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 Cope’s 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.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/ece3.10201

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


 Over the last 50 years, access to new data and analytical tools has expanded the study of analytical paleobiology, contributing to innovative analyses of biodiversity dynamics over Earth's history. Despite—or even spurred by—this growing availability of resources, analytical paleobiology faces deep-rooted obstacles that stem from the need for more equitable access to data and best practices to guide analyses of the fossil record. Recent progress has been accelerated by a collective push toward more collaborative, interdisciplinary, and open science, especially by early-career researchers. Here, we survey four challenges facing analytical paleobiology from an early-career perspective: (1) accounting for biases when interpreting the fossil record; (2) integrating fossil and modern biodiversity data; (3) building data science skills; and (4) increasing data accessibility and equity. We discuss recent efforts to address each challenge, highlight persisting barriers, and identify tools that have advanced analytical work. Given the inherent linkages between these challenges, we encourage discourse across disciplines to find common solutions. We also affirm the need for systemic changes that reevaluate how we conduct and share paleobiological research.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/06257CFF62B32846B5C90F939BCC744E/S0094837323000039a.pdf/div-class-title-challenges-and-directions-in-analytical-paleobiology-div.pdf

Challenges and directions in analytical paleobiology


 The fossil record is spatiotemporally heterogeneous: taxon occurrence data have patchy spatial distributions, and this patchiness varies through time. Large-scale quantitative paleobiology studies that fail to account for heterogeneous sampling coverage will generate uninformative inferences at best and confidently draw wrong conclusions at worst. Explicitly spatial methods of standardization are necessary for analyses of large-scale fossil datasets, because nonspatial sample standardization, such as diversity rarefaction, is insufficient to reduce the signal of varying spatial coverage through time or between environments and clades. Spatial standardization should control both geographic area and dispersion (spread) of fossil localities. In addition to standardizing the spatial distribution of data, other factors may be standardized, including environmental heterogeneity or the number of publications or field collecting units that report taxon occurrences. Using a case study of published global Paleobiology Database occurrences, we demonstrate strong signals of sampling; without spatial standardization, these sampling signatures could be misattributed to biological processes. We discuss practical issues of implementing spatial standardization via subsampling and present the new R package divvy to improve the accessibility of spatial analysis. The software provides three spatial subsampling approaches, as well as related tools to quantify spatial coverage. After reviewing the theory, practice, and history of equalizing spatial coverage between data comparison groups, we outline priority areas to improve related data collection, analysis, and reporting practices in paleobiology.

Spatial standardization of taxon occurrence data—a call to action

Abstract Phylodynamic models can be used to estimate diversification trajectories from time-calibrated phylogenies. Here we apply two such models to phylogenies of non-avian dinosaurs, a clade whose evolutionary history has been widely debated. Although some authors have suggested that the clade experienced a decline in diversity, potentially starting millions of years before the end-Cretaceous mass extinction, others have suggested that the group remained highly diverse right up until the Cretaceous-Paleogene (K-Pg) boundary. Our results show that model assumptions, likely with respect to incomplete sampling, have a large impact on whether dinosaurs appear to have experienced a long-term decline or not. The results are also highly sensitive to the topology and branch lengths of the phylogeny used. Developing comprehensive models of sampling bias, and building larger and more accurate phylogenies, are likely to be necessary steps for us to determine whether dinosaur diversity was or was not in decline before the end-Cretaceous mass extinction. 

Mechanistic phylodynamic models do not provide conclusive evidence that non-avian dinosaurs were in decline before their final extinction

The fossil record is spatiotemporally heterogeneous: taxon occurrence data have patchy spatial distributions, and this patchiness varies through time. Large-scale quantitative paleobiology studies that fail to account for heterogeneous sampling coverage will generate uninformative inferences at best and confidently draw wrong conclusions at worst. Explicitly spatial methods of standardization are necessary for analyses of large-scale fossil datasets, because nonspatial sample standardization, such as diversity rarefaction, is insufficient to reduce the signal of varying spatial coverage through time or between environments and clades. Spatial standardization should control both geographic area and dispersion (spread) of fossil localities. In addition to standardizing the spatial distribution of data, other factors may be standardized, including environmental heterogeneity or the number of publications or field collecting units that report taxon occurrences. Using a case study of published global Paleobiology Database occurrences, we demonstrate strong signals of sampling; without spatial standardization, these sampling signatures could be misattributed to biological processes. We discuss practical issues of implementing spatial standardization via subsampling and present the new R package divvy to improve the accessibility of spatial analysis. The software provides three spatial subsampling approaches, as well as related tools to quantify spatial coverage. After reviewing the theory, practice, and history of equalizing spatial coverage between data comparison groups, we outline priority areas to improve related data collection, analysis, and reporting practices in paleobiology. 

pdf/spatial-standardization-of-taxon-occurrence-data-a-call-to-3mm07knaef.pdf

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/2041-210X.14099

palaeoverse: A community‐driven R package to support palaeobiological analysis

A fundamental question in dinosaur evolution is how they adapted to long-term climatic shifts during the Mesozoic and when they developed environmentally independent, avian-style acclimatization, becoming endothermic.1Roger T.D.K. Olson E.C. A Cold Look at the Warm-Blooded Dinosaurs. Westview Press for the American Association for the Advancement of Science, 1980Google Scholar,2Bakker R.T. Anatomical and ecological evidence of endothermy in dinosaurs.Nature. 1972; 238: 81-85https://doi.org/10.1038/238081a0Crossref Scopus (136) Google Scholar The ability of warm-blooded dinosaurs to flourish in harsher environments, including cold, high-latitude regions,3Chiarenza A.A. Fiorillo A.R. Tykoski R.S. McCarthy P.J. Flaig P.P. Contreras D.L. The first juvenile dromaeosaurid (Dinosauria: Theropoda) from Arctic Alaska.PLOS ONE. 2020; 15e0235078https://doi.org/10.1371/journal.pone.0235078Crossref PubMed Scopus (10) Google Scholar,4Druckenmiller P.S. Erickson G.M. Brinkman D. Brown C.M. Eberle J.J. Nesting at extreme polar latitudes by non-avian dinosaurs.Curr. Biol. 2021; 31: 3469-3478.e5https://doi.org/10.1016/j.cub.2021.05.041Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar raises intriguing questions about the origins of key innovations shared with modern birds,5Ostrom J.H. Osteology of Deinonychus antirrhopus, an Unusual Theropod from the Lower Cretaceous of Montana. Yale University Press, 1969https://doi.org/10.2307/j.ctvqc6gzxCrossref Google Scholar,6Brusatte S.L. O'Connor J.K. Jarvis E.D. The origin and diversification of birds.Curr. Biol. 2015; 25: R888-R898https://doi.org/10.1016/j.cub.2015.08.003Abstract Full Text Full Text PDF PubMed Scopus (178) Google Scholar indicating that the development of homeothermy (keeping constant body temperature) and endothermy (generating body heat) played a crucial role in their ecological diversification.7Olsen P. Sha J. Fang Y. Chang C. Whiteside J.H. Kinney S. Sues H.-D. Kent D. Schaller M. Vajda V. Arctic ice and the ecological rise of the dinosaurs.Sci. Adv. 2022; 8eabo6342https://doi.org/10.1126/sciadv.abo6342Crossref Scopus (19) Google Scholar Despite substantial evidence across scientific disciplines (anatomy,8Codd J.R. Manning P.L. Norell M.A. Perry S.F. Avian-like breathing mechanics in maniraptoran dinosaurs.Proc. Biol. Sci. 2008; 275: 157-161https://doi.org/10.1098/rspb.2007.1233Crossref PubMed Scopus (49) Google Scholar reproduction,9Tanaka K. Zelenitsky D.K. Therrien F. Kobayashi Y. Nest substrate reflects incubation style in extant archosaurs with implications for dinosaur nesting habits.Sci. Rep. 2018; 8: 3170https://doi.org/10.1038/s41598-018-21386-xCrossref PubMed Scopus (14) Google Scholar energetics,10Clarke A. Dinosaur energetics: setting the bounds on feasible physiologies and ecologies.Am. Nat. 2013; 182: 283-297https://doi.org/10.1086/671259Crossref PubMed Scopus (14) Google Scholar biomechanics,10Clarke A. Dinosaur energetics: setting the bounds on feasible physiologies and ecologies.Am. Nat. 2013; 182: 283-297https://doi.org/10.1086/671259Crossref PubMed Scopus (14) Google Scholar osteohistology,11Bailleul A.M. O'Connor J. Schweitzer M.H. Dinosaur paleohistology: review, trends and new avenues of investigation.PeerJ. 2019; 7e7764https://doi.org/10.7717/peerj.7764Crossref PubMed Scopus (26) Google Scholar palaeobiogeography,12Chiarenza A.A. Mannion P.D. Farnsworth A. Carrano M.T. Varela S. Climatic constraints on the biogeographic history of Mesozoic dinosaurs.Curr. Biol. 2022; 32: 570-585.e3https://doi.org/10.1016/j.cub.2021.11.061Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar geochemistry,13Dawson R.R. Field D.J. Hull P.M. Zelenitsky D.K. Therrien F. Affek H.P. Eggshell geochemistry reveals ancestral metabolic thermoregulation in Dinosauria.Sci. Adv. 2020; 6eaax9361https://doi.org/10.1126/sciadv.aax9361Crossref Scopus (23) Google Scholar,14Tagliavento M. Davies A.J. Bernecker M. Staudigel P.T. Dawson R.R. Dietzel M. Götschl K. Guo W. Schulp A.S. Therrien F. et al.Evidence for heterothermic endothermy and reptile-like eggshell mineralization in Troodon, a non-avian maniraptoran theropod.Proc. Natl. Acad. Sci. USA. 2023; 120e2213987120https://doi.org/10.1073/pnas.2213987120Crossref PubMed Scopus (3) Google Scholar and soft tissues15Wiemann J. Menéndez I. Crawford J.M. Fabbri M. Gauthier J.A. Hull P.M. Norell M.A. Briggs D.E.G. Fossil biomolecules reveal an avian metabolism in the ancestral dinosaur.Nature. 2022; 606: 522-526https://doi.org/10.1038/s41586-022-04770-6Crossref PubMed Scopus (26) Google Scholar,16Barrett P.M. Evans D.C. Campione N.E. Evolution of dinosaur epidermal structures.Biol. Lett. 2015; 1120150229https://doi.org/10.1098/rsbl.2015.0229Crossref Scopus (28) Google Scholar,17Motani R. Gold D.A. Carlson S.J. Vermeij G.J. Amniote metabolism and the evolution of endothermy.Nature. 2023; 621: E1-E3https://doi.org/10.1038/s41586-023-06411-yCrossref PubMed Scopus (1) Google Scholar), a consensus on dinosaur thermophysiology remains elusive.1Roger T.D.K. Olson E.C. A Cold Look at the Warm-Blooded Dinosaurs. Westview Press for the American Association for the Advancement of Science, 1980Google Scholar,12Chiarenza A.A. Mannion P.D. Farnsworth A. Carrano M.T. Varela S. Climatic constraints on the biogeographic history of Mesozoic dinosaurs.Curr. Biol. 2022; 32: 570-585.e3https://doi.org/10.1016/j.cub.2021.11.061Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar,15Wiemann J. Menéndez I. Crawford J.M. Fabbri M. Gauthier J.A. Hull P.M. Norell M.A. Briggs D.E.G. Fossil biomolecules reveal an avian metabolism in the ancestral dinosaur.Nature. 2022; 606: 522-526https://doi.org/10.1038/s41586-022-04770-6Crossref PubMed Scopus (26) Google Scholar,17Motani R. Gold D.A. Carlson S.J. Vermeij G.J. Amniote metabolism and the evolution of endothermy.Nature. 2023; 621: E1-E3https://doi.org/10.1038/s41586-023-06411-yCrossref PubMed Scopus (1) Google Scholar,18Grady J.M. Enquist B.J. Dettweiler-Robinson E. Wright N.A. Smith F.A. Dinosaur physiology. Evidence for mesothermy in dinosaurs.Science. 2014; 344: 1268-1272https://doi.org/10.1126/science.1253143Crossref PubMed Scopus (117) Google Scholar,19Benton M.J. The origin of endothermy in synapsids and archosaurs and arms races in the Triassic.Gondwana Res. 2021; 100: 261-289https://doi.org/10.1016/j.gr.2020.08.003Crossref Scopus (35) Google Scholar Differential thermophysiological strategies among terrestrial tetrapods allow endotherms (birds and mammals) to expand their latitudinal range (from the tropics to polar regions), owing to their reduced reliance on environmental temperature.20Santini L. Isaac N.J.B. Maiorano L. Ficetola G.F. Huijbregts M.A.J. Carbone C. Thuiller W. Global drivers of population density in terrestrial vertebrates.Global Ecol. Biogeogr. 2018; 27: 968-979https://doi.org/10.1111/geb.12758Crossref Scopus (76) Google Scholar By contrast, most reptilian lineages (squamates, turtles, and crocodilians) and amphibians are predominantly constrained by temperature in regions closer to the tropics.21Chiarenza A.A. Waterson A.M. Schmidt D.N. Valdes P.J. Yesson C. Holroyd P.A. Collinson M.E. Farnsworth A. Nicholson D.B. Varela S. Barrett P.M. 100 million years of turtle paleoniche dynamics enable the prediction of latitudinal range shifts in a warming world.Curr. Biol. 2023; 33: 109-121.e3https://doi.org/10.1016/j.cub.2022.11.056Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar Determining when this macroecological pattern emerged in the avian lineage relies heavily on identifying the origin of these key physiological traits. Combining fossils with macroevolutionary and palaeoclimatic models, we unveil distinct evolutionary pathways in the main dinosaur lineages: ornithischians and theropods diversified across broader climatic landscapes, trending toward cooler niches. An Early Jurassic shift to colder climates in Theropoda suggests an early adoption of endothermy. Conversely, sauropodomorphs exhibited prolonged climatic conservatism associated with higher thermal conditions, emphasizing temperature, rather than plant productivity, as the primary driver of this pattern, suggesting poikilothermy with a stronger dependence on higher temperatures in sauropods. 

Early Jurassic origin of avian endothermy and thermophysiological diversity in dinosaurs

Exploring deep time biogeographic dynamics

The division of food space among mammalian species on biomes

Classic Hypotheses of Area, Time, and Climatic Stability Fall Short in Explaining High Tropical Species Richness

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