Achelidelphys ampla Lafargue and Laubier, 1977

Boxshall, Geoff A. & Marchenkov, Andrey, 2007, A revision of the Brementia - group of genera (Copepoda: Notodelphyidae), with descriptions of a new genus and four new species, Zootaxa 1459, pp. 37-68 : 55-57

Achelidelphys ampla Lafargue and Laubier, 1977

Material examined: Holotype female, reg. no. ZMA CO. 102.629.

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

Antennules forming short, tapering lobe on either side of frontal margin of cephalosome; surface ornamented with short spinules and vestiges of apical setae present ( Fig. 9 B). Antenna to maxilliped lacking. Legs 1–3 biramous; rami represented by unsegmented, tapering lobes: exopodal lobe laterally-directed, with broad base and unarmed tip ( Fig. 9 C), carrying smaller endopodal lobe ventrally. Leg 4 uniramous, comprising tapering, posterolaterally-directed lobe representing exopod. Uterus not expanded into exopods of legs. Leg 5 absent.

Body length of female 1.55–2.60 mm. Male unknown.

Remarks: Achelidelphys ampla has a compact uterus which does not extend into the exopodal lobes of the legs when full of stored eggs. This character, in combination with the lack of any median ventral processes on the metasome, serves to distinguish A. ampla from all other species. In A. ampla there is a pair of ventral process on the cephalosome originating anterior and lateral to the labrum. The origin of these antenno-medial processes is uncertain but we tentatively interpret them as homologous with the antenno-medial processes present in most Anoplodelphys species. A similar pair of antenno-medial processes is present in A. drachi but is absent in all other Achelidelphys species.

Figures

FIGURE 9. Achelidelphys ampla Lafargue and Laubier, 1978, holotype female (ZMA CO. 106.629). A, Urosome, dorsal; B, Antennule, showing ornamentation and vestigial apical setae; C, Tip of leg 1, showing ornamentation. Achelidelphys chengae Lafargue & Laubier, 1978, holotype female (ZMA CO. 106.638). D, Urosome, dorsal; E, Tip of antennule, showing vestigial apical setae. All scale bars = 100 μm.