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Axel Meyer - One of the best experts on this subject based on the ideXlab platform.

  • Convergent Evolution of Cichlid Fish Pharyngeal Jaw Dentitions in Mollusk-crushing Predators: Comparative X-ray Computed Tomography of Tooth Sizes, Numbers, and Replacement
    Integrative and comparative biology, 2020
    Co-Authors: C. Darrin Hulsey, Axel Meyer, J. Todd Streelman
    Abstract:

    Dental convergence is a hallmark of cichlid fish adaptive radiations. This type of repeated evolution characterizes both the oral Jaws of these fishes as well as their Pharyngeal Jaws that are modified gill arches used to functionally process prey like hard-shelled mollusks. To test several hypotheses regarding the evolution of cichlid crushing Pharyngeal dentitions, we used x-ray computed tomography (CT) scans to comparatively examine dental evolution in the Pharyngeal Jaw of a diversity of New World Heroine cichlid lineages. The substantial variation in erupted tooth sizes and numbers as well as replacement teeth found in these fishes showed several general patterns. Larger toothed species tended to have fewer teeth suggesting a potential role of spatial constraints in cichlid dental divergence. Species with larger numbers of erupted Pharyngeal teeth also had larger numbers of replacement teeth. Replacement tooth size is almost exactly predicted (r = 0.99) from the size of erupted teeth across all of the species. Mollusk crushing was therefore highly associated with not only larger Pharyngeal teeth, but also larger replacement teeth. Whether dental divergence arises as a result of environmental induced plasticity or originates via trophic polymorphism as found in the species Herichthys minckleyi, there appear to be general rules that structure interspecific divergence in cichlid Pharyngeal erupted and replacement dentitions.

  • Genetic linkage of distinct adaptive traits in sympatrically speciating crater lake cichlid fish
    Nature communications, 2016
    Co-Authors: Carmelo Fruciano, Paolo Franchini, Viera Kovacova, Kathryn R. Elmer, Frederico Henning, Axel Meyer
    Abstract:

    Our understanding of how biological diversity arises is limited, especially in the case of speciation in the face of gene flow. Here we investigate the genomic basis of adaptive traits, focusing on a sympatrically diverging species pair of crater lake cichlid fishes. We identify the main quantitative trait loci (QTL) for two eco-morphological traits: body shape and Pharyngeal Jaw morphology. These traits diverge in parallel between benthic and limnetic species in the repeated adaptive radiations of this and other fish lineages. Remarkably, a single chromosomal region contains the highest effect size QTL for both traits. Transcriptomic data show that the QTL regions contain genes putatively under selection. Independent population genomic data corroborate QTL regions as areas of high differentiation between the sympatric sister species. Our results provide empirical support for current theoretical models that emphasize the importance of genetic linkage and pleiotropy in facilitating rapid divergence in sympatry.

  • Adaptive phenotypic plasticity in the Midas cichlid fish Pharyngeal Jaw and its relevance in adaptive radiation
    BMC evolutionary biology, 2011
    Co-Authors: Moritz Muschick, Marta Barluenga, Walter Salzburger, Axel Meyer
    Abstract:

    Phenotypic evolution and its role in the diversification of organisms is a central topic in evolutionary biology. A neglected factor during the modern evolutionary synthesis, adaptive phenotypic plasticity, more recently attracted the attention of many evolutionary biologists and is now recognized as an important ingredient in both population persistence and diversification. The traits and directions in which an ancestral source population displays phenotypic plasticity might partly determine the trajectories in morphospace, which are accessible for an adaptive radiation, starting from the colonization of a novel environment. In the case of repeated colonizations of similar environments from the same source population this "flexible stem" hypothesis predicts similar phenotypes to arise in repeated subsequent radiations. The Midas Cichlid (Amphilophus spp.) in Nicaragua has radiated in parallel in several crater-lakes seeded by populations originating from the Nicaraguan Great Lakes. Here, we tested phenotypic plasticity in the Pharyngeal Jaw of Midas Cichlids. The Pharyngeal Jaw apparatus of cichlids, a second set of Jaws functionally decoupled from the oral ones, is known to mediate ecological specialization and often differs strongly between sister-species. We performed a common garden experiment raising three groups of Midas cichlids on food differing in hardness and calcium content. Analyzing the lower Pharyngeal Jaw-bones we find significant differences between diet groups qualitatively resembling the differences found between specialized species. Observed differences in Pharyngeal Jaw expression between groups were attributable to the diet's mechanical resistance, whereas surplus calcium in the diet was not found to be of importance. The Pharyngeal Jaw apparatus of Midas Cichlids can be expressed plastically if stimulated mechanically during feeding. Since this trait is commonly differentiated - among other traits - between Midas Cichlid species, its plasticity might be an important factor in Midas Cichlid speciation. The prevalence of Pharyngeal Jaw differentiation across the Cichlidae further suggests that adaptive phenotypic plasticity in this trait could play an important role in cichlid speciation in general. We discuss several possibilities how the adaptive radiation of Midas Cichlids might have been influenced in this respect.

  • Broad taxonomic applicability of microsatellites developed for the highly polymorphic neotropical cichlid, Amphilophus citrinellum.
    Animal genetics, 2000
    Co-Authors: Katharina Noack, Anthony B. Wilson, Axel Meyer
    Abstract:

    Neotropical cichlids are some of the most important food fishes of Central America. In addition to its important economic role as part of the freshwater fishery, the Midas cichlid, Amphilophus citrinellum, exhibits a high level of intraspecific variation in both coloration and Pharyngeal Jaw morphology, which has made it a model species for the study of incipient, possibly, sympatric speciation. While behavioural and ecological studies of A. citrinellum have been numerous and thorough, investigations of the genetic variation of this species are almost completely missing. We have previously found exceedingly low levels of variation in the mitochondrial control region and cytochrome b gene which suggests a recent origin of the species (Meyer et al. unpublished data).

Peter C. Wainwright - One of the best experts on this subject based on the ideXlab platform.

  • A peacock bass (Cichla) functional novelty relaxes a constraint imposed by the classic cichlid Pharyngeal Jaw innovation
    Biological Journal of the Linnean Society, 2020
    Co-Authors: Edward D. Burress, Peter C. Wainwright
    Abstract:

    Abstract Innovations may provide access to new resources but often result in significant trade-offs. Pharyngognathy is a classic Pharyngeal Jaw innovation in which the left and right lower Pharyngeal Jaw (LPJ) bones are united into a single structure, producing a strong bite but reduced gape. Throughout cichlids, Pharyngeal suturing occurs along the entire medial border between LPJ bones, except in peacock bass (Cichla), where these bones are connected by ligaments only in their anterior region. We show that this limited attachment permits the Jaw bones to spread apart and we link this feature to an increase in Pharyngeal gape that is comparable to non-pharyngognathous species. The capacity of the LPJ bones to spread apart is strongest in juveniles and is mostly lost during development. Juvenile Cichla exhibit size-specific Pharyngeal gape similar to non-pharyngognathous percomorphs; however, adults exhibit Pharyngeal gape on par with other predatory cichlids. Relaxation of Pharyngeal suturing offsets a major deleterious consequence of pharyngognathy by reducing gape limitation and we propose this may accelerate the ontogenetic transition to piscivory. Partial reversal of the classic cichlid Pharyngeal Jaw innovation highlights the functional trade-offs that often accompany innovations and may be a major cause of variation in their macroevolutionary consequences.

  • Head Shape Modulates Diversification of a Classic Cichlid Pharyngeal Jaw Innovation.
    The American naturalist, 2019
    Co-Authors: Edward D. Burress, Milton Tan, Peter C. Wainwright
    Abstract:

    AbstractFunctional innovations are often invoked to explain the uneven distribution of ecological diversity. Innovations may provide access to new adaptive zones by expanding available ecological o...

  • A Pharyngeal Jaw evolutionary innovation facilitated extinction in Lake Victoria cichlids
    Science (New York N.Y.), 2015
    Co-Authors: Matthew D. Mcgee, Samuel R. Borstein, Russell Y. Neches, Heinz H. Buescher, Ole Seehausen, Peter C. Wainwright
    Abstract:

    Evolutionary innovations, traits that give species access to previously unoccupied niches, may promote speciation and adaptive radiation. Here, we show that such innovations can also result in competitive inferiority and extinction. We present evidence that the modified Pharyngeal Jaws of cichlid fishes and several marine fish lineages, a classic example of evolutionary innovation, are not universally beneficial. A large-scale analysis of dietary evolution across marine fish lineages reveals that the innovation compromises access to energy-rich predator niches. We show that this competitive inferiority shaped the adaptive radiation of cichlids in Lake Tanganyika and played a pivotal and previously unrecognized role in the mass extinction of cichlid fishes in Lake Victoria after Nile perch invasion.

  • The Evolution of Pharyngognathy: A Phylogenetic and Functional Appraisal of the Pharyngeal Jaw Key Innovation in Labroid Fishes and Beyond
    Systematic biology, 2012
    Co-Authors: Peter C. Wainwright, Samantha A. Price, W. Leo Smith, Kevin L. Tang, John S. Sparks, Lara A Ferry, Kristen L. Kuhn, Ron I. Eytan, Thomas J. Near
    Abstract:

    The perciform group Labroidei includes approximately 2600 species and comprises some of the most diverse and successful lineages of teleost fishes. Composed of four major clades, Cichlidae, Labridae (wrasses, parrotfishes, and weed whitings), Pomacentridae (damselfishes), and Embiotocidae (surfperches); labroids have been an icon for studies of biodiversity, adaptive radiation, and sexual selection. The success and diversification of labroids have been largely attributed to the presence of a major innovation in the Pharyngeal Jaw apparatus, pharyngognathy, which is hypothesized to increase feeding capacity and versatility. We present results of large-scale phylogenetic analyses and a survey of Pharyngeal Jaw functional morphology that allow us to examine the evolution of pharyngognathy in a historical context. Phylogenetic analyses were based on a sample of 188 acanthomorph (spiny-rayed fish) species, primarily percomorphs (perch-like fishes), and DNA sequence data collected from 10 nuclear loci that have been previously used to resolve higher level ray-finned fish relationships. Phylogenies inferred from this dataset using maximum likelihood, Bayesian, and species tree analyses indicate polyphyly of the traditional Labroidei and clearly separate Labridae from the remainder of the traditional labroid lineages (Cichlidae, Embiotocidae, and Pomacentridae). These three "chromide" families grouped within a newly discovered clade of 40 families and more than 4800 species (>27% of percomorphs and >16% of all ray-finned fishes), which we name Ovalentaria for its characteristic demersal, adhesive eggs with chorionic filaments. This fantastically diverse clade includes some of the most species-rich lineages of marine and freshwater fishes, including all representatives of the Cichlidae, Embiotocidae, Pomacentridae, Ambassidae, Gobiesocidae, Grammatidae, Mugilidae, Opistognathidae, Pholidichthyidae, Plesiopidae (including Notograptus), Polycentridae, Pseudochromidae, Atherinomorpha, and Blennioidei. Beyond the discovery of Ovalentaria, this study provides a surprising, but well-supported, hypothesis for a convict- blenny (Pholidichthys) sister group to the charismatic cichlids and new insights into the evolution of pharyngognathy. Bayesian stochastic mapping ancestral state reconstructions indicate that pharyngognathy has evolved at least six times in percomorphs, including four separate origins in members of the former Labroidei, one origin in the Centrogenyidae, and one origin within Beloniformes. Our analyses indicate that all pharyngognathous fishes have a mechanically efficient biting mechanism enabled by the muscular sling and a single lower Jaw element. However, a major distinction exists between Labridae, which lacks the widespread, generalized percomorph Pharyngeal biting mechanism, and all other pharyngognathous clades, which possess this generalized biting mechanism in addition to pharyngognathy. Our results reveal a remarkable history of pharyngognathy: far from a single origin, it appears to have evolved at least six times, and its status as a major evolutionary innovation is reinforced by it being a synapomorphy for several independent major radiations, including some of the most species rich and ecologically diverse percomorph clades of coral reef and tropical freshwater fishes, Labridae and Cichlidae. (Acanthomorpha; Beloniformes; Centrogenyidae; key innovation; Labroidei; Ovalentaria; Pharyngeal Jaws; Perciformes.)

  • Functional innovations and morphological diversification in parrotfish.
    Evolution; international journal of organic evolution, 2010
    Co-Authors: Samantha A. Price, David R Bellwood, Peter C. Wainwright, Erem Kazancıoğlu, David C. Collar, Thomas J. Near
    Abstract:

    The association between diversification and evolutionary innovations has been well documented and tested in studies of taxonomic richness but the impact that such innovations have on the diversity of form and function is less well understood. Using phylogenetically rigorous techniques, we investigated the association between morphological diversity and two design breakthroughs within the Jaws of parrotfish. Similar intramandibular joints and other modifications of the Pharyngeal Jaws have evolved repeatedly in teleost fish and are frequently hypothesized to promote diversity. We quantified morphological diversity within six functionally important oral Jaw traits using the Brownian motion rate of evolution to correct for phylogenetic and time-related biases and compared these rates across clades that did and did not possess the intramandibular joint and the parrotfish Pharyngeal Jaw. No change in morphological diversity was associated with the Pharyngeal Jaw modification alone but rates of oral Jaw diversification were up to 8× faster in parrotfish species that possessed both innovations. Interestingly, this morphological diversity may not have led to differential resource uses as available data suggest that members of this clade show remarkable homogeneity of diet.

Phillip S. Lobel - One of the best experts on this subject based on the ideXlab platform.

  • The Pharyngeal Jaw apparatus of the Cichlidae and Pomacentridae: function in feeding and sound production
    Reviews in Fish Biology and Fisheries, 2003
    Co-Authors: Aaron N. Rice, Phillip S. Lobel
    Abstract:

    Labroid fishes (PerciformesLabroidei) possess a highly developed Pharyngeal Jaw apparatus (PJA). A tremendous body of literature describes the anatomy and function in feeding in these fishes. For fishes of the families Pomacentridae and Cichlidae (damselfishes and cichlids), there are also numerous descriptions of the sounds these male fishes produce in reproductive or agonistic behavioral contexts. A growing amount of acoustic, behavioral, and physiological circumstantial evidence draws support for the PJA also being the sound producing mechanism. The present review discusses the evolutionary and ecological aspects of the PJA, the anatomy and function, as well as the acoustical biology of pomacentrids and cichlids. Using existing evidence, we propose and examine the possibility that the PJA (either muscles and/or bone) is used in this behavior. Should the PJA be involved in sound production, the duality in function for both feeding and sound production creates an interrelationship between trophic biology and sexual selection. Thus, particularly in cichlids, the expansion into available trophic niches, mediated by the food processing ability of the versatile PJA may influence female mate choices and serve as a substrate for sympatric speciation.

  • Enzyme activities of Pharyngeal Jaw musculature in the cichlid Tramitichromis intermedius: implications for sound production in cichlid fishes.
    The Journal of Experimental Biology, 2002
    Co-Authors: Aaron N. Rice, Phillip S. Lobel
    Abstract:

    Owing to its high degree of complexity and plasticity, the cichlid Pharyngeal Jaw apparatus has often been described as a key evolutionary innovation. The majority of studies investigating Pharyngeal muscle behavior and function have done so in the context of feeding. Analysis of enzyme activities (citrate synthase, 3-hydroxyacyl-CoA dehydrogenase and L-lactate dehydrogenase) of Pharyngeal muscles in the Lake Malawi cichlid Tramitichromis intermedius revealed differences between Pharyngeal Jaw muscles and between males and females. Therefore, these muscles have different performance characteristics, resulting in different functional characteristics of the muscles within the complex. Furthermore, the differences between muscles of males and females represent fundamental differences in muscular metabolic processes between sexes. This study is the first to demonstrate that the Pharyngeal anatomy is not only used for food processing but is possibly responsible for sound production, in turn influencing sexual selection in cichlid fish.

Walter Salzburger - One of the best experts on this subject based on the ideXlab platform.

  • Where Am I? Niche constraints due to morphological specialization in two Tanganyikan cichlid fish species.
    Ecology and evolution, 2020
    Co-Authors: Lukas Widmer, Adrian Indermaur, Bernd Egger, Walter Salzburger
    Abstract:

    Food resource specialization within novel environments is considered a common axis of diversification in adaptive radiations. Feeding specializations are often coupled with striking morphological adaptations and exemplify the relation between morphology and diet (phenotype-environment correlations), as seen in, for example, Darwin finches, Hawaiian spiders, and the cichlid fish radiations in East African lakes. The cichlids' potential to rapidly exploit and occupy a variety of different habitats has previously been attributed to the variability and adaptability of their trophic structures including the Pharyngeal Jaw apparatus. Here we report a reciprocal transplant experiment designed to explore the adaptability of the trophic structures in highly specialized cichlid fish species. More specifically, we forced two common but ecologically distinct cichlid species from Lake Tanganyika,; Tropheus moorii; (rock-dweller), and; Xenotilapia boulengeri; (sand-dweller), to live on their preferred as well as on an unpreferred habitat (sand and rock, respectively). We measured their overall performance on the different habitat types and explored whether adaptive phenotypic plasticity is involved in adaptation. We found that, while habitat had no effect on the performance of; X. boulengeri; ,; T. moorii; performed significantly better in its preferred habitat. Despite an experimental duration of several months, we did not find a shift in the morphology of the lower Pharyngeal Jaw bone that would be indicative of adaptive phenotypic plasticity in this trait.

  • Testing the stages model in the adaptive radiation of cichlid fishes in East African Lake Tanganyika
    Proceedings. Biological sciences, 2014
    Co-Authors: Moritz Muschick, Patrik Nosil, Marius Roesti, Marie T. Dittmann, Luke J. Harmon, Walter Salzburger
    Abstract:

    Adaptive radiation (AR) is a key process in the origin of organismal diversity. However, the evolution of trait disparity in connection with ecological specialization is still poorly understood. Available models for vertebrate ARs predict that diversification occurs in the form of temporal stages driven by different selective forces. Here, we investigate the AR of cichlid fishes in East African Lake Tanganyika and use macroevolutionary model fitting to evaluate whether diversification happened in temporal stages. Six trait complexes, for which we also provide evidence of their adaptiveness, are analysed with comparative methods: body shape, Pharyngeal Jaw shape, gill raker traits, gut length, brain weight and body coloration. Overall, we do not find strong evidence for the ‘stages model’ of AR. However, our results suggest that trophic traits diversify earlier than traits implicated in macrohabitat adaptation and that sexual communication traits (i.e. coloration) diversify late in the radiation.

  • Sequence analyses of the distal-less homeobox gene family in East African cichlid fishes reveal signatures of positive selection.
    BMC evolutionary biology, 2013
    Co-Authors: Eveline T. Diepeveen, Fabienne D Kim, Walter Salzburger
    Abstract:

    Gen(om)e duplication events are hypothesized as key mechanisms underlying the origin of phenotypic diversity and evolutionary innovation. The diverse and species-rich lineage of teleost fishes is a renowned example of this scenario, because of the fish-specific genome duplication. Gene families, generated by this and other gene duplication events, have been previously found to play a role in the evolution and development of innovations in cichlid fishes - a prime model system to study the genetic basis of rapid speciation, adaptation and evolutionary innovation. The distal-less homeobox genes are particularly interesting candidate genes for evolutionary novelties, such as the Pharyngeal Jaw apparatus and the anal fin egg-spots. Here we study the dlx repertoire in 23 East African cichlid fishes to determine the rate of evolution and the signatures of selection pressure. Four intact dlx clusters were retrieved from cichlid draft genomes. Phylogenetic analyses of these eight dlx loci in ten teleost species, followed by an in-depth analysis of 23 East African cichlid species, show that there is disparity in the rates of evolution of the dlx paralogs. Dlx3a and dlx4b are the fastest evolving dlx genes, while dlx1a and dlx6a evolved more slowly. Subsequent analyses of the nonsynonymous-synonymous substitution rate ratios indicate that dlx3b, dlx4a and dlx5a evolved under purifying selection, while signs of positive selection were found for dlx1a, dlx2a, dlx3a and dlx4b. Our results indicate that the dlx repertoire of teleost fishes and cichlid fishes in particular, is shaped by differential selection pressures and rates of evolution after gene duplication. Although the divergence of the dlx paralogs are putative signs of new or altered functions, comparisons with available expression patterns indicate that the three dlx loci under strong purifying selection, dlx3b, dlx4a and dlx5a, are transcribed at high levels in the cichlids’ Pharyngeal Jaw and anal fin. The dlx paralogs emerge as excellent candidate genes for the development of evolutionary innovations in cichlids, although further functional analyses are necessary to elucidate their respective contribution.

  • Molecular Characterization of Two Endothelin Pathways in East African Cichlid Fishes
    Journal of Molecular Evolution, 2011
    Co-Authors: Eveline T. Diepeveen, Walter Salzburger
    Abstract:

    The adaptive radiations of cichlid fishes in East Africa have been associated with the acquisition of evolutionary novelties as well as the ecological opportunities existing in the East African Great lakes. Two remarkable evolutionary innovations are the Pharyngeal Jaw apparatus, found in all cichlid species, and the anal fin egg-spots of mouthbrooding cichlids. Based on their conserved functions during the development of both the Jaw apparatus and pigmentation, the endothelin ligands and receptors form a putative link between these naturally and sexually selected traits. Here we study the evolutionary history of four members of two endothelin pathways (Edn1/EdnrAa and Edn3b/EdnrB1a) to elucidate their possible roles during the evolution and development of key innovations in East African cichlids species. The analyses performed on partial sequences (ca. 6,000 bp per taxon) show that all four endothelin family members evolved under purifying selection, although both ligands are characterized by an accelerated rate of protein evolution in comparison to the receptors. In accordance with earlier findings, we show that the mature protein sequence of Edn1 and Edn3 are highly conserved, also in cichlids, whereas the preproendothelin parts are variable indicating relaxed selective constraints. In the receptors, nonsynonymous substitutions were mainly found in the ligand-binding domains suggesting functional divergence. Gene expression assays with Real-Time PCR indeed reveal that the two studied endothelin pathways are expressed in the cichlid Pharyngeal Jaw and in the haplochromine egg-spot (among other pigment-cell containing tissues), suggesting their involvement during morphogenesis of naturally and sexually selected traits in cichlids.

  • Adaptive phenotypic plasticity in the Midas cichlid fish Pharyngeal Jaw and its relevance in adaptive radiation
    BMC evolutionary biology, 2011
    Co-Authors: Moritz Muschick, Marta Barluenga, Walter Salzburger, Axel Meyer
    Abstract:

    Phenotypic evolution and its role in the diversification of organisms is a central topic in evolutionary biology. A neglected factor during the modern evolutionary synthesis, adaptive phenotypic plasticity, more recently attracted the attention of many evolutionary biologists and is now recognized as an important ingredient in both population persistence and diversification. The traits and directions in which an ancestral source population displays phenotypic plasticity might partly determine the trajectories in morphospace, which are accessible for an adaptive radiation, starting from the colonization of a novel environment. In the case of repeated colonizations of similar environments from the same source population this "flexible stem" hypothesis predicts similar phenotypes to arise in repeated subsequent radiations. The Midas Cichlid (Amphilophus spp.) in Nicaragua has radiated in parallel in several crater-lakes seeded by populations originating from the Nicaraguan Great Lakes. Here, we tested phenotypic plasticity in the Pharyngeal Jaw of Midas Cichlids. The Pharyngeal Jaw apparatus of cichlids, a second set of Jaws functionally decoupled from the oral ones, is known to mediate ecological specialization and often differs strongly between sister-species. We performed a common garden experiment raising three groups of Midas cichlids on food differing in hardness and calcium content. Analyzing the lower Pharyngeal Jaw-bones we find significant differences between diet groups qualitatively resembling the differences found between specialized species. Observed differences in Pharyngeal Jaw expression between groups were attributable to the diet's mechanical resistance, whereas surplus calcium in the diet was not found to be of importance. The Pharyngeal Jaw apparatus of Midas Cichlids can be expressed plastically if stimulated mechanically during feeding. Since this trait is commonly differentiated - among other traits - between Midas Cichlid species, its plasticity might be an important factor in Midas Cichlid speciation. The prevalence of Pharyngeal Jaw differentiation across the Cichlidae further suggests that adaptive phenotypic plasticity in this trait could play an important role in cichlid speciation in general. We discuss several possibilities how the adaptive radiation of Midas Cichlids might have been influenced in this respect.

Carmelo Fruciano - One of the best experts on this subject based on the ideXlab platform.

  • Genetic linkage of distinct adaptive traits in sympatrically speciating crater lake cichlid fish
    Nature communications, 2016
    Co-Authors: Carmelo Fruciano, Paolo Franchini, Viera Kovacova, Kathryn R. Elmer, Frederico Henning, Axel Meyer
    Abstract:

    Our understanding of how biological diversity arises is limited, especially in the case of speciation in the face of gene flow. Here we investigate the genomic basis of adaptive traits, focusing on a sympatrically diverging species pair of crater lake cichlid fishes. We identify the main quantitative trait loci (QTL) for two eco-morphological traits: body shape and Pharyngeal Jaw morphology. These traits diverge in parallel between benthic and limnetic species in the repeated adaptive radiations of this and other fish lineages. Remarkably, a single chromosomal region contains the highest effect size QTL for both traits. Transcriptomic data show that the QTL regions contain genes putatively under selection. Independent population genomic data corroborate QTL regions as areas of high differentiation between the sympatric sister species. Our results provide empirical support for current theoretical models that emphasize the importance of genetic linkage and pleiotropy in facilitating rapid divergence in sympatry.

  • Pharyngeal Jaw shape
    2016
    Co-Authors: Carmelo Fruciano
    Abstract:

    Lower Pharyngeal Jaw shape data in TPS format. The data contains all landmarks and semilandmarks (prior to sliding). The dataset comprises missing landmark whose position has been reconstructed through reflection (please, see the paper for details)

  • Traditional and geometric morphometrics detect morphological variation of lower Pharyngeal Jaw in Coris julis (Teleostei, Labridae)
    Italian Journal of Zoology, 2011
    Co-Authors: Carmelo Fruciano, Concetta Tigano, Venera Ferrito
    Abstract:

    In the present study, variation in the morphology of the lower Pharyngeal element between two Sicilian populations of the rainbow wrasse Coris julis has been explored by the means of traditional morphometrics for size and geometric morphometrics for shape. Despite close geographical distance and probable high genetic flow between the populations, statistically significant differences have been found both for size and shape. In fact, one population shows a larger lower Pharyngeal element that has a larger central tooth. Compared to the other population, this population also has medially enlarged lower Pharyngeal Jaws with a more pronounced convexity of the medial-posterior margin. The results are discussed in the light of a possible more pronounced durophagy of this population