Just out @ Science Avian egg shape: Form, function, and evolution Author(s) Mary Caswell Stoddard, Ee Hou Yong, Derya Akkaynak, Catherine Sheard, Joseph A. Tobias, L. Mahadevan Abstract: Avian egg shape is generally explained as an adaptation to life history, yet we currently lack a global synthesis of how egg-shape differences arise and evolve. Here, we apply morphometric, mechanistic, and macroevolutionary analyses to the egg shapes of 1400 bird species. We characterize egg-shape diversity in
Just out @ Nature Hidden morphological diversity among early tetrapods Author(s) Jason D. Pardo, Matt Szostakiwskyj, Per E. Ahlberg & Jason S. Anderson Abstract: Phylogenetic analysis of early tetrapod evolution has resulted in a consensus across diverse data sets in which the tetrapod stem group is a relatively homogenous collection of medium- to large-sized animals showing a progressive loss of ‘fish’ characters as they become increasingly terrestrial, whereas the crown group demonstrates marked
Just out @ Proceedings of the Royal Society B Testing the molecular clock using mechanistic models of fossil preservation and molecular evolution Author(s) Rachel C. M. Warnock, Ziheng Yang, Philip C. J. Donoghue Abstract: Molecular sequence data provide information about relative times only, and fossil-based age constraints are the ultimate source of information about absolute times in molecular clock dating analyses. Thus, fossil calibrations are critical to molecular clock dating, but competing methods are difficult to
Just out @ Proceedings of the Royal Society B Hierarchical complexity and the size limits of life Author(s) Noel A. Heim, Jonathan L. Payne, Seth Finnegan, Matthew L. Knope, Michał Kowalewski, S. Kathleen Lyons, Daniel W. McShea, Philip M. Novack-Gottshall, Felisa A. Smith, Steve C. Wang Abstract: Over the past 3.8 billion years, the maximum size of life has increased by approximately 18 orders of magnitude. Much of this increase is associated with two major evolutionary innovations: the evolution of eukaryotes from prokaryotic cells approximately 1.9 billion years ago (Ga),
Just out @ Historical Biology Heritability: the link between development and the microevolution of molar tooth form Author(s) P. David Polly & Orin B. Mock Abstract: The developmental gene expression, morphogenesis, and population variation in mammalian molar teeth has become increasingly well understood, providing a model system for synthesizing evolution and developmental genetics. In this study, we estimated additive genetic covariances in molar shape (G) using parent-offspring regression in Cryptotis parva, the Least Shrew.
Just out @ Journal of Vertebrate Paleontology Dental eruption and growth in Hyracoidea (Mammalia, Afrotheria) Author(s) Robert J. Asher, Gregg F. Gunnell, Erik R. Seiffert, David Pattinson, Rodolphe Tabuce, Lionel Hautier & Hesham M. Sallam Abstract: We investigated dental homologies, development, and growth in living and fossil hyracoids and tested if hyracoids and other mammals show correlations between eruption patterns, gestation time, and age at maturity. Unlike living species, fossil hyracoids simultaneously possess replaced P1 and canine teeth.
Just out @ Historical Biology Disentangling faunal skeletal profiles. A new probabilistic framework Author(s) Ana B. Marín-Arroyo & David Ocio Abstract: Faunal skeletal profiles from archaeological assemblages have been long analysed regarding differential transport of carcasses to infer hunting preferences, human mobility, or even dietary stress. However, the existence of several possible accumulating agents, together with the effect of bone attrition, is known to introduce a potential bias, thus hindering the possibilities
Just out @ Journal of Morphology What did the “Unossified zone” of the non-mammalian therapsid braincase house? Author(s) Michael Laaß, Burkhard Schillinger, Anders Kaestner Abstract: Most nonmammalian synapsids possess a mid-dorsal depression in the brain cavity known as the “unossified zone.” It remains obscure which structures this zone contained, and, as candidates, the vermis of the cerebellum, the superior sagittal sinus, a junction of several blood vessels, the pineal gland or
Just out @ Journal of Morphology Evidence for convergent evolution of a neocortex-like structure in a late Permian therapsid Author(s) Michael Laaß, Anders Kaestner Abstract: The special sensory, motor, and cognitive capabilities of mammals mainly depend upon the neocortex, which is the six-layered cover of the mammalian forebrain. The origin of the neocortex is still controversial and the current view is that larger brains with neocortex first evolved in late Triassic
Just out @ Science Increase in predator-prey size ratios throughout the Phanerozoic history of marine ecosystems Author(s) Adiël A. Klompmaker, Michał Kowalewski, John Warren Huntley, Seth Finnegan Abstract: The escalation hypothesis posits that predation by increasingly powerful and metabolically active carnivores has been a major driver of metazoan evolution. We test a key tenet of this hypothesis by analyzing predatory drill holes in fossil marine shells, which provide a ~500-million-year