Benthozoa

Benthozoa is an obsolete term formerly used in invertebrate zoology. It referred to a grouping of animals that live on or in the benthos, the ecological region at the lowest level of a body of water such as an ocean or lake, including the sediment surface and some sub-surface layers.

The term Benthozoa is no longer considered a valid taxonomic or phylogenetic grouping. The animals historically classified within this broad category represented a highly diverse collection of phyla and classes, united only by their benthic lifestyle. These include a vast array of organisms such as:

• Various types of worms (e.g., polychaetes, nematodes)
• Mollusks (e.g., clams, snails)
• Crustaceans (e.g., crabs, shrimp)
• Echinoderms (e.g., starfish, sea urchins)
• Sponges
• And many other invertebrate groups

Modern biological classification relies on evolutionary relationships and genetic data to define taxonomic groups. Because the animals that were once considered Benthozoa do not share a common ancestor exclusive of other animals, the term is no longer useful in scientific classification. Instead, biologists now study benthic organisms within their respective taxonomic groups, focusing on their specific adaptations to the benthic environment. Studies of benthic ecosystems remain a vibrant and important area of research in ecology and marine biology.