pattern. Main river channels did not form apparent barriers to dispersal. The most widespread lineage had strong signal of recent population expansion. Conclusions: We conclude that dispersal of a Nothobranchius species from a wet part of the genus distribution (tropical lowland) is not constrained by main river channels and closely related lineages frequently coexist in secondary contact zones. We also demonstrate contemporary connection between the Ruvu and Rufiji river basins. Our data do not provide genetic support for existence of recently described cryptic species from N. melanospilus complex, but cannot resolve this issue.

Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

“… † fWHR was not consistently and/or significantly associated with sexual dimorphism. Two other dimensions used in previous research but not included in the present study are: 1) fWHR eyelids (zygion to zygion/ highest point of the upper lip to the highest point of the eyelids): Alhajis & Ward (2013) [ 183 ]; Anderl et al, (2016) [ 184 ]; Chan et al (2020) [ 185 ]; Efferson & Vogt (2013) [ 186 ]; He et al (2019) [ 187 ]; Kramer et al (2012)*† [ 26 ]; Leboa & Karwowski (2016) [ 188 ]; Lewis et al (2012) [ 58 ]; Noser et al, (2018)* [ 64 ]; Stirrat & Perrett (2010) [ 62 ]; Wen & Zheng (2020) [ 173 ]; Żelaźniewicz et al (2020) [ 189 ]; Zhang et al (2018) [ 190 ]. 2) fWHR whole face (zygion to zygion/ between the center of the hairline to the center of the chin): Lee et al (2018) [ 191 ]; Polo et al (2019; forehead)* [ 192 ]; Zebrowitz et al (2015; top of the head in infants) [ 128 ].…”

Following the Mangroves: diversification in the banded lampeye Aplocheilichthys spilauchen (Duméril, 1861) (Cyprinodontiformes: Procatopodidae) along the Atlantic coast of Africa

“…Studies on the evolution of the Congo River drainage (Beadle, 1981 ; Burke, 1996 ; Giresse, 2005 ; Goudie, 2005 ; Stankiewicz & de Wit, 2006 ; Runge, 2007 ), deposition patterns in the Congo deep sea fan (Lavier et al, 2001 ; Leturmy et al, 2003 ; Lucazeau et al, 2003 ; Anka & Séranne, 2004 ; Anka et al, 2009 ; Savoye et al, 2009 ) and freshwater fish diversification in the basin (Goodier et al, 2011 ; Schwarzer et al, 2011 ; Alter et al, 2015 , 2017 ; Arroyave et al, 2020 ; Stiassny & Alter, in press) reveal a complex geologic history for the most diverse river basin in Africa. In the western basin, sedimentary studies suggest a protracted history of shifting and intermittent outflow of the Congo River into the Atlantic during the Cenozoic.…”

Molecular systematics of the Sicista tianschanica species complex: a contribution from historical DNA analysis

“…It should be highlighted that the use of historical samples has been crucial in recent studies to reveal cryptic diversity within many branches of the rodent Tree of Life ( De Abreu et al, 2020 ; Castañeda-Rico et al, 2020 ; Emmons & Fabre, 2018 ).…”