Definition of Chaetognatha in US English:


plural noun

  • A small phylum of marine invertebrates that comprises the arrow worms.

    • ‘Also unresolved are the phylogenetic positions of Cycloneuralia, Chaetognatha, Gnathostomulida, Cycliophora, and Micrognathozoa.’
    • ‘Instead, Rouse's conclusion that ‘groups such as the Arthropoda, Brachiopoda, Chaetognatha, Ectoprocta, Gastrotricha, Phoronida may have lost a prototroch’ is totally gratuitous, and remains unaddressed by his own data.’
    • ‘Pelagic species were from the Chaetognatha, Cnidaria, Crustacea, Ctenophora, and Mollusca, and benthic species were from the Chordata, Crustacea, Mollusca, and Echinodermata.’
    • ‘Nielsen and Nielsen et al. come to generally comparable results, although sometimes the additional taxa Rotifera, Acanthocephala and Chaetognatha were included in Aschelminthes.’
    • ‘Also absent are the Chaetognatha (arrow-worms), which have been considered the basalmost branch of the Deuterostomia in the past, but are currently regarded by many as basal protostomes.’


Modern Latin (plural), from Greek khaitē ‘long hair’ + gnathos ‘jaw’.