Quadrisegmentum yirrgay, Hughes & Takeuchi, 2016

Hughes, Lauren Elizabeth & Takeuchi, Ichiro, 2016, Two New Species of Quadrisegmentum (Phtisicidae: Amphipoda: Crustacea) from the Central Indo-Pacific, with Notes on the Type Species Q. triangulum Hirayama, 1988, Records of the Australian Museum 68 (5), pp. 231-244 : 236-243

Quadrisegmentum yirrgay sp. nov.

Figs 6–10

Quadrisegmentum triangulum . — Guerra-Garcia, 2003: 104–105, fig. 9a. — Guerra-Garcia, 2006: 440, fig. 39. —Guerra-Garcia & Lowry, 2009: 323–325.

Type material. Holotype ♂ 9.0 mm, AM P.98563, outer reef slope,Ashmore Reef , Coral Sea, Queensland, Australia (10°26'16"S 144°25'47"E), red calcareous cylindrical algae, 19 January 1993, coll. S.J. Keable ( QLD 704 ); paratype ♂ 9.0 mm, AM P.98564,outer reef slope,Ashmore Reef,Coral Sea, Queensland, Australia (10°26'16"S 144°25'47"E), red calcareous cylindrical algae, 19 January 1993, coll. S.J. Keable ( QLD 704 ); many specimens, AM P.61630, outer reef slope, Ashmore Reef, Coral Sea, Queensland, Australia (10°26'16"S 144°25'47"E), red calcareous cylindrical algae, 19 January 1993, coll. S.J.Keable ( QLD 704 ) . Paratypes: ♀, 6 mm, AM P.61624,eastern edge of outer reef slope, Ashmore Reef , Coral Sea, Queensland, Australia (10°09'10"S 144°34'43"E) calcareous red tubular algae, 24 January 1993, coll. S.J. Keable ( QLD 734 ) ; 2 specimens (1 ♂ and 1 ♀), AM P.61627, eastern edge of outer reef slope Ashmore Reef , Coral Sea, Queensland, Australia (10°09'10"S 144°34'43"E) mixed sponges, 24 January 1993, coll. S.J. Keable ( QLD 736 ) ; 4 specimens (2 ♂♂ and 2♀♀), AM P.61629, outer reef slope, Ashmore Reef , Coral Sea, Queensland, Australia (10°13'10"S 144°24'53"E) sponges, 22 January 1993, coll. S.J. Keable ( QLD 722 ) ; 1 ♂, AM P.61625, outer reef slope, Ashmore Reef , Coral Sea, Queensland, Australia (10°26'16"S 144°25'47"E) sediment, algae and rubble, 19 January 1993, coll S.J. Keable ( QLD 705 ) .

145°28'E), 2 m, mixed algae from bommie, 28 September 1978, coll. J.K. Lowry ( QLD 1 ); 2 specimens (1 ♂ and 1♀), AM P.32314, off southern Point of Mermaid Cove, Lizard Island (14°39'S 145°27'E), 3–6.1 m, filamentous algae with stone washings and scrapings from crevices, 8 October 1978, coll. C. J. Short & P.C. Terrill (QLD–25); 1 ♀, AM P.32318, fringing reef between Bird Islet and South Island, Lizard Island (14°40'S 145°28'E), 25 m, green algae Halophila sp. and mixed algae from grass beds off reef base, 9 October 1978, coll. J.K. Lowry ( QLD 29 ); 2 ♂♂, AM P.32320, reefs at western end of Blue Lagoon , Lizard Island (14°40'S 145°28'E), 3 m, sand near artificial reefs, 5 October 1978, coll. P.C. Terrill ( QLD 33 ); 16 specimens (6 ♂♂, 9 ♀♀, 1 juvenile), AM P.32325, Mermaid Cove , Lizard Island (14°40'S 145°28'E), subtidal to 2 m, mixed algae, coral rubble and silt, 14 October 1978, coll. J.K. Lowry (QLD–48); 1 ♀, AM P.32326, off North Point , Lizard Island (14°39'S 145°27'E), 3–6.1 m, red algae ( Galaxaura sp.) and coral rubble from subtidal caves, 14 October 1978, coll. J.K. Lowry ( QLD 49 ); 9 specimens (7 ♂♂, 1 ♀, 1 juvenile), AM P.32327, off North Point , Lizard Island (14°39'S 145°27'E), 3–6.1 m, mixed algae, 14 October 1978, coll. J.K. Lowry ( QLD 50 ); 7 specimens (4 ♂♂ and 3 ♀♀), AM P.32328, Lizard Island , off North Point, Lizard Island (14°39'S 145°27'E), 6.1 m, green calcareous alga Halimeda sp., 14 October 1978, coll. P.C. Terrill ( QLD 52 ); 1 ♂, AM P.61626, Great Barrier Reef , inside outer barrier, Lizard Island (10°34'29"S 143°55'17" E), 15 m, rubble, 16 January 1993, coll. S.J. Keable ( QLD 682 ); 1 ♂, AM P.61712, between Palfrey Island and Lizard Island , western side of Blue Lagoon, Lizard Island (14°41'S 145°27'E), 7 October 2001; 5 specimens (2♂♂ and 3 ♀♀), AM P.61713, between Palfrey Island and Lizard Island , western side of Blue Lagoon, Lizard Island (14°41'S 145°27'E), 7 October 2001; 1 ♀, AM P.61714, between Palfrey Island and Lizard Island , western side of Blue Lagoon, Lizard Island (14°41'S 145°27'E), 2–3 m, coral rubble, 7 October 2001, coll. J.M. Guerra-García & S.J. Keable ( QLD 1469 ); 8 specimens (4 ♂♂ and 4 ♀♀), AM P.61715, Coconut Beach , Lizard Island (14°41'S 145°27'E), 6 m, fine live hard coral encrusted with calcareous red algae and filamentous red/green/brown algal turf, 8 October 2001, coll. J.M. Guerra-García & S.J. Keable ( QLD 1476 ); 3 specimens (1 ♀ and 2 juveniles), AM P.61716, Crystal Beach , Lizard Island (14°41'S 145°27'E), 5 m, thick branching coral rubble encrusted with red algal turf and black sponge half buried in sediment, 9 October 2001, coll. J.M. Guerra-García & S.J. Keable ( QLD 1483 ); 1 juvenile, AM P.61717, Crystal Beach , Lizard Island (14°41'S 145°27'E), 4 m, thin branching live coral heavily encrusted Island (14°41'S 145°27'E), 25 m, gorgonian (cf. Menella sp.), 14 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1544 ); 1 ♂, AM P.61724, reef slope on south side of South Island , Lizard Island (14°41'S 145°27'E), 20 m, gorgonian (cf. Mopsella sp.), 14 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1545 ); 2 ♂♂, AM P.61725, north–east side of Lizard Island , reef slope south of "Washing Machine" (14°41'S 145°27'E), 18 m, brown sponge cf. Clathria reinwardti , 16 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1565 ); 1 ♀, AM P.61726, north–east side of Lizard Island , reef slope south of "Washing Machine" (14°41'S 145°27'E), 6 m, green calcareous alga Halimeda macroloba , 16 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1568 ); 1 ♀, AM P.61727, north–east side of Lizard Island , reef slope south of "Washing Machine" (14°41'S 145°27'E), 5 m, sediment with green alga Halimeda cylindracea Decaisne 1842 , Udotea and Caulerpa spp., 16 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1569 ); 2 specimens (1 ♂ and 1 juvenile), AM P.61728, north–east side of Lizard Island , reef slope south of "Washing Machine" (14°41'S 145°27'E), 6 m, mixed silty filamentous red algae and green alga Caulerpa taxifolia (M.Vahl) C. Agardh 1817 , 16 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1573 ); 1 ♂, AM P.61729, Pidgin Point , Lizard Island (14°41'S 145°27'E), 20 m, sponge cf. Clathria reinwardti , 18 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1581 ); 1 ♂, AM P.61730, reef just south–west of Osprey Island , Lizard Island (14°41'S 145°27'E), 10–12 m, fine–medium sand with some shell, 18 October 2001, coll. J.M. Guerra-Garcia & S.J. Keable ( QLD 1588 ); 1 mature ♀, AM P.61731, Granite Bluff , Lizard Island (14°40'S 145°28'E), reef rock, 30 August 1976, coll. P.A. Hutchings (25–1); 4 ♂♂, AM P.61732, northern end of Mermaid Beach , Lizard Island (14°41'S 145°27'E), 4 m, brown alga Padina sp., 12 October 2001, coll. J.M. Guerra- Garcia & S.J. Keable ( QLD 1533 ) .

Tasman Sea : 7 specimens (6 ♂♂ and 1 ♀), AM P.61581, patch reef in lagoon, Middleton Reef , Elizabeth and Middleton Reefs (29°27'36"S 159°06'42"E), prolific coral cover on top of bommie, 6 December 1987 (Site 12); 1 ♂, AM P.61582, The Sound , large alcove near lagoon entrance, Middleton Reef , Elizabeth and Middleton Reefs (29°27'42"S 159°05'24"E), rubble wash, 5 December 1987 (Site 7); 1 ♂, AM P.61475, reef front south of North Passage , straight out from Signal Point, Lord Howe Island (31°31'36"S 159°03'E) coralline algae, coll. G.D. Fenwick, 11 May 1977 ( LHA 17 ) .

Papua New Guinea: ♂ 6.1 mm, whole animal SEM pin mount, AM P.97779, The Quarry , near the village of Bunu 2, Madang (4°46'30"S 145°48'E), coral slope with rubble, sand, ascidian Didemnum molle (Herdmann, 1886) and sponges, 21 January 1990, coll. J.K. Lowry ( PNG 69); ♀ 6.1 mm, AM P.98565, The Quarry, near the village of Bunu 2, Madang (4°46'30"S 145°48'E), coral slope with rubble, sand, ascidian Didemnum molle and sponges, 21 January 1990, coll. J.K. Lowry ( PNG 69); 3 specimens (2 ♂ and 1 mature ♀), AM P.61534, base of reef slope, outer face, Horseshoe Reef, Bootless Inlet (9°30'30"S 147°15'30"E) green calcareous alga Halimeda opuntia (Linnaeus) J.V. Lamouroux 1816 , 28 October 1980, coll. S.P. Arnam & J.K. Lowry (PNG-23); 1 mature ♀, AM P.61533, Horseshoe Reef, Bootless Inlet (9°30'30"S 147°15'30"E) coral rubble from reef front slope, 29 October 1980, coll. S.P. Arnam & J.K. Lowry (PNG-32); 1 ♂, AM P.61536, Horseshoe Reef, Port Moresby (9°36'30"S 147°17'54"E) gorgonian, 2 November 1980, coll. A.J. Bruce ( AJB 206 ); 4 specimens (3 ♂♂ and 1 damaged juvenile), AM P.61537, Lion Island , Manunouma Islands (9°32'17"S 147°06'13"E), gorgonian, 5 November 1980, coll. A.J. Bruce (AJB-208); 4 specimens (3 ♂♂ and 1 mature ♀), AM P.61535, outside Horseshoe Reef, Bootless Inlet (9°30'30"S 147°17'30"E), crinoids from outer reef face, 9 November 1980, coll. S.P. Arnam & J.K. Lowry (PNG-63); 74 specimens, AM P.61531, The Quarry, near the village of Bunu 2 (4°46'30"S 145°48'E), coral slope with rubble, sand, ascidian Didemnum molle and sponges, 21 January 1990, coll. J.K. Lowry ( PNG 69); 1 ♂, AM P.61532, The Quarry, near the village of Bunu 2 (4°46'30"S 145°48'E), coral slope with rubble, sand and black sponge, coll. J.K. Lowry, 21 January 1990 ( PNG 68) .

Type locality. Ashmore Reef, off Great Barrier Reef, Coral Sea, Queensland, Australia (10°26'16"S 144°25'47"E). (The present “Ashmore Reef” is the different “ Ashmore Reef”, Timor Sea, north-west Western Australia , type locality for Q. triangulum )

Etymology. “Yirrgay” is the lost spoken language of a coastal indigenous group in Far North Queensland. Applied as a noun in apposition.

Description. (Based on holotype ♂, body length 9.0mm, AM P.98563 and male, body length, 6.1 mm, SEM AM P.97779 for abdomen).

Body Somites sub-slender. Head and pereonite 1 combined, completely fused, suture absent, with pair of apically truncate dorsodistal projections. Pereonite 2, with small acute anterolateral projection and larger acute mid lateral projection. Pereonite 3, with minute mid-lateral projection. Pereonites 4–6 without anterior or mid-lateral projections Pereon. Gnathopod 1 basis similar in length to ischium, merus and carpus combined; carpus subequal to merus length, posterior margin with slender setae; propodus triangular; palm defined by prominent, curved, bifid process with 2 apical robust setae; dactylus falcate, inner margin lined with setules. Gill 2 subovate, length 0.6× pereonite 2 length. Gnathopod 2 begins ⅓ along posterior margin of pereonite 2; basis length 1.4× pereonite 2 length, 2.1× ischium, merus and carpus combined; merus subrectangular, distally swollen (length 2× width), longer than to carpus; carpus subrectangular (length 2× width); propodus subovate, longer than wide (length 2.1× width); palm 60% of posterior margin, 3 proximal projections each with robust seta.

Gill 3 elongate, length 0.6× pereonite 3. Pereopod 3 basis longest, 0.4× pereopod 3 length; ischium 0.1× basis length; merus 0.7× basis length; carpus 0.25× basis length; propodus 1.1× carpus length with 2 large robust setae along palm, dactylus recurved. Gill 4 subequal to gill 3. Pereopod 4 shorter than pereopod 3, length 0.30× body; basis longest, 0.6× pereopod 3 length; ischium 0.25× basis length; merus 0.6× basis length; carpus 0.3× basis length; propodus longer than carpus, length 1.1× carpus with 4 large robust setae along palm; dactylus recurved.

Pereopod 5 article 1 length 0.9× article 2; article 2 longest, 1.1× article 3; dactylus recurved. Pereopod 6 basis longest, 0.37× pereopod 6 length; ischium 0.08× basis length; merus 0.6× basis length; carpus 0.33× basis length, anterior margin without robust setae; propodus 0.6× basis length, anterior margin with 4 groups of long robust setae (proximal group only with paired robust setae); dactylus recurved. Pereopod 7 0.8× pereopod 6; basis 0.27× pereopod 7 length; ischium 0.25× basis length; merus length subequal to basis; carpus 0.65× basis length, anterior margin with 1 robust seta; propodus 0.8× basis length, anterior margin with 3 groups of long robust setae (middle group only with paired robust setae) and distal small robust setae; dactylus recurved.

Pleon. Uropod 1 elongate, without setae (broken). Uropod 2 (broken). Telson small, with a pair of setae (Based on SEM AM P.97779).

Female. (based on paratype AM P.61624). Pereonite 2 with small anterolateral and small acute mid-lateral projections. Pereonite 4 with rounded anterolateral projection. Antenna 1 long 0.75× body length; article 2 longest, 2× article 1 length; flagellum with 8 articles. Antenna 2 shorter than antenna 1; flagellum 4-articulated, length ½× antenna 1.

Remarks. See remarks for Q. atauro sp. nov.

Distribution. Australia: Ashmore Reef, Coral Sea, Lizard Island (current study; Guerra-Garcia, 2006; Guerra-Garcia & Lowry, 2009). Lord Howe Island. ( Guerra-García, 2006). Elizabeth and Middleton Reef ( Guerra-García, 2006). Papua New Guinea: Motupore Island, Manunouma Islands, Port Morseby and Madang ( Guerra-García, 2003).

Figures

Figure 6.Quadrisegmentum yirrgay sp. nov., holotype male habitus,9.0 mm,AMP.98563; paratype female, 6 mm, AM P.61624, Ashmore Reef, Coral Sea, Queensland, Australia.

Figure 7. Quadrisegmentum yirrgaysp. nov., holotype male 9.0 mm,AM P.98563,Ashmore Reef, Coral Sea, Queensland,Australia, scales 0.1 mm.

Figure 8. Quadrisegmentum yirrgay sp. nov., holotype male 9.0 mm, AM P.98563,Ashmore Reef, Coral Sea, Queensland, Australia, scales 0.1 mm. Antenna 1 more than ⅓× body length (broken); peduncle article 2 longest, 2× article 1; article 3 length 0.8× article 2; flagellum with more than 4 articles (broken). Upper lip weakly notched. Mandible right, incisor with 4 teeth, lacinia mobilis with 5 teeth followed by 2 plates; palp 3-articulate; article 2 longest; article 3 with 1 distal and 2 midlateral slender setae, anterodistal margin pubescent. Mandible left, incisor with 5 teeth, lacinia mobilis followed by 2 plates; Lower lip setose on outer lobe. Maxilla 1 outer plate with 6 robust setae; palp 2-articulate, article 2 with 3 long and 2 short robust seate.Maxilliped basal endite (inner plate) larger than ischial endite (outer plate), basal endite with 3 apically serrate robust setae; ischial endite (outer plate) margin with several slender setae; palp 4-articulate; article 2 lateral expanded, with 5 setae; article 3 with sub-triangular distal projection.

Figure 9. Quadrisegmentum yirrgay sp. nov., male, 6.1 mm, AM P.97779, Madang, Papua New Guinea, scales habitus 1 mm, all other scales 100 µm.

Figure 10. Quadrisegmentum yirrgay sp. nov., male, 6.1 mm, AM P.97779, Madang, Papua New Guinea, scales Ur 20 µm, all other scales 100 µm.