Date of Award

Fall 1-31-2017

Document Type

Thesis

Degree Name

Master of Science in Biology - (M.S.)

Department

Federated Department of Biological Sciences

First Advisor

Daphne F. Soares

Second Advisor

Brooke Elizabeth Flammang-Lockyer

Third Advisor

Gregory F. Weber

Abstract

The genus Sinocyclocheilus endemic to southern China and contains many cavefish species. There are approximately sixty species, of which roughly forty are cave-adapted. Cave Sinocyclocheilus are characterized not only by lack of pigmentation and eyes depending on the species, but also by a unique prominent horn on the top of the skull and dorsal hump rostral under the dorsal fin. The horn and the hump are generally considered troglomorphic characteristics, although their functions are still elusive. Here, the development of these distinctive structures in the species, S. furcodorsalis, was examined by using micro CT scans. The horn of the fish is supported by outgrowth of the supraoccipital bone, forming a basal ossified shelf and a prominent dorsal spinous process, also known as the neural spine. The hump is a caudal extension of the horn. The micro CT scans of seven fish were examined and positive allometry results exist for skull length relative to the neural spine length. However, other features refuted the hypothesis that heterochrony underlies hump and horn development in S. furcodorsalis.

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Biology Commons

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