Platypterygius australis, an Australian Cretaceous ichthyosaur

摘要: Sufficient material has been assembled to restore the powerful pectoral girdle and large fore limbs of Platypterygius australis (M'Coy). A reasonable approximation line action dorsal ventral muscles which principally affected trim low-set fin-blades was along middle fin. Increased tension brought nearer horizontal (to a diving position) varying amounts relaxation during forward movement allowed mainly water resistance increase tilt. The flexible blade edges were crucial in this. Unequal on blades would have caused turning animal with whatever rapidity desired. Allowing both rise together stalling point could checked abruptly as it struck prey. Large relative absolute increases portions coracoids adjacent median symphysis highlight development young individuals. Positive allometric growth this area stopped quite suddenly animals approached 6 m total length, leaving only general size increase.