Topic
Bathybates
About: Bathybates is a research topic. Over the lifetime, 5 publications have been published within this topic receiving 220 citations.
Papers
TL;DR: It is proposed on the basis of a linearized tree analysis that the Bathybatini comprise two distinct lineages, the genera Hemibates and Bathybates, that seeded the primary lacustrine Tanganyika radiation independently.
Abstract: The cichlid species flock of Lake Tanganyika represents a polyphyletic assemblage of eight ancestral lineages, which colonized the emerging lake independently. Our study is focused on one of these lineages, the Bathybatini, a tribe of specialized piscivorous cichlids of the deep pelagic zone. By analyzing three mtDNA gene segments of all eight species of the tribe and two species of the closely related Trematocarini, we propose on the basis of a linearized tree analysis that the Bathybatini comprise two distinct lineages, the genera Hemibates and Bathybates, that seeded the primary lacustrine Tanganyika radiation independently. The genus Hemibates is likely to represent a distinct lineage that emerged simultaneously with the tribe Trematocarini and the genus Bathybates and should be therefore treated as a distinct tribe. Within the genus Bathybates, B. minor clearly represents the most ancestral split and is likely to have diverged from the remaining species in the course of the “primary lacustrine Tanganyika radiation” during which also the radiations of the Lamprologini and the H-lineage took place. The remaining “large” Bathybates species also diversified almost simultaneously and in step with the diversification of other Tanganyikan lineages—the Limnochromini and Cyprichromini—with B. graueri occupying the most ancestral branch, suggesting that these were induced by the same environmental changes. The lack of geographic color morphs suggests that competition and resource partitioning, rather than allopatric speciation, promoted speciation within the genus Bathybates.
59 citations
TL;DR: The highly variable mitochondrial DNA indicated recent population expansion, but no ongoing parasite speciation, confirming, for the first time in freshwater, reduced parasite host specificity in the deepwater realm, probably an adaptation to low host availability.
Abstract: Lake Tanganyika is well-known for its high species-richness and rapid radiation processes. Its assemblage of cichlid fishes recently gained momentum as a framework to study parasite ecology and evolution. It offers a rare chance to investigate the influence of a deepwater lifestyle in a freshwater fish-parasite system. Our study represents the first investigation of parasite intraspecific genetic structure related to host specificity in the lake. It focused on the monogenean flatworm Cichlidogyrus casuarinus infecting deepwater cichlids belonging to Bathybates and Hemibates. Morphological examination of C. casuarinus had previously suggested a broad host range, while the lake’s other Cichlidogyrus species are usually host specific. However, ongoing speciation or cryptic diversity could not be excluded. To distinguish between these hypotheses, we analysed intraspecific diversity of C. casuarinus. Monogeneans from nearly all representatives of the host genera were examined using morphometrics, geomorphometrics and genetics. We confirmed the low host-specificity of C. casuarinus based on morphology and nuclear DNA. Yet, intraspecific variation of sclerotized structures was observed. Nevertheless, the highly variable mitochondrial DNA indicated recent population expansion, but no ongoing parasite speciation, confirming, for the first time in freshwater, reduced parasite host specificity in the deepwater realm, probably an adaptation to low host availability.
47 citations
TL;DR: Cichlidogyrus species infecting African Great Lake cichlids are summarized and proposed as model for the influence of host ecology on disease transmission.
Abstract: Lake Tanganyika’s biodiversity and endemicity sparked considerable scientific interest. Its monogeneans, minute parasitic flatworms, have received renewed attention. Their host-specificity and simple life cycle render them ideal for parasite speciation research. Because of the wide ecological and phylogenetic range of its cichlids, Lake Tanganyika is a “natural experiment” to contrast factors influencing monogenean speciation. Three representatives of Bathybatini (Bathybates minor, B. fasciatus, B. vittatus), endemic predatory non-littoral cichlids, host a single dactylogyridean monogenean species. It is new to science and described as Cichlidogyrus casuarinus sp. nov. This species and C. nshomboi and C. centesimus, from which it differs by the distal end of the accessory piece of the male apparatus and the length of its heel, are the only Cichlidogyrus species with spirally coiled thickening of the penis wall. In Cichlidogyrus, this feature was only found in parasites of endemic Tanganyika tribes. The seemingly species-poor Cichlidogyrus community of Bathybatini may be attributed to meagre host isolation in open water. The new species infects cichlids that substantially differ phylogenetically and ecologically. This may be an adaptation to low host availability. Cichlidogyrus species infecting African Great Lake cichlids are summarized and proposed as model for the influence of host ecology on disease transmission.
36 citations
TL;DR: Comparisons of phylogenetic trees of Hemibates and Bathybates species obtained with nuclear multilocus AFLP data with nuclear and mitochondrial data established a well-supported phylogeny and suggested ecological segregation during speciation.
Abstract: Hybridization among littoral cichlid species in Lake Tanganyika was inferred in several molecular phylogenetic studies. The phenomenon is generally attributed to the lake level-induced shoreline and habitat changes. These allow for allopatric divergence of geographically fragmented populations alternating with locally restricted secondary contact and introgression between incompletely isolated taxa. In contrast, the deepwater habitat is characterized by weak geographic structure and a high potential for gene flow, which may explain the lower species richness of deepwater than littoral lineages. For the same reason, divergent deepwater lineages should have evolved strong intrinsic reproductive isolation already in the incipient stages of diversification, and, consequently, hybridization among established lineages should have been less frequent than in littoral lineages. We test this hypothesis in the endemic Lake Tanganyika deepwater cichlid tribe Bathybatini by comparing phylogenetic trees of Hemibates and Bathybates species obtained with nuclear multilocus AFLP data with a phylogeny based on mitochondrial sequences. Consistent with our hypothesis, largely congruent tree topologies and negative tests for introgression provided no evidence for introgressive hybridization between the deepwater taxa. Together, the nuclear and mitochondrial data established a well-supported phylogeny and suggested ecological segregation during speciation.
TL;DR: Stable nitrogen and carbon isotope analyses of food web structure indicate a complex food web with overlapping omnivory with some specialist fish species, and confirm that mercury is biomagnifying through the Tanganyika food web at rates similar to those seen in Lakes Malawi and Victoria, the other two African Great Lakes.
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2016 | 1 |
| 2015 | 1 |
| 2012 | 1 |
| 2008 | 1 |
| 2005 | 1 |