Quadrimaera brownorum, Hughes, Lauren E., 2015

Hughes, Lauren E., 2015, Maeridae from the Indo-Pacific: Elasmopus, Leeuwinella gen. nov., Maeropsis, Pseudelasmopus and Quadrimaera (Amphipoda: Crustacea), Zootaxa 4059 (2), pp. 201-256 : 230-232

Quadrimaera brownorum sp. nov.

( Figs 29–32 )

Type material. Holotype male, 4.5 mm, dissected, 3 slides, AM P.92677, Cape Leveque , Cygnet Bay, Western Australia, 16°28'40"S, 123°02'06"E, hand collected on snorkel, 10 April 2008, coll. J. Jelbart, MI WA 1068.

Paratypes: 1 female, 4.5 mm, dissected, 3 slides, AM P.92790Cape Leveque , Cygnet Bay, Western Australia, 16°28'40"S, 123°02'06"E, hand collected on snorkel, 10 April 2008, coll. J. Jelbart, MI WA 1068; 12 specimens, AM P.80976, Cape Leveque , Cygnet Bay, Western Australia, 16°28'40"S, 123°02'06"E, hand collected on snorkel, 10 April 2008, coll. J. Jelbart, MI WA 1068.

Type locality. Cape Leveque , Cygnet Bay, Western Australia 1628'40"S, 12302'06"E.

Etymology. Named in honor of the Brown family, owners of the Cygnet Bay Pearl Farm, whose gracious support made collecting in Cape Leveque possible.

Description. Of holotype male, 4.5 mm AM P.92677.

Head. Eyes round; lateral cephalic lobe broad, apically truncate, anteroventral margin with excavate, anteroventral corner acute. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, with 1 long distal slender robust setae on posterior margin; peduncular article 2 longer than article 3; flagellum articles as long as broad, or broader than long, with 13 articles; accessory flagellum long, more than half length of primary flagellum, with 6 articles. Antenna 2 peduncular article 4 longer than article 5; flagellum with 8 articles. Mandible accessory setal row, well developed with 4 setae; palp well developed, article 1 length 1.9 × width, shorter than article 2, inner margin weakly produced rounded; article 2 length 0.9 × article 3, lined with long slender setae; article 3 rectilinear, long, 2.5 × as long as broad, longer than article 1, with 3 lateral and 3 apical slender setae.

Pereon. Gnathopod 1 coxa anterior margin straight, anteroventral corner subquadrate, not produced, ventral margin without robust setae, posteroventral corner without notch; basis anterodistal corner without lobes; ischium anterodistal corner without lobes; merus with posteroventral corner subquadrate; carpus length twice width, 1.5 × propodus length, posterior margin lined with long setae, with rows of setae covering medial surface; propodus subovate, medial surface setal comb absent, palm subacute, weakly convex, entire, lined with slender setae, defined by posterodistal corner with 1 robust seta; dactylus closing along palm, unguis present. Gnathopod 2 subchelate; coxa posteroventral corner without notch, ventral margin without robust setae; basis broad, anterodistal corner lateral margin with well-developed lobe; ischium anterodistal corner without lobe; merus with subquadrate posteroventral corner; carpus compressed, length 0.6 × width, anterior margin with 1 robust seta, posterior margin with a few slender setae; propodus quadrate, length 1.1 × width, posterior margin with a few slender setae, palm length one third of propodus posterior margin, angle transverse, distal shelf subquadrate with 4 pairs of robust setae, palm with rounded medial excavation and subacute projection margin lined with robust setae, palm defined by posteroventral corner (90° angle, large subacute tooth and 1 robust seta; dactylus broad, falcate, posterior margin with medial sinus, reach end of and closing along palm. Pereopods 3–4 coxa subquadrate; basis long, length 3 × width; merus, carpus and propodus not broadened; dactylus unguis bicuspidate. Pereopods 5–7 basis expanded, posterior margin weakly serrate, posteroventral corner rounded; merus and carpus expanded; dactylus unguis bicuspidate. Pereopod 7 propodus expanded.

Pleon. Pleonites 1–3 dorsally smooth. Epimera 1–3 posterior and ventral margins smooth, posteroventral corner with acute tooth. Uropod 1 peduncle with 1 basofacial seta, length 1.4 × outer ramus; inner ramus slightly longer than outer ramus. Uropod 2 peduncle shorter than outer ramus; inner ramus slightly shorter than outer ramus. Uropod 3 peduncle 0.9 × inner ramus; inner ramus shorter than outer ramus, length 1.6 × width, apically truncate with long robust setae. Telson as long as broad, deeply cleft (80%), lobes weakly divergent, scarely tapering distally, lobes apically truncate, each lobe with 5–7 apical robust setae.

Remarks. The convex palm of gnathopod 2 and dactylus posterior margin with sinus align Q. brownorum sp. nov. with Q. gregoryi sp. nov also from Western Australia, as well as Q. inaequipes ( A. Costa, 1851) from the Caribbean and Q. massavensis (Kossman, 1880) from north east Africa and female specimens of Q. santiniae Krapp-Schickel & Ruffo, 2006 from the isolated Amsterdam Island in the Indian Ocean. The more distally broad dactylus of gnathopod 2 in males and females separates Q. brownorum sp. nov. from the latter species. The telson apical margins are also more densely setose in Q. brownorum sp. nov with 5 long robust setae while Q. gregoryi and Q. massavensis have only 3 robust setae, Q. inaequipes 2 or 3 robust setae and only 2 robust setae in Q. santiniae .

Distribution. Western Australia: Cygnet Bay (current study).

Figures

FIGURE 29. Pseudelasmopus walkerae sp. nov. holotype male, 3 mm, AM P. 92517, Emily Bay, Norfolk Island, scales 0.1 mm.

FIGURE 30. Quadrimaera brownorum sp. nov. holotype male, habitus, 4.5 mm, AM P. 92677, Cygnet Bay, Western Australia.

FIGURE 31. Quadrimaera brownorum sp. nov. holotype male 4.5 mm, AM P. 92677, Cygnet Bay, Western Australia, scales 0.1 mm.

FIGURE 32. Quadrimaera brownorum sp. nov. holotype male 4.5 mm, AM P. 92677, Cygnet Bay, Western Australia, scales 0.1 mm.