Biology subjects

Galvez-Lopez, E.

Publications and source records attributed to Galvez-Lopez, E..

3 recordsLinked to original sources

bioRxiv2022

Evolution of scapula size and shape in Carnivora: locomotor habits and differential shape scaling

The effect of size, phylogeny, and locomotor habit, on shape was tested in 213 scapulas from 101 carnivoran species using 3D geometric morphometric methods. The sampled species spanned the whole size range and locomotor patterns in Carnivora. The results of the present study indicate that, in this order, scapula shape responds to the complex interaction of allometric, phylogenetic, and functional effects. Furthermore, evidence for differential scaling in the shape of the carnivoran scapula was found, which might be related to scaling differences among carnivoran families. Additionally, most allometric shape variation in the carnivoran scapula was related to size changes along phyletic lines. Locomotor-related shape differences were assessed using canonical variate analysis. Most locomotor habits could be significantly separated from each other based on scapula shape, although high misclassification rates were obtained when comparing semiarboreal and semifossorial carnivorans to other locomotor types. Locomotor indicators in the scapula shape of extant carnivorans seemed independent of size or shared ancestry and could be related to muscular function. These locomotor indicators were then used to infer the locomotor habits of several internal nodes of the carnivoran phylogeny, whose scapular size and shape was reconstructed using weighted square-change parsimony. According to scapula size and shape, the carnivoran ancestor was a medium-sized scansorial animal (i.e., it spent most of its time on the ground, but was a good climber).

evolutionary biology↗

bioRxiv2022

Scaling pattern of the carnivoran hind limb: Main deviations from a conservative pattern.

The scaling pattern of the hind limb in Carnivora was determined using a sample of 13 variables measured on the femur, tibia, and calcaneus, of 429 specimens belonging to 141 species. Standardized major axis regressions on body mass were calculated for all variables, using both traditional regression methods and phylogenetically independent contrasts (PIC). Significant differences were found between the allometric slopes obtained with traditional and PIC regression methods, emphasizing the need to take into account phylogenetic relatedness in scaling studies. Overall, the scaling of the carnivoran hind limb conformed to geometric similarity, although some deviations from its predictions (including differential scaling) were detected, especially in relation with swimming adaptations. The scaling pattern of several phyletic lines and locomotor habits within Carnivora was also determined. Significant deviations from the scaling pattern of the order were found in some phyletic lines, but not in the locomotor habit subsamples. This suggests that the scaling of the carnivoran hind limb is both more heavily influenced by phylogenetic relatedness than by locomotor specializations, and more conservative than that of the forelimb. Finally, together with our previous work on the carnivoran forelimb, the results of the present study suggest that, in large non-aquatic carnivorans, size-related increases in bone stresses are compensated primarily by limb posture changes instead of by modifying limb bone scaling. However, increasing bone robusticity might also occur in the forelimb in response to the heavier stresses acting on the forelimbs due to asymmetrical body weight distribution.

zoology↗

bioRxiv2022

Scaling pattern of the carnivoran forelimb: Locomotor types, differential scaling and thoughts on a dying similarity

The scaling pattern of the forelimb in Carnivora was determined using a sample of 30 variables measured on the scapula, humerus, radius, ulna, and third metacarpal, of 429 specimens belonging to 137 species of Carnivora. Standardized major axis regressions on body mass were calculated for all variables, using both traditional regression methods and phylogenetically independent contrasts (PIC). In agreement with previous studies on the scaling of the appendicular skeleton, conformity to either the geometric similarity hypothesis or the elastic similarity hypothesis was low. The scaling pattern of several phyletic lines and locomotor types within Carnivora was also determined, and significant deviations from the scaling pattern of the order were found in some of these subsamples. Furthermore, significant evidence for differential scaling was found for several variables, both in the whole sample and in various phylogenetic and locomotor subsamples. Contrary to previous studies, significant differences were found between the allometric exponents obtained with traditional and PIC regression methods, emphasizing the need to take into account phylogenetic relatedness in scaling studies. In light of these and previous results, we conclude that similarity hypotheses are too simplistic to describe scaling patterns in the carnivoran appendicular skeleton, and thus we propose that scaling hypotheses should be built from similarities in the scaling patterns of phylogenetically narrow samples of species with similar locomotor requirements. The present work is a first step in the study of those samples.

zoology↗