The anatomy of the bifurcated neural spine and its occurence within Tetrapoda
Article first published online: 21 APR 2014
© 2014 Wiley Periodicals, Inc.
Journal of Morphology
Volume 275, Issue 9, pages 1053–1065, September 2014
How to Cite
Woodruff, D. C. (2014), The anatomy of the bifurcated neural spine and its occurence within Tetrapoda. J. Morphol., 275: 1053–1065. doi: 10.1002/jmor.20283
- Issue published online: 25 JUL 2014
- Article first published online: 21 APR 2014
- Manuscript Accepted: 28 MAR 2014
- Manuscript Revised: 15 MAR 2014
- Manuscript Received: 18 NOV 2013
- nuchal ligament;
Vertebral neural spine bifurcation has been historically treated as largely restrictive to sauropodomorph dinosaurs; wherein it is inferred to be an adaptation in response to the increasing weight from the horizontally extended cervical column. Because no extant terrestrial vertebrates have massive, horizontally extended necks, extant forms with large cranial masses were examined for the presence of neural spine bifurcation. Here, I report for the first time on the soft tissue surrounding neural spine bifurcation in a terrestrial quadruped through the dissection of three Ankole-Watusi cattle. With horns weighing up to a combined 90 kg, the Ankole-Watusi is unlike any other breed of cattle in terms of cranial weight and presence of neural spine bifurcation. Using the Ankole-Watusi as a model, it appears that neural spine bifurcation plays a critical role in supporting a large mobile weight adjacent to the girdles. In addition to neural spine bifurcation being recognized within nonavian dinosaurs, this vertebral feature is also documented within many members of temnospondyls, captorhinids, seymouriamorphs, diadectomorphs, Aves, marsupials, artiodactyls, perissodactyls, and Primates, amongst others. This phylogenetic distribution indicates that spine bifurcation is more common than previously thought, and that this vertebral adaptation has contributed throughout the evolutionary history of tetrapods. Neural spine bifurcation should now be recognized as an anatomical component adapted by some vertebrates to deal with massive, horizontal, mobile weights adjacent the girdles. J. Morphol. 275:1053–1065, 2014. © 2014 Wiley Periodicals, Inc.