Biology subjects

Godoy, P. L.

Publications and source records attributed to Godoy, P. L..

4 recordsLinked to original sources

bioRxiv2022

Turtle body size evolution is determined by lineage-specific specializations rather than global trends

Organisms display considerable variety of body sizes and shapes, and macroevolutionary investigations help to understand the evolutionary dynamics behind to such variations. Turtles (Testudinata) show great body size disparity, especially when their rich fossil record is accounted for. We explored body size evolution in turtles, testing which factors might influence the observed patterns and evaluating the existence of long-term directional trends. We constructed the most comprehensive body size dataset for the group to date, tested for correlation with paleotemperature, estimated ancestral body sizes, and performed macroevolutionary model-fitting analyses. We found no evidence for directional body size evolution, even when using very flexible models, thereby rejecting the occurrence of Copes rule. We also found no significant effect of paleotemperature on overall through-time body size patterns. In contrast, we found a significant influence of habitat preference on turtle body size. Freshwater turtles display a rather homogenous body size distribution through time. In contrast, terrestrial and marine turtles show more pronounced variation, with terrestrial forms being restricted to larger body sizes, up to the origin of testudinids in the Cenozoic, and marine turtles undergoing a reduction in body size disparity after the extinctions of many groups in the mid-Cenozoic. Our results therefore suggest that long-term, generalized patterns are probably explained by factors specific to certain groups and related at least partly to habitat use.

evolutionary biology↗

bioRxiv2019

A unique predator in a unique ecosystem: modelling the apex predator from the Late Cretaceous crocodyliform-dominated fauna in Brazil.

ABSTRACTTheropod dinosaurs were relatively scarce in the Late Cretaceous ecosystems of southeast Brazil. Instead, hypercarnivorous crocodyliforms known as baurusuchids were abundant and probably occupied the ecological role of apex predators. Baurusuchids exhibited a series of morphological adaptations hypothesised to be associated with this ecological role, but quantitative biomechanical analyses of their morphology have so far been lacking. Here, we employ a biomechanical modelling approach, applying finite element analysis (FEA) to models of the skull and mandibles of a baurusuchid specimen. This allowed us to characterise the craniomandibular apparatus of baurusuchids, as well as to compare the functional morphology of the group to that of other archosaurian carnivores, such as theropods and crocodylians. Our results support the ecological role of baurusuchids as specialised apex predators in the continental Late Cretaceous ecosystems of South America. With a relatively weak bite force (∼600 N), baurusuchids’ predation strategies likely relied on other morphological specializations, such as ziphodont dentition and strong cervical musculature. Comparative assessments of the stress distribution and magnitude of scaled models of other predators (the theropod Allosaurus fragilis and the living crocodylian Alligator mississippiensis) consistently show different responses to loadings under the same functional scenarios, suggesting distinct predatory behaviours for these animals. The unique selective pressures in the arid to semi-arid Late Cretaceous ecosystems of southeast Brazil, which were dominated by crocodyliforms, possibly drove the emergence and evolution of the biomechanical features seen in baurusuchids, which are distinct from those previously reported for other predatory taxa.View Full Text

paleontology↗

bioRxiv2019

Crocodylomorph cranial shape evolution and its relationship with body size and ecology

Crocodylomorpha, which includes living crocodylians and their extinct relatives, has a rich fossil record, extending back for more than 200 million years. Unlike modern semi-aquatic crocodylians, extinct crocodylomorphs exhibited more varied lifestyles, ranging from marine to fully terrestrial forms. This ecological diversity was mirrored by a remarkable morphological disparity, particularly in terms of cranial morphology, which seems to be closely associated with ecological roles in the group. Here, I use geometric morphometrics to comprehensively investigate cranial shape variation and disparity in Crocodylomorpha. I quantitatively assess the relationship between cranial shape and ecology (i.e. terrestrial, aquatic, and semi-aquatic lifestyles), as well as possible allometric shape changes. I also characterise patterns of cranial shape evolution and identify regime shifts. I found a strong link between shape and size, and a significant influence of ecology on the observed shape variation. Terrestrial taxa, particularly notosuchians, have significantly higher disparity, and shifts to more longirostrine regimes are associated with large-bodied aquatic or semi-aquatic species. This demonstrates an intricate relationship between cranial shape, body size and lifestyle in crocodylomorph evolutionary history. Additionally, disparity-through-time analyses were highly sensitive to different phylogenetic hypotheses, suggesting the description of overall patterns among distinct trees. For crocodylomorphs, most results agree in an early peak during the Early Jurassic and another in the middle of the Cretaceous, followed by nearly continuous decline until today. Since only crown-group members survived through the Cenozoic, this decrease in disparity was likely the result of habitat loss, which narrowed down the range of crocodylomorph lifestyles.View Full Text

paleontology↗

bioRxiv2018

The multi-peak adaptive landscape of crocodylomorph body size evolution

Background Little is known about the long-term patterns of body size evolution in Crocodylomorpha, the > 200-million-year-old group that includes living crocodylians and their extinct relatives. Extant crocodylians are mostly large-bodied (3–7 m) predators. However, extinct crocodylomorphs exhibit a wider range of phenotypes, and many of the earliest taxa were much smaller (< 1.2 m). This suggests a pattern of size increase through time that could be caused by multi-lineage evolutionary trends of size increase or by selective extinction of small-bodied species. In this study, we characterise patterns of crocodylomorph body size evolution using a model fitting-approach (with cranial measurements serving as proxies). We also estimate body size disparity through time and quantitatively test hypotheses of biotic and abiotic factors as potential drivers of crocodylomorph body size evolution.Results Crocodylomorphs reached an early peak in body size disparity during the Late Jurassic, and underwent essentially continually decreases in disparity since then. A multi-peak Ornstein-Uhlenbeck model outperforms all other evolutionary models fitted to our data (including both uniform and non-uniform), indicating that the macroevolutionary dynamics of crocodylomorph body size are better described within the concept of an adaptive landscape, with most body size variation emerging after shifts to new macroevolutionary regimes (analogous to adaptive zones). We did not find support for a consistent evolutionary trend towards larger sizes among lineages (i.e., Cope’s rule), or strong correlations of body size with climate. Instead, the intermediate to large body sizes of some crocodylomorphs are better explained by group-specific adaptations. In particular, the evolution of a more aquatic lifestyle (especially marine) correlates with increases in average body size, though not without exceptions.Conclusions Shifts between macroevolutionary regimes provide a better explanation of crocodylomorph body size evolution than do climatic factors, suggesting a central role for lineage-specific adaptations rather than climatic forcing. Shifts leading to larger body sizes occurred in most aquatic and semi-aquatic groups. This, combined with extinctions of groups occupying smaller body size regimes (particularly during the Late Cretaceous and Cenozoic), gave rise to the upward-shifted body size distribution of extant crocodylomorphs compared to their smaller-bodied terrestrial ancestors.AbbreviationsCranial measurementsDCLdorsal cranial lengthODCLorbito-cranial lengthEvolutionary modelsBMBrownian motionEBEarly burstOUOrnstein-UhlenbeckBMSmulti-regime BM model that allows parameter σ2 to varyOUMVmulti-regime OU model that allows θ and σ2 to varyOUMAmulti-regime OU model in which θ and α can varyOUMVAOU model in which all three parameters (θ, α and σ2) can varyModel parametersθtrait optimum of OU-based modelsαattraction parameter of OU-based modelsσ2Brownian variance or rate parameter of BM or OU-based modelsμevolutionary trend parameter of BM-based modelsZ0estimated trait value at the root of the tree of OU-based modelsOptimality criteriaAICAkaike’s information criterionAICcAkaike’s information criterion for finite sample sizesBICBayesian information criterionpBICphylogenetic Bayesian information criterionView Full Text

paleontology↗