Suborder CYMOTHOIDA Wägele, 1989

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Regional Maps

• Cymothoida Wägele, J.W. 1989. Evolution und phylogenetisches System der Isopoda. Stand der Forschung und neue Erkenntnisse. Zoologica (Stuttgart) 140: 1-262 [188].

Introduction

The Cymothoida include those families of the former Flabellifera that are scavengers, ectoparasites, blood-sucker or predators (Dreyer & Wägele 2001). Primitively, the group has evolved from the scavenging and predatory feeding strategy towards parasitism on fish and other Crustacea. In the most basal families (e.g., Cirolanidae) the mandibular molar is an articulating toothed blade. This structure and the whole mandible is variously modified and reduced to a more piercing structure in the more parasitic families.

While it is possible to place some families into a larger monophyletic group (former suborder Anthuridea into superfamily Anthuroidea), the remainding families are treated separately. Wägele (1989) and Brandt & Poore (2003) treated the suborder "Epicaridea" as two superfamilies within the Cymothoida but there is now evidence that they are now monophyletic and are treated as such in AFD (Boyko et al., 2013; An et al., 2022).

Diagnosis

Head-pereonite 1 free. Dorsal pereopodal coxal plates present (secondarily reduced in some species); coxal plate of pereopod 1 fused to tergite; coxal plate 7 present; ventral coxal plates 1–7 (medial extension of coxa replacing sternite) obsolete (not distinguished from sternite). Pleotelson incorporating pleonite 6 only, pleonites 1– 5 free. Pleotelson underside flat, without ventrolateral ridges (pleopods not enclosed laterally). Penial processes medial, closer to midpoint than to pereopods. Mandibular lacinia mobilis absent; molar flat triangular blade-like or conical process, or sometimes reduced or absent, or absent (rarely); palp present. Maxilla trilobed (reduced in Anthuroidea, absent Gnathiidae). Maxillipedal endite rarely longer than palp article 1 (or absent), distally tapering and with few setae. Pereopods 1–3 more or less prehensile, directed anteriorly; pereopods 4–7 directed posteriorly. Pleopodal exopods uniarticulate. Pleopod 1 biramous. Pleopod 2 biramous. Pleopod 3 biramous; endopod more or less oval or rectangular, rounded distally. Telsonic region of pleotelson elongate, anus situated anteriorly on pleotelson. Uropod situated anterolaterally on pleotelson; peduncle not operculate; rami ventral to pleotelson, articulating from side to side in vertical axis inside branchial chamber.

General References

An, J., Yin, X., Chen, R., Boyko, C.B. & Liu, X. 2022. Integrative taxonomy of the subfamily Orbioninae Codreanu, 1967 (Crustacea: Isopoda) based on mitochondrial and nuclear data with evidence that supports Epicaridea Latreille, 1825 as a suborder. Molecular Phylogenetics and Evolution 180: 107681

Boyko,C.B., Moss,J., Williams,J.D. & Sheilds,J.F. 2013. A molecular phylogeny of Bopyroidea and Cryptoniscoidea (Crustacea: Isopoda). Systematics and Biodiversity 11(4): 495-506 [Date published 16/12/2013]

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

Dreyer, H. & Wägele, J.-W. 2001. Parasites of crustaceans (Isopoda: Bopyridae) evolved from fish parasites: molecular and morphological evidence. Zoology (Jena) 103: 157-178

Wägele, J.W. 1989. Evolution und phylogenetisches System der Isopoda. Stand der Forschung und neue Erkenntnisse. Zoologica (Stuttgart) 140: 1-262

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