@article{1319c9322fc04455be6e1163f67454db,
title = "Increased variation in numbers of presacral vertebrae in suspensory mammals",
abstract = "Restricted variation in numbers of presacral vertebrae in mammals is a classic example of evolutionary stasis. Cervical number is nearly invariable in most mammals, and numbers of thoracolumbar vertebrae are also highly conserved. A recent hypothesis posits that stasis in mammalian presacral count is due to stabilizing selection against the production of incomplete homeotic transformations at the lumbo-sacral border in fast-running mammals, while slower, ambulatory mammals more readily tolerate intermediate lumbar/sacral vertebrae. We test hypotheses of variation in presacral numbers of vertebrae based on running speed, positional behaviour and vertebral contribution to locomotion. We find support for the hypothesis that selection against changes in presacral vertebral number led to stasis in mammals that rely on dorsomobility of the spine during running and leaping, but our results are independent of running speed per se. Instead, we find that mammals adapted to dorsostability of the spine, such as those that engage in suspensory behaviour, demonstrate elevated variation in numbers of presacral vertebrae compared to dorsomobile mammals. We suggest that the evolution of dorsostability and reduced reliance on flexion and extension of the spine allowed for increased variation in numbers of presacral vertebrae, leading to departures from an otherwise stable evolutionary pattern.",
author = "Williams, {Scott A.} and Spear, {Jeffrey K.} and Lauren Petrullo and Goldstein, {Deanna M.} and Lee, {Amanda B.} and Peterson, {Amy L.} and Miano, {Danielle A.} and Kaczmarek, {Elska B.} and Shattuck, {Milena R.}",
note = "Funding Information: We thank E. Buchholtz and D. Pilbeam for generously sharing data; F. Galis for providing species information from her and her colleagues{\textquoteright} study; M. Grabowski for statistical advice; and N. Duncan, G. Garcia, E. Hoeger, S. Ketelsen, A. Marcato, B. O{\textquoteright}Toole, M. Surovy, E. Westwig (American Museum of Natural History), M. Milella, M. Ponce de Le{\'o}n, C. Zollikofer (Anthropological Institute and Museum, University of Zurich), Y. Haile-Selassie, L. Jellema (Cleveland Museum of Natural History), H. Taboada (Department of Anthropology, New York University), D. Katz, T. Weaver (Department of Anthropology, University of California, Davis), B. Patterson, A. Goldman, M. Schulenberg, L. Smith, W. Stanley (Field Museum of Natural History), C. McCaffery, D. Reed (Florida Museum of Natural History, University of Florida), J. Chupasko, J. Harrison, M. Omura (Harvard Museum of Comparative Zoology), E. Gilissen, W. Wendelen (Mus{\'e}e Royal de l{\textquoteright}Afrique Centrale), S. Jancke, N. Lange, F. Mayer (Mus{\'e}e f{\"u}r Naturkunde, Berlin), C. Conroy (Museum of Vertebrate Zoology, University of California, Berkeley), L. Gordon, K. Helgen, E. Langan, D. Lunde, J. Ososky, R. Thorington (National Museum of Natural History, Smithsonian Institution), J. Soderberg, M. Tappen (Neil C. Tappen Collection, Universtity of Minnesota), S. Bruaux, G. Lenglet (Royal Belgian Institute of Natural Sciences) and M. Hiermeier (Zoologische Staatssammlung M{\"u}nchen) for facilitating access to specimens in their care. S.A.W. was funded through the National Science Foundation (No. BCS-0925734), the Leakey Foundation (No. 33517) and the New York University Research Challenge Fund. Publisher Copyright: {\textcopyright} 2019, The Author(s), under exclusive licence to Springer Nature Limited.",
year = "2019",
month = jun,
day = "1",
doi = "10.1038/s41559-019-0894-2",
language = "English (US)",
volume = "3",
pages = "949--956",
journal = "Nature Ecology and Evolution",
issn = "2397-334X",
publisher = "Nature Publishing Group",
number = "6",
}