Ecomorphological changein lobe-finned fishes (Sarcopterygii):disparity and rates

Ecomorphological change;in lobe;finned fish;disparity;Ecology and Evolutionary Biology

Juarez, BryanZelditch, Miriam ;

University of Michigan

关键词: Ecomorphological change;    in lobe;    finned fish;    disparity;    Ecology and Evolutionary Biology;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/112032/BHJ%20Thesis.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Patterns of vertebrate cranial/post-cranial trait diversification are not well-understood. Two ecological hypotheses, the ;;head-first’ model and the ;;stages’ model, predict the ordered decoupling of cranial/post-cranial ecomorphological diversification. Rate (tempo) analyses andmacroevolutionary model-fitting (mode) analyses are often used to test whether cranial traits or post-cranial traits diversify earlier in vertebrates. Here we reconstructed the tempo and mode of cranial/post-cranial trait evolution in lobe-finned fishes (Sarcopterygii), a group containing coelacanths, lungfishes, and tetrapodomorph fishes, to test for differences in the timing of vertebrate cranial/post-cranial trait diversification. We collected full-skeletal geometric morphometric coordinate and PC-reduced data for 57 species of aquatic and semi-aquatic lobe-fins since the Paleozoic. We performed rate, raw disparity through time, phylogenetic signal and model-fitting (multivariate BM, EB and OU) analyses using both coordinate data and PC-reduced data but did not model-fit the coordinate data due to computational constraints. The BM (best fit model) rate parameter is highest for post-cranial traits but cranial trait disparity is highest throughout the majority of lobe-fin evolution, supporting the ;;head-first’ model, with peaks in the Middle to Upper Devonian and Jurassic. We also find that PCA reduction increasestrait variance, creating bias in favor of early post-cranial trait diversification. We conclude that cranial ;;head-first’ ecomorphological diversification drove the early Paleozoic radiation of aquatic and semi-aquatic lobe-fins, but more research may be needed to understand conflicting patterns in the Mesozoic when taxonomic diversity was substantially lower among ;;living fossils”. viiEcomorphological change in lobe-finned fishes (Sarcopterygii): disparity and ratesBy: Bryan H. Juarez1and Lauren C. Sallan21Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor; [e-mail] and Environmental Science & Evolution Cluster, University of Pennsylvania; [e-mail]: Lobe fin, geometric morphometrics, PCA, Brownian Motion, Early Burst