stenopterygius

christhesmallbee  asked:

yes hello, idk if i asked this before so sorry if i did but have you done a post on temnodontosaurus? its my #1 fav marine reptile so if you did/do one id probably give u like. a whole bird.

Temnodontosaurus was discovered in England in 1811 by Mary Anning (who will eventually get her own post here).  At the time, marine reptiles were virtually unknown to science, and the biblical Flood was widely perceived as a literal truth, leading to a variety of incorrect interpretations as to what the fossil actually represented.  This includes:

  • A crocodile
  • A whale
  • A large fish
  • A relative of the platypus
  • A transitional form between amphibians and reptiles

(A Temnodontosaurus skull.  Photo from Wikimedia Commons.)

It was eventually sussed out that Temnodontosaurus was a marine reptile.  More specifically, it was an icthyosaur, one of the fish-like marine reptiles that inhabited the world’s oceans from the Triassic to the Middle Cretaceous.  In fact, it was initially assigned to the genus Icthyosaurus, before being reclassified in 1889.

Temnodontosaurus is notable for its great size, maxing out somewhere between 30 and 40 feet in length - twice as big as the modern great white shark.  They filled a similar predatory niche in the oceans of Early Jurassic Europe, using their long and powerful jaws to snatch up fish, molluscs, and smaller marine reptiles - as pictured in the Dmitry Bogdanov illustration below, which shows a Temnodontosaurus killing a smaller icthyosaur known as Stenopterygius.  (This illustration is directly supported by the fossil record; fossilized Temnodontosaurus specimens have been found with Stenopterygius remains in their stomachs.)

Temnodontosaurus is also notable for its huge eyes - perhaps the largest of any known vertebrate, at 8 inches in diameter.  It was likely a very visually-oriented hunter, capable of tracking the movements of its prey in chaotic underwater environments.

3

Extant cetaceans exhibit hyperphalangy, a condition where the finger have an increased number of bones. The first digit, however,has a reduced number of bones (so hypophalangy) and is actually absent in several baleen whales; only Pilot Whales have hyperphalangy on this digit. The fifth digit generally has the ancestral number of bones for baleen whales but toothed whales typically have reduction; Kogia is an exception with hyperphalangy. In toothed whales, the second and third digits have the most number of bones whereas in baleen whales it is the third and fourth digits.

First Image: (A) Orca, (B) Sperm Whale, © North Atlantic Right Whale, (D) Humpback Whale, (E) Ichthyosaur (Stenopterygius sp.)

Second Image: (A) Orca, (B) North Atlantic Right Whale, © Sei Whale

Cooper, L. et al. (2007) Evolution of Hyperphalangy and Digit Reduction in the Cetacean Manus. The Anatomical Record 290 654–672