A Rare Occurance

Fish fossils are somewhat rare especially when you consider that fish are the oldest and most diverse of all vertebrate animals. Because of their fragile, delicate bodies and limited bone structure, fish needed special conditions for fossilization to occur. Except for shark teeth, which are the nearly indestructible remains of the cartilaginous species, fish fossils are less often found and available for collection.

The Green River formation of southern Utah and southwestern Wyoming, however, is an Eocene formation that contains fossilized fish, along with rays and numerous plant fossils. At fossilicous.com, we have many beautiful examples of these delicate fossil remains in a variety of price-ranges to suit your budget.

Fish are defined as the group of vertebrate animals that have gills and do not have limbs with digits (fingers or toes.) There are some 32,000 species of fish in three main groupings living in today’s oceans. The groups are the jawless fish or agnathans, the cartilaginous fish or chondrichthyans and the bony fish called Osteichthyes.

The agnathans are the oldest and most primitive group. In modern oceans lampreys and hagfish are among the few remaining representatives of a group that began in the early Paleozoic Era about 500 million years ago. They do not have scales or paired fins and instead of jaws they have a kind of toothed circular mouth that can attach to another fish to rasp at the skin and take their blood.

The first fish to have jaws were the placoderms. These fish had bony plates covering their head and thorax. There were many species of placoderms but as a group they were short lived from a geologic perspective. The earliest examples of placoderms are found in the Silurian Period and the whole group became extinct by the end of the Devonian Period.

Chondrichthyans came along about 400 million years ago. This group is made up of sharks, skates, and rays. Like the agnathans, this group of fish have skeletons made completely of cartilage. They also have scales, jaws, and paired fins. As a group the chondrichthyans have been very successful predators.

The bony fishes or osteichthyans made their appearance about 200 million years ago. They have skeletons made entirely of bone rather than cartilage. These fish also have scales, paired fins, and jaws. The bony fish are by far the most extensive group of fish in today’s oceans.

We currently have two types of fish fossils available for sale:Knightia fish fossils from the Green River Formation and Dastilbe fish fossils from the Santana formation of Brazil