Varjatoonidae

Varjatoonidae is a proposed family of extinct ray-finned fish. The family was first described based on fossil remains discovered in the late Cretaceous period, dating back approximately 85 to 70 million years ago. Fossils attributed to Varjatoonidae have been found in various locations, suggesting a relatively widespread distribution during the Mesozoic Era.

The defining characteristics of Varjatoonidae are primarily derived from skeletal morphology. These fish typically possessed a fusiform body shape, indicating adaptations for active swimming. Key features often cited include the structure of their fins, particularly the pectoral and pelvic fins, and the arrangement of their scales and teeth. The exact phylogenetic placement of Varjatoonidae within the larger framework of fish evolution is still debated among paleontologists. Some studies suggest a closer relationship to modern teleost fish, while others propose a more basal position within the actinopterygian lineage.

The paleoenvironment in which Varjatoonidae lived is believed to have been marine, likely in shallow coastal waters or estuaries. Their diet is inferred from the structure of their jaws and teeth, suggesting they were likely piscivores or molluscivores. The extinction of Varjatoonidae, like many other Mesozoic fish groups, is often associated with the Cretaceous-Paleogene extinction event, although the precise causes and timing of their disappearance remain subjects of ongoing research. Further fossil discoveries are needed to fully understand the diversity, behavior, and evolutionary significance of this extinct fish family.