Kinorhynchs

Kinorhynchs are a phylum of microscopic, segmented marine invertebrates. They are commonly known as mud dragons or hedgehog worms. These animals are typically found in marine sediments worldwide, from intertidal zones to the deep sea. They are characterized by their elongated, cylindrical bodies, which are divided into a distinct head region and a trunk composed of 11 segments. The head bears a crown of spines and a protrusible oral stylet used for feeding.

The body of a kinorhynch is covered by a cuticle, which is molted periodically as the animal grows. Their locomotion is achieved through muscular contractions and the coordinated movement of adhesive tubes located on the ventral side of each trunk segment. Kinorhynchs are detritivores or herbivores, feeding primarily on diatoms and other algae found in the sediment. They use their oral stylet to pierce algal cells and ingest their contents.

Reproduction in kinorhynchs is sexual, with separate sexes. Fertilization is internal, and the eggs are typically laid in the sediment. The larval stages are often planktonic before settling into the benthos. Kinorhynchs play a role in marine benthic ecosystems as grazers and as a food source for small invertebrates. Despite their small size, they are a diverse group with over 250 described species. Their unique morphology and lifestyle make them an interesting subject of study in marine biology and invertebrate zoology.