dailyfossil:Stethacanthus - The Ironing Board SharkWhen: Late Devonian to Early Carboniferous (385 -
dailyfossil:Stethacanthus - The Ironing Board SharkWhen: Late Devonian to Early Carboniferous (385 - 320 million years ago)Where: The seas that covered what is now North America and Europe What: Stethacanthus is an extinct shark. Over all this ancient shark is an excellent example of the amount of conservation the simple shark body plan has seen throughout the eons. It is relatively small, 2.3ft/70 cm long, and has a general form very much like an extant shark. The one major exception to this is the shape of its dorsal fin. It was flattened and covered with enlarged denticles (the particles in shark skin that give it it’s sandpaper texture). The head of Stethacanthus was also topped with enlarged denticles. Though some sort of courtship role has been suggested for the structures, detailed studies have determined that the dorsal fin could be flexed forward, to start to come into occlusion with the patch of denticles on the top of the head. This would give the illusion of a much bigger mouth than Stethacanthus actually possessed, allowing this little pre-historic shark to hopefully scare off potential predators. -- source link
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