Pleiotropic jaw morphology links the evolution of mechanical modularity and functional feeding convergence in Lake Malawi cichlids

Hulsey, C. Darrin; Alfaro, Michael E.; Zheng, Jimmy; Meyer, Axel; Holzman, Roi

doi:10.1098/rspb.2018.2358

Cited by 28 publications

(33 citation statements)

References 72 publications

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“…In particular, cranial structures in fish are useful morphological metrics for understanding trophic specialization processes. For instance, African cichlids illustrate how dramatic craniofacial differences reflect adaptations to alternative feeding niches (Hulsey, Alfaro, Zheng, Meyer, & Holzman, ).…”

Section: Introductionmentioning

confidence: 99%

A geographical cline in craniofacial morphology across populations of Mesoamerican lake‐dwelling fishes

et al. 2020

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Together, the complex geological history and climatic diversity of Mesoamerica create a rich source of biodiversity from which evolutionary processes can be studied. Here, we discuss highly divergent morphs of lake‐dwelling fishes distributed across Mexico and Central America, originally recognized as members of different genera (Astyanax and “Bramocharax”). Recent phylogenetic studies, however, suggest these morphs group within the same genus and readily hybridize. Despite genetic similarities, Bramocharax morphs exhibit stark differences in cranial shape and dentition. We investigated the evolution of several cranial traits that vary across morphs collected from four lakes in Mexico and Nicaragua and discovered an ecomorphological cline from northern to southern lakes. Northern populations of sympatric morphs exhibit a similar cranial shape and tooth morphology. Southern populations of Bramocharax morphs, however, showed a larger disparity in maxillary teeth, length and frequency of unicuspid teeth, an elongated snout, and a streamlined cranium compared to Astyanax morphs. This divergence of craniofacial morphology likely evolved in association with differences in trophic niches. We discuss the morphological differences across the four lake systems in terms of geological history and trophic dynamics. In summary, our study suggests that Bramocharax morphs are likely locally adapted members derived from independent Astyanax lineages, highlighting an interesting parallel evolutionary pattern within the Astyanax genus.

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Section: Introductionmentioning

confidence: 99%

A geographical cline in craniofacial morphology across populations of Mesoamerican lake‐dwelling fishes

et al. 2020

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“…These factors often operate simultaneously, and may lead to idiosyncratic outcomes because 36 of differences in ancestral conditions and/or evolvability between lineages (historical 37 contingency; e.g., Gould 2002;Agrawal 2017;Blount et al 2018). Recent studies have demonstrated that idiosyncrasies among lineages occupying similar niches, termed "incomplete" convergence (sensu Herrel et al 2004), might be more prevalent than previously recognized (Losos 2010;Moen et al 2016;Hulsey et al 2019). As such, close examination into the nature of apparently convergent phenotypes and their ancestral conditions is required to fully comprehend the various evolutionary processes underlying convergence.…”

Section: Introductionmentioning

confidence: 99%

Wing musculature reconstruction in extinct flightless auks (PinguinusandMancalla) reveals incomplete convergence with penguins (Spheniscidae) due to differing ancestral states

Watanabe

Field

Matsuoka

2020

Preprint

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Despite longstanding interest in convergent evolution, factors that result in deviations from fully convergent phenotypes remain poorly understood. In birds, the evolution of flightless wing-propelled diving has emerged as a classic example of convergence, having arisen in disparate lineages including penguins (Sphenisciformes) and auks (Pan-Alcidae, Charadriiformes). Nevertheless, little is known about the functional anatomy of the wings of flightless auks because all such taxa are extinct, and their morphology is almost exclusively represented by skeletal remains. Here, in order to re-evaluate the extent of evolutionary convergence among flightless wing-propelled divers, wing muscles and ligaments were reconstructed in two extinct flightless auks, representing independent transitions to flightlessness: Pinguinus impennis (a crown-group alcid), and Mancalla (a stem-group alcid). Extensive anatomical data were gathered from dissections of 12 species of extant charadriiforms and 4 aequornithine waterbirds including a penguin. It was found that the wings of both flightless auk taxa were characterized by an increased mechanical advantage of wing elevator/retractor muscles, and decreased mobility of distal wing joints, both of which are likely advantageous for wing-propelled diving and parallel similar functional specializations in penguins. However, the conformations of individual muscles and ligaments underlying these specializations differ markedly between penguins and flightless auks, instead resembling those in each respective group’s close relatives. Thus, the wings of these flightless wing-propelled divers can be described as convergent as overall functional units, but are incompletely convergent at lower levels of anatomical organization—a result of retaining differing conditions from each group’s respective volant ancestors. Detailed investigations such as this one may indicate that, even in the face of similar functional demands, courses of phenotypic evolution are dictated to an important degree by ancestral starting points.

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“…Instead, the density of species within the morphospace was evidently the product of differential extinction. (Hulsey, Alfaro, Zheng, Meyer, & Holzman, also found little evidence that cichlid jaw morphology evolved towards inferred optima in morphospace. )…”

Section: Predictions For Macroevolutionary Dynamicsmentioning

confidence: 99%

Developmental bias, macroevolution, and the fossil record

Jablonski

2019

Evolution and Development

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A fuller understanding of the role of developmental bias in shaping large-scale evolutionary patterns requires integrating bias (the probability distribution of variation accessible to an ancestral phenotype) with clade dynamics (the differential survival and production of species and evolutionary lineages). This synthesis could proceed as a two-way exchange between the developmental data available to neontologists and the strictly phenotypic but richly historical and dynamic data available to paleontologists. Analyses starting in extant populations could aim to predict macroevolution in the fossil record from observed developmental bias, while analyses starting in the fossil record, particularly the record of extant species and lineages, could aim to predict developmental bias from macroevolutionary patterns, including the broad range of extinct phenotypes. Analyses in multivariate morphospaces are especially effective when coupled with phylogeny, theoretical and developmental models, and diversity-disparity plots. This research program will also require assessing the "heritability" of an ancestral bias across phylogeny, and the tendency for bias change in strength and orientation over evolutionary time. Such analyses will help find a set of general rules for the macroevolutionary effects of developmental bias, including its impact on and interactions with the other intrinsic and extrinsic factors governing the movement, expansion, and contraction of clades in morphospace.

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Pleiotropic jaw morphology links the evolution of mechanical modularity and functional feeding convergence in Lake Malawi cichlids

Cited by 28 publications

References 72 publications

A geographical cline in craniofacial morphology across populations of Mesoamerican lake‐dwelling fishes

A geographical cline in craniofacial morphology across populations of Mesoamerican lake‐dwelling fishes

Wing musculature reconstruction in extinct flightless auks (PinguinusandMancalla) reveals incomplete convergence with penguins (Spheniscidae) due to differing ancestral states

Developmental bias, macroevolution, and the fossil record

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