Phylum: Annelida
Worms are represented by fossils ranging from PreCambrian through Recent times, although the fossil record is poor. Only a few of them had any hard parts such as jaws, so most of the fossil record is limited to tubes, impressions, trails, and such. Soft parts were preserved only rarely.
Worms are so diverse that they are divided into nine phyla. Of those nine phyla, only one is considered important from a paleontological standpoint: the phylum Annelida. This phylum is important because it is believed that arthropods derived from them. Annelids and arthropods are similar in two ways: they both have segmented bodies, and their nervous systems are structured in a similar manner.
Annelids are composed of many ringlike segments which are very similar. They range in length from a few millimeters to nearly three meters, and their diameter ranges up to 25 mm (one inch). They include earthworms, leeches, and many marine worms. The marine worms live in shallow water and along the seashore. Some are free-moving, while others live in burrows or tubes.
The class Polychaeta is a marine worm. The jaws have been found in many systems of rocks. In Kansas, we are most likely to find its tubes preserved in Lower Cretaceous rocks.
Worms are so diverse that they are divided into nine phyla. Of those nine phyla, only one is considered important from a paleontological standpoint: the phylum Annelida. This phylum is important because it is believed that arthropods derived from them. Annelids and arthropods are similar in two ways: they both have segmented bodies, and their nervous systems are structured in a similar manner.
Annelids are composed of many ringlike segments which are very similar. They range in length from a few millimeters to nearly three meters, and their diameter ranges up to 25 mm (one inch). They include earthworms, leeches, and many marine worms. The marine worms live in shallow water and along the seashore. Some are free-moving, while others live in burrows or tubes.
The class Polychaeta is a marine worm. The jaws have been found in many systems of rocks. In Kansas, we are most likely to find its tubes preserved in Lower Cretaceous rocks.