Sunamphitoe dampierensis, Peart, Rachael A., 2017

Peart, Rachael A., 2017, Analysis of the genus Sunamphitoe Spence Bate, 1857 (Amphipoda: Ampithoidae) with descriptions of eight new species, Zootaxa 4269 (3), pp. 301-345 : 315-320

Sunamphitoe dampierensis sp. nov.

( Figs 9–12 )

Type material. Holotype: male, 9 mm, WAM C70212, 2.7 m, from Sargassum sp., west side of Malus Island , Dampier Archipelago, Western Australia, Australia, 20°30.612’S 116°38.918’E, coll. R. Peart, 27 August 1999 . Paratypes: female, 10 mm, WAM C70213, 4 m, on Sargassum sp., south side of Kendrew Island , Dampier Archipelago, Western Australia, Australia, 20°28.987’S 116°32.549’E, coll. R. Peart, 30 August 1999 ; 1 specimen, AM P62575, 4 m, on Sargassum sp., south side of Kendrew Island , Dampier Archipelago, Western Australia, Australia, 20°28.987’S 116°32.549’E, coll. R. Peart, 30 August 1999 ; 6 specimens, WAM C70214, 2.7 m, on Sargassum sp., west side of Malus Island , Dampier Archipelago, Western Australia, Australia, 20°30.612’S 116°38.918’E, coll. R. Peart, 27 August 1999 .

Other material examined. Australia, Western Australia: 3 specimens (AM P62576), 2 specimens (AM P62577), 3 specimens ( WAM C70215), 2 specimens (AM P62579), 2–3 m, on Sargassum sp., west side of Malus Island, Dampier Archipelago , 20°30.612’S 116°38.918’E, coll. R. Peart, 27 August 1999 ; 1 specimen (AM P62580), sand, sponge and algae, Georgeff Reef, Dampier Archipelago , 20°29.243’S 116°36.974’E, coll. R. Peart, 29 August 1999 ; 2 specimens ( WAM 70216), 7 specimens (AM P62582), 0.5 m, on Sargassum oligocystum, Tish Point, Rosemary Island, Dampier Archipelago , 20°29.671’S 116°35.894’E, coll. R. Peart, 30 August 1999 ; 2 specimens (AM P62583), 4 specimens ( WAM C70217), 3 specimens (AM P62585), 4.4 m, on Sargassum sp., south side of Kendrew Island, Dampier Archipelago , 20°28.987’S 116°32.549’E, coll. R. Peart, 30 August 1999 .

Type locality. Malus Island, Dampier Archipelago, Western Australia, Australia.

Diagnosis. Antenna 2 slender, similar to but shorter than antenna 1. Mandible palp absent/ vestigial stump. Maxilla 1 inner plate with one slender seta. Maxilla 2 inner and outer plate narrow. Lower Lip outer plate notched, inner and outer plates of equal size. Gnathopod 2 carpus much shorter than propodus; propodus narrow; palm extremely acute, entire, with rounded tooth at base of dactylus, without posterodistal tooth defining palm, without defining robust setae; dactylus overreaching palm, inner margin smooth. Pereopod 5 distal articles slender. Uropod 3 peduncle with four distal robust setae; outer ramus without patch of small conical lateral denticles, with lateral setal fringe. Telson distally truncate, apical cusps small, with apical and lateral slender setae, no denticles.

Description. (Based on holotype male, 9 mm, WAM C70212, and paratype female, 10 mm, WAM C70213.)

Head as long as deep. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2 (1.1 ×); article 2 longer than article 3 (3.7 ×); article 3 shorter than article 1 (0.25 ×); primary flagellum with 33 articles. Antenna 2 not densely setose on ventral margin; peduncular article 4 longer than article 5; flagellum with eight articles. Mandible molar well developed, triturating; with eight robust setae in accessory setal row. Maxilla 1 palp well developed, with apical robust setae. Maxilliped outer plate with developed setation (robust setae large), reaching midlength of palp article 3; article 4 without setules.

Pereon. Gnathopod 1 smaller than gnathopod 2, with long, dense, plumose setae on margins; coxa not produced anteroventrally, anteroventral corner rounded, ventral margin with row of small setules and long tuft of slender setae in posteroventral corner; basis subequal to coxa, with sparse, plumose or simple, slender setae, anteroventral lobe small and rounded, with three slender setae along margin; merus produced to form small, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, subequal to propodus (0.9 ×), carpal lobe truncated, anterior margin with slender setae only; propodus narrow (length 1.6 × width), subrectangular; palm transverse, entire, without midmedial tooth, without posterodistal tooth defining palm, with one defining robust seta; dactylus overreaching palm, inner margin denticulate. Gnathopod 2 without densely setose margins; coxa ventral margin with row of small setules and with some of long slender setae; basis longer than coxa, with sparse slender setae, anteroventral lobe small and rounded, with two or three slender setae; merus produced to form long, subacute distoventral lobe, anterior margin with setae absent; carpus shorter than merus, subtriangular, anterior margin with slender setae only; propodus ovoid, not produced into anterodistally setose lobe; dactylus tapering evenly, acute, reaching beyond the propodus.

Pereopods 3–4 basis and merus expanded. Pereopods 5–7 simple. Pereopod 5 basis with marginal robust setae, without medial slender setae; merus subrectangular; propodus not expanded distally, subrectangular, with three distal simple striated robust setae; dactylus slightly curved.

Pleon. Epimeron 3 posteroventral corner narrowly rounded. Uropod 1, in situ, reaching rami of uropod 2; peduncle with more than five robust setae, and with long setal fringe; inner ramus slightly longer than outer ramus, with three to five marginal robust setae, slender setae absent; outer ramus with more than five marginal robust setae, slender setae absent. Uropod 2 peduncle with more than five robust setae, setal fringe absent; inner ramus slightly longer than outer ramus, with more than five marginal robust setae, slender setae absent; outer ramus with more than five marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (1.4 × width), long with respect to rami length (2.2 ×), marginal robust setae absent, marginal slender setae present, with more than five distal slender setae; rami broad; outer ramus shorter than inner ramus; inner ramus with three distal robust setae, with more than five distal slender setae.

Female. Antenna 1 peduncular article 1 longer than article 2 (1.3 ×), article 2 longer than article 3 (2.8 ×), article 3 shorter than article 1 (0.3 ×); primary flagellum with 20 articles. Antenna 2 flagellum with 13 articles. Gnathopod 1 subequal in size to gnathopod 2, not densely setose on margins; basis posterodistal lobe with one slender seta. Gnathopod 2 basis anteroventral lobe reduced, with one slender seta; merus produced to form small, rounded distoventral lobe; carpus longer than merus, subequal in length to propodus; propodus subrectangular; palm transverse, without midmedial tooth, defined by one robust seta; dactylus inner margin denticulate.

Etymology. Named after the type locality, the Dampier Archipelago.

Remarks. Sunamphitoe dampierensis sp. nov. is similar to species from a group from the north Pacific Ocean, particularly Korea ( Fig. 1 , clade 19), which share the dactylus of gnathopod 2 greatly overreaching the palm of the propodus. Sunamphitoe dampierensis differs from these species by having the lobes of the lower lip outer plate of even size (rather than the outer longer) and the setation of uropod 3 rami and peduncle differs.

Habitat. Sunamphitoe dampierensis sp. nov. occurs on Sargassum sp. at 2–5 m depth.

Distribution. Dampier Archipelago, Western Australia, Australia.

Figures

FIGURE 1. One of fifteen most parsimonious trees (length 335 steps, consistency index 0.248, retention index 0.440). Clade numbers correspond to character state reconstructions listed in Appendix C. (p) indicates former placement in Peramphithoe. * indicates species described in this paper.

FIGURE 9. Sunamphitoe dampierensis sp. nov., holotype male, 9 mm, WAM C 70212 and paratype, female 10 mm, WAM C 70213, Malus Island, Dampier Archipelago, Western Australia, Australia.

FIGURE 10. Sunamphitoe dampierensis sp. nov., holotype male, 9 mm, WAM C 70212, and paratype female, 10 mm, WAM C 70213, Malus Island, Dampier Archipelago, Western Australia, Australia. Scales 0.5 mm for antennae 1 – 2 and 0.2 mm for mouthparts.

FIGURE 11. Sunamphitoe dampierensis sp. nov., holotype male, 9 mm, WAM C 70212, and paratype female, 10 mm, WAM C 70213, Malus Island, Dampier Archipelago, Western Australia, Australia. Scales 0.5 mm.

FIGURE 12. Sunamphitoe dampierensis sp. nov., holotype male, 9 mm, WAM C 70212, and paratype female, 10 mm, WAM C 70213, Malus Island, Dampier Archipelago, Western Australia, Australia. Scales 0.5 mm for pereopods 3 – 5 and 0.2 mm for uropods 1 – 3 and telson.