Weakfish enter New Yorks waters in spring and head south in fall. The adaptation was successful: Helicoprion evolved around 300 million years ago and survived the Permian mass extinction before eventually disappearing in the early Triassic, about 225 million years ago. weak) skin around the mouth which tears easily when hooked. The roof of its mouth was lined with flat, bony plates that probably served as a cutting board for chopping up prey. ![]() Helicoprion apparently put its bizarre mouthparts to good use. The largest fossil whorls are more than 50 centimetres in diameter. Unlike other sharks, it did not shed the old teeth but retained them, extruding them forward on a base of fused tooth and cartilage, which eventually formed a snaggly whorl. Like other sharks, Helicoprion is thought to have had teeth that erupted continuously, pushing the old ones forward. Although it was clearly a type of shark, it had one of the most unusual facial adaptations ever seen: a structure like a circular saw protruding from its lower jaw. ![]() Around 275 million years ago, a creature called Helicoprion roamed the oceans.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |