HORTON, Jaquan M.*; RANCHES, Gregory; SUMMERS, Adam P.; University of California, Irvine; University of California, Irvine; University of California, Irvine: The morphology, mechanical properties, and composition of the acellular ribs in a teleost fish�Myoxocephalus polyacanthocephalus.

The material properties of cellular bone have been studied extensively, however, little is known about either the cellular or acellular bone of fishes. Teleost fish, many of which have skeletons comprised entirely of acellular bone, represent over half of extant vertebrates, 95% of all fishes, and are a model system to investigate the material properties of these two types of bone. We studied the great sculpin�Myoxocephalus polyacanthocephalus (n=9), a sit-and-wait benthic predator that inhabits the temperate waters of the Pacific Northwest and has an acellular bony skeleton. We used a three-point-bending technique and custom MatLab script to assess stiffness and cross-sectional area along each rib and the rib series. The composition of ribs was also quantified. The ribs of the great sculpin are hollow cylinders of acellular bone. Stiffness (E) decreased distally along the rib but varied across the rib series. First and second moment of area decreased distally along the rib and along the rib series. The average rib is comprised of approximately 65% inorganic material.