ZOO 2090 Lecture Notes - Lecture 5: Bothriolepis, Dermal Bone, Actinopterygii

• School: University of Guelph
• Department: Zoology
• Course: ZOO 2090
• Professor: Jinzhong Fu

Document Summary

Bothriolepis the three skeletal elements to remember from this is the 1. palatoquadrate 2. Trend toward increased number of skull bones in actinopterygians. Teleosts skulls are diverse, with numerous bones and increased liberation between elements ! maneuverable jaws and palate ! diverse feeding mechanisms. New bones resulted from multiplication of centers of ossi cation within larger bones (e. g. , palatoquadrate ! quadrate, metapterygoid and other bones) one big piece can become a bunch of smaller pieces. Early gnathostomes had wide mouths, far back hinge, and upper jaw fused with braincase. Teleosts have narrow mouth, hinge moved forward, and both upper and lower jaws can move forward independently of the braincase. Suction driven by volume change of buccal cavity (arrows show muscle action) Despite the great diversity of teleosts, the basic pattern of skull bones is preserved. 1) euautostylic: upper jaw braced against braincase directly, hyomandibula not involved.