Academic literature on the topic 'Cichlids – Africa, East'
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Journal articles on the topic "Cichlids – Africa, East"
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VERBURG, PIET, and ROGER BILLS. "Two new cichild species Neolamprologus (Teleostei: Cichlidae) from Lake Tanganyika, East Africa." Zootaxa 1612, no. 1 (2007): 25–44. http://dx.doi.org/10.11646/zootaxa.1612.1.2.
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Two new cichlid species, Neolamprologus walteri sp. nov. and N. chitamwebwai sp. nov., from the Bangwe peninsula (Tanzania), on the east coast of Lake Tanganyika, are described. Both species belong to the N. savoryi species complex, characterised by a lunate tail with long filaments. Neolamprologus chitamwebwai and N. walteri are highly stenotopic species, restricted to rocky habitat. They occur sympatrically with each other and with two other species of the complex but occupy different microhabitats. Neolamprologus walteri lives in large numbers in sheltered areas with rubble substrate whereas N. chitamwebwai occurs in much lower numbers on more exposed parts of the rocky shores, with large boulders, lower sedimentation rates, coarser sediment, and higher visibility. The two new species although closely related, show clear ecological differentiation. Evidence of ecological differentiation between closely related sympatric cichlids is rare in literature. Closely related sympatric cichlids in the large African lakes (with literature mainly referring to Lake Victoria and Lake Malawi) have been suggested to differ little in diet and habitat use, which has encouraged the idea that cichlid species can coexist without niche partitioning. Our paper provides a different perspective with cichlids from Lake Tanganyika.
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Takahashi, Tetsumi, and Stephan Koblmüller. "The Adaptive Radiation of Cichlid Fish in Lake Tanganyika: A Morphological Perspective." International Journal of Evolutionary Biology 2011 (May 10, 2011): 1–14. http://dx.doi.org/10.4061/2011/620754.
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Lake Tanganyika is the oldest of the Great Ancient Lakes in the East Africa. This lake harbours about 250 species of cichlid fish, which are highly diverse in terms of morphology, behaviour, and ecology. Lake Tanganyika's cichlid diversity has evolved through explosive speciation and is treated as a textbook example of adaptive radiation, the rapid differentiation of a single ancestor into an array of species that differ in traits used to exploit their environments and resources. To elucidate the processes and mechanisms underlying the rapid speciation and adaptive radiation of Lake Tanganyika's cichlid species assemblage it is important to integrate evidence from several lines of research. Great efforts have been, are, and certainly will be taken to solve the mystery of how so many cichlid species evolved in so little time. In the present review, we summarize morphological studies that relate to the adaptive radiation of Lake Tanganyika's cichlids and highlight their importance for understanding the process of adaptive radiation.
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Duponchelle, F., A. J. Ribbink, A. Msukwa, J. Mafuka, D. Mandere, and H. Bootsma. "Food partitioning within the species-rich benthic fish community of Lake Malawi, East Africa." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 7 (2005): 1651–64. http://dx.doi.org/10.1139/f05-075.
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Temporal diet patterns were studied for nine species of haplochromine cichlids in Lake Malawi, East Africa, using a combination of stable isotope and stomach content analyses. The results illustrate the complementarity of the two approaches in elucidating dietary differences. Evidence was found that benthic algal production contributed to the energy requirements of offshore fishes that occupy depths between 10 and 30 m. The importance of the lake fly Chaoborus edulis as a food source for demersal fishes was confirmed, supporting the recent hypothesis that deep demersal fish production is principally sustained through the pelagic food chain rather than from benthic detrital sources. Isotopic differences were observed among species with apparently similar diets, feeding behavior, and depth preferences, suggesting that important resource partitioning exists among Lake Malawi benthic haplochromine cichlids.
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RISCH, SARAH, and JOS SNOEKS. "Geographic variation in Neolamprologus niger (Poll, 1956) (Perciformes: Cichlidae) from Lake Tanganyika (Africa)." Zootaxa 1857, no. 1 (2008): 21. http://dx.doi.org/10.11646/zootaxa.1857.1.2.
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Intraspecific morphological variation in Neolamprologus niger from seven localities along the north-western shoreline of Lake Tanganyika (Luhanga, Bemba, Ubwari West, Ubwari East, Yungu, Kabimba and Kalemie) was investigated. As a result of geographical variation, the populations could be categorized into a northern, a central and a southern group. A clear clinal pattern was found for several meristics and measurements. The lack of knowledge on the geographical variation in African cichlids and its implication for further taxonomic research is discussed.
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Koffi NGoran, Bienvenu, Kouadio Justin Konan, Annigbe Justin Eyi, and Koffi Kouakou. "LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTOR FOR THREE EXPLOITED SYMPATRIC CICHLIDS INHABITED MARGINAL LAGOONS OF THE SOUTH-EAST OF COTE DIVOIRE, WEST AFRICA." International Journal of Advanced Research 9, no. 03 (2021): 147–54. http://dx.doi.org/10.21474/ijar01/12567.
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This study investigated the length-weight relationships (LWRs) and condition factors (K) of three Cichlids viz., Sarotherodonmelanotheron, Coptodonguineensis and the hybrid Coptodonguineensis x Coptodonzillii in three small lagoons invaded by macrophytes from the South-east of Cote dIvoire. Fishes were caught monthly from September 2017 to August 2019 using traps, gill nets, harpoons and hawks. Standard length and weight of individuals were taken to the nearest 1 mm and 0.1 g respectively. A total of 721, 932and 755 specimens were collected respectively in Ono, Kodjoboue and Hebe lagoons. For all species, two size classes namely sizes of 7-12 cm and 14-29 cm were encountered. About 65-70% of individuals have sizes varying from 14 cm to 20 cm vs. 20-25% of individuals with size ranging between 7 and 10 cm. The growth patterns were significant with a coefficient of determination (r²) varying from 0.89 to 0.98. The slope values were 2.88-2.97 for S. melanotheron, 2.84-2.85 for C. guineensis and 2.90-2.98 for hybrids, with a significant variation according to sexes and localities. The condition factor showed the range of 3.96 ± 0.61 to 4.25 ± 1.97, indicating that despite being invaded by several macrophytes, the environment of these lagoons is well suitable for Cichlids.
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Danley, Patrick D., Martin Husemann, Baoqing Ding, Lyndsay M. DiPietro, Emily J. Beverly, and Daniel J. Peppe. "The Impact of the Geologic History and Paleoclimate on the Diversification of East African Cichlids." International Journal of Evolutionary Biology 2012 (July 19, 2012): 1–20. http://dx.doi.org/10.1155/2012/574851.
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The cichlid fishes of the East African Great Lakes are the largest extant vertebrate radiation identified to date. These lakes and their surrounding waters support over 2,000 species of cichlid fish, many of which are descended from a single common ancestor within the past 10 Ma. The extraordinary East African cichlid diversity is intricately linked to the highly variable geologic and paleoclimatic history of this region. Greater than 10 Ma, the western arm of the East African rift system began to separate, thereby creating a series of rift basins that would come to contain several water bodies, including the extremely deep Lakes Tanganyika and Malawi. Uplifting associated with this rifting backponded many rivers and created the extremely large, but shallow Lake Victoria. Since their creation, the size, shape, and existence of these lakes have changed dramatically which has, in turn, significantly influenced the evolutionary history of the lakes' cichlids. This paper reviews the geologic history and paleoclimate of the East African Great Lakes and the impact of these forces on the region's endemic cichlid flocks.
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Hoerner, Marie E. "TESTING FOR DIFFERENCES IN RATES OF SPECIATION, EXTINCTION, AND MORPHOLOGICAL EVOLUTION IN FOUR TRIBES OF CICHLIDS ENDEMIC TO LAKE TANGANYIKA, EAST AFRICA." Evolution 65, no. 12 (2011): 3398–412. http://dx.doi.org/10.1111/j.1558-5646.2011.01390.x.
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Ahi, Ehsan P., Anna Duenser, Pooja Singh, Wolfgang Gessl, and Christian Sturmbauer. "Appetite regulating genes may contribute to herbivory versus carnivory trophic divergence in haplochromine cichlids." PeerJ 8 (January 20, 2020): e8375. http://dx.doi.org/10.7717/peerj.8375.
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Feeding is a complex behaviour comprised of satiety control, foraging, ingestion and subsequent digestion. Cichlids from the East African Great Lakes are renowned for their diverse trophic specializations, largely predicated on highly variable jaw morphologies. Thus, most research has focused on dissecting the genetic, morphological and regulatory basis of jaw and teeth development in these species. Here for the first time we explore another aspect of feeding, the regulation of appetite related genes that are expressed in the brain and control satiety in cichlid fishes. Using qPCR analysis, we first validate stably expressed reference genes in the brain of six haplochromine cichlid species at the end of larval development prior to foraging. We next evaluate the expression of 16 appetite related genes in herbivorous and carnivorous species from the parallel radiations of Lake Tanganyika, Malawi and Victoria. Interestingly, we find increased expression of two appetite-regulating genes (anorexigenic genes), cart and npy2r, in the brain of carnivorous species in all the three lakes. This supports the notion that appetite gene regulation might play a part in determining trophic niche specialization in divergent cichlid species, already prior to exposure to different diets. Our study contributes to the limited body of knowledge on the neurological circuitry that controls feeding transitions and adaptations in cichlids and other teleosts.
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Moser, Florian N., Jacco C. van Rijssel, Salome Mwaiko, Joana I. Meier, Benjamin Ngatunga, and Ole Seehausen. "The onset of ecological diversification 50 years after colonization of a crater lake by haplochromine cichlid fishes." Proceedings of the Royal Society B: Biological Sciences 285, no. 1884 (2018): 20180171. http://dx.doi.org/10.1098/rspb.2018.0171.
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Adaptive radiation research typically relies on the study of evolution in retrospective, leaving the predictive value of the concept hard to evaluate. Several radiations, including the cichlid fishes in the East African Great Lakes, have been studied extensively, yet no study has investigated the onset of the intraspecific processes of niche expansion and differentiation shortly after colonization of an adaptive zone by cichlids. Haplochromine cichlids of one of the two lineages that seeded the Lake Victoria radiation recently arrived in Lake Chala, a lake perfectly suited for within-lake cichlid speciation. Here, we infer the colonization and demographic history, quantify phenotypic, ecological and genomic diversity and diversification, and investigate the selection regime to ask if the population shows signs of diversification resembling the onset of adaptive radiation. We find that since their arrival in the lake, haplochromines have colonized a wide range of depth habitats associated with ecological and morphological expansion and the beginning of phenotypic differentiation and potentially nascent speciation, consistent with the very early onset of an adaptive radiation process. Moreover, we demonstrate evidence of rugged phenotypic fitness surfaces, indicating that current ecological selection may contribute to the phenotypic diversification.
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Svardal, Hannes, Fu Xiang Quah, Milan Malinsky, et al. "Ancestral Hybridization Facilitated Species Diversification in the Lake Malawi Cichlid Fish Adaptive Radiation." Molecular Biology and Evolution 37, no. 4 (2019): 1100–1113. http://dx.doi.org/10.1093/molbev/msz294.
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Abstract The adaptive radiation of cichlid fishes in East African Lake Malawi encompasses over 500 species that are believed to have evolved within the last 800,000 years from a common founder population. It has been proposed that hybridization between ancestral lineages can provide the genetic raw material to fuel such exceptionally high diversification rates, and evidence for this has recently been presented for the Lake Victoria region cichlid superflock. Here, we report that Lake Malawi cichlid genomes also show evidence of hybridization between two lineages that split 3–4 Ma, today represented by Lake Victoria cichlids and the riverine Astatotilapia sp. “ruaha blue.” The two ancestries in Malawi cichlid genomes are present in large blocks of several kilobases, but there is little variation in this pattern between Malawi cichlid species, suggesting that the large-scale mosaic structure of the genomes was largely established prior to the radiation. Nevertheless, tens of thousands of polymorphic variants apparently derived from the hybridization are interspersed in the genomes. These loci show a striking excess of differentiation across ecological subgroups in the Lake Malawi cichlid assemblage, and parental alleles sort differentially into benthic and pelagic Malawi cichlid lineages, consistent with strong differential selection on these loci during species divergence. Furthermore, these loci are enriched for genes involved in immune response and vision, including opsin genes previously identified as important for speciation. Our results reinforce the role of ancestral hybridization in explosive diversification by demonstrating its significance in one of the largest recent vertebrate adaptive radiations.
Dissertations / Theses on the topic "Cichlids – Africa, East"
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Jambo, Collins Mayeso. "Aspects of the ecology and reproductive biology of three cichlid fish species of Southern Lake Malombe (Malawi)." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005067.
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The three major species Lethrinops ''pinkhead'', Otopharynx argyrosoma "red" and Copadichromis. cf virginalis which used to dominate the catches (by weight) of Lake Malombe in the past decade were investigated. In order to make rational recommendations regarding size and boundary of the existing sanctuary area (lightly fished), distribution and abundance, population structure and reproductive biology of the three species were related to habitat types of the southern part of the lake (south western side and south eastern side). Analysis of catch composition showed that species richness was higher in the south eastern side than in the south western side of the lake. Rare species such as Labeo mesops and Opsaridium microiepis were observed in the south eastern side and there was visual absence of such species in the south western side of the lake. The overall fish abundance was significantly greater in the south eastern side than in the south western side of the lake. In the south eastern side, the catch per unit effort (CPUE) was twice that of the south western side (P< 0.05). Seasonal fluctuations in CPUE were also prominent, with the highest peak occurring during September-October period. However, there was an indication of weak relationship among CPUE, phytoplankton biomass, temperature and water depth. The length-weight relationships revealed that growth of the three species closely followed the cubic law for isometric growth in both sides of the lake. Differences in regression coefficients between sides were not significant (ttest, P>0.05). The length-frequency distribution analysis revealed that the three species had the same growth rate regardless of habitat type. However, females grew faster than males. An investigation of reproductive biology showed that the three species have low fecundity and they are asynchronous spawners, with a breeding peak during August and September period. Furthermore, the length-fecundity relationships for L. ''pinkhead'', and 0. argyrosoma "red" indicated that fecundity was more closely related to length in the south eastern side than in the south western side. Based on the above characteristics of L. ''pinkhead'', 0. argyrosoma "red" and C. cf virginalis, and the substrate types, it was strongly suggested that the existing sanctuary (lightly fished) in the south eastern side of the lake could immediately be enlarged to conserve the fish stocks, favourable substratum and aquatic animals that may be of tourists concern.
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Bills, Ian Roger. "Eco-ethology of shell-dwelling cichlids in Lake Tanganyika." Thesis, Rhodes University, 1997. http://hdl.handle.net/10962/d1005109.
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Observations of habitats are reported. A series of underwater experiments were conducted in natural habitats to answer questions concerning a) why Lamprologus ocellatus and Lamprologus ornatipinnis bury gastropod shells refuges into the substrate, and b) to examine interspecies differences in shell-using behaviours. Some behaviour patterns were analysed using phylogenetic methods. Lamprologus ocellatus and L. ornatipinnis responded to new shells in a variety of ways, shells were moved, buried (and used) or hidden (buried and not used). How shells are utilised seems to be dependant on a complex of factors such as the size and quality of new the shell and the number already in the territory. Shell use may also be affected by neighbour species, sex, size and predation levels. There are interspecific differences in the size of shells used and the methods of shell use. The latter results in species-characteristic shell orientations, vertical burial in L. ocellatus and horizontal burial in L. ornatipinnis. Shell orientation does affect other species/use of shells. Shell movement and vertical orientation appear to be apomorphic while shell hiding and burial are pleisiomorphic within the genus Lamprologus. Numerous cues are involved in stimulating shell burial. Most of these cues are actively sought by the fish by external and internal inspections. Shell burial therefore appears to be a method of reducing the information gathering ability of potential shell-dwelling competitors. Shell burial can therefore be regarded as an investment process which enhances the residents ability to defend its territory. Males can also control the distribution of open shells within teritories and thus control mate access to shells. This behaviour could be a significant factor in the evolution of marked sexual dichromatism exhibited within the genus.
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Schedel, Frédéric Dieter Benedikt [Verfasser], and Gerhard [Akademischer Betreuer] Haszprunar. "Phylogeny, divergence time estimates and systematics of African cichlids (Cichlidae: Pseudocrenilabrinae), with a focus on the rheophilic cichlids of East and Central Africa / Frédéric Dieter Benedikt Schedel ; Betreuer: Gerhard Haszprunar." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1219852236/34.
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Tyers, Alexandra Morton. "Divergence and speciation of East African haplochromine cichlid fish." Thesis, Bangor University, 2013. https://research.bangor.ac.uk/portal/en/theses/divergence-and-speciation-of-east-african-haplochromine-cichlid-fish(35db9b7b-0775-4cd5-94f3-556a6f3cacd6).html.
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In the Great Lakes of the East African Rift Valley, cichlid fishes have diversified into hundreds of species with great variety of ecomorphological, secondary sexual and behavioural characteristics. A strong role for sexual selection in their speciation is indicated by the presence of many closely related ecologically similar sympatric species which differ in male secondary sexual characteristics. A review of previous research finds that reproductive isolation by direct mate choice may be a common isolating barrier among sympatric species. Observations of partial assortative mating among divergent geographic populations have lead to theories of intralacustrine allopatric speciation of habitat specialists by divergence of signal traits involved in conspecific recognition. Here I demonstrate that signal and preference divergence among populations is not limited to patchily distributed lacustrine endemics, but can also occur in the widely distributed riverine generalist lineage that is phylogenetically basal to the large lacustrine radiations, suggesting a role for divergence of secondary sexual traits in allopatry throughout adaptive radiation. This thesis also adds to the evidence for ecological divergence and peripatric speciation of lacustrine habitat specialists in the absence of significant colour differentiation. In simulated intruder choice tests, males tend to bias aggression towards males of their own species or populations, which may aid in the co-existence of allopatrically diverged populations under secondary sympatry and help to facilitate speciation, or even drive divergence of male traits that are involved in signalling during both courtship and territorial interactions. Results from preliminary investigations into individual variation in mate preference suggest that partial assortative mating among allopatric populations may be due to variation within, rather than among, individuals in their choice of mate. Within-individual variation may be unlikely to cause divergence, but has the potential to aid in colonisation of new areas by a relaxation of directional selection allowing for divergence of male traits by environmental or other social selection pressures. To draw any firm conclusions about the impact of variation in mate choice on speciation, much more data from a wider variety of lineages is needed. Mate choice experiments, carried out as part of a larger ongoing project into sympatric divergence of haplochromine cichlids in isolated crater lakes, found little consistency of female mate choice despite morphological and genetic differentiation of forms. This indicates that, in contrast to previously tested sympatric species of cichHds, at the beginnings of adaptive radiation variety may not be maintained solely through reproductive isolation by direct mate choice. Observations of interactions among animals may frequently reveal unexpected results with regards to what is and is not a species - for example, strong assortative mating among phenotypically similar allopatric populations and that assortative mating alone may not maintain diversity in sympatric populations. Behavioural experiments can complement more modern genetic and genomic techniques and therefore continue to be a valuable tool in the study of speciation and the mechanisms involved in divergence and the maintenance of diversity.
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Ford, A. G. P. "Evolutionary relationships of East African soda lake cichlid fish." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1471875/.
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This thesis examines the evolutionary relationships of the Alcolapia soda lake cichlid fishes of East Africa. The introduction presents background on the soda lakes in which the cichlids are found, the taxonomy and biology of the fishes, as well as the theoretical background to the study. Chapter two discusses the methods used in the thesis, addressing the benefits and limitations of each, as well as their suitability to the study in hand. Chapter three investigates the phylogenetics and phylogeography of soda lake cichlids sampled at several populations around the soda lakes and a single transplanted population outside of the focal lakes, employing a large genomic dataset generated through restriction site associated DNA (RAD) sequencing, and demonstrates low levels of interspecific genomic differentiation with high levels of ongoing gene flow. Chapter four uses the RAD dataset to test for signals of selection between Alcolapia species, employing genome-wide scans and outlier detection to characterise peaks of genomic divergence between species. Chapter five combines morphological (geometric morphometrics) and ecological (stable isotope, stomach contents) data with the RAD dataset from chapter three to consider biologically relevant diversification between Alcolapia species, testing for convergence and niche adaptation. Chapter six examines the ecomorphology of the soda lake fishes at an intraspecific level, testing for effects of geography and environment on morphological differentiation between populations. Finally, chapter seven draws together the conclusions inferred from the thesis, and discusses possible future directions for research in this system.
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Urban, Sabine [Verfasser]. "Genetic Basis of Color Pattern Evolution in East African Cichlids / Sabine Urban." Konstanz : KOPS Universität Konstanz, 2020. http://d-nb.info/1222909650/34.
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Loh, Yong-Hwee Eddie. "Genetic variation in fast-evolving East African cichlid fishes: an evolutionary perspective." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41148.
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Cichlid fishes from the East African Rift lakes Victoria, Tanganyika and Malawi represent a preeminent example of replicated and rapid evolutionary radiation. In this single natural system, numerous morphological (eg. jaw and tooth shape, color patterns, visual sensitivity), behavioral (eg. bower-building) and physiological (eg. development, neural patterning) phenotypes have emerged, much akin to a mutagenic screen. This dissertation encompasses three studies that seek to decipher the underpinnings of such rapid evolutionary diversification, investigated via the genetic variation in East African cichlids.
We generated a valuable cichlid genomic resource of five low-coverage Lake Malawi cichlid genomes, from which the general properties of the genome were characterized. Nucleotide diversity of Malawi cichlids was low at 0.26%, and a sample genotyping study found that biallelic polymorphisms segregate widely throughout the Malawi species flock, making each species a mosaic of ancestrally polymorphic genomes. A second genotyping study expanded our evolutionary analysis to cover the entire East African cichlid radiation, where we found that more than 40% of single nucleotide polymorphisms (SNPs) were ancestral polymorphisms shared across multiple lakes. Bayesian analysis of genetic structure in the data supported the hypothesis that riverine species had contributed significantly to the genomes of Malawi cichlids and that Lake Malawi cichlids are not monophyletic. Both genotyping studies also identified interesting loci involved in important sensory as well as developmental pathways that were well differentiated between species and lineages. We also investigated cichlid genetic variation in relation to the evolution of microRNA regulation, and found that divergent selection on miRNA target sites may have led to differential gene expression, which contributed to the diversification of cichlid species.
Overall, the patterns of cichlid genetic variation seem to be dominated by the phenomena of extensive sharing of ancestral polymorphisms. We thus believe that standing genetic variation in the form of ancestrally inherited polymorphisms, as opposed to variations arising from new mutations, provides much of the genetic diversity on which selection acts, allowing for the rapid and repeated adaptive radiation of East African cichlids.
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Pierotti, Michele E. R. "Origin, maintenance and evolutionary consequences of male mating preference variation in East African cichlid fishes." Thesis, University of Hull, 2007. http://hydra.hull.ac.uk/resources/hull:11614.
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Ngatunga, Benjamin Peter. "A taxonomic revision of the shallow-water species of the genera Lethrinops, Tramitichromis and Taeniolethrinops (Teleostei, Cichlidae) from Lake Malawi/Nyasa/Niassa (East Africa)." Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1007443.
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In order for the SADC/GEF Lake Malawi/Nyasa Biodiversity Conservation Project to draw out sound strategic management and conservation recommendations to the riparian countries of Malawi, Mozambique and Tanzania, the need and urgency for revising the taxonomy of some of the scientifically and economically important fish groups was accorded high priority. This study is a contribution towards achieving those goals. It is a taxonomic revision of the shallow-water species of the genera Taenioiethrinops, Tramitichromis and Lethrinops. These three genera are grouped as Lethrinops 'sensu lato' in this thesis, corresponding to the definition of Lethrinops prior to the revision by Eccles & Trewavas (1989). All members have a characteristic dentition: the outer teeth in the lower jaw curve inwards posteriorly ending just behind the inner row(s), rather than continuing backwards as a single series, as in most other Malawian haplochromines. The decision to consider shallow-water Lethrinops 'sensu lato' separately from the deepwater ones was not arbitrary, but rather based on available ecological and morphological evidence. Unanticipatedly, on the course of this study, evidence from molecular genetics has helped to strengthen the distinction. Economically, Lethrinops is important for human food and for the aquarium trade. Lethrinops are precocial fish producing very few young at a time and are consequently unlikely to recover quickly from heavy fishing pressure. To evolutionary biologists, Lethrinops 'sensu lato' is challenging because until now most theories about the evolution of Lake Malawi cichlids have not taken the sand-dwelling fishes fully into consideration. A better knowledge of the distribution patterns of these cichlids, of which Lethrinops are the major representatives, can help in explaining the underlying mechanisms of speciation in sand-dwelling cichlids. Lethrinops 'sensu lato' is taxonomically one of the most complex groups of Lake MalawilNyasa haplochromines. The species are closely related and very difficult to differentiate, and the taxonomy is confused and in urgent need of revision. This is more important since taxonomy plays an important role in most of the key criteria of conservation.The principal objective of this study was to carry out a taxonomic revision of this group and to provide a key to the identification of the species. Further objectives include the mapping of their distribution and analysing their phylogenetic relationships. Large samples were collected (by trawling, gill netting, beach seining and purchased from local fishermen) from depths less than 20m and from numerous well-defined localities all around the lake. Seventeen type specimens of the 21 described species of the shallow-water Lethrinops 'sensu lato' were examined and compared with this recently collected material. The data of about 500 fish specimens were subjected to principal component analyses (PCA). To further evaluate morphological differences between taxa of comparable size, non- parametric, distribution-free Mann-Whitney U-tests were used. Within the shallow-water Lethrinops 'sensu lato' three genera are recognized which can be separated by characters such as head shape, pharyngeal morphology and dentition, number and shape of gill-rakers, number of the pectoral fin rays and melanin pattern. So far in this study, 28 taxa have been recognized. The overlapping measurements and meristics compound the difficulty inherent in the identification and classification of members of the three genera. The genera Tramitichromis and Taeniolethrinops are typically shallow- water taxa. Within the genus Taeniolethrinops four described species, (T. cyrtonotus, T.forcicauda, T. laticeps and T. praeorbitalis) were distinguished. Within the genus Tramitichromis nine species were distinguished, five of which are described (T. brevis, T. intermedius, T. lituris, T. trilineata and T. variabilis); four represent undescribed species and are given a working name (T. sp. 'brevis 2', T. sp. 'maculae', T. sp. 'pharyngeals' and T. sp. 'variabilis deep'). For convenience, the shallow water Lethrinops 'sensu stricto' were divided into three natural groups, according to shared morphological features. • The first group is the lethrinus group, including three species (L. lunaris, L. leptodon and L. lethrinus) with relatively lolong snouts and remnants of the horizontal stripes. • Another group included eight taxa (L. microstoma, L. macrophthalmus, L. macrochir, L. auritus, L. parvidens, L. sp. 'parvidens deep', L. 'black dorsal auritus', L. sp. 'domira blotch' and L. sp. 'turneri') with a relatively short snout and a small mouth set low on the profile. Within this group, special attention has been paid to the confusion involving L. auritus and a new species to be described soon, L. sp. 'turneri' . • The last group of Lethrinops 'sensu stricto' is ill defmed and has an intermediate snout and with a lesser round head. Within this group L. oculatus, which was described on the basis of a single specimen, is synonymised with L. marginatus. The other valid species of this group are Lethrinops albus and L.furcifer. Nearly all species seem to have a lake-wide distribution. All are associated with sandy substrata where they feed mainly on insect larvae and ostracods. Mitochondrial DNA sequence data indicate that Lethrinops 'sensu lato' as currently defmed is not monophyletic but is paraphyletic or more probably polyphyletic. It is further suggested that the typical Lethrinops dentition provides no particular strong evidence for affimity among shallow-water Lethrinops s.s., Tramitichromis and Taeniolethrinops. The need for management and conservation of this scientifically exciting group of fishes has been pointed out.
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Clabaut, Céline [Verfasser]. "Morphometric, molecular phylogenetic and gene expression approaches towards the understanding of the adaptive radiations of the East African cichlids / vorgelegt von Céline Clabaut." 2006. http://d-nb.info/978818857/34.
Full textBooks on the topic "Cichlids – Africa, East"
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Snoeks, Jos. The haplochromines (Teleostei, Cichlidae) of Lake Kivu (East Africa): A taxonomic revision with notes on their ecology. Koninklijk Museum voor Midden-Afrika, 1994.
Find full textBook chapters on the topic "Cichlids – Africa, East"
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Sturmbauer, Christian, Martin Husemann, and Patrick D. Danley. "Explosive Speciation and Adaptive Radiation of East African Cichlid Fishes." In Biodiversity Hotspots. Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-20992-5_18.
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