Coriollianassa nyinggulu, 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 : 192-196

Coriollianassa nyinggulu sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:E210BEFB-935A-

48F6-99C8-79CE3F6BEAF1

Figures 19 , 20

Callianassa sp. MoV 4962.— Poore et al., 2008: 94 (North West

Shelf, Australia).

Material examined. Holotype. Australia. WA, North West Shelf , off Ningaloo South, 22.079° S, 113.796° E, 201–206 m ( CSIRO stn SS10/2005/146), NMV J53455 (male, 7.6 mm) . Other material. Australia, NT, Arafura Sea, 9° 18.21' S, 133° 41.82' E, 187 m, gravel ( CSIRO stn SS05/2005/029/GR052), AM P.74540 (male, 3.9 mm) .

Diagnosis. Rostrum acute, with weak dorsal carina, with ventral straight keel-like carina. Antennular peduncle reaching to midpoint of antennal peduncle article 4. Maxilliped 3 merus with rounded oblique mesiodistal margin. Telson trapezoidal, 1.1 times as long as wide.

Description of male holotype. Rostrum laterally compressed, situated well below upper level of carapace, dorsally moderately carinate, with ventral straight keel-like carina, acute in dorsal and lateral views. Carapace almost straight, depressed anteriorly, in lateral view, as long as pleomeres 1–3 combined; orbital margin concave; anterolateral angle produced anteroventrally as narrow lobe; subanterolateral margin convex, anterior margin of branchiostegite set well back, almost vertical; cervical groove across 0.75 length of carapace, almost reaching linea thalassinica. Pleomere 1 tergite waisted in dorsal view, with shallow saddle visible in lateral view; posterior section flat in lateral view.Pleomere 2 widest, wider than long, laterally flared. Pleomeres 3–5 each wider than long; pleura each with patch of plumose setae. Pleomere 6 0.8 times as long as wide, as long as pleomere 5, with slight ventrolateral projection.

Eyestalk as long as wide, with oblique dorsal face diverging from rostrum, with sharp slightly upturned ventrolateral margin, anterolateral margin oblique, anteromedial angle thin, rounded in dorsal view, overreaching distal margin of antennular peduncle article 1. Cornea subdistal, domed.

Antennular peduncle reaching to midpoint of antennal peduncle article 4; article 1 clearly visible in dorsal view; article 2 shorter than article 1; article 3 1.6 times as long as articles 1 and 2 combined; articles 2 and 3 with longitudinal ventral row of sparse long setae. Antennal peduncle article 5 0.5 length of article 4; scaphocerite with bifid apex.

Maxilliped 3 ischium tapering, 1.5 times as long as wide at base, crista dentata comprising row of about 18 strong, irregular, erect spines, stronger distally, overlapping distal margin; merus about 0.7 times as long as ischium measured along outer margin, about 1.35 times as wide as long, wider than distal margin of ischium, with distinct oblique mesiodistal margin; carpus shorter than merus; propodus ovoid, 1.8 times as long as wide; dactylus digitiform, 0.7 times as long as propodus.

Male major cheliped massive, carpus-palm upper margin 0.95 carapace length. Ischium expanding distally, upper margin sinuous, unarmed; lower margin with row of 10 spines (proximal 3 minute). Merus as long as ischium, 1.8 times as long as wide (tooth excluded), tapering distally; upper margin convex, unarmed; lower margin with oblique spine bearing a subproximal tubercle, plus row of small tubercles distal to spine. Carpus 1.5 times as long as wide, with constricted “neck”; margins carinate; upper margin smooth, concave over proximal third; lower margin convex, distally rounded. Propodus upper margin 0.75 times as long as carpus; palm barrel-shaped, 1.1 times as long as wide; upper margin carinate; lateral surface smooth, convex, with tubercle in gape; mesial surface slightly convex, with slight angle in gape set back from lateral peg; lower margin carinate, with row of setae extending onto fixed finger; fixed finger 0.9 times as long as palm, barely depressed; cutting edge denticulate. Dactylus reaching as far as fixed finger, curved 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 few rounded teeth diminishing distally; mesial surface with tufts of setae along cutting edge.

Minor cheliped missing.

Pereopod 2 merus lower margin slightly sinusoidal, 3.2 times as long as wide; carpus about twice as long as wide; chela subtriangular; palm about twice as wide as upper margin; dactylus 3 times as long as palm upper margin. Pereopod 3 carpus subtriangular, 2.6 times as long as wide; propodus suboval with produced lower proximal margin, upper margin 1.3 times width, lower margin convex, faintly undulate, marginal setae clustered on prominences, with 1 slender spiniform seta subdistally; dactylus about 0.8 times as long as propodus upper margin. Pereopod 4 carpus 0.7 length of merus; propodus 0.8 times as long as carpus, with dense grooming setae distally on lower margin, scattered stiff setae on outer surface, with spiniform seta parallel to dactylus; dactylus half as long as propodus. Pereopod 5 slender, with chela about as long as carpus, slightly curving; dactylus as long as fixed finger.

Male pleopod 1 uniarticulate, 8 times as long as wide, with few distal short setae. Pleopod 2 tubercle-like. Pleopods 3–5 biramous, rami narrow; appendix interna slender, rod-like, projecting well beyond mesial margin of endopod, bearing coupling hooks on apical margin.

Uropodal endopod and exopod overreaching posterior margin of telson. Endopod oval, about 1.7 times as long as wide; anterior margin slightly convex; anterodistal margin with 8 spiniform setae; distal margin convex, with fringe of setae; posterior margin with 4 stouter marginal setae; upper surface without spiniform setae. Exopod dilating to rounded distal margin, 1.5 times as long as wide, exceeding endopod by about one third length; anterior margin convex, setose; posterior margin with numerous slender setae, with about 8 blade-like setae, indistinguishably merged with distal margin; upper surface with 2 submarginal slender setae near midpoint; dorsal plate curved, short, about one third exopod width, with row of about 12 stiff setae distinct from setal row of distal margin.

Telson elongate-trapezoidal, 1.1 times as long as wide, broadest at anterior fifth, narrowing posteriorly; greatest width 1.4 times posterior width; dorsal surface with few medial setae anterior to midlength; lateral margin with 2 spiniform setae near posterolateral angle; posterior margin convex, with median tooth.

Etymology. Nyinggulu is the name given to the Ningaloo reef and coast by the local Indigenous people (noun in apposition).

Distribution. Northwest Australian Shelf, Sahul Shelf; 187– 206 m.

Remarks. C. nyinggulu is notable for the broad oval uropodal exopod, the stiletto-shaped rostrum, and the length of the antennular peduncle relative to the antennal peduncle (it reaches the midpoint of article 5, whereas it reaches only the distal margin of article 4 in all other species).

Figures

Figure 19. Coriollianassa nyinggulu sp. nov. NW Australia, NMV J53455, male, 7.6 mm. a, eyestalks, carapace, pleon, telson, right uropod; b, carapace, eyestalk, antennular, antennal peduncles, pleomeres 1, 2; c, anterior carapace, eyestalk, base of antennule (lateral); d, anterior carapace, eyestalk, antennular, antennal peduncles (dorsal view); e, telson, right uropod; f, major cheliped (left, mesial); g, cheliped fingers (lateral); h, i, right pleopods 1, 2 (in situ). Scale bars = 1 mm.

Figure 20. Coriollianassa nyinggulu sp. nov. NW Australia, NMV J53455, male, 7.6 mm. a, maxilliped 3; b–e, pereopods 2–5. Scale bar = 1 mm.