Spinicallianassa westralia, 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 : 250-253

Spinicallianassa westralia sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:941976E5-CABA-

4F59-A8BA-6EFAC22483DC

Figures 57 , 58

Callianassa sp. MoV 4963.— Poore et al., 2008: 94.

Material examined. Holotype. Australia, WA, off Jurien Bay , 29.8069° S, 114.431° E, 114 m ( CSIRO stn SS10/2005/083), NMV J53456 (female, 3.5 mm) . Paratype. Australia, WA, North West Shelf , Imperieuse L 23 transect, 18° 27.37' S, 120° 08.41' E, 80 m ( CSIRO stn SS05/2007/82), NMV J71759 (ovigerous female, 3.3 mm) .

Diagnosis. Telson 1.2 times as wide as long, with dorsal transverse row of long setae and 1 or 2 pairs of spiniform setae, 1 pair of sublateral spiniform setae, anterolateral lobes rounded, lateral margins tapering to slightly rounded posterolateral corners; posterior margin convex with slight medial concavity. Uropodal endopod 1.9 times as long as wide, with 5 well spaced spiniform setae on face, with 3 or 4 along anterodistal margin; anterior margin with small subdistal tooth. Uropodal exopod 1.7 times as long as wide, distal margin convex, dorsal plate comprising 5–7 spiniform setae, anterior margin with 3 distal spiniform setae. Maxilliped 3 ischium twice as long as wide; merus almost semicircular.

Description of holotype. Rostrum triangular, situated at level of dorsal carapace, 0.65 length of eyestalk. Carapace dorsally weakly convex in lateral view; orbital margin transverse, curving into sides of rostrum; anterolateral lobe prominent; subanterolateral margin almost horizontal; anterior margin of branchiostegite convex; cervical groove deeply incised, across 0.85 length of carapace, not reaching linea thalassinica.

Eyestalk 0.8 as wide as long, with dorsal face depressed anteriorly (basally about three quarters as high as wide), with rounded ventrolateral margin, lateral margins almost parallel proximal to cornea, anteromedial angle asymmetrically rounded in dorsal view, with slight depression medial-distal to cornea, reaching distal margin of antennular peduncle article 1. Cornea densely pigmented, occupying mid-distal of eyestalk.

Antennular peduncle little longer than antennal peduncle; article 1 visible in dorsal view; article 3 longer than articles 1 and 2 combined; article 2 with dense longitudinal ventral row of long setae; article 3 with well-spaced ventral setae. Antennal peduncle article 5 0.7 length of article 4; scaphocerite acute, curved.

Maxilliped 3 ischium dilating distally, 1.2 times as long as wide, crista dentata comprising about 16 small, unevenly spaced teeth; merus 0.5 length of ischium measured along outer margin, 1.5 times as wide as long, with mesiodistal margin convex, overreaching articulation of carpus; carpus as long as merus outer margin; propodus ovoid-tapering, 1.7 times as long as wide; dactylus tapering, shorter than propodus, with scattered setae along upper margin, dense row of short setae along distal lower margin.

Pereopods 1 (chelipeds) unequal, dissimilar. Major cheliped carpus-palm upper margin as long as carapace. Ischium expanding distally, upper margin almost straight, unarmed; lower margin with row of 7 similar oblique spines. Merus 0.8 length of ischium, 1.7 times as long as wide (tooth excluded), ovate; upper margin convex, unarmed; lower margin with oblique spine proximal one third way along margin. Carpus almost as long as wide; upper margin carinate; lower margin carinate. Propodus upper margin 1.5 times as long as carpus; palm 1.2 times as long as wide; upper margin convex, carinate over entire length; lateral surface smooth, convex, with ill-defined depression at base of finger; distolateral margin of palm with lower angle; mesial surface convex, distomesial margin transverse, set back from distolateral margin, with tubercle at lower limit; lower margin carinate, with row of setae extending onto fixed finger; fixed finger 0.65 length of palm, triangular; cutting edge lateral, with steep step before distal concavity. Dactylus slightly overreaching fixed finger, curved, with acute tip; upper margin ridged, with dense tufts of long setae; lateral surface with few tufts of long setae along cutting edge; cutting edge unarmed.

Minor cheliped carpus-palm upper margin 0.75 carapace length. Ischium upper margin smooth, lower margin with row of 5 similar oblique spines. Merus about as long as ischium; lower margin unarmed. Carpus wider distally, 1.1 times as long as merus, twice as long as wide, upper and lower margins carinate. Palm 1.25 times as long as wide; upper margin convex, carinate; lateral face convex, without ridge leading onto finger; lower margin not carinate, with row of long setae extending onto fixed finger; distomesial margin oblique, with obsolete tubercle at lower limit. Fixed finger 0.75 length of palm, cutting edge smooth. Dactylus tapering, curved, unarmed.

Pereopod 2 merus lower margin slightly sinusoidal, 2.8 times as long as wide; carpus 1.8 times as long as wide; chela subtriangular; palm about 1.4 times as wide as upper margin; dactylus twice as long as palm upper margin. Pereopod 3 carpus subtriangular, twice as long as wide; propodus oval, upper margin convex, 1.2 times as long as greatest width, lower margin convex, with lower proximal margin not produced, with 1 slender subdistal spiniform seta, with gaps between clusters of marginal setae; dactylus nearly straight, shorter than propodus upper margin. Pereopods 4, 5 missing.

Pleopod 1 minute, uniarticulate. Pleopod 2 biramous, small, without setae.

Uropod endopod and exopod overreaching posterior margin of telson. Endopod oval, widest near midpoint, 1.8 times as long as wide; upper surface with 5 small spiniform setae (2 on dorsal rib, 2 near anterior margin, 1 near posterior margin); anterior margin straight, with minuscule distal tooth; distal margin evenly convex, with 3 spiniform setae near anterodistal margin; posterior margin convex, setose. Exopod widest near midpoint, 1.8 times as long as wide; anterior margin slightly convex, with 3 separated spiniform setae; with about 14 blade-like setae on posterior margin indistinguishably merged with distal margin; dorsal plate extending one quarter way across exopod, with few stiff setae merging with those on distal margin; distal and posterior margins also furnished with row of fine setae; upper face with 1 small spiniform seta and 2 fine setae near anterior margin.

Telson 1.2 times as wide as long, broadest at anterior third, narrowing posteriorly to obtusely rounded posterolateral corners, each with 2 spiniform setae; posterior margin medially excavate, setose; dorsal surface with transverse row of 4 medial fine long setae plus 2 pairs (1 pair in paratype) of spiniform setae, 2 submedial longitudinal rows of very fine setae, scattered fine setae, 1 sublateral pair of spiniform setae and accompanying fine seta.

Variation. The paratype has a narrower major cheliped and narrower maxilliped 3.

Etymology. Contraction of Western Australia, where the species is found (noun in apposition).

Distribution. West Central Australian Shelf ( Australia, WA), 80– 114 m.

Remarks. The uropodal exopod of Spinicallianassa westralia is narrower than in other species of the genus and is characterised by two long marginal spiniform setae and one submarginal on the anterior margin; the dorsal plate comprises few setae and extends only a small fraction across the exopod.

Figures

Figure 57. Spinicallianassa westralia sp. nov. Australia, WA. NMV J53456, holotype female, 3.6 mm: a, b, eyestalks, carapace (lateral, dorsal); c, telson, uropod; d, e, antennular, antennal peduncles, eyestalks, anterior carapace (lateral, dorsal); f, g, maxilliped 3 (inner, outer views); h, major cheliped (right, mesial view); i, major cheliped fingers (lateral); j, minor cheliped (left, mesial view); k, l, pereopods 2, 3; m, n, pleopods 1, 2. Scale bars = 1 mm.

Figure 58. Spinicallianassa westralia sp. nov. Australia, North West Shelf, NMV J71759, paratype ovigerous female, 3.3 mm. a, b, eyestalks, carapace, pleomeres 1, 2 (dorsal, lateral); c, d, antennular, antennal peduncles, eyestalk, anterior carapace (lateral, dorsal); e, pleomere 6, telson, left uropod; f, g, maxilliped 3 (inner, outer); h, major cheliped (left, mesial); i, major cheliped fingers (lateral); j, minor cheliped (right, mesial); k, pereopod 3. Scale bars = 1 mm.