Parelasmopus aumogo, Hughes, 2011

HUGHES, L. E., 2011, New species of Hoho, Mallacoota and Parelasmopus (Maeridae: Amphipoda) from Australian waters, Zootaxa 2955 (1), pp. 1-79 : 68-71

Parelasmopus aumogo sp. nov.

(Figs 44, 45)

Type material. Holotype, male, 10.5 mm, dissected, 4 slides, AM P.85232 . Paratypes: female, 6.8 mm, dissected, 1 slide, AM P.85233; 2 males, 4 females, AM P.81475, Emily Bay (29°03'36"S 167°57'12"E), 3 m, rubble encrusted in algae, 20 May 2008, coll. J.K. Lowry, MV Jenny (MI NFK 89 ) .

Additional material examined. 1 male, 3 females, AM P.81480, Swiss Cheese Reef , near Kingston wharf (29°00'22"S 167°56'50"E), 16.6 m, coral rubble, airlift on scuba, 15 May 2008, coll. R. T . Springthorpe , MV Jenny (MI NFK 36 ) ; 1 male, AM P.81470, Fig Valley Reef (29°03'20"S 167°55'44"E), 18.5 m, coral rubble with algal tufts and sediment, airlift on scuba, 19 May 2008, coll. R. T . Springthorpe , MV Jenny (MI NFK 67 ) ; 1 male, 3 female, AM P.81478, Gun Club Reef , near Anson Point (29°00'25"S 167°54'45"E), 14.6 m, coral rubble on sand, airlift on scuba, 17 May 2008, coll. R. T . Springthorpe , MV Jenny (MI NFK 62 ) ; 1 male, AM P.81479, Duncombe Bay (29°03'30"S 167°57'13"E), 16 m, coral rubble, airlift on scuba, 13 May 2008, coll. R. T . Springthorpe , MV Jenny (MI NFK 19 ) ; 1 male, 3 female, AM P.81477, ' The Wall' dive site, Nepean Island (29°04'18"S 167°57'41"E), 16.5 m, brown algae, 15 May 2008, coll. L.E. Hughes, MV Jenny (MI NFK 46 ) ; 1 male, AM P.81476, Cow Bay ,

Type locality. Emily Bay , Norfolk Island, Tasman Sea (29°03'36"S 167°57'12"E) .

Etymology. Aumogo is Polynesian for toothed small comb, in reference to the short robust setae along the palm of the male gnathopod two.

Description. Based on holotype male, 10.5 mm, AM P.85232.

Head. Eyes ovate; lateral cephalic lobe broad, truncated, anteroventral margin with notch/slit. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, without robust setae along posterior margin; article 2 longer than article 3; flagellum articles broader than long, with 10+ articles; accessory flagellum minute, with 4 articles. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; article 4 subequal in length to article 5; flagellum with 9 articles. Maxilla 1 inner plate subtriangular, with 2 apical plumose setae. Lower lip outer lobes with two pair of ducts, mandibular lobes apically subacute. Mandible accessory setal row well developed with 4 setae; molar well developed, triturative; mandibular palp well developed, 3-articulate; article 1 distally swollen, four times as long as broad, longer than article 2; article 2 shorter than article 3, without setae; article 3 rectolinear, long (5 times as long as broad), subequal to article 1, with 2 apical setae.

Pereon. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, rounded, posteroventral corner notched; carpus about twice as long as broad, subequal in length to propodus; propodus medial surface with comb, palm acute, convex, entire, defined by posterodistal corner, with 1 robust setae. Gnathopod 2 subchelate; coxa posteroventral corner notched; basis slender, anterodistal corner subquadrate; merus acutely produced distoventrally; carpus compressed, lobate, projecting between merus and propodus; propodus expanded, with slen- der medial setal bunch, palm acute, convex, smooth, subrectangular distomedial shelf, with 5 robust setae on shelf, palmar margin lined with a row of robust setae, without teeth, subpalmar surface with rounded nodules, without posterodistal robust setae; dactylus with posteroproximal shelf, apically falcate, closing along palm. Pereopod 4 coxa posteroventral lobe well developed, with subrectangular posteromedial corner. Pereopods 5–7 basis slightly expanded, posterior margin weakly crenulate, without long slender setae; merus and carpus not broadened; carpus and propodus without, slender setae along posterior margin; propodus not expanded posterodistally; dactylar ungues simple. Pereopods 5–6 basis posterior margin straight, posteroventral corner subquadrate. Pereopod 7 basis posterior margin convex, posteroventral corner broadly rounded. Pereonite 7 without carina.

Pleon. Pleonites 1–3 without carina. Epimera 1–2 posteroventral corner with small acute tooth. Epimeron 3 ventral margin smooth, posteroventral margin smooth, posteroventral corner with strongly produced acute tooth. Urosomite 1 bicarinate, subtriangular. Urosomites 2–3 without carina. Uropod 1 peduncle with 1 basofacial robust seta; outer ramus slightly shorter than inner ramus. Uropod 2 outer ramus slightly shorter than inner ramus. Uropod 3 rami distally subacute, apical robust setae long; inner ramus long, (length 2.4 times breadth), subequal in length to outer ramus; outer ramus longer than peduncle. Telson deeply cleft, as long as broad, tapering distally, lobes truncated with short inner and long outer apical cusps, apical conical extension reaching at least halfway along longest seta, 3 long and 4 short apical robust setae.

Female (sexually dimorphic characters), based on AM P.85233. Gnathopod 2 carpus short, not lobate, enclosed by merus and propodus; propodus linear, with slender setae along posterior margin, palm about one third length of propodus, without distomedial shelf, palmar without teeth, margin lined with a row of robust setae, defined by posteroventral corner, with 3 posterodistal robust setae; dactylus without posteroproximal shelf.

Remarks. Parelasmopus aumogo sp. nov. is closely related to P. mallacootaformis described from nearby New Caledonia. Both species have a weakly expanded gnathopod 2 propodus palm acute with dense medial setal bunch, pereopods 5–7 posterior margins of the basis weakly serrate and telson with similar apical robust setal arrangement.

Parelasmopus aumogo sp. nov. can be distinguished from P. mallacootaformis by the gnathopod 2 palmar margin lined with a row of robust setae and subpalmar surface with rounded nodules. These fine scale characters are best observed as a slide mount. In P. aumogo sp. nov. the epimeron 2 posterior distal corner has a small acute tooth and epimeron 3 is produced acute. This further separates P. aumogo sp. nov. from P. mallacootaformis where epimera 2 posterior distal corner has a well developed acute tooth and epimeron 3 is produced acute with minutely serrate ventral and posterior margins.

Distribution. Australia. Norfolk Island, Nepean Island, Philip Island (current study).