EEB267H1 Lecture Notes - Great White Shark, Megamouth Shark, Manta Ray
1 Mar 2013
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The selachii: selachos (cartilaginous fish) roughly 490 species of sharks roughly 660 species of skates and rays: dorsoventrally flattened, pectoral fins enlarged and fused to body. The hyostylic jaw (found in most living sharks) Upper jaw attached to skull by only one ligament (in yellow) . The hyomandibula (= epihyoid [red]) articulates with the skull and the upper jaw . The ceratohyoid [green] articulates with the lower jaw. Note: the hyoid arch is now involved primarily with feeding! As a predatory shark approaches its prey: the lower jaw gapes wide open and the upper jaw is pushed forward by the hyomandibula. The amount it can be pushed forward depends on the length of the ligament that attaches the upper jaw to the skull (this varies among different species of shark). As all this is happening the shark"s eyes roll tailward in their sockets to protect them from injury.
