Monogenea in deepwater Lake Tanganyika cichlids: reduced specifity or hidden diversity?
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| Year of publication | 2014 |
| Type | Appeared in Conference without Proceedings |
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| Description | Our study was focused on monogenean species flock in the deep water cichlids in Lake Tanganyika, African Great Rift Valley. The lake is, because of its history, from an evolutionary point of view one of the most important study areas for biodiversity scientists. Surprisingly, the knowledge about its parasitological fauna is insufficient. There are only few studies about the cichlids’ monogenean fauna and only one of these provided some information about deepwater hosts. We tested the apparent decrease of the Cichlidogyrus host specifity in the deepwater habitat by multivariate statistic approaches of morphological characters and genetic characterisation by means of established markers with different rates of molecular evolution to answer the question: is the seemingly low host-specificity caused by cryptic speciation or by a real decrease in host preference? And how broad does this host range go? Fish specimens were collected during the field in 2013 which took its place along the Burundese and Congolese shorelines of Lake Tanganyika and was organized by Masaryk University in cooperation with the Vertebratology department of Czech Academy of Sciences, the Karl-Franzens University of Graz, the Centre de Recherche en Hydrobiologie in Uvira, Fishes of Burundi and the Université du Burundi. To complete the taxon coverage and include some geographical variation, fishes from the collection of the Royal Museum for Central Africa in Belgium were dissected during October 2014. A total number of 12 cichlid specieswhich represent members of endemic Bathybatini (Teleostei, Cihlidae) and also species from other tribes were examined during 2013 and 2014. Cichlidogyrus species were recorded from 8 of them including Bathybates minor, Bathybates horni, Bathybates vittatus, Bathybates fasciatus, Hemibates stenosoma, Trematocara unimaculatum, Gnathocromis pfefferi and Benthochromis tricoti. All these species spent their life in the deep water calm, except G. pfefferi which prefers the intermediate habitat. Provisional results indicate members of Bathybatini are infected by a single monogenean species called Cichlidogyrus casuarinus. The description of two new Cichlidogyrus species from T. unimaculatum and B. tricoti is in process. The reduction of Cichlidogyrus host specifity among Bathybatini is evident in the genetic part of this study. According to the previous studies (in marine system) it is supposed this pattern is probably correlated with lower host availability in the deepwater realm. On the other hand our morphometricsas well as geomorphometric analyses show some kind of differentiation of C. casuarinus influenced by host species which can be probably explained by phenotypic adaptations. Where does this intraspecific variation come from? For investigating parasite speciation mechanisms and answering this question other samples and information about host ecology are necessary. |
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