Article
Article
Chaetognatha
Article By:
Pierrot-Bults, Annelies C. Zoological Museum, University of Amsterdam, Amsterdam, The Netherlands.
Pierce, E. Lowe Department of Zoology, University of Florida, Gainesville, Florida.
Last reviewed:October 2019
DOI:https://doi.org/10.1036/1097-8542.123200
A strictly marine phylum, commonly referred to as arrow worms. Chaetognaths were first discovered in 1775 near the Dutch coast. Currently, there are approximately 130 recognized species of Chaetognatha, of which 100 are pelagic (living in the open oceans) and 30 are benthic (living on or near the sea bottom). Because of the restraints of the environment, the body plan of chaetognaths is very similar throughout the phylum, and morphological differences are slight. Recent molecular work has revealed a number of cryptic species, so the number of species is still uncertain. There used to be 10 genera, but some specialists have divided the most speciose genus, Sagitta, into 10 new genera, bringing the total number to 20.
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