Family EXPANATHURIDAE Poore, 2001

Eisothistos sp.

© Copyright from Poore unpublished.

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Introduction

The Expanathuridae are on first impression a heterogeneous family, but this is less apparent when the highly derived genus Eisothistos is ignored. Characters which unite the remaining genera include: absence of statocysts, presence of a maxillipedal endite and palp of five articles, anterodistal serrate setae on the propodus of pereopod 7, and the weakly operculiform pleopod 1. Some genera have highly ornamented telson and uropodal margins (not seen in other families).

The family is most diverse in the tropics but occurs also in southern temperate areas. Nothing is known of its biology. Poore (2001) provided a key to genera and listed all the species.

Diagnosis

Body 10–15 times as long as wide, non-males rarely more elongate (pereonite 7 wider than long, much shorter than pereonite 6). Pleonites 1–5 together not more than twice as long as wide, free and articulating or fused; with plumose setae on margins of epimera or posterior margins of pleonite 5 and sometimes pleonite 4. Antenna 2 flagellum of fewer than 10 articles, shorter than peduncle, or of numerous articles, longer than or shorter than peduncle. Mouthparts not produced anteriorly. Mandible tapering and incisor simple, or compact and with weakly-toothed transverse incisor (rarely). Maxillipedal endite reaching palp article 3, or absent or obsolete; palp narrow and tapering distally to rounded apex (c. three times as long as wide) or reduced, digitiform (Eisothistos), with 5 free articles or with 2 or more articles fused. Pereopods 2 and 3 carpus not or weakly produced posterodistally; propodus with 1 robust seta in addition to posterodistal robust seta, or with posterodistal robust seta only, or without posterodistal robust seta. Pereopods 4–7 propodus with more than 1 robust setae in addition to posterodistal robust seta, or with posterodistal robust seta only. Pereopod 7 propodus with anterodistal serrate setae. Pleopods: pleopod 1 exopod and endopod together weakly operculiform, or pleopod 1 exopod operculiform alone (Expanathura only). Statocysts absent.

General References

Poore, G.C.B. 2001. Families and genera of Isopoda Anthuridea. Crustacean Issues 13: 63-173

History of changes