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The annelids (/ ˈ æ n ə l ɪ d z /), also known as the segmented worms, comprise a large phylum called Annelida (/ ə ˈ n ɛ l ɪ d ə /; from Latin anellus 'little ring'). [ 3 ] [ a ] The phylum contains over 22,000 extant species , including ragworms , earthworms , and leeches .
List of annelid families describes the taxa relationships in the phylum Annelida, which contains more than 17,000 extant species including ragworms, earthworms, ...
Pleistoannelida is a group of annelid worms that comprises the vast majority of the diversity in phylum Annelida.Discovered through phylogenetic analyses, it is the largest clade of annelids, comprised by the last common ancestor of the highly diverse sister groups Errantia and Sedentaria (Clitellata and related polychaetes) and all the descendants of that ancestor.
The annelids, collectively called Annelida, are a large phylum of animals, comprising the segmented worms, with about 15 000 modern species including the well-known earthworms and leeches The main article for this category is Annelid .
This list of prehistoric annelids is an attempt to create a comprehensive listing of all genera that have ever been included in Annelida which have been found ...
Like most annelids, with a few exceptions like Sipuncula, Echiura and Diurodrilus, [27] the leech is a segmented animal, but unlike other annelids, the segmentation is masked by secondary external ring markings . [28] The number of annulations varies, both between different regions of the body and between species. [24]
Trochophores exist as a larval form within the trochozoan clade, which include the entoprocts, molluscs, annelids (including echiurans and sipunculans) and nemerteans. Together, these phyla make up part of the Lophotrochozoa ; it is possible that trochophore larvae were present in the life cycle of the group's common ancestor.
The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of unsegmented marine annelid worms.Sipuncula was once considered a phylum, but was demoted to a class of Annelida, based on recent molecular work.