Ampithoe pseudongana, Peart, 2007

Peart, Rachael A., 2007, A review of the Australian species of Ampithoe Leach, 1814 (Crustacea: Amphipoda: Ampithoidae) with descriptions of seventeen new species, Zootaxa 1566 (1), pp. 1-95 : 69-74

Ampithoe pseudongana sp. nov.

( Figs 54–57 )

Type material. Holotype: WAM C38540, male, 9 mm, Shelley Beach, Bunker Bay, near Cape Naturaliste , S of Bussleton, WA, 33°32.56’S 115°01.79’E, 4 Dec 2000, 0.5 m, from mixed brown algae (mainly Sargassum sp. ), R. A. Peart . Paratypes: WAM C38541, female, 10 mm, type locality ; AM P61877, 15 specimens, type locality ; AM P61875–P61876, 4 specimens, Shelley Beach, Bunker Bay , near Cape Naturaliste, S of Bussleton, WA, 33°32.56’S 115°01.79’E, 4 Dec 2000, 0.5 m , R. Peart; AM P61878–P61880, 8 specimens, from seagrass, Eagle Beach, near Cape Naturaliste, SW of Bussleton , WA, 33°33.69’S 115°03.90’E, 5 Dec 2000, 0.5 m , R. Peart; AM P61881–P61884, 25 specimens, Canal Rocks, south of Yallingup, WA, 33°40.28’S 114°59.67’E, 6 Dec 2000, 0.5 m , from Sargassum sp. , R. Peart.

Diagnosis. Antenna 2 robust, better developed than antenna 1, with short, dense setae on ventral margin. Lower lip with lateral lobe longer than medial lobe. Maxilla 1 inner plate with three slender setae. Gnathopod 1 carpal lobe subacute; carpus shorter than propodus; palm excavate, without midmedial tooth, with a posterodistal tooth defining palm; dactylus subequal in length to palm. Gnathopod 2 without densely setose margins; basis posterodistal lobe large and rounded, with more than 3 slender setae; carpus shorter than propodus; palm acute, entire, with a rounded midmedial tooth, with a small subacute posterodistal tooth defining palm, with 1 defining robust seta; dactylus subequal in length to palm. Pereopod 3 basis narrow; merus expanded. Pereopods 5–7 weakly prehensile. Pereopod 5 merus subrectangular. Uropod 3 peduncle with 10 distal robust setae, outer ramus shorter than inner ramus, with patch of small conical lateral denticles, without lateral setal fringe; inner ramus with 7 distal robust setae. Telson distally rounded, apical cusps small.

Description. Based on holotype, male, 9 mm, WAM C38540. Head as long as deep. Antenna 2 peduncular article 4 longer than article 5; flagellum 14-articulate. Mandible molar with 4 or 5 robust setae in accessory setal row; palp stout, long, apically setose, article 1 shorter than article 2 (0.32 x), article 2 longer than article 3 (1.3 x), article 3 longer than article 1 (2.38 x). Lower lip mandibular lobe with curved margins, rounded apically. Maxilla 1 palp with apical robust setae. Maxilla 2 inner plate narrow, outer plate broader. Maxilliped outer plate with developed setation (robust setae large).

Pereon. Gnathopod 1 coxa subequal to gnathopod 2 coxa, produced distoventrally, distoventral margin rounded, anterior margin concave, ventral margin with a row of small setules; basis subequal to coxa, with sparse (sometimes plumose) slender setae, posterodistal lobe reduced, 2 or 3 slender setae; merus produced to form a small, acute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with 1 robust seta and slender setae; propodus narrow (length 1.66 x width), subrectangular; palm with 1 defining robust seta; dactylus inner margin denticulate. Gnathopod 2 coxa ventral margin with a row of small setules; basis shorter than coxa, with fringe of long, slender, plumose setae; merus produced to form a short, subacute distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, anterior margin with slender setae only; propodus broad (length 0.97 x width), subtriangular, not produced into an anterodistally setose lobe; dactylus tapering evenly, acute, inner margin denticulate. Pereopod 5 basis with marginal robust setae, with medial slender setae; distal articles slender; propodus slightly expanded distally, subrectangular, with 3 distal simple striated robust setae; dactylus strongly curved. Pereopod 6 basis posterior margin rounded proximally, straight distally, with marginal robust setae, without medial slender setae; merus subrectangular; propodus slightly expanded distally, with 3 distal simple striated robust setae; dactylus strongly curved. Pereopod 7 basis with marginal robust setae, with medial slender setae; propodus defined distally by 3–5 simple robust setae.

Pleon. Epimeron 3 posteroventral corner broadly rounded. Uropod 1 peduncle with more than 5 robust setae, with a long setal fringe; inner ramus slightly shorter than outer ramus, with more than 5 marginal robust setae, slender setae absent; outer ramus with 3–5 marginal robust setae, slender setae absent. Uropod 2 peduncle with more than 5 robust setae, setal fringe absent; inner ramus slightly shorter than outer ramus, with more than 5 marginal robust setae, slender setae absent; outer ramus with 3–5 marginal robust setae, slender setae absent. Uropod 3 peduncle longer than broad (1.37 x width), short with respect to the rami length (1.94 x), with marginal robust setae absent, marginal slender setae absent, with more than 5 distal slender setae; inner ramus with more than 5 distal slender setae. Telson with apical and lateral slender setae.

Female. (sexually dimorphic characters). Based on paratype, 10 mm, WAM C38541. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2 (1.31 x), article 2 longer than article 3 (3.3 x), article 3 shorter than article 1 (0.23 x); primary flagellum with 14 articles; accessory flagellum absent. Antenna 2 with sparse setae on ventral margin; flagellum with 22 articles. Gnathopod 1 subequal in size to gnathopod 2, not densely setose on margins; basis shorter than coxa, with fringe of long, slender, plumose setae, posterodistal lobe small and round; merus produced to form a short, rounded distoventral lobe; carpus anterior margin with slender setae only; propodus ovoid; palm convex, without posterodistal tooth defining the palm. Gnathopod 2 basis with sparse (sometimes plumose) slender setae, posterodistal lobe small and round; propodus ovoid; palm without a midmedial tooth.

Etymology. This species is very similar to A. ngana Poore & Lowry, 1997 , from the east coast of Australia, the species name alludes to this similarity.

Remarks. Ampithoe pseudongana sp. nov. is similar to A. ngana , A. eremitis sp. nov., A. hiana sp. nov. and A. peronana sp. nov., but is closest in morphology to A. hiana . Characters distinguishing A. pseudongana from A. hiana are outlined under the account of the latter.

Habitat. Brown algae: Cystophora sp. , Sargassum sp.

Distribution. Cape Naturaliste, Western Australia, Australia.

Figures

FIGURE 54. Ampithoe pseudongana sp. nov., holotype, male, WAM C38540, 9 mm. Paratype, female, WAM C 38541, 10 mm. Bussleton, Western Australia, Australia.

FIGURE 55. Ampithoe pseudongana sp. nov., holotype, male, WAM C38540, 9 mm. Paratype, female, WAM C 38541, 10 mm. Bussleton, Western Australia, Australia. Scales represent 0.5 mm for antennae 1–2 and 0.2 mm for mouthparts. Male antenna 1 missing.

FIGURE 56. Ampithoe pseudongana sp. nov., holotype, male, WAM C38540, 9 mm. Paratype, female, WAM C 38541, 10 mm. Bussleton, Western Australia, Australia. Scales represent 0.5 mm.

FIGURE 57. Ampithoe pseudongana sp. nov., holotype, male, WAM C38540, 9 mm. Bussleton, Western Australia, Australia. Scales represent 0.5 mm for pereopods 3–7 and 0.2 mm for uropods 1–3 and telson. Pereopod 4 identical to pereopod 3.