Fluctuations in Evolutionary Integration Allow for Big Brains and Disparate Faces

Evans, Kory M.; Waltz, Brandon T.; Tagliacollo, Victor A.; Sidlauskas, Brian L.; Albert, James S.

doi:10.1038/srep40431

Cited by 46 publications

(40 citation statements)

References 61 publications

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“…As prior work shows, there is no clear rule about the impact of integration on diversification, and neither the constraint nor facilitation hypothesis have been consistently supported (Porto et al 2008;Claverie and Patek 2013;Gerber 2013;Goswami et al 2014Goswami et al , 2015Evans et al 2017). In our study, the effect of integration appears to be positive, as evidenced by the combination of higher disparity, higher net rate of evolution, and higher integration in acanthomorphs compared to nonacanthomorphs.…”

Section: Discussioncontrasting

confidence: 85%

“…, ; Evans et al. ). In our study, the effect of integration appears to be positive, as evidenced by the combination of higher disparity, higher net rate of evolution, and higher integration in acanthomorphs compared to nonacanthomorphs.…”

Section: Discussionmentioning

confidence: 99%

“…Simulations have shown that strong integration, depending on the structure of trait covariance, can lead to both higher and lower variation than expected under a random walk of uncorrelated traits, as well as enhance and bias responses to selection (Goswami et al 2014). The effects of integration on the ability of populations to respond to selection have been demonstrated in several empirical systems (Marroig et al 2009;Haber 2016;Evans et al 2017).…”

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confidence: 99%

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Integration and modularity of teleostean pectoral fin shape and its role in the diversification of acanthomorph fishes

Tissandier

Larsson

2019

Evolution

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Phenotypic integration and modularity describe the strength and pattern of interdependencies between traits. Integration and modularity have been proposed to influence the trajectory of evolution, either acting as constraints or facilitators. Here, we examine trends in the integration and modularity of pectoral fin morphology in teleost fishes using geometric morphometrics. We compare the fin shapes of the highly diverse radiation of acanthomorph fishes to lower teleosts. Integration and modularity are measured using two‐block partial least squares analysis and the covariance ratio coefficient between the radial bones and lepidotrichia of the pectoral fins. We show that the fins of acanthomorph fishes are more tightly integrated but also more morphologically diverse and faster evolving compared to nonacanthomorph fishes. The main pattern of shape covariation in nonacanthomorphs is concordant with the main trajectory of evolution between nonacanthomorphs and acanthomorphs. Our findings support a facilitating role for integration during the acanthomorph diversification. Potential functional consequences and developmental mechanisms of fin integration are discussed.

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Section: Discussioncontrasting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Integration and modularity of teleostean pectoral fin shape and its role in the diversification of acanthomorph fishes

Tissandier

Larsson

2019

Evolution

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“…Neotropical electric fishes (Gymnotiformes: Teleostei) represent an excellent case study for sexual weaponry. In this clade, fishes exhibit a wide diversity of skull shapes ranging from highly foreshortened skull shapes to highly elongate skull shapes [7, 8]. Amongst this diversity is an interesting pattern of sexual dimorphism, where males grow elongate snouts and oral jaws for use in agonistic jaw-locking battles, a trait that has evolved multiple times independently [9-11] (Figure S1; Movie 1).…”

Section: Introductionmentioning

confidence: 99%

From Armament to Ornament: Performance Trade-Offs in the Sexual Weaponry of Neotropical Electric Fishes

Evans

et al. 2018

Preprint

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The evolution of sexual weaponry is thought to have marked effects on the underlying static allometry that builds them. These weapons can negatively affect organismal survivability by creating trade-offs between trait size and performance. Here we use three-dimensional geometric morphometrics to study the static allometry of two species of sexually dimorphic electric fishes (Apteronotus rostratus and Compsaraia samueli) in which mature males grow elongate jaws used in agonistic male-male interactions. We quantify jaw mechanical advantage between the sexes of both species to track changes in velocity and force transmission associated with the development of sexual weaponry. We find evidence for trade-offs between skull shape and mechanical advantage in C. samueli, where males with longer faces exhibit lower mechanical advantages, suggesting weaker bite forces. In contrast, males, and females of A. rostratus exhibit no difference in mechanical advantage associated with facial elongation. We hypothesize that differences in the functionality of the sexual weaponry between the two species may drive divergences in the allometric scaling of mechanical advantage.

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“…The genus exhibits one of the fastest rates of skull shape evolution among gymnotiforms (Evans et al, 2017a).…”

Section: Introductionmentioning

confidence: 99%

Taxonomic revision of the deep channel electric fish genus Sternarchella (Teleostei: Gymnotiformes: Apteronotidae), with descriptions of two new species

2017

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This paper provides a taxonomic revision of the Neotropical electric fish genus Sternarchella, with redescriptions of seven valid species and descriptions of two new species. A maximum parsimony analysis of 76 morphological characters from seven ingroup and seven outgroup taxa recovered a non-monophyletic Sternarchella, in which a clade comprising two species with a ventral mouth (S. orinoco + S. sima) is the sister group to a clade comprising seven species that possess a terminal or superior mouth. Nested within this higher-diversity clade is the genus Magosternarchus (recognized herein as a junior synonym of Sternarchella) comprising M. duccis and M. raptor. The Magosternarchus clade forms a polytomy with S. orthos and S. schotti. Sternarchella calhamazon + a new species from the upper Río Madeira (sister species to S. calhamazon), and a new larger-bodied species from the central and upper Río Amazonas also form a clade. Sternarchella orthos is distributed in both the Amazon and Orinoco basins, where it exhibits considerable phenotypic diversity. Sternarchella orthos includes most specimens from the Amazon formerly assigned to the nominal species S. terminalis (recognized herein as a junior synonym of S. schotti).Keywords: Amazon, Evolution, Geometric morphometrics, Identification key, Magosternarchus.Este artigo propõe uma revisão taxonômica do gênero Neotropical de peixe-elétrico Sternarchella, incluindo a redescrição de sete espécies válidas e duas novas espécies. Análise de máxima parcimônia com 76 caracteres morfológicos e amostragem de sete grupos internos e sete grupos externos indica que Sternarchella não constitui grupo monofilético, sendo um clado composto por duas espécies com bocas ventrais (S. orinoco + S. sima) e outro com sete espécies com bocas terminais ou superiores. Dentro deste último clado estão as espécies do gênero Magosternarchus (reconhecido aqui como um sinônimo júnior de Sternarchella): M. duccis e M. raptor. O clado de Magosternarchus forma uma politomia com S. orthos e S. schotti. Sternarchella calhamazon + uma nova espécie do alto rio Madeira (espécie irmã de S. calhamazon) e uma nova espécie de corpo maior do rio Amazonas central e superior também formam um clado. Sternarchella orthos está distribuída nos rios amazônicos e no Orinoco, onde apresenta elevada diversidade fenotípica. Sternarchella orthos inclui a maioria dos espécimes do rio Amazonas anteriormente atribuídos à S. terminalis (considerada neste estudo como sinônimo júnior de S. schotti).Palavras-chave: Amazônia, Chave de identificação, Evolução, Magosternarchus, Morfometria geométrica.

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Fluctuations in Evolutionary Integration Allow for Big Brains and Disparate Faces

Cited by 46 publications

References 61 publications

Integration and modularity of teleostean pectoral fin shape and its role in the diversification of acanthomorph fishes

Integration and modularity of teleostean pectoral fin shape and its role in the diversification of acanthomorph fishes

From Armament to Ornament: Performance Trade-Offs in the Sexual Weaponry of Neotropical Electric Fishes

Taxonomic revision of the deep channel electric fish genus Sternarchella (Teleostei: Gymnotiformes: Apteronotidae), with descriptions of two new species

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