Otoliths of sympatric species – a case study on the annual killifish Nothobranchius from the East African savannah
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1
Ludwig-Maximilians University, Department of Earth and Environmental Sciences, Palaeontology & Geobiology, Germany
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2
Academy of Sciences of the Czech Republic, Brno, Czech Republic, Institute of Vertebrate Biology, Czechia
Members of the aplocheiloid killifish genus Nothobranchius are small (3–15 cm), have a short lifecycle (3–12 months) and are widely distributed in tropical and subtropical Eastern and Central Africa. About 62 valid species of Nothobranchius are currently known. Their diversification is apparently exclusively allopatric, but up to four species of Nothobranchius can co-occur syntopically in the same pools as a result of secondary sympatry. Here we studied a comprehensive dataset based on a total of 86 individuals representing five extant species of Nothobranchius PETERS, 1868, from East Africa: the sympatric pairs N. rubripinnis SEEGERS, 1986 and N. ruudwildekampi COSTA, 2009 (Eastern Tanzania), and N. orthonotus (PETERS, 1844) and N. furzeri JUBB, 1971 (Southern Mozambique), and two isolated populations of N. korthausae MEINKEN, 1973 (Eastern Tanzania). Otolith characters were analysed based on SEM images, and otolith morphometry was conducted using uni- and multivariate statistics. We found the otoliths of the studied species of Nothobranchius diagnostic at the species level, even in the case of closely related species diagnosable otherwise only by minor differences in coloration (like N. korthausae and N. ruudwildekampi). A notable feature of the otoliths of the sympatric species pairs was that the sulcus morphology clearly differs between the members of each pair. These distinctive sulcus morphologies in the otoliths of the studied sympatric species may be linked to species-specific hearing capabilities, perhaps constituting a case of character displacement in an area of secondary sympatry. The new data may also facilitate future recognition of fossil species of Nothobranchius. As no fossil remains of extant aplocheiloid killifishes have yet been described, the discovery of fossil otoliths of Nothobranchius would significantly advance understanding of the evolutionary history of this interesting group of fishes.
References
Reichenbacher, B. & Reichard, M. (2014). Otoliths of Five Extant Species of the Annual Killifish Nothobranchius from the East African Savannah. – PLoS ONE 9(11): e112459. doi:10.1371/journal.pone.0112459
Keywords:
Killifishes,
otolith,
sympatric species,
East Africa,
evolutionary history,
Otolith morphometry,
Otolith morphology,
sulcus
Conference:
XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015.
Presentation Type:
Oral Presentation
Topic:
Otoliths as a tool to study fish life cycles
Citation:
Reichenbacher
B and
Reichard
M
(2015). Otoliths of sympatric species – a case study on the annual killifish Nothobranchius from the East African savannah.
Front. Mar. Sci.
Conference Abstract:
XV European Congress of Ichthyology.
doi: 10.3389/conf.fmars.2015.03.00127
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Received:
23 Nov 2015;
Published Online:
24 Nov 2015.
*
Correspondence:
Prof. Bettina Reichenbacher, Ludwig-Maximilians University, Department of Earth and Environmental Sciences, Palaeontology & Geobiology, Munich, Germany, b.reichenbacher@lrz.uni-muenchen.de