Animal Phyla/Kinorhyncha

Paracentrophyes quadridentatus, a mud dragon.

• Kinorhyncha
• Name Meaning: Motion snout
• English Common Name: Mud dragons
• Major distinguishing characteristics: Eleven segments, each with a dorsal plate
• Approximate number of species described: about 150

Natural History

The Kinorhyncha are widespread in mud or sand at all depths in marine waters. They live in the sand or mud.

Taxonomy

The Phylum is divided into two orders.

• Order Cyclorhagida
• Order Allomalorhagida

Anatomy

Mud dragons are segmented and limbless. They have a body with three parts, the head, neck, and a trunk of eleven segments.

They do not have cilia, but do have a number of spines along the body, plus up to 7 circles of spines around the head. These spines are used for locomotion.

The Fossil Record

There is apparently no fossil record of these very small animals.

Quiz

• Kinorhyncha Quiz

References and Further Reading

• Kinorhyncha at Wikipedia
• Kinorhyncha at Tree of Life
• Kinorhyncha at Encyclopedia of Life