Capnellidae

Capnellidae is a family of marine annelids belonging to the order Terebellida. The family is commonly known as the “capitellid worms” or “capitellids”. These worms are typically small, often less than 5 cm in length, and are characterized by their distinctive segmented bodies with a distinct head region and a tail end that is often tapered or rounded. Capitellids are widespread in marine environments, particularly in coastal areas with high levels of organic matter. They are often found in sediments, burrows, or amongst seaweed.

Eunephthya granulata

Characteristics

The following characteristics are common to members of the Capnellidae family:

  • Segmented bodies: Capitellid worms have distinct segments, with each segment typically bearing a pair of parapodia (fleshy appendages used for locomotion).
  • Distinctive head region: The head region of capitellids is usually well-defined, with a pair of antennae and a mouth surrounded by tentacles.
  • Tapered or rounded tail end: The tail end of the worm is usually tapered or rounded, with a terminal anus.
  • Presence of a prostomium: The prostomium is a distinct lobe that extends from the first segment, typically bearing antennae or sensory palps.
  • Diversity of body shapes: Capitellids can exhibit a range of body shapes, from elongated and slender to short and stout.
  • Coloration: Capitellid worms are generally white or pale-colored, although some species can be brightly colored.

Ecology

Capitellid worms are often found in areas with high levels of organic matter, such as:

  • Intertidal zones: They are commonly found in the sediments of intertidal areas, particularly in areas with high levels of organic matter.
  • Estuaries: Estuaries often provide suitable habitats for capitellids, as they typically have high levels of organic matter and salinity fluctuations.
  • Deep-sea environments: Some capitellid species can be found in deep-sea habitats, particularly in areas with abundant food sources.

Capitellids play an important role in marine ecosystems. They are deposit feeders, ingesting organic matter from the sediments and contributing to the breakdown of organic matter. Some capitellids are also known to be bioturbators, meaning they modify sediments by burrowing and creating tunnels, which can improve sediment aeration and water circulation.

Examples of Capitellid Species

The Capnellidae family includes a wide variety of species, with notable examples including:

  • Capitella capitata: This species is a common and widespread capitellid worm, often found in polluted habitats.
  • Mediomastus ambiseta: This species is known for its ability to tolerate a wide range of environmental conditions.
  • Notomastus latericeus: This species is a burrowing worm that is commonly found in intertidal mudflats.

References

For further information about Capnellidae, refer to the following websites: