EEB267H1 Lecture Notes - Lecture 5: Manta Ray, Clasper, Hagfish
2 Feb 2017
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Document Summary
Includes sharks, skates and rays: not monophyletic, they are paraphyletic. Skates, rays: dorsoventrally flattened, pectoral fins enlarged, fused to body, freshwater and marine stingray, rays have venom in caudal fin spine, skates are sharp and rays are rounded, bottom feeders, venom in rays. Occurs in both marine and freshwater rays. Causes a long period of bleeding in victim. Dogfish: dorsal spines, not clear if venomous, painful. Hyostylic jaw: ligament attaches upper jaw to skull. Variations in length affects how much the upper jaw can be forced outward by the hyomandibula: hyomandibula. Moves with skull and upper jaw at either ends. Level of stiffness due to tesserae varies amongst species. Gives sharks their goofy overbite: ceratohyoid. Moves with hyomandibula and lower jaw at either ends: no operculum. Feeding strategies: biting, or spike and slice. Ceratohyoid pushes lower jaw up so that it closes into prey item, holds prey. Eyes roll backwards to protect them from injury.
