Metopa cf. clypeata ( Krøyer, 1842 )

Krapp-Schickel, T., 2009, New and poorly described stenothoids (Crustacea, Amphipoda) from the Pacific Ocean., Memoirs of Museum Victoria 66 (1), pp. 95-116 : 116

Metopa cf. clypeata ( Krøyer, 1842)

Fig. 16

Leucothoe clypeata Krøyer 1842:157 ; 1845: 545 pl. 6, fig. 2a–f Metopa clypeata Tandberg & Vader 2009: 3 figs. 1–9, 19–21 (see here for elaborate synonymy)

Material examined:

• 42°N, 130° 30'E ( Japan Sea ), 16. 11.1881 Suensen coll., 8mm 1 es. alcohol. 1 slide, ZMUC CRU-20196 .

• 30° 50'N, 122° 40'E Japan, Nagasaki, Gutzloff & Schönau coll.: 21 specimens 6mm, 1 ad. 12mm. ZMUC CRU-20197 .

Remarks. It seems strange that the Atlantic species M. clypeata is found also on the Northern Pacific Coasts, but morphologically there is absolutely no difference to the meticulously redescribed type in Tandberg & Vader, 2009. As already mentioned in M. koreana , M. clypeata can become quite large (up to 15mm), has a more or less smooth, only shallowly waved or finely serrated palm on Gn 2 in both sexes with a 90° palmar corner, and robust, poorly spinose uropods and telson.

Gurjanova 1951:417 describes the species as follows:

„A1 longer than A2, Gn1 straight, article 4 expanded with wide hilly lobe, article 5 elongate and widening in the middle, distally narrowing, article 6 narrow, linear, shorter than article 5. Dactylus with 7–8 setae on ventral margin.

Gn2 with strong subchela; on surface of cup-shaped article 5 rows of small glistening humps, article 6 very big, 2x as long as article 5; distally somewhat widened. Palmar margin nearly horizontal with large tooth-shaped prolongation, in males near this tooth a deep sinus. In all peraeopods the inner margin of the dactylus with teeth.

U3 basal article with 5–6 short robust setae, 2 rami equal to length of outer margin of basal article (= peduncle).

Telson with 2 pairs of lateral spines. Length up to 12mm.

Geographical distribution: amphiboreal, known from western and eastern Groenland, Spitzbergen, bay of St. Lawrence, lives in hydroid colonies. Tschukots Sea, Bering, Ochotks, Japanese Sea. Data of Jsrzhinskij (1870) from the White Sea until now not confirmed.“

This species is not very commonly found, and at sites far apart: Tandberg & Vader 2009: Greenland (type locality), Bering Sea, Point Barrow, Alaska, Gulf of St. Lawrence in depths from 20 to 300m; older reports from Bohuslän ( Sweden), Banff ( Scotland), Christiansund(W-Norway) and Tromsø (N-Norway). Now also from the Pacific Ocean?.

Figures

Figure 16: Metopa cf. clypeata:?sex. 8mm, Japan Sea.