BELTR�N, JL*; KAJIURA, SM; KOOB, TJ; PORTER, ME; SUMMERS, AP; University of California, Irvine; Florida Atlantic University; Shriners Hospital for Children, Tampa; University of California, Irvine; University of California, Irvine: The diversity of elasmobranch cartilage

We measured the material properties and biochemical composition of jaw or chondrocranium cartilage from seven shark species (silky, sandbar, oceanic whitetip, bull, smooth hammerhead, shortfin mako, greenland, pacific sleeper) and one ray species (smooth-tail mobula). Multiple 8.0mm or 10.0mm cylindrical plugs were tested by compressing them three times to ten percent of initial thickness (ε=0.10) at 2mm/sec. Plugs were lyophilized to determine water content. Collagen and glucosaminoglycan (GAG) content were measured with hydroxyproline assays and CE analysis respectively. Stiffness, strength, and strain differed among species (p<0.0001). Chondrichthian cartilage is less stiff than mammalian bone. However, most species are comparable in strength to trabecular bone with values ranging from 11-172 MPa. Water, GAG, and collagen content differed among species (p<0.0001). Chondrichthian cartilage had 10-20% more water content than mammalian cartilage. Mammalian cartilage is composed of ~15% more collagen than shark cartilage, but mammalian cartilage was similar in content to the ray (45% DW). There was a large variation among species in GAG content which ranged from 13%-61% of dry weight.