Comparative Brain Morphology of the Greenland and Pacific Sleeper Sharks and its Functional Implications

Authors

Kara E. Yopak, University of North Carolina Wilmington
Bailey C. McMeans, University of Toronto
Christopher G. Mull, Simon Fraser University
Kirk W. Feindel, The University of Western Australia
Kit M. Kovacs, Norsk Polarinstitutt
Christian Lydersen, Norsk Polarinstitutt
Aaron T. Fisk, Great Lakes Institute for Environmental Research
Shaun P. Collin, The University of Western Australia

Document Type

Article

Publication Date

12-1-2019

Publication Title

Scientific Reports

Volume

9

Issue

1

Abstract

In cartilaginous fishes, variability in the size of the brain and its major regions is often associated with primary habitat and/or specific behavior patterns, which may allow for predictions on the relative importance of different sensory modalities. The Greenland (Somniosus microcephalus) and Pacific sleeper (S. pacificus) sharks are the only non-lamnid shark species found in the Arctic and are among the longest living vertebrates ever described. Despite a presumed visual impairment caused by the regular presence of parasitic ocular lesions, coupled with the fact that locomotory muscle power is often depressed at cold temperatures, these sharks remain capable of capturing active prey, including pinnipeds. Using magnetic resonance imaging (MRI), brain organization of S. microcephalus and S. pacificus was assessed in the context of up to 117 other cartilaginous fish species, using phylogenetic comparative techniques. Notably, the region of the brain responsible for motor control (cerebellum) is small and lacking foliation, a characteristic not yet described for any other large-bodied (>3 m) shark. Further, the development of the optic tectum is relatively reduced, while olfactory brain regions are among the largest of any shark species described to date, suggestive of an olfactory-mediated rather than a visually-mediated lifestyle.

DOI

10.1038/s41598-019-46225-5

E-ISSN

20452322

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Yopak, Kara E.; McMeans, Bailey C.; Mull, Christopher G.; Feindel, Kirk W.; Kovacs, Kit M.; Lydersen, Christian; Fisk, Aaron T.; and Collin, Shaun P.. (2019). Comparative Brain Morphology of the Greenland and Pacific Sleeper Sharks and its Functional Implications. Scientific Reports, 9 (1).
https://scholar.uwindsor.ca/glierpub/298

PubMed ID

31296954