What are the limits on whale ear bone size? Non-isometric scaling of the cetacean bulla

PeerJ

article

Sabrina L. Groves¹  Carlos Mauricio Peredo¹  Nicholas D. Pyenson¹ 

[1] Department of Paleobiology, National Museum of Natural History;Department of Biological Sciences, Mount Holyoke College;Department of Earth and Environmental Science, University of Michigan - Ann Arbor;Department of Marine Biology, Texas A&M University - Galveston;Department of Paleontology and Geology

关键词: Cetacean;    Whale;    Allometry;    Bulla;    Ear;    Scaling;    Odontocete;    Mysticete;    Stem cetacean;    Evolution;   

DOI  :  10.7717/peerj.10882

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The history of cetaceans demonstrates dramatic macroevolutionary changes that have aided their transformation from terrestrial to obligate aquatic mammals. Their fossil record shows extensive anatomical modifications that facilitate life in a marine environment. To better understand the constraints on this transition, we examined the physical dimensions of the bony auditory complex, in relation to body size, for both living and extinct cetaceans. We compared the dimensions of the tympanic bulla, a conch-shaped ear bone unique to cetaceans, with bizygomatic width—a proxy for cetacean body size. Our results demonstrate that cetacean ears scale non-isometrically with body size, with about 70% of variation explained by increases in bizygomatic width. Our results, which encompass the breadth of the whale fossil record, size diversity, and taxonomic distribution, suggest that functional auditory capacity is constrained by congruent factors related to cranial morphology, as opposed to allometrically scaling with body size.

【 授权许可】

CC BY