Paranoplodelphys simplex, Boxshall, Geoff A. & Marchenkov, Andrey, 2007

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 : 49-51

Paranoplodelphys simplex n. sp.

Type material: Holotype female, 2 paratype females. Registration nos: MNHN-Cp2317 (Holotype in alcohol), MNHN-Cp2318 (paratype female in alcohol), BMNH 2006.1188. (1 paratype female in alcohol).

Type Locality: Mescha island, Djibouti: collected at depth of 0–20 m, in 1996

Host: Didemnum dicolla Monniot and Monniot, 1999 [ MNHN reg. no. of host: A2 DID C 397-401]

Locality in host: within the common tunic between the zooids (F. Monniot, pers. comm.).

Etymology: the species name refers to the extreme reduction in limbs exhibited by this species.

Description: Adult female body ( Fig. 5 A–D) highly transformed, vermiform and lacking external segmentation: indistinctly divided into 3 regions, cephalosome, metasome and urosome, by shallow furrows. Body length of holotype female 1.63 mm (ranging from 1.63–1.70 mm for 3 studied specimens). Cephalosome with broad, rounded frontal margin; bearing single pair of appendages (antennules) ventrolaterally, and strongly developed labrum. Rostrum absent. Metasome more or less cylindrical, but tapering posteriorly; bearing 2 pairs of legs (legs 1 and 2). Developing eggs in uterus visible through body wall ( Fig. 5 C). Metasome lacking expressed segmentation but with visible cuticular folds indicating division into 4 somites; fourth somite bearing urosome inserted dorsally. Urosome ( Fig. 5 E) reduced, unsegmented, incorporating caudal rami represented by cluster of caudal setae ( Fig. 5 E). Entire body surface densely ornamented with relatively short setules, similar to those of A. africana (cf. Fig. 1 D).

Antennules ( Fig. 5 A–B, D) extremely reduced, represented by pair of small conical protrusions located near anterolateral corners of labrum. No other cephalosomal appendages observed.

Labrum ( Fig. 5 A–B, D) massive, conical, with rounded posterior tip reaching anterior border of base of leg 2. Surface of labrum ornamented with setules.

Legs 1 and 2 only present ( Fig. 5 A–B, D); legs 3 and 4 absent. Legs 1 and 2 originating close to each other, just behind cephalosome. Leg 1 biramous, with common protopodal base bearing unsegmented, conical rami; endopodal lobe elongate, massive, exopodal lobe very reduced. Leg 2 uniramous, unsegmented, present as conical process half as long as endopodal lobe of leg 1.

Leg 5 ( Fig. 5 E–F) well developed as simple lobes armed with 2 setae located near anterior margin of urosome: 1 seta apical, other subapical.

Male unknown.

Remarks: The new species can be distinguished from all other species attributed to the Brementia -group of genera by extreme reduction: in particular by the absence of a rostrum, the loss of the antenna and all oral appendages, by the decrease in size of the exopodal lobe of leg I, and by the possession of a uniramous leg 2. Without access to developmental stages it is not possible to identify the homology of the remaining ramus on leg 2.

Figures

FIGURE 1. Anoplodelphys africana n. sp. holotype female (MNHN-Cp 2323). A, Habitus, lateral; B, Habitus, ventral; C, Cephalosome and first pedigerous somite, ventral, with inset showing detail of post-labral pore (? maxillary gland opening); D, Surface ornamentation from lateral surface of third metasomal somite; E, Tip of antennule, showing vestiges of antennulary setae. Scale bars: A – C = 500 μm, D = 50 μm, E = 25 μm.

FIGURE 5. Paranoplodelphys simplex n. gen. et n. sp. A, Habitus of holotype female (MNHN-Cp 2317) lateral; B, Habitus, ventral; C, Habitus of paratype (BMNH 2006.118), dorsal view showing developing eggs within uterus; D, Habitus, ventral; E, Urosome of holotype female (MNHN-Cp 2317) in situ on metasome, ventral view showing surface ornamentation and clusters of caudal setae representing fully incorporated caudal rami; F, Fifth leg. Scale bars: A – D = 500 μm, E = 100 μm, F = 25 μm.