Harpinia crenulata Boeck

King, Rachael A., Myers, Alan A. & McGrath, David, 2004, A review of shallow-water Irish and British Harpinia Boeck (Crustacea: Amphipoda: Phoxocephalidae) species including the first detailed descriptions of the males of Harpinia laevis Sars and Harpinia pectinata Sars, Journal of Natural History 38 (10), pp. 1263-1286 : 1269-1273

Harpinia crenulata Boeck

(figures 4–6)

Harpina crenulata Boeck, 1871: 136 .

Harpinia crenulata Boeck, 1876: 221 , pl. 8, figure 2; Sars, 1895: 158, pl. 55, figure 2; Chevreux, 1900: 36; Walker, 1901: 300; Chevreux, 1902: 693; Stebbing, 1906: 141; Chevreux, 1911: 189, pl. 10, figures 14, 15; Chevreux and Fage, 1925: 110, figure 105; Stephensen, 1942: 152–153; Ruffo, 1946: 50; Ledoyer, 1968: 191; Febvre-Chevalier, 1969: 471; Carpine, 1970: 134; Karaman, 1973: 53, figures 4–6; Ledoyer, 1977: 402; Lincoln, 1979: 376, figures 175h, 178a–i; Karaman, 1993: 645–646, figures 442, 443.

Material examined

Norway: Risør ( ZMO F13235) (W); Raunefjorden , 120 m (NHM 1986.718.37) . France: Cannes (Walker Collection, NHM 1925.9.8.310-311). England: Turnaware Point , Cornwall 50°12.4∞N, 5°2.5∞W, 10 m (NHM 1986.745.2) .

Type locality North-East Atlantic.

Description

Female. Size: 4 mm. Has been comprehensively described and illustrated by Sars (1895) and later by Karaman (1993). All specimens agree with both descriptions.

Male (sexually dimorphic characters). Size: up to 3.5 mm. Antenna 1 with tufts of fine, long setae on peduncular article 3 and article 1 of flagellum, article 1 of flagellum elongate, flagellum with five articles, accessory flagellum with four articles. Antenna 2 with tufts of fine, long setae on peduncular articles 3–4, flagellum with four articles. Coxa 1–3 without spines. Gnathopods 1 and 2 with propodus only slightly longer and narrower than female, gnathopod 1 with robust seta defining palm. Pereopod 7 basis with seven to eight indistinct spines, each with associated short seta. Epimeron 3 posteroventral corner round with very small excavated notch with associated seta. Pleonites without dorsal setae. Urosome elongate, narrow, with dorsal elevation anterior to telson insertion. Uropod 3 elongate, outer ramus article 2 longer than half length of article 1, without long apical seta, inner ramus three-quarters length of outer ramus article 1, without long apical seta.

Distribution

North Atlantic Ocean: Norway, Iceland and Greenland to French coast, Western Mediterranean Sea.

Discussion

The lack of a distinct posterodistal spine on epimeron 3 unites H. crenulata , H. laevis and H. truncata . For females, H. crenulata can be identified from these two species by the basis of pereopod 7 which has many small marginal spines with long setae, the notched epimeron 3 and the short inner ramus of uropod 3. Males of H. crenulata are most similar to H. laevis given the morphology of gnathopods 1 and 2, in which the propodus is not as narrow as in H. antennaria and H. pectinata , and possesses a robust seta on gnathopod 1. Antenna 1 peduncular articles 3 and 4 are also relatively bare of tufts of setae in these species (present in H. antennaria and H. pectinata ). Males of H. crenulata can be distinguished by the rounded epimeron 3 with excavated notch, the basis of pereopod 7, which has few very small marginal spines and the short inner ramus of uropod 3.

There are some differences between the male illustrated here and that of Sars (1895). Sars illustrated the male with a long uropod 3 inner ramus (exceeding article 1), whereas the males examined (from Norway) here all have a short inner ramus (three-quarters length of article 1). The females of H. crenulata have a short inner ramus (in agreement with Sars) and this rami length ratio seems to be conserved between the sexes of the material examined. It could be possible that this is an age/size-class related variable character.

The variation in the amount of crenulation of epimeron 3 noted by Sars (1895) has also been found in the material examined here (figure 4B, C).