Routakosteus

Routakosteus is a genus of prehistoric ray-finned fish that lived during the Late Cretaceous period, approximately 99 to 93 million years ago. It is known from a single species, Routakosteus kochi, which was discovered in the Upper Cretaceous sediments of the Kachchh Basin in western India. The genus name, Routakosteus, is derived from the Sanskrit word "routaka," meaning "to laugh," and "kosteus," a reference to the fish's costal structure. The specific epithet, kochi, honors the Indian paleontologist Dr. S. Koch, who first described the fossil.

Routakosteus is notable for its unique combination of features. It possessed a long, slender body with a distinctive costal structure, which is a series of ribs that extend along the sides of the body. This structure is similar to that found in some modern ray-finned fish, but it is more pronounced in Routakosteus. The fish also had a large, triangular head with a long, pointed snout, and a set of small, tooth-like structures on its upper jaw. Its tail fin was forked, typical of many ray-finned fish.

The fossil remains of Routakosteus include a nearly complete skull and several vertebrae, which have provided valuable insights into the anatomy and evolution of early ray-finned fish. The discovery of Routakosteus has helped to fill a gap in the fossil record, providing a better understanding of the diversity and evolution of these early fish. Despite its unique features, Routakosteus is considered to be a basal member of the ray-finned fish group, suggesting that it may have been an early ancestor of modern ray-finned fish.