Oradarea dawa, Lowry & Myers, 2003

Lowry, J. K. & Myers, A. A., 2003, New Amphipod Crustaceans From The Indo-West Pacific (Amathillopsidae: Eusiridae: Iphimediidae), Raffles Bulletin of Zoology 51 (2), pp. 219-256 : 225-228

Oradarea dawa , new species

( Figs. 1 , 5-8 )

Material examined. – Holotype – female, 1.5 mm, AM P46998, off Ilôt Maitre , New Caledonia, 22 19.61’S 166 24.07’E, Padina - type alga, 10.5 m, ORSTOM divers, coll. Georges Bargibant, 14 Nov.1995, stn NCL-98.

Paratypes – sex unknown, 8 specimens, same station data; 4 specimens, AM P48370, Thio , New Caledonia, Halimeda from fringing reef, 1 m, coll. A. A. Myers, 20 Nov.1995, stn NCL-215 ; 10 specimens AM P46997, off Ilôt Maitre , New Caledonia, 22 19.61’S 166 24.07’E, Amansia , 10.5 m, ORSTOM divers, coll. Georges Bargibant, 14 Nov.1995, stn NCL-96 ; 3 specimens AM P46993, off Ilôt Maitre , New Caledonia, 22 19.61’S 166 24.07’E, coralline algal “reef”, 10.5 m, ORSTOM divers, coll. Georges Bargibant, 14 Nov.1995, stn NCL-99 ; 1 specimen AM P46991, off Ilôt Maitre , New Caledonia, 22 19.35’S 166 25.85’E, large hard coral block and coarse sand, some algae, 21 m, coll. J. K. Lowry, 10 Nov.1995, stn NCL-64 ; 1 specimen, AM P46999, Baie de St. Marie , New Caledonia, 22 18.05’S 166 28.13’E, thick coral rubble, 13 m, coll. J. K. Lowry, 29 Nov.1995, stn NCL-209 ; 1 specimen AM P46975, off Ilôt Maitre , New Caledonia, 22 20.57’S 166 25.43’E, red alga, 20 m, coll. I. Takeuchi, 7 Nov.1995, stn NCL-38 ; 10 specimens AM P46994, off Ilôt Maitre , New Caledonia, 22 19.61’S 166 24.07’E, Amansia glomerata , 10.5 m, coll. J. K. Lowry, 14 Nov.1995, stn NCL-94 .

Type locality. – Off Ilôt Maitre, New Caledonia.

Description. – Head laterocephalic lobes truncated, ventrolateral margin without spine; eye of medium size. Body without robust setae, without spines, without carina, with single, pleonites 1-2 with mid-dorsal processes; integumental scales present. Antenna 1 peduncle about as long as head; peduncular article 2 without sharp spines; accessory flagellum present, with 1 article. Mandible incisor transverse, broad, toothed, laminate; accessory setal row present; molar well developed, triturating; palp inserted medially, article 3 not exceptionally elongate. Labium outer lobes entire; inner lobes absent; mandibular processes long, subround distally. Maxilla 1 inner plate triangular, with setae along medial margin; palp not flabellate, well developed, 2-articulate, article 1 long. Maxilla 2 inner plate with oblique setal row. Maxilliped palp of moderate length, not strongly raptorial; palp 4-articulate, article 4 reduced; article 2 not produced.

Pereon. Gnathopod 1 dissimilar to gnathopod 2, shorter to gnathopod 2, subchelate, not flagellate; coxa directed ventrally, ventrally truncated; ischium elongate; carpus not lobate; propodus subrectangular. Gnathopod 2 subchelate; coxa similar in length to coxa 1, ventrally truncated; ischium elongate; carpus long; not lobate along posterior margin of propodus; propodus narrow, rectilinear. Pereopods 3–7 merus posteroventral lobe slightly projecting along carpus. Pereopod 3 coxa ventrally truncated. Pereopods 4–5 coxae not forming ventral crescentic curve. Pereopods 4-6 coxa without ventral points.

Pleon. Epimeron 3 without spines along posterior margin; posteroventral corner subquadrate. Telson emarginate, truncated, longer than broad, margins tapering distally, without dorsal robust setae.

Remarks. – Oradarea dawa does not appear to be very closely related to its nearest tropical congener, O. shoemakeri Pirlot from Sulawesi. That species has a very long article 1 of antenna 1, strong lateral carinae on pleonites 1-3 and epimeron three with two teeth. In having pleonites 1-2 with dorsal tooth and pereonite 7 non-dentate, O. dawa is most similar to O. bidentata and O. ocellata from the Antarctic. It differs from O. bidentata in its truncated head lobes, in the short article 1 of antenna 1, and in its distally truncated telson. It differs from O. ocellata in the much broader basis of pereopods 5-7, which also have a more serrated posterior margin. and in the strong acute posteroventral tooth on epimera 1-3. Both O. bidentata (11 mm) and O. ocellata (17 mm) are much larger than O. dawa .

Distribution. – New Caledonia.

Etymology. Named for the French research vessel Dawa, from which this species was collected.

Figures

Fig. 1. Oradarea dawa, new species, AM P64452: A, Pereopod 7 basis, showing scale patterns, scale bar = 30; B, Pereopod 7 basis, showing groups of scales with proximal insertion line and sockets where scales are missing, scale bar = 10. Iphimedia caledoniana, new species, AM P64453: C, Pereopod 7 basis, showing scale patterns, scale bar = 30; D, Pereopod 7 basis, close up showing groups of scales with proximal insertion line and sockets where scales are missing, scale bar = 10.

Fig. 5. Oradarea dawa, new species, female, 1.5 mm, AM P46998; off Ilôt Maitre, South-east Lagoon, New Caledonia.

Fig. 6. Oradarea dawa, new species, female, 1.5 mm, AM P46998; off Ilôt Maitre, South-east Lagoon, New Caledonia. Scale bar = 0.1mm.

Fig. 7. Oradarea dawa, new species, female, 1.5 mm, AM P46998; off Ilôt Maitre, South-east Lagoon, New Caledonia. Scale bar = 0.1mm.

Fig. 8. Oradarea dawa, new species, female, 1.5 mm, AM P46998; off Ilôt Maitre, South-east Lagoon, New Caledonia. Scale bar = 0.1mm.