Leptolepis

Extinct genus of ray finned fishes

Leptolepis (from λεπτός , 'slight' and λεπίς 'scale') is an extinct genus of stem teleost fish that lived in what is now Europe during the Jurassic period (Toarcian–Callovian ages). Leptolepis autissiodorensis
Leptolepis coryphaenoides
Leptolepis jaegeri
Leptolepis nathorsti
Leptolepis normandica
Leptolepis saltviciensis
Leptolepis woodwardi

Length of Leptolepis was about long, and superficially resembled the unrelated modern herring. While more basal teleosts such as Pholidophorus had skeletons composed of a mixture of bone and cartilage, Leptolepis resembled modern teleosts in possessing a skeleton completely made of bone. Another modern development in Leptolepis were its cycloid scales, which lacked the covering of ganoine present in more basal teleosts. These two developments made swimming easier, as the bony spine was now more resistant to the pressure caused by the S movements made while swimming. Mass graves of Leptolepis have indicated that species probably lived in schools which would provide some protection from predators while the creatures fed on surface plankton. Pelagosaurus was a known predator of Leptolepis, as a Pelagosaurus fossil was found with Leptolepis remains in its stomach. Clarkeiteuthis is known from three specimens with Leptolepis in its arms, which estimate that Leptolepis is probably most common prey of Clarkeiteuthis.

Known only from a single nearly complete skeleton found at Rabbit Valley, Colorado. A fish that was deeper bodied than its co occurring contemporaries Morrolepis and Hulettia. The Morrison cf. Leptolepis probably had a live mass of about It is the only teleost fish known from the formation and was morphologically more highly derived than other Morrison fish. A specific example of apomorphy in cf. Leptolepis is its "more modern tail structure" compared to Morrolepis. It is believed to have fed on fish and small invertebrates.