Achelidelphys drachi Lafargue and Laubier, 1978

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

Achelidelphys drachi Lafargue and Laubier, 1978

Material examined: Holotype female, reg. no. ZMA CO. 106.637.

Differential Diagnosis: Body highly transformed, stellate ( Fig. 8 A–B); segmentation indistinct with segmental boundaries marked by superficial folds. Cephalosome with frontal margin merging into elongate, tapering, anterolaterally-directed antennulary lobes. Rostrum elongate, anteroventrally-directed lobe ( Fig. 8 B), without accessory median lobe. Post-rostral median lobe absent. Labrum inflated, forming rounded, slightly-elongate 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 and produced laterally, giving body stellate appearance. Mid-ventral metasomal process present between second legs. Urosome vestigial, located terminally; bearing partly incorporated caudal rami ( Fig. 8 C). Surface of body, rostrum, labrum, cephalosomic processes and legs densely ornamented with surface setules.

Antennules forming elongate, tapering lobe directed antero-laterally on either side of frontal margin of cephalosome. Antenna to maxilliped lacking. Legs 1–3 biramous; rami represented by unsegmented, elongate lobes: exopodal lobes laterally-directed, with broad base, carrying elongate endopod ventrally. Leg 4 uniramous, comprising tapering, 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 2.50 mm. Male unknown.

Remarks: This species carries an additional tiny unpaired process on the ventral midline about at the level of the first pair of legs. The homology of this process is uncertain (i.e. whether it is a serial homologue of the processes present between legs 2–4 in A. steinitzi , for example). This species can be distinguished from its congeners by the extreme length of the tapering lobes derived from the antennules, rostrum and leg rami. The paired antenno-medial processes are shared only with A. ampla among the members of Achelidelphys .

Figures

FIGURE 8. Achelidelphys steinitzi Lafargue and Laubier, 1977, holotype female (ZMA CO. 106.628). A, Urosome, dorsal. Achelidelphys drachi Lafargue & Laubier, 1978, holotype female (ZMA CO. 106.637). B, Habitus, dorsal; C, Habitus, ventral; D, Urosome, dorsal. Scale bars: A = 100 μm, B – C = 1 mm, D = 100 μm.