Aqaballianassa papua, Poore, 2023

Poore, Gary C. B., 2023, New records, one new genus and 21 new species of Callianassidae (Crustacea, Axiidea) from the Indo-West Pacific, Memoirs of Museum Victoria 82, pp. 167-255 : 173-176

Aqaballianassa papua sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:0BA416C6-E2F4-

444C-A629-B714EC4D617A

Figures 1a , 5–7

Aqaballianassa PNG-1166.— Robles et al., 2020: figs 1, 3, 6.

Material examined. Holotype. Papua New Guinea. Madang Province, W of Tab I., 05° 10.2' S, 145° 50.4' E, 1–3 m ( PAPUA NIUGINI stn PR243), MNHN IU-2013-7117 * (hermaphrodite, 4.1 mm) . Paratypes. Papua New Guinea. Madang Province, NE of Tab I., 1 –22 m ( PAPUA NIUGINI stn PR155), MNHN IU-2013-7114 *# (hermaphrodite, 3.4 mm), MNHN IU-2016-8150 (ovigerous hermaphrodite, 3.2 mm) ; W of Tab I., 05° 10.2' S, 145° 50.4' E, 1–3 m ( PAPUA NIUGINI stn PR243), MNHN IU-2013-7107 (ovigerous female, 3.1 mm) . New Britain, Kavieng Lagoon, Nago I. wharf, sand, 02° 36.3' S, 150° 46.2' E, 3–12 m (KAVIENG 2014 stn KR06), MNHN IU-2016-8151 *# (hermaphrodite, 3.6 mm), MNHN IU-2014-1056 (hermaphrodite, 4.1 mm) ; N of Sek I., inner slope, 05° 04.7'S, 145° 48.9'E, 8 m ( PAPUA NIUGINI stn PS47 ), MNHN IU-2013-7068 * (juvenile, 2.3 mm); MNHN IU-2017-1356 (juvenile, 2.5 mm) .

Diagnosis. Major cheliped merus 1.6 times as long as wide, lower margin with distally directed proximal tooth; propodus palm 1.25 times as long as carpus, as long as wide, with oblique gape (as wide as base of each finger) bearing distolateral short square tooth; fixed finger 0.6 length of palm; dactylus stout, overreaching fixed finger. Uropod endopod oval-tapering, widest proximally, 1.1 times as long as greatest width; upper face usually with 1 subproximal and 2 subdistal short spiniform setae; anterior margin convex, or straight with subdistal spine; anterodistal margin with 1–3 short spiniform setae; exopod 1.2–1.3 times as wide as length of anterior margin. Telson 1.23 times as wide as long,taperingtoaboutthree-quartersgreatestwidth;posterolateral margins with 1 or 2 short spiniform setae, posterior margin sometimes with spiniform seta(e) near midpoint.

Description of holotype. Hermaphrodite. Rostrum triangular, acute, with sharp lateral margin and slight ventral keel, situated level with dorsal carapace, shorter than eyestalks. Carapace dorsally flat, as long as pleomeres 1 and 2 combined; orbital margin almost transverse, separated from anterolateral angle by deepnotch;anterolateralangledirectedanteriorly;subanterolateral margin oblique; branchiostegal sclerite elongate-oval, protected laterally by domed section dorsal margin of branchiostegite; anterior margin of branchiostegite convex; cervical groove deeply incised, across 0.8 length of carapace, reaching linea thalassinica. Thoracic sternite 7 wider than long, anterior margin with broad rounded median lobe; ventral surface flat. Pleomere 1 tergite with transverse groove, posterior half much wider than anterior half. Pleomere 2 1.1 times as long as wide. Pleomeres 3–5 each wider than long; pleura each with patch of plumose setae. Pleomere 6 about as long as wide, 1.1 times as long as pleomere 5, with posterior lateral groove dorsal to ridge leading to lateral notch.

Eyestalk about 1.3 times as long as wide, with dorsal face close to rostrum; sharp ventrolateral margin, anterolateral margin oblique, anteromedial angle rounded or angular in dorsal view, overreaching distal margin of antennular peduncle article 1. Cornea densely pigmented, occupying anterolateral margin of eyestalk.

Antennular peduncle reaching beyond distal margin of antennal peduncle; article 1 not visible in dorsal view; article 3 little longer than articles 1 and 2 combined; articles 2 and 3 with longitudinal ventral row of long setae. Antennal peduncle article 5 half as long as article 4; scaphocerite minute, comma-shaped, with acute apex.

Mandible molar process rounded, without tooth; incisor process with proximal obsolete teeth. Maxilliped 3 ischium dilating distally, 1.2 times as long as wide, crista dentata consisting of row of about 11 small, well-spaced teeth, stronger distally; merus about half as long as ischium measured along outer margin, about twice as wide as long, wider than ischium, with mesiodistal margin produced as convex lobe beyond base of carpus; carpus longer than merus outer margin; propodus ovoid-tapering, 1.7 times as long as wide; dactylus digitiform, 0.6 times as long as propodus.

Pereopods 1 (chelipeds) unequal, dissimilar. Female major cheliped massive, carpus-palm upper margin 1.2 times carapace length. Ischium barely expanding distally, upper margin concave, unarmed; lower margin with row of 8 spines. Merus as long as ischium, 1.7 times as long as wide (tooth excluded), ovate; upper margin convex, unarmed; lower margin with subproximal spine, scalloped over distal oblique third. Carpus about as long as wide; margins carinate; upper margin smooth; lower margin convex. Propodus upper margin 1.25 times as long as carpus; palm widest subproximally, tapering, 1.05 times as long as wide; upper margin carinate; lateral surface smooth, convex, with deep concave gape; mesial surface slightly convex, with square tooth set back from distolateral margin; lower margin sharply carinate, with row of setae extending onto fixed finger; fixed finger 0.6 times as long as palm, not depressed; cutting edge with blade along lateral margin; dactylus overreaching fixed finger, hooked distally, with acute tip; upper margin with tufts of long setae; lateral surface with few tufts of long setae along cutting edge; cutting edge with small teeth over distal half.

Minor cheliped carpus-palm upper margin 0.9 times carapace length. Ischium upper margin smooth, lower margin with row of 7 spines. Merus about as long as ischium; lower margin with tooth about one sixth along. Carpus wider distally, 1.2 times as long as merus, 1.7 times as long as wide. Palm slightly swollen, 1.2 times as long as wide; upper margin barely convex; lower margin sharply carinate, with row of long setae extending onto fixed finger. Fixed finger deep, triangular, three-quarters as long as palm, cutting edge denticulate except over distal third. Dactylus as long as palm, curved; cutting edge smooth.

Pereopod 2 merus lower margin slightly sinusoidal, 2.8 times as long as wide; carpus about 1.8 times as long as wide; chela subtriangular; palm about 1.5 times as wide as upper margin; dactylus twice as long as palm upper margin. Pereopod 3 carpus subtriangular, twice as long as wide; propodus suboval with produced lower proximal margin, upper margin equal to greatest width, lower margin convex, faintly undulate, marginal setae clustered on prominences, with one slender spiniform seta subdistally; dactylus about 0.75 times as long as propodus upper margin. Pereopod 4 coxa flattened ventrally, immovable; merus 1.8 times as long as ischium; carpus 0.8 length of merus; propodus as long as carpus, with dense grooming setae distally on lower margin, scattered stiff setae on outer surface, with long spiniform setae parallel to dactylus; dactylus half as long as propodus. Pereopod 5 slender; coxa with semicircular gonopore; with chela about as long as carpus, slightly curving, fixed finger shorter than dactylus.

Pleopod 1 of 2 articles at right angles; ramus 1.3 times as long as peduncle; setose. Pleopod 2 biramous; peduncle almost straight; exopod slightly shorter than endopod; endopod of 2 articles. Pleopods 3–5 biramous, rami narrow; appendix interna slender, rod-like, projecting well beyond mesial margin of endopod, bearing short coupling hooks on apical margin.

Uropod endopod and exopod overreaching posterior margin of telson. Endopod oval-tapering, widest proximally, about 1.3 times as long as wide; upper surface with 1 proximal and 2 distal spiniform setae; anterior margin slightly convex; anterodistal margin with 3–5 short spiniform setae; distal margin narrow-convex, with fringe of setae; posterior margin setose. Exopod widest at midpoint, 1.2 times as long as wide, exceeding endopod by about half its length; anterior margin slightly concave, with 1 spiniform seta and 2 submarginal slender setae about two-thirds along; all margins with numerous slender setae, with more than 20 blade-like setae indistinguishably merged with distal margin; dorsal plate extending about one third across exopod, with row of about 15 stiff setae merging anteriorly with similar setae on distal margin.

Telson trapezoidal, 1.25 times as wide as long, broadest at anterior third, narrowing posteriorly; greatest width 1.4 times posterior width; dorsal surface with few medial setae and pair of spiniform setae near anterior margin, second pair of lateral spiniform setae posterior to midlength; posterolateral angle with 1 or 2 spiniform setae; posterior margin with median tooth.

Variation. Rostrum wider, longer and more depressed in some individuals than others; eyestalk mesiodistal lobe angular to rounded (cf. fig. 5c, d, n, o, q, r). Uropod endopod narrower and more tapered in larger individuals than juveniles (cf. fig. 5e, p), with small tooth on anterior margin in one juvenile (fig. 5p).

Colour. Carapace and pleon essentially translucent/white with pale orange dorsal band across anterior of carapace. Chelipeds carpi with asymmetrical distal pale orange band; palms with patchy orange colour distolaterally (fig. 7).

Etymology. From Papua New Guinea (noun in apposition).

Distribution. Eastern and Western Coral Triangle ( Papua New Guinea, Indonesia); 1– 22 m.

Remarks. Robles et al.’s (2020) molecular phylogram attributed four individuals (of seven) to Aqaballianassa PNG-116, one remote from the other three. Only hermaphrodites are known, all individuals with both female and male gonopores on pereopodal coxae 3 and 5 respectively. Aqaballianassa papua has a shorter telson and usually a longer rostrum than the other common species from the region, A. lewtonae . The major cheliped of two of the largest individuals has a shallow gape between the cheliped fingers with a molar-like tooth on the mesial margin (fig. 6a, i); another of similar size has a deeper gape and a blunt mesial tooth.

Figures

Figure 1. Dactylus of maxilliped 3 of representatives of two callianassoid families. Eucalliacidae. a, Calliaxina kensleyi (Dworschak, 2005), MNHN IU-2016-8084. Callianassidae. b, Caviallianassa moorea sp. nov., UF 28875; c, Paratrypaea sp, MNHN IU-2013-7035; d, Praedatrypaea lobetobensis sp. nov., MNHN IU-2015-109; e, Praedatrypaea orientalis (Bate, 1888), AM P.74473; f, Rayllianassa amboinensis (De Man, 1888), UF 8700; g, Rayllianassa bifida sp. nov., MNHN IU-2013-7137; h, Rudisullianassa pandan sp. nov., MNHN IU-2013-7063; i, Rudisullianassa rudisulcus Komai, Fujita and Maenosono, 2014, MNHN IU-2013-7121; j, Scallasis amboinae Bate, 1888, MNHN IU-2013-12303; k, Spinicallianassa spinicauda (Komai, Maenosono and Fujita, 2014), MNHN IU-2014-2778; l, Spinicallianassa papetoai sp. nov., UF 29280.

Figure 5. Aqaballianassa papua sp. nov. Papua New Guinea. MNHN IU-2013-7117, holotype hermaphrodite, 4.1 mm: a, dorsal carapace, pleon, telson; b, lateral carapace, pleomere 1; c, d, anterior carapace, eyestalk, antennule, antennal peduncles; e, pleomere 6, uropod, telson; f, g, pleomere 6 ventral, left lateral; h, left mandible, lateral; i, right mandible, mesial; j, maxilliped; k–m, pleopods 1–3. MNHN IU-2016-8150, ovigerous female, 3.2 mm: n, anterior carapace, eyestalks. MNHN IU-2016-8151, female, 3.6 mm: o, anterior carapace, eyestalks. MNHN IU- 2013-7068, female, 2.3 mm: p, telson, uropods; q, r, anterior carapace, eyestalks, antennule, antennal peduncles. Scale bars = 1 mm.

Figure 6. Aqaballianassa papua sp. nov. Papua New Guinea. MNHN IU-2013-7117, holotype hermaphrodite, 4.1 mm: a, major cheliped (left, mesial) b, major cheliped fingers (lateral); c, minor cheliped, right; d–g, pereopods 2–5; h, pereopod 5 coxa (mesial); i, thoracic sternum 7, pereopodal coxae 3–5. MNHN IU-2016-8151, hermaphrodite, 3.6 mm: j, major cheliped (right, mesial). MNHN IU-2013-7114, hermaphrodite, 3.4 mm: k, major cheliped (right, mesial). Scale bars = 1 mm.

Figure 7. Aqaballianassa papua sp. nov. Papua New Guinea. MNHN IU-2014-1056 (colour photographs by Zdeněk Ďuriš).