Brementia balneolensis Chatton and Brément, 1915

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 : 51

Brementia balneolensis Chatton and Brément, 1915

Material examined: none.

Differential Diagnosis: Body eruciform, with indistinct segmentation. Cephalosome with narrow frontal margin bearing anteroventrally-directed rostrum. Rostrum forming simple lobe, without accessory median lobe. Post-rostral median lobe absent. Labrum a hemispherical lobe. Lateral margin of cephalosome expanded ventrally to produce ridge-like swelling. Metasome with about 30% of length extending posterior to origin of leg 4. Metasomal somites bearing ventrally-directed legs near lateral margins, lacking mid-ventral processes between legs. Urosome small, narrow and carrying partly-incorporated caudal rami. Caudal rami lobate, armed with setal remnants distally. Surface of body, rostrum, labrum, cephalosomic processes and legs densely ornamented with surface setules.

Antennule tapering with traces of segmentation, with apical segment setose. Antenna indistinctly 3-segmented, with distal segment incorporating reduced distal claw, and bearing 2 vestigial setal elements. Mandible forming large cylindrical lobe with vestigial gnathobase proximally bearing reduced setal elements; mandibular palp with bilobed apex. Maxillule represented by cylindrical lobe, bifid at apex. Maxilla indistinctly segmented, syncoxal part forming triangular lobe bearing vestiges of enditic armature along medial margin; basis bearing reduced claw and vestige of endopod. Maxilliped reduced to tiny conical lobe.

Legs 1 to 3 biramous, ventrally-directed; each comprising long basal part (derived from protopod), carrying short, unsegmented rami distally. Leg 4 reduced, largely incorporated into body somite, weakly bilobed distally, with lobes representing rami. Leg 5 not observed.

Body length of female approximately 2.35 mm. Male unknown.

Remarks: This is a strongly transformed copepod from the colonial ascidian Didemnum commune on the Mediterranean coast of France. It was redescribed to modern standards by Laubier and Lafargue (1974), based on new material collected from Polysyncraton canetense (Brément, 1913) in the same area. Despite the transformed body and swimming legs, this copepod retains a full set of mouthparts, although all are reduced in comparison with basal notodelphyids ( Boxshall & Halsey 2004).