Cymothoida Wägele, 1989

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Suggested Common Name: Wormpods and Fisheaters
Number of subordinate taxa: over 2000 species in 2 superfamilies worldwide, 490 species in both superfamilies in our area
Etymology: after Cymothoa Fabricius, 1787. Common name refers to the two consituent superfamilies, see those for more information.
Taxonomic History: one of the many former members of Flabellifera, which was divided into seperate suborders over the course of the late 1980s to early 2000s.
Size Range: Largest among suborders, ranging from a few millimeters to a quarter of a meter.
Taxonomic History: (modified from Bruce & Poore, 2003) Antenna 1 lacking scale (present in Bathynomus). Mandible lacinia absent (sometimes present); molar flat and blade-like or conical, sometimes absent. Maxilliped endites rarely longer than palp segment 1 (or absent entirely), usually tapering distally with few setae. Pereopods 1-7 coxae fused to tergites into coxal plates. Pereonite 7 dorsal coxal plate similar to others. Pleonites 1-5 usually free (fused in some groups). Pleonite 1 similar to others when free. Pleopods 3-5 endopods more or less oval or rectangular, rounded distally. Telson underside flat, lacking lateral ridges. Uropods (when present) rami ventral to telson, articulating from side to side along vertical axis inside branchial space.
Type taxon: Cymothooidea Leach, 1814
Notes: This huge suborder (third only to Oniscidea and Asellota in species) has an almost bewildering morphological and ecological diversity. Unifying features for this group are very difficult to parse out, especially due to numerous novel developments and widespread reductions. Members of this suborder are almost entirely marine, although there are some radiations into subterranean environments and a few parasitic species follow their hosts inland.
Until very recently Epicaridea was considered an infraorder in Cymothoida, but recent genetic analysis has shown that it should be elevated to the subordinal level. See the Epicaridea account for more information.

Subordinate taxa: Anthuroidea, Cymothooidea

Key to larger groups
1 a. Uropods folded over telson to form a flower-shaped "shovel"; maxilla 2 absent; body elongate-cylindrical; benthic burrowers --> Anthuroidea
b. Uropods not folded over telson, forming a retractable tailfan (pleopod-like in Anuropidae); body
ovate (highly modified in Gnathiidae); maxilla 2 present (vestigial in Gnathiidae) voracious predators or parasites --> Cymothooidea


Brandt, A., & Poore, G. C. (2003). Higher classification of the flabelliferan and related Isopoda based on a reappraisal of relationships. Invertebrate Systematics, 17(6):893-923.

Published: Jan 1, 2023