Annelida

Also known as annelid, annelids, segmented worms, segmented worm

The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments.

AI overview

Annelids, also called segmented worms, are a diverse group of animals that includes familiar species like earthworms, ragworms, and leeches, with over 22,000 known species alive today. They matter because they have successfully adapted to live in many different environments—from ocean floors and tidal zones to freshwater and moist soil—making them important parts of ecosystems worldwide.

AI-generated from the Wikipedia summary — may contain errors.

Species

annelids

Annelida

PHYLUM

KingdomAnimalia
PhylumAnnelida

Habitatmarine, brackish, freshwater

Observations recorded9,907,382

via GBIF

Research

17,405 papers

via PubMed

Wikidata facts

Image: Nereis pelagica.jpg

Show 6 more facts

taxon common name: kolobarniki
taxon name: Annelida
Commons category: Annelida
earliest date: 530000000-
start time: 516000000-
Commons gallery: Annelida

Sources (6)

via Wikidata · CC0

~44 min read

Article

21 sections

Contents

Classification and diversity
Distinguishing features
Description
Segmentation
Body wall, chaetae and parapodia
Nervous system and senses
Coelom, locomotion and circulatory system
Respiration
Feeding and excretion
Reproduction and life cycle
Asexual reproduction
Sexual reproduction
Ecological significance
Interaction with humans
Evolutionary history
Fossil record
Internal relationships
External relationships
Notes
References
External links

The annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into Polychaetes (almost all marine), Oligochaetes (which include earthworms) and Hirudinea (leech-like species). Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychaetes. Annelids are considered members of the Lophotrochozoa, a "super-phylum" of protostomes that also includes molluscs, brachiopods, and nemerteans.