Sipuncula, or Sipunculida, commonly known as peanut worms, comprises about 162 species of marine worms that have secondarily lost their body segmentation. Once treated as its own phylum of unsegmented worms, Sipuncula was reclassified as a class within the phylum Annelida following molecular studies, and its members typically live in burrows or in the empty shells and crevices of other marine organisms.
Facts
Taxonomic Rank Scientific Name Member Species/Taxa Count Geographic DistributionAll oceans including polar waters, equatorial waters and the abyssal zone, most species in shallow water 1 Defining CharacteristicsUnsegmented bulbous trunk and a narrower retractable introvert 1 Identification
Distinguishing AppearanceWorms from 2 to 720 mm long, most under 10 cm 1 Classification
Living or Extinct Sources
1. Peanut worm, Wikipedia
Lead paragraph
The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of marine annelid worms
Taxonomy
This is a relatively understudied group, and it is estimated there may be around 162 species worldwide.
Distribution and habitat
All sipunculid worms are marine and benthic; they are found throughout the world's oceans including polar waters, equatorial waters and the abyssal zone, but the majority of species occur in shallow water
Lead paragraph, body
The body is divided into an unsegmented, bulbous trunk and a narrower, anterior section, called the "introvert", which can be retracted into the trunk.
Anatomy
Sipunculans are worms ranging from 2 to 720 mm (0.1 to 28.3 in) in length, with most species being under 10 cm (4 in).
View the Source2. Wikidata (taxon extant/extinct status)
Wikimedia Foundation / Wikidata contributorsQ205712, descriptionView the Source Wikidata: Sipuncula
Wikidata Q205712, class allow-list match (w-wdresolver-0926)View the Source Wikipedia: Sipuncula
WikipediaIn Group: Annelid Classes, LeadQuote, In Group: Annelid Classes, Lead
The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of marine annelid worms, that have secondarily lost their segmentation.
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