Leptolepis is a leptolepid leptolepiform ray-finned bony fish from the Middle Triassic-Early Cretaceous of the entire world. It was officially named in 1843 by Louis Agassiz. It was one of the most successful and widespread Mesozoic bony fishes, and was thought to be a species of typical carp before finally being described as its own genus.
Physiology[]
Leptolepis resembled the generic herring. It was a ray-finned fish with a torpedo-shaped body, thin, skinny fins, and a mid-sized head with semi-small jaws. Its body would have been covered in scaly skin.
Diet[]
Leptolepis was a planktivore, sucking up colonies of plankton drifting through the water. Its small, toothless mouth would have been used to filter plankton from the water.
Ecology[]
Leptolepis was an evolutionary step-up from earlier bony fish, as it had a skeleton made completely of bone (while earlier ray-fins and lobe-fins were partially made of cartilage); as well as this, unlike the scales of earlier bony fish, its scales were no longer covered in ganoine. Those two features made swimming easier, as its bony spine would no longer feel pressure as it propelled itself through the water with lateral undulation. Massive bone beds containing Leptolepis specimens confirmed that the ray-finned fish swam around in schools. This would have been especially useful, as it would serve to protect the fish from predators such as Nothosaurus, Cymbospondylus, Metriorhynchus, Cryptoclidus, and Ophthalmosaurus.
In popular culture[]
Leptolepis was featured in the 3rd episode of the 1999 documentary Walking with Dinosaurs, where it is shown as a common prey item for predators like Cryptoclidus. As well as this, it was shown as fully capable of forming bait balls, similar to modern saltwater fish.