scholarly journals On the origin of the Synodontis catfish species flock from Lake Tanganyika

2006 ◽  
Vol 2 (4) ◽  
pp. 548-552 ◽  
Author(s):  
Julia J Day ◽  
Mark Wilkinson
Keyword(s):  
Lake Tanganyika ◽  
Sequence Data ◽  
Phylogenetic Study ◽  
Species Flock ◽  
East African ◽  
Extrinsic Factors ◽  
Factors Affecting ◽  
Fossil Calibration ◽  
Mtdna Sequence ◽  
Species Flocks

Species flocks within Great Lakes provide unique insights into the factors affecting diversification. Lake Tanganyika (LT) is of particular interest because it contains many endemic groups for which general factors affecting diversification can be discerned. Here, we present the first phylogenetic study of the LT Synodontis (Siluriformes, Mochokidae) species flock using mtDNA sequence data. Our data reveal some previously unrecognized species diversity and indicate that the LT species flock is not monophyletic, and that two closely related clades of endemics may have independently colonized LT. Other comparable small species flocks are characterized by a single colonization event. Molecular date estimates of the timing of the initial within-lake diversification of the LT endemics, based on a fossil calibration, are comparable to those reported for other groups, suggesting that extrinsic factors maybe important common causes of clade diversification. The basal divergence in the sampled Synodontis reveals an East–West African faunal split seen in many terrestrial, but few aquatic groups, the timing of which coincides with East African rifting events.

Molecular evolution of freshwater snail intermediate hosts within the Bulinus forskalii group

Parasitology ◽  
2001 ◽  
Vol 123 (7) ◽  
pp. 277-292 ◽  
Author(s):  
C. S. JONES ◽  
D. ROLLINSON ◽  
R. MIMPFOUNDI ◽  
J. OUMA ◽  
H. C. KARIUKI ◽  
...  
Keyword(s):  
Sequence Data ◽  
Random Amplified Polymorphic Dna ◽  
Sequence Divergence ◽  
Freshwater Snail ◽  
Coi Gene ◽  
Species Differentiation ◽  
Intermediate Hosts ◽  
East African ◽  
Species Complexes ◽  
Mtdna Sequence

Freshwater snails of the Bulinus forskalii group are one of four Bulinus species complexes responsible for the transmission of schistosomes in Africa and adjacent regions. The species status of these conchologically variable and widely distributed planorbids remains unclear, and parasite compatibility varies considerably amongst the eleven taxa defined, making unambiguous identification and differentiation important prerequisites for determining their distributions and evolutionary relationships. Random Amplified Polymorphic DNA (RAPD) analyses were used to investigate relationships between taxa, with particular emphasis on Central and West African representatives. RAPD-derived phylogenies were compared with those from other independent molecular markers, including partial sequences of mitochondrial cytochrome oxidase subunit I (COI) gene, and the nuclear ribosomal RNA internal transcribed spacer 1 region (ITS1). The phylogenetic reconstructions from the three approaches were essentially congruent, in that all methods of analysis gave unstable tree topologies or largely unresolved branches. There were large sequence divergence estimates between species, with few characters useful for determining relationships between species and limited within species differentiation. Nuclear and mtDNA sequence data from Central and East African representatives of the pan-African B. forskalii showed little evidence of geographical structuring. Despite the unresolved structure within the phylogenies, specimens from the same species clustered together indicating that all methods were capable of differentiating taxa but could not establish the inter-specific relationships with confidence. The limited genetic variation displayed by B. forskalii, and the evolution and speciose nature of the group, are discussed in the context of the increasingly arid climate of the late Miocene and early Pliocene of Africa.

scholarly journals Back to Tanganyika: a case of recent trans-species-flock dispersal in East African haplochromine cichlid fishes

2015 ◽  
Vol 2 (3) ◽  
pp. 140498 ◽  
Author(s):  
Britta S. Meyer ◽  
Adrian Indermaur ◽  
Xenia Ehrensperger ◽  
Bernd Egger ◽  
Gaspard Banyankimbona ◽  
...  
Keyword(s):  
Lake Tanganyika ◽  
Lake Victoria ◽  
Species Flock ◽  
East African ◽  
Cichlid Species ◽  
African Great Lakes ◽  
Cichlid Fishes ◽  
Haplochromine Cichlid ◽  
Lake Victoria Region ◽  
Adaptive Radiations

The species flocks of cichlid fishes in the East African Great Lakes are the largest vertebrate adaptive radiations in the world and illustrious textbook examples of convergent evolution between independent species assemblages. Although recent studies suggest some degrees of genetic exchange between riverine taxa and the lake faunas, not a single cichlid species is known from Lakes Tanganyika, Malawi and Victoria that is derived from the radiation associated with another of these lakes. Here, we report the discovery of a haplochromine cichlid species in Lake Tanganyika, which belongs genetically to the species flock of haplochromines of the Lake Victoria region. The new species colonized Lake Tanganyika only recently, suggesting that faunal exchange across watersheds and, hence, between isolated ichthyofaunas, is more common than previously thought.

scholarly journals Phylogeny of the Lake Tanganyika Cichlid Species Flock and Its Relationship to the Central and East African Haplochromine Cichlid Fish Faunas

2002 ◽  
Vol 51 (1) ◽  
pp. 113-135 ◽  
Author(s):  
Walter Salzburger ◽  
Axel Meyer ◽  
Sanja Baric ◽  
Erik Verheyen ◽  
Christian Sturmbauer
Keyword(s):  
Lake Tanganyika ◽  
Cichlid Fish ◽  
Species Flock ◽  
East African ◽  
Cichlid Species ◽  
Haplochromine Cichlid

scholarly journals Trophic specialisation reflected by radular tooth material properties in an “ancient” Lake Tanganyikan gastropod species flock

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wencke Krings ◽  
Marco T. Neiber ◽  
Alexander Kovalev ◽  
Stanislav N. Gorb ◽  
Matthias Glaubrecht
Keyword(s):  
Mechanical Properties ◽  
Lake Tanganyika ◽  
Ecological Niches ◽  
Species Flock ◽  
Trophic Specialization ◽  
East African ◽  
Tooth Morphology ◽  
Lake Formation ◽  
Feeding Substrate ◽  
Radular Tooth

Abstract Background Lake Tanganyika belongs to the East African Great Lakes and is well known for harbouring a high proportion of endemic and morphologically distinct genera, in cichlids but also in paludomid gastropods. With about 50 species these snails form a flock of high interest because of its diversity, the question of its origin and the evolutionary processes that might have resulted in its elevated amount of taxa. While earlier debates centred on these paludomids to be a result of an intralacustrine adaptive radiation, there are strong indications for the existence of several lineages before the lake formation. To evaluate hypotheses on the evolution and radiation the detection of actual adaptations is however crucial. Since the Tanganyikan gastropods show distinct radular tooth morphologies hypotheses about potential trophic specializations are at hand. Results Here, based on a phylogenetic tree of the paludomid species from Lake Tanganyika and adjacent river systems, the mechanical properties of their teeth were evaluated by nanoindentation, a method measuring the hardness and elasticity of a structure, and related with the gastropods’ specific feeding substrate (soft, solid, mixed). Results identify mechanical adaptations in the tooth cusps to the substrate and, with reference to the tooth morphology, assign distinct functions (scratching or gathering) to tooth types. Analysing pure tooth morphology does not consistently reflect ecological specializations, but the mechanical properties allow the determination of eco-morphotypes. Conclusion In almost every lineage we discovered adaptations to different substrates, leading to the hypothesis that one main engine of the flock’s evolution is trophic specialization, establishing distinct ecological niches and allowing the coexistence of taxa.

Adaptive radiation of Lake Tana's (Ethiopia) Labeobarbus species flock (Pisces, Cyprinidae)

2008 ◽  
Vol 59 (5) ◽  
pp. 391 ◽  
Author(s):  
Martin de Graaf ◽  
Eshete Dejen ◽  
Jan W. M. Osse ◽  
Ferdinand A. Sibbing
Keyword(s):  
Prey Species ◽  
Prey Size ◽  
Species Flock ◽  
East African ◽  
Lake Tana ◽  
Ecological Diversification ◽  
Ecological Selection ◽  
Cyprinid Fishes ◽  
Temporal Dimensions ◽  
Species Flocks

Studying species flocks (e.g. Darwin’s finches, Caribbean anoline lizards, East African cichlid fishes) has proven to be highly successful in understanding the forces driving speciation. The only known, intact species flock of cyprinid fishes, the 15 Labeobarbus species in Lake Tana (Ethiopia), includes eight piscivorous species. Piscivory is a rare specialisation among the highly successful (>2000 species) but mostly benthivorous Cyprinidae. The extent and mechanisms of diversification of this remarkable Labeobarbus species flock, particularly among the unexpected piscivorous species, are still largely unknown. In the present study we demonstrate that all 15 Labeobarbus species are segregated to a great extent along spatial, trophic and/or temporal dimensions. The spatial distribution, diet (prey species but not prey size), time of active feeding and predation techniques differed significantly among the eight piscivores. Lake Tana’s cyprinids displayed their retained potential for ecological diversification and speciation, including the uncommon specialisation of piscivory. The latter is probably a result of the absence of common African specialist piscivores in Lake Tana. We suggest that the evolution of Lake Tana’s Labeobarbus species flock at this stage is predominantly structured by ecological selection models. The labeobarbs most likely underwent sequential stages of radiation and speciation: habitat divergence followed by trophic divergence.

scholarly journals PSI-40 Two mitochondrial lineages revealed in North American yak

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 477-477
Author(s):  
Leah K Treffer ◽  
Edward S Rice ◽  
Anna M Fuller ◽  
Samuel Cutler ◽  
Jessica L Petersen
Keyword(s):  
Sequence Data ◽  
Haplotype Network ◽  
Ovis Aries ◽  
Similar Species ◽  
Nucleotide Polymorphisms ◽  
Mt Dna ◽  
Protein Coding ◽  
Sister Clade ◽  
Mtdna Sequence ◽  
The Impact

Abstract Domestic yak (Bos grunniens) are bovids native to the Asian Qinghai-Tibetan Plateau. Studies of Asian yak have revealed that introgression with domestic cattle has contributed to the evolution of the species. When imported to North America (NA), some hybridization with B. taurus did occur. The objective of this study was to use mitochondrial (mt) DNA sequence data to better understand the mtDNA origin of NA yak and their relationship to Asian yak and related species. The complete mtDNA sequence of 14 individuals (12 NA yak, 1 Tibetan yak, 1 Tibetan B. indicus) was generated and compared with sequences of similar species from GeneBank (B. indicus, B. grunniens (Chinese), B. taurus, B. gaurus, B. primigenius, B. frontalis, Bison bison, and Ovis aries). Individuals were aligned to the B. grunniens reference genome (ARS_UNL_BGru_maternal_1.0), which was also included in the analyses. The mtDNA genes were annotated using the ARS-UCD1.2 cattle sequence as a reference. Ten unique NA yak haplotypes were identified, which a haplotype network separated into two clusters. Variation among the NA haplotypes included 93 nonsynonymous single nucleotide polymorphisms. A maximum likelihood tree including all taxa was made using IQtree after the data were partitioned into twenty-two subgroups using PartitionFinder2. Notably, six NA yak haplotypes formed a clade with B. indicus; the other four haplotypes grouped with B. grunniens and fell as a sister clade to bison, gaur and gayal. These data demonstrate two mitochondrial origins of NA yak with genetic variation in protein coding genes. Although these data suggest yak introgression with B. indicus, it appears to date prior to importation into NA. In addition to contributing to our understanding of the species history, these results suggest the two major mtDNA haplotypes in NA yak may functionally differ. Characterization of the impact of these differences on cellular function is currently underway.

Early-Stage Extension in the Southwest East African Rift: Integration of New Seismic Reflection Data

2016 ◽  
Author(s):  
Christopher A. Scholz ◽  
Douglas Wood
Keyword(s):  
Seismic Reflection ◽  
Lake Tanganyika ◽  
Early Stage ◽  
East African Rift ◽  
East African ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Legacy Data ◽  
African Rift ◽  
Water Depths

ABSTRACT The western branch of the East African Rift is characterized by modest amounts of extension and by deeply-subsided, fault-controlled basins filled with large, deep lakes. Lakes Tanganyika and Nyasa (Malawi) are two of the largest lakes in the world, with maximum water depths of 1450 and 700 m respectively. Newly acquired seismic reflection data, along with newly reprocessed legacy data reveal thick sedimentary sections, in excess of 5 km in some localities. The 1980's vintage legacy data from Project PROBE have been reprocessed through pre-stack depth migration in Lake Tanganyika, and similar reprocessing of legacy data from Lake Nyasa (Malawi) is underway. New high-fold and large-source commercial data have recently been collected in southern Lake Tanganyika, and new academic data have been acquired in the northern and central basins of Lake Nyasa (Malawi) as part of the 2015 SEGMeNT project. In the case of Lake Tanganyika, new data indicate the presence of older sediment packages that underlie previously identified "pre-rift" basement (the "Nyanja Event"). These episodes of sedimentation and extension may substantially predate the modern lake. These deep stratal reflections are absent in many localites, possibly on account of attenuation of the acoustic signal. However in one area of southern Lake Tanganyika, the newly-observed deep strata extend axially for ~70 km, likely representing deposits from a discrete paleolake. The high-amplitude Nyanja Event is interpreted as the onset of late-Cenozoic rifting, and the changing character of the overlying depositional sequences reflects increasing relief in the rift valley, as well as the variability of fluvial inputs, and the intermittent connectivity of upstream lake catchments. Earlier Tanganyika sequences are dominated by shallow lake and fluvial-lacustrine facies, whereas later sequences are characterized by extensive gravity flow deposition in deep water, and pronounced erosion and incision in shallow water depths and on littoral platforms. The age and provenance of the sub-Nyanja Event sequences is unknown, but may correlate to Miocene, Cretaceous or Karroo-age sedimentary packages documented elsewhere in the southwestern part of the East African Rift, including in the region around Lakes Rukwa and Nyasa (Malawi).

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