Family MESAMPHISOPODIDAE Nicholls, 1943

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Introduction

This family is distributed in surface freshwaters in South Africa and the Northern Territory, Australia. Of the two genera included by Nicholls in his Mesamphisopodinae, Mesamphisopus is South African and Hyperoedesipus is herein removed to Hypsimetopodidae. Eophreatoicus is now the only Australian genus provisionally included here, although Nicholls (1943) placed it in Phreatoicopsinae. Eophreatoicus, which has many undescribed species around the Arnhem Plateau, Northern Territory, and two new genera from Western Australia may be members of a basal clade near, but not including Mesamphisopus (see cladogram in Wilson & Keable 2001), suggesting that the composition of this family will need further consideration.

Database Notes

This family might be paraphyletic because Mesamphisopus and Eophreatoicus (clustering with two new genera from WA) branch off independently of one of the basal lineages in the phreatoicidean cladogram (May, 2000 results, GDFW)

Diagnosis

Body robust, sub-cylindrical. Head short; with well-marked cervical groove; antennal, genal and clypeal notches present. Eyes prominent. Pereonite 1 overlaps head. Coxae fused to tergites. Gut without typhlosole and hind gut caecae. Pleonal epimera well developed. Pleotelson posterior margin reflexed, with distinct lateral plates; dorsal uropodal ridge present but lacking setae. Both mandibles with lacinia mobilis. Pereopods with articular plate on propodus. Pleopods with setae only on margins of endites. Appendix masculina stout, longer than endopod, curved apically. Uropodal protopod dorsomedial margin with distinct plate.

General References

Nicholls, G.E. 1943. The Phreatoicoidea. Part I. The Amphisopidae. Papers and Proceedings of the Royal Society of Tasmania 1942: 1-145

Wilson, G.D.F & Keable, S.J. 2001. Systematics of the Phreatoicidea. pp. 175-194 in Brusca, R.C. & Kensley, B. (eds). Isopod Systematics and Evolution. Crustacean Issues 13: 175-194

History of changes