Mallacoota kunmunyah, Hughes, 2011

HUGHES, L. E., 2011, New species of Hoho, Mallacoota and Parelasmopus (Maeridae: Amphipoda) from Australian waters, Zootaxa 2955 (1), pp. 1-79 : 45-51

Mallacoota kunmunyah sp. nov.

(Figs 26–30)

Type material. Holoytpe male, 6.2 mm, dissected, 3 slides, NTM CR16975 . Paratypes: gravid female (female masculine phenotype), 9.5 mm, dissected, 4 slides, NTM CR011689; 1 gravid female (female diminutive phenotype), 6.0 mm, dissected, 1 slide, NTM CR16977 ; 1 female (masculine phenotype), dissected, 1 slide, NTM CR16976 , 4 nautical miles east of Blaze Reef, Fog Bay, Beagle Gulf , Northern Territory (12º51”57’S 130º14”5’E), mud and shale, 7 m, 4 October 1993, coll. R. S. Williams (Beagle Gulf Marine Park Survey) .

Additional material examined. Northern Territory. 1 specimen, NTM Cr 16978, 6 nm north-east of Cape Ford, Anson Bay , Beagle Gulf , (13°25.02’S 129°55.98E), fine sandy mud, 16 m, 1 October 1993, coll. R. S. Williams (Beagle Gulf Marine Park Survey) . Western Australia. 1 male, 6.5 mm, dissected, 3 slides, AM P.85215, inside lines, Cygnet Bay Pearl Farm, Cygnet Bay , Cape Leveque (16°28'50"S 123°02'16"E), 2 m, epiphytic growth from pearl shell panels, 23 May 2010, coll. J.K. Lowry and K.B. Attwood ( MIWA 1095 ) ; 10 males (without oostegites), AM P.83911, inside lines, Cygnet Bay Pearl Farm Cygnet Bay, Cape Leveque (16°28'50"S 123°02'16"E), 2

m, epiphytic growth from pearl shell panels, 23 May 2010, coll. J.K. Lowry & K.B. Attwood ( MIWA 1095 ); 25+ males (without oostegites), AM P.83910, outside lines, Cygnet Bay Pearl Farm Cygnet Bay , Cape Leveque (16°28'50"S 123°02'16"E), 2 m, epiphytic growth from pearl shell panels, 23 May 2010, coll. J.K. Lowry & K.B. Attwood ( MIWA 1095 ); 1 males, AM P.85216, near Mistaken Island , Vancouver Peninsula, King George Sound

(35°04'S 117°56'E), 6 m, segrasses, 13 December 1983, coll. R. T. Springthorpe (WA 121); 1 male specimen, AM P.79391, West Island , south-east of Hopetoun (33°57'S 120°07'E) , 15 m, on algae, 12 May 1973, coll. S. Shepherd (WA 5).

Type locality. 4 nautical miles east of Blaze Reef, Fog Bay, Beagle Gulf , Northern Territory (12º51”57’S 130º14”5’E).

Etymology. Name after the fisheries vessel Kunmunyah, used as a noun in apposition.

Description. Based on male holotype, 6.2 mm, NTM CR016975.

Head. Eyes ovate; lateral cephalic lobe broad, truncated, anteroventral margin with notch/slit. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, without robust setae along posterior margin; article 2 longer than article 3; flagellum articles longer than broad, with 25 articles; accessory flagellum minute, with 3 articles. Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; article 4 length than article 5; flagellum with 9 articles. Maxilla 1 inner plate subtriangular, with 2 apical plumose setae. Lower lip outer lobes with single pair of ducts, mandibular lobes apically rounded. Mandible accessory setal row well developed with 3 setae; molar well developed, triturative; mandibular palp well developed, 3-articulate; article 1 twice as long as broad, shorter than article 2; article 2 subequal to article 3, with 2 slender setae; article 3 rectolinear, long (5 times as long as broad), longer than article 1, with 2 medial and 2 apical setae.

Pereon. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, rounded; carpus about twice as long as broad, carpus shorter than propodus; propodus medial surface with comb, palm acute, convex, entire, defined by posterodistal corner, with 4 robust setae. Gnathopod 2 subchelate; basis slender, anterodistal lobes well developed paired; merus with rounded distoventral corner; carpus compressed, lobate, projecting between merus and propodus; propodus massive, with proximal dense setal bunch (not extending past the mid posteroventral tooth and 4 posterodistal robust setae, subpalmar surface smooth; dactylus without posteroproximal shelf, apically subacute, closing along palm. Pereopod 4 coxa posteroventral lobe well developed, with subrectangular posteromedial corner. Pereopods 5–7 basis slightly expanded, posterior margin castelloserrate, without long slender setae; merus and carpus not broadened; carpus and propodus with few long, slender setae along posterior margin; propodus not expanded posterodistally; dactylar ungues simple. Pereopods 5–6 basis linear, posterior margin straight, posteroventral corner broadly rounded. Pereopod 7 basis posterior margin convex, posteroventral corner broadly rounded. Pereonite 7 without carina.

Pleon. Pleonites 1–3 without carina. Epimeron 1 posteroventral corner with small acute tooth. Epimeron 2 posteroventral corner produced acute. Epimeron 3 ventral margin smooth, posteroventral margin smooth, posteroventral corner produced acute. Urosomite 1 bicarinate, subtriangular. Urosomites 2–3 without carina. Uropod 1 peduncle with 1 basofacial 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 2.2 times breadth), subequal in length to outer ramus; outer ramus longer than peduncle. Telson deeply cleft, as long as broad, long, tapering distally, with short inner and long outer apical cusps, apical conical extension reaching at least halfway along longest seta, each lobe with 3 long and 1 short apical robust setae.

Female, masculine phenotype. (sexually dimorphic characters), based on NTM CR011689. Gnathopod 2 propodus without dense medial setal bunch, palm defined by posteroventral corner with 4 robust setae.

Female, diminutive phenotype. (sexually dimorphic characters), based on NTM CR16977. Gnathopod 2 basis anterodistal corner subquadrate; carpus short, not lobate, enclosed by merus and propodus; propodus linear, palm acute, smooth, about one third length of propodus, without distomedial shelf, without teeth, defined by posteroventral corner with 1 robust setae; dactylus apically subacute.

Remarks. Mallacoota kunmunyah sp. nov. has the male gnathopod 2 convex palm without a distomedial shelf similar to that of M. diemenensis . Several characters including the male gnathopod 2 palm defining tooth and lack of dorsal bicariantions separate M. kunmunyah sp. nov. from M. diemenensis . The palm defining tooth in conjuction with the absence of other palmar structures, readily separate M. kunmunyah sp. nov. from other Australian Mallacoota species.

Mallacoota kunmunyah sp. nov. has male and female individuals with similar enlarged gnathopod 2, as well as females which display the more typical diminutive gnathopod form. Both females phenotypes show pereopods 5 to 7 basis posterior margin castelloserrate and telsonic with large outer apicies and four long and one short robust setae, which link them morphologically to the male specimen.

Material from Cygnet Bay collections included only male individuals.

Distribution. Northern Territory: Beagle Gulf (current study). Western Australia: Cygnet Bay, Cape Leveque; Vancouver Peninsula, King George Sound; West Island, Hopetoun (current study).