Phylogenetic signal, function and integration in the subunits of the carnivoran mandible

Meloro, Carlo; Raia, Pasquale; Carotenuto, Francesco; Cobb, Samuel N.

doi:10.1007/s11692-011-9135-6

Cited by 41 publications

(26 citation statements)

References 66 publications

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“…Bennett & Goswami 2013). The cranium and the lower jaw are composed of different modules and have different integration patterns (Goswami 2006;Goswami et al 2009;Marroig et al 2009;Goswami & Polly 2010;Meloro et al 2011;Bennett & Goswami 2013), which could result in different of evolutionary constraints. The degrees of modularity and integration of the cranium and lower jaw could be a result of functional constraints, with the jaw more related to food intake and processing, while the cranium also has to support and protect the brain and sensitive organs, for the same reason, it is expected that the mandible and the viscerocranium portion of the cranium was less constrained during the evolution of these clades and more correlated with feeding habits than the neurocranium (Radinsky 1981;Slater & Van Valkenburgh 2009;Figueirido et al 2011;Prevosti et al 2012;Goswami et al 2012.…”

Section: Discussionmentioning

confidence: 99%

Differences in mandibular disparity between extant and extinct species of metatherian and placental carnivore clades

Echarri

Prevosti

2015

LET

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There are a number of studies relating to skull morphology differences within the carnivoran clades of both placentals and metatherians. It is difficult to compare these studies because of differences in taxonomic sampling, for example some include fossil taxa while others include non‐carnivoran placentals. As a consequence, we studied mandible morphology in a broad range of both extant and extinct carnivorous species, including Carnivora, Marsupialia and Sparassodonta to test for differences between these clades. We used geometric morphometrics and two disparity indexes, the variance and Procrustes distances mean. When including fossil species, we found no significant differences for both disparities in some analyses, except after the exclusion of the sabretooth morphotype. This can be explained by the extreme morphology of this morphotype, which increases the variance and reduces the disparity effect of the other species in the analyses. Using Procrustes distances, we found significant differences in disparity distances between Carnivora and Metatheria for most of the analyses. We also found significant differences using the variance index in some analyses. The mandibular disparity in Carnivora is greater than in carnivorous metatherian mammals for most of the cases and this can be related with differences in evolutionary history and constraints of both groups. The pattern found in the mandible is similar to that found in the face of the skull but was not observed in the braincase, due to differences in skull function and mandible function.

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Section: Discussionmentioning

confidence: 99%

Differences in mandibular disparity between extant and extinct species of metatherian and placental carnivore clades

Echarri

Prevosti

2015

LET

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“…Once detected, the phylogenetic signal, Phylogenetic Generalized Least Square (PGLS, Rohlf, 2001Rohlf, , 2006c, was employed into PLS models to validate the association of cranium shape with size or dentition (cf. Meloro et al, 2011;Meloro, 2012;Piras et al, 2012). PGLS allows incorporating phylogenetic information (=OTU covariance matrix) as error term in ordinary least square models.…”

Section: Comparative Methodsmentioning

confidence: 99%

“…Jones, 2004Jones, , 2008Stayton & Ruta, 2006;Pierce et al, 2009;Young et al, 2010Young et al, , 2011Brusatte et al, 2012;Bhullar et al, 2012;Foth & Rauhut, in press;Foth et al, 2012). Many of these studies (Stayton & Ruta, 2006;Pierce et al, 2009;Meloro, 2011;Brusatte et al, 2012;Foth et al, 2012) used specific measures of morphological disparity (Foote, 1992(Foote, , 1993(Foote, , 1997Wills et al, 1994;Ciampaglio et al, 2001) to quantify morphological diversity during different time bins that may span several million years. However, very few have considered the technique promoted by Harmon et al (2003), which involves a time-calibrated branching pattern of a phylogenetic hypothesis (cf.…”

Section: Introductionmentioning

confidence: 99%

Tooth and cranial disparity in the fossil relatives of Sphenodon (Rhynchocephalia) dispute the persistent ‘living fossil’ label

Meloro

Jones

2012

J of Evolutionary Biology

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The tuatara (Sphenodon punctatus) is the only living representative of Rhynchocephalia, a group of small vertebrates that originated about 250 million years ago. The tuatara has been referred to as a living fossil; however, the group to which it belongs included a much greater diversity of forms in the Mesozoic. We explore the morphological diversity of Rhynchocephalia and stem lepidosaur relatives (Sphenodon plus 13 fossil relatives) by employing a combination of geometric morphometrics and comparative methods. Geometric morphometrics is used to explore cranium size and shape at interspecific scale, while comparative methods are employed to test association between skull shape and size and tooth number after taking phylogeny into account. Two phylogenetic topologies have been considered to generate a phylomorphospace and quantify the phylogenetic signal in skull shape data, the ancestral state reconstruction as well as morphological disparity using disparity through time plots (DTT). Rhynchocephalia exhibit a significant phylogenetic signal in skull shape that compares well with that computed for other extinct vertebrate groups. A consistent form of allometry has little impact on skull shape evolution while the number of teeth significantly correlates with skull shape also after taking phylogeny into account. The ancestral state reconstruction demonstrates a dramatic shape difference between the skull of Sphenodon and its much larger Cretaceous relative Priosphenodon. Additionally, DTT demonstrates that skull shape disparity is higher between rather than within clades while the opposite applies to skull size and number of teeth. These results were not altered by the use of competing phylogenic hypotheses. Rhynchocephalia evolved as a morphologically diverse group with a dramatic radiation in the Late Triassic and Early Jurassic about 200 million years ago. Differences in size are not marked between species whereas changes in number of teeth are associated with co-ordinated shape changes in the skull to accommodate larger masticatory muscles. These results show that the tuatara is not the product of evolutionary stasis but that it represents the only survivor of a diverse Mesozoic radiation whose subsequent decline remains to be explained.

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“…; Nogueira, Peracchi & Monteiro ; Monteiro & Nogueira ; Meloro et al . ; Gómez‐Robles & Polly ; Parsons, Márquez & Albertson ; Clune, Mouret & Lipson ). In addition, researchers have compared patterns across different empirical systems to determine the extent to which levels of modularity or integration are consistent, and to decipher how these trends may differ across levels of biological organization (e.g.…”

Section: Introductionmentioning

confidence: 99%

Evaluating modularity in morphometric data: challenges with the RV coefficient and a new test measure

2016

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Summary1: Modularity describes the case where patterns of trait covariation are unevenly dispersed across traits. Specifically, trait correlations are high and concentrated within subsets of variables (modules), but the correlations between traits across modules are relatively weaker. For morphometric datasets, hypotheses of modularity are commonly evaluated using the RV coefficient, an association statistic used in a wide variety of fields.2: In this article I explore the properties of the RV coefficient using simulated data sets. Using data drawn from a normal distribution where the data were neither modular nor integrated in structure, I show that the RV coefficient is adversely affected by attributes of the data (sample size and the number of variables) that do not characterize the covariance structure between sets of variables. Thus, with the RV Accepted ArticleThis article is protected by copyright. All rights reserved. coefficient, patterns of modularity or integration in data are confounded with trends generated by sample size and the number of variables, which limits biological interpretations and renders comparisons of RV coefficients across datasets uninformative.3: As an alternative I propose the covariance ratio (CR) for quantifying modular structure, and show that it is unaffected by sample size or the number of variables. Further, statistical tests based on the CR exhibit appropriate type I error rates, and display higher statistical power relative to the RV coefficient when evaluating modular data. 4:Overall, these findings demonstrate that the RV coefficient does not display statistical characteristics suitable for reliable assessment of hypotheses of modular or integrated structure, and therefore should not be used to evaluate these patterns in morphological datasets. By contrast, the covariance ratio meets these criteria and provides a useful alternative method for assessing the degree of modular structure in morphological data.

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Phylogenetic signal, function and integration in the subunits of the carnivoran mandible

Cited by 41 publications

References 66 publications

Differences in mandibular disparity between extant and extinct species of metatherian and placental carnivore clades

Differences in mandibular disparity between extant and extinct species of metatherian and placental carnivore clades

Tooth and cranial disparity in the fossil relatives of Sphenodon (Rhynchocephalia) dispute the persistent ‘living fossil’ label

Evaluating modularity in morphometric data: challenges with the RV coefficient and a new test measure

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