Achelidelphys chengae Lafargue and Laubier, 1978

Material examined: Holotype female, reg. no. ZMA CO. 106.638.

Differential Diagnosis: Body highly transformed, stellate; segmentation indistinct with segmental boundaries marked by superficial folds. Cephalosome with frontal margin merging into tapering anterolaterallydirected antennulary lobes. Rostrum simple, frontally-directed lobe, without accessory median lobe. Post-rostral median lobe absent. Labrum forming tapering, posteriorly-directed lobe. Lateral margin of cephalosome not produced into ridge-like swellings. Antenno-medial processes absent. Metasome truncated, with urosome hardly extending posterior to origin of leg 4. Legs 1–4 transformed, originating laterally, each occupying entire margin of somite and produced laterally, giving body stellate appearance. Mid-ventral metasomal processes absent. Urosome vestigial, located terminally; bearing partly incorporated caudal rami with short caudal setae (Fig. 9 D). Surface of body, rostrum, labrum, cephalosomic processes, and legs sparsely ornamented with minute surface setules.

Antennules forming bluntly-rounded lobe on either side of frontal margin of cephalosome, with vestigial apical setae (Fig. 9 E). Antenna to maxilliped lacking. Legs 1–3 biramous; rami represented by unsegmented, tapering lobes; exopodal lobe laterally-directed, with broad base, carrying smaller endopodal lobe ventrally. Leg 4 uniramous comprising short, posterolaterally-directed lobe representing exopod. Exopodal lobes of legs 2–4 each housing internal expansion of uterus, containing eggs visible through body wall. Leg 5 absent.

Body length of female 1.35–1.90 mm. Male unknown.

Remarks: Achelidelphys chengae also lacks any median ventral processes on the metasome as does A. ampla, but in the adult female the uterus extends into the exopodal lobes of legs 2–4 when full of stored eggs. It also differs from A. ampla in the lack of antennomedial processes.