Mielinoida

Mielinoida is a class of ray-finned fish in the infraclass Holostei, order Amiiformes. These ancient fish belong to the group of holostean fish that are primarily known for their fossil record, with the earliest known representatives dating back to the Early Cretaceous period, approximately 145 million years ago.

Mielinoida were characterized by their unique skull morphology, characterized by an elongated and narrow snout, as well as narrow interorbital bones. Additionally, they were known to possess an elevated neurocranium. These features distinguish them from other members of the infraclass Holostei.

Fossil records of mielinoida are scarce, and most findings come from Cretaceous rock formations in Asia and North America. These fossils often show similarities with modern-day bowfins, however, mielinoida are classified as distinct entities.

Some notable characteristics include the relatively small size of braincase speciments compared to the body size, as well as symmetrically formed caudal peduncles. In some well-preserved specimens, scales and complete sets of dermal denticles are preserved, allowing for in-depth analysis of their biological habits.

Mielinoida likely fed on small aquatic organisms and were capable of weight-bearing oneself on both their lateral and ventral sides, through flexation of the dorsal and anal fins. However, their habits and exact feeding behavior are not documented due to the limitations of the fossil record. Despite this, the study of mielinoida has contributed significantly to our understanding of the evolution of Holostei.