Pontocrates norvegicus ( Boeck, 1860 )

Myers, Alan A. & Ashelby, Christopher W., 2022, A revision of the genus Pontocrates Boeck, 1871 (Amphipoda, Oedicerotidae) with the description of P. moorei sp. nov. and the re-establishment of P. norvegicus (Boeck, 1860), Zootaxa 5115 (4), pp. 582-598 : 591-593

Pontocrates norvegicus ( Boeck, 1860)

( Fig. 6 )

Oediceros norvegicus Boeck, 1860 , 650.

Pontocrates norvegicus Boeck, 1871 , 171.— Boeck, 1876, 288, pl. 16, fig. 4.

Kroyera arenaria Reibisch, 1905 , 182, fig. 6–10 (in part).

Pontocrates arenarius Sars, 1895 , 693, suppl. Pl. 6, fig. 2, pl. 7 fig. 1.— Stebbing, 1906, p. 241.— Stephensen, 1926, 79.— Stephensen, 1928, 215, fig. 43.— Stephensen, 1929, 114, fig. 27.— Oldevig, 1933, 129, fig. 2.— Schellenberg, 1942, 179, fig. 48.— Gurjanova, 1951, 524, fig. 342.- Ledoyer, 1993, 604, figs 415, 416 (in part).

Type material. There is no material of Oediceros norvegicus Boeck in the Zoological Museum in Oslo from either Haugesund or Christianafjord, the two localities listed by Boeck (1871). No localities were given for the species in Boeck, 1860. One vial (F14274) contains two specimens from Farsund, Norway. The label in this vial has the handwriting of G.O. Sars, but is marked with a ‘B’ that denotes Boeck. It is not dated. Neither Boeck nor Sars list Farsund as a locality for Oediceros norvegicus or Pontocrates norvegicus . We therefore assume that the original type material is no longer extant.

Description (female, Christianafjord, based on Sars (1895), 7.0 mm)

Head Head rostrum short, strongly deflected, triangular in frontal view. Antenna 1 less than one third body length; peduncular articles 2 and 3 subequal; flagellum subequal in length with peduncle, with 9 articles, Antenna 2 only a little longer than antenna 1; flagellum with 11 articles.

Pereon. Gnathopod 1 coxa subrectangular, distal margin substraight; merus without distal extension; propodus subtriangular, 1.5 x as long as broad, palm moderately oblique, smooth, distinct from substraight posterior margin, without club-shaped robust setae. Gnathopod 2 coxa narrowing uniformly towards distal end; basis very elongate, slender, approximately parallel-sided; carpus small but with elongate spur that extends beyond tip of the propodus; propodus very elongate, slender, chelate. Pereopod 3 coxa distal margin sinuous, with posterodistal concavity; basis stout, less than 3 x as long as broad, posterior margin convex, anterior margin substraight; carpus and propodus short and stout, subequal in length; propodus subrectangular, distally truncate; dactylus distinct; anterodistal margin of merus and posterior margins of merus carpus and propodus and distal margin of propodus clothed in very long setae. Pereopod 5 basis anterior margin strongly convex; merus wedge-shaped with exceedingly long setae; carpus slender, posterior margin irregular, with long setae; propodus longer than carpus, slender, anterodistal margin with long setae; dactylus short less than one quarter length of propodus. Pereopod 6 similar to pereopod 5 but more elongate, propodus subequal in length with carpus. Pereopod 7 very long, more than half body length, basis posterior margin substraight.

Pleon. Epimera 1–3 rounded. Uropods 1–3 slender, peduncles extending about the same length. Uropod 1 peduncle much longer than subequal rami. Uropod 2 peduncle a little longer than subequal rami. Uropod 3 rami subequal with each other and with peduncle. Telson distally rounded, not incised.

Male (sexually dimorphic characters). Antenna 2 about three-quarters body length, peduncular articles 4 and 5 subequal, flagellum with about 60 articles.

Habitat. Recorded by Sars (1895) as occurring in 10 fathoms (18 m).

Remarks. This species was illustrated and described by Sars (1895) under the name Pontocrates norvegicus Boeck , but at the same time he incorrectly made P. arenarius (Spence Bate) a synonym. Pontocrates norvegicus differs from P. arenarius (Spence Bate) in having coxa 1 subrectangular (subtriangular in P. arenarius ), coxa 2 evenly narrowing distally (with posterodistal concavity in P. arenarius ); coxa 3 concave posterodistally, (evenly convex in P. arenarius ) and pereopod 5 basis posterior margin smooth (crenulated in P. arenarius ).

Ledoyer (1993) records P. arenarius from the Mediterranean, but his Figure 416 appears to include illustrations of both P. arenarius and P. norvegicus . The figures of the coxa of Pereopod 3 the basis of peropod 5 and the basis of pereopod 7 are those of P. norvegicus , while the figures of gnathopod 1 and gnathopod 2 are attributable to P. arenarius . It would appear therefore that both species occur in the Mediterranean.

Pontocrates norvegicus is apparently significantly larger than the other known species of the genus with the exception of P. altamarinus .

Figures

FIGURE 6. Pontocrates norvegicus (Boeck), Christianafjord, Norway, modified from Sars, 1895.