EEB267H1 Lecture Notes - Lecture 12: Aquatic Animal, Acanthostega, Crutching
16 Feb 2017
School
Department
Course
Professor
Document Summary
In ray-finned fishes: gas-filled structure used as a gas-bladder, primary as buoyancy control, developmentally unknown. Actinistia (coelocanths: fat-filled structure, buoyancy control. Fish/sharks have 2 pairs of nostrils, one on each side: anterior and posterior nostrils open to the environment. Water goes in one nostril, goes through olfactory sac and goes out the other nostril. Nose functions in odor detection: chemical cues able to smell things in the nose. Clavicle, humerus and scapula form pectoral girdle. Bones of the pelvic girdle (pelvis: very strong and robust supports a lot of weight important to move on land femur (thigh bone) tibia (shin) fibula. Phalanges (toes/digits) tarsals (heel bone and other small bones) paired pectoral fins and paired pelvic fins are very old. Paired appendages are at least as old as jawed fishes in fishes, they function as fins fin rays fins made and structured by bone skeletal elements involved in limb formation. Have well-developed lobe fins leaves well-kept fossil record.
