Harpinia laevis Sars 1891

Harpinia laevis

(figures 7–9)

Harpinia laevis Sars, 1895: 161, pl. 56; Stebbing, 1906: 145; Stephensen, 1942: 156; Lincoln, 1979: 378, figures 175g, 179a–e.

Material examined

Norway: Risør (ZMO F13235). Ireland: North West Mayo (NMI 22 1998): Station Z 1FA (54°20∞ 52.5N, 11°03∞ 28.44W), 355 m, fine sand; Station Z 12FC (54°20∞ 19.93N, 11°03∞ 40.68W), 347 m, fine silty sand; Station Z 8FA (54°19∞ 47.86N, 11°03∞ 25.20W), 343 m, fine sand (W); Station Z 2FB (54°20∞ 36.35N, 11°03∞ 27.65W), 351 m, fine sand.

Type locality Coast of Norway.

Description

Female. Size: up to 4 mm. Described and illustrated by Sars (1895) and later by Lincoln (1979) from Norwegian specimens.

Male (sexually dimorphic characters). Size: up to 3 mm. Head without spine on dorsolateral margins. Antenna 1 with tuft of long, fine setae on peduncular article 3 and flagellar article 1, article 1 of flagellum elongate, flagellum with five articles, accessory flagellum with four articles. Antenna 2 with small tuft of fine short setae on peduncular article 4. Coxa 1–3 without spines, flagellum with six articles. Gnathopods 1 and 2 with an elongate, narrow propodus, gnathopod 1 with robust seta defining palm. Pereopod 7 basis with six to seven indistinct spines, each with small associated marginal seta. Urosomites narrow, urosomal segment 2 with dorsal elevation anterior to insertion of telson. Epimeron 3 posterodistal corner with excavated notch and small spine. Uropod 3 rami elongate, outer ramus article 2 longer than half length of article 1, without apical seta, inner ramus almost as long as article 1 of outer ramus, without apical seta.

Distribution North-East Atlantic: Norway to north-west Ireland.

Discussion

This is not a commonly collected species. Females are similar to H. crenulata and H. truncata with the rounded epimeron 3 and lack of spines on coxae 1–3. Harpinia laevis females are distinguished by the relatively smooth, rounded basis of pereopod 7 which lack long marginal setae.

The males can be readily identified from those of H. pectinata and H. antennaria by the broadly rounded epimeron 3 (a small notch/spine is present but can be difficult to see). Harpinia laevis males are separated from those of H. crenulata by the shape of the basis of pereopod 7 and the inner ramus of uropod 3, which is almost as long as article 1 of outer ramus and has a long apical seta. The male of H. truncata is undescribed and while it may be similar to H. laevis, the characteristics of the H. truncata female are insufficient to hypothesize the form of the male for comparison.