Meeting Abstract

P2-158    Histological comparison of shark dermis across various ecomorphologies Schuitema, OA*; Habegger, ML; University of North Florida, Jacksonville, FL; University of North Florida, Jacksonville, FL olivia.schuitema@unf.edu

The integument of fishes plays different crucial roles ranging from protection and structural support to hydrodynamic function. Among fishes, shark skin has been widely investigated with most studies focusing on the superficial epidermal layer, where dermal denticles are observed. Deeper to this layer lies the dermis, and although this is the dominant layer of the integument, little is known about its composition and morphology. Shark dermis consists of two layers, the stratum laxum and stratum compactum that house collagen and elastin fibers. Morphological differences in the composition of these layers and the number of fibers present may reflect shark’s swimming functional demands. It could be expected that swimming patterns and ecologies may correlate with dermis thickness and fiber density across species, although the extent of such is unknown. The goal of this study is to characterize and quantify the dermis layer among four shark species with different ecologies and swimming profiles, including Ginglymostoma cirratum, Carcharhinus limbatus, Sphyrna mokarran and, Isurus oxyrinchus. Sixteen areas along the body were sampled and stained using histological techniques to identify collagen and elastin fibers, and to quantify dermal layer thickness. Preliminary results indicated that the dermis was thinner in the flank of all species examined. Additionally, thicker collagen bundles were found in the I. oxyrunchus in the caudal region, while S. mokarran had a higher density of elastin fibers in the pectoral fin region. The results of this research and their possible implications in swimming ecology and locomotion will be further discussed.