Evolutionary and morphological patterns underlying carnivoran body shape diversity

Abstract

The diversity of body shapes is one of the most prominent features of phenotypic variation in vertebrates. Biologists, however, still lack a full understanding of the underlying morphological components that contribute to its diversity, particularly in endothermic vertebrates such as mammals. In this study, hypotheses pertaining to the evolution of the cranial and axial components that contribute to the diversity of carnivoran body shapes were tested. Three trends were found in the evolution of carnivoran body shapes: (1) carnivorans exhibit diverse body shapes with intrafamilial variation predicted best by family clade age, (2) body shape is driven by strong allometric effects of body size where species become more elongate with decreasing size, and (3) the thoracic and lumbar regions and rib length contribute the most to body shape variation, albeit pathways differ between different families. These results reveal the morphological patterns that led to increased diversity in carnivoran body shapes and elucidate the similarities and dissimilarities that govern body shape diversity across vertebrates.

Masticatory muscle architectural correlates of dietary diversity in Canidae, Ursidae, and across the order Carnivora

“…Also unsurprisingly, the most statistically significant findings were among the Musteloidea—the lineage that spans both the greatest dietary diversity and body size range in the order. Therefore, musteloids have proven to be interesting as an example of myological diversity that is consistent with the diversity observed in other morphological features of this clade (Law, 2019, 2021). Similarly, interesting observations might be found within Ursids with the addition of the durophagous giant panda ( A. melanoleuca ) to the dataset.…”

Body size, shape and ecology in tetrapods

“…Body shape also plays a determinant role at multiple physiological levels; for example, in describing the space available for accommodating major organ systems 4 , 5 , and body surface area for heat exchange 6 , 7 . Because different environments and behaviours place different demands on the functional mechanics and physiologies of organisms, it is expected that body proportions should vary across animals occupying different ecological niches 8 – 14 . However, modification of body size and shape by ecological pressures may also be constrained by other factors, notably phylogenetic history and the ecological trajectory of evolutionary change 3 , 15 , 16 .…”

“…Given the universal potential for natural selection to act upon body shape, it is not surprising that many studies have sought to investigate associations between body proportions and ecological niche occupation 8 – 14 . While these studies have regularly identified important trends in the evolution of body proportions 8 – 14 , they have tended to focus on individual taxonomic or ecological groups, or on an individual aspect of body shape. However, to our knowledge, no study has systematically investigated allometric patterns or ecological differences in whole-body proportions across a highly diverse sample of extinct and extant tetrapods.…”

Genetic basis of body shape variation along the benthic-pelagic axis in cichlid fishes

“…Friedman, Price, & Wainwright, 2021;Ruff, 1991;Schluter, 1996aSchluter, , 2000Smith, Nelson-Maney, Parsons, Cooper, & Albertson, 2015). A major axis of this morphological variation is body elongation, which occurs within reptiles (Bergmann & Irschick, 2012;Losos, 2009;Wiens & Slingluff, 2001), carnivorous mammals (Law, 2019(Law, , 2021, and fishes (S. T.…”

“…Friedman, Price, & Wainwright, 2021;Ruff, 1991;Schluter, 1996aSchluter, , 2000Smith, Nelson-Maney, Parsons, Cooper, & Albertson, 2015). A major axis of this morphological variation is body elongation, which occurs within reptiles (Bergmann & Irschick, 2012;Losos, 2009;Wiens & Slingluff, 2001), carnivorous mammals (Law, 2019(Law, , 2021, and fishes (S. T. Friedman et al, 2020;Price et al, 2019;Ward & Mehta, 2010). Within fishes, elongation of the body is associated with a major ecomorphological divergence, the benthic-pelagic axis.…”