Praedatrypaea mandu, 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 : 210-213

Praedatrypaea mandu sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:82790EBF-E2B2-

42CA-8F0B-C732F534E188

Figures 30 , 31

Praedatrypaea propinqua .— Robles et al., 2020: figs 1, 3, 6.

Material examined. Holotype. Australia. WA, Carnarvon Shelf , W of Mandu , Cape Range, 22.119°– 22.121° S, 113.8424°– 113.8418° E, 80 m (Geosciences Australia stn SOL4469_1_019_ MAPS02 , 18 Jun 2008), NMV J59650 *# (ovigerous female, 2.6 mm) . Paratypes, collected with holotype: NMV J59276 (male, 2.7 mm), NMV J72486 (female, incomplete, 2.8 mm), NMV J72487 (female, lacking pereopods 1–4, 2.8 mm) . Other material. Australia. WA, northeastern North West Shelf to off Geraldton: 12.434° S, 123.601° E, 100 m ( CSIRO stn SS05/2007/185), NMV J60030 (2) ; 19.79° S, 115.476° E, 102 m ( CSIRO stn SS05/2007/24), NMV J60027 (ovigerous female, 2.8 mm; 3 males) ; 22.1188° S, 113.8209° E, 100 m ( Geosciences Australia stn SOL4769_1_012_ MAPS01 ), NMV J71758 (3 males, 2.4–3.5 mm, no chelipeds) ; 22.8486° S, 113.511° E, 100 m ( CSIRO stn SS10/2005/135), NMV J53453 (male, 3.2 mm; ovigerous female, 3.1 mm) ; 22.8514° S, 113.513° E, 100 m ( CSIRO stn SS10/2005/136), NMV J60031 (4) ; 28.986° S, 113.836° E, 117 m ( CSIRO stn SS07/2005/109), NMV J60356 (male, 2.7 mm).

Diagnosis. Antennular peduncle reaching distal margin of antennal peduncle article 5. Maxilliped 3 ischium about 1.55 times as long as wide; merus oval, about 1.5 times as wide as long, with tooth on convex distal margin. Chelipeds meri upper margins each unarmed. Major cheliped merus lower margin with spine at midpoint; carpus 1.4 times as long as wide; palm 1.15 times as long as carpus, 1.35 times as long as wide; fingers, cutting edges with obsolete teeth. Uropod endopod twice as long as wide; anterior margin slightly convex, with 4 distal stout setae; distal-posterior margin tapered, oblique; dorsal face with irregular row of 5 or 6 spiniform setae close to anterior margin. Uropod exopod rectangular, truncate distally, twice as long as wide; anterior margin straight, setose. Telson 0.85 as long as wide, widest at strong lateral lobes at midpoint; posterior margin convex, with median spine; without spiniform setae on posterolateral margins. Male pleopods 1, 2 absent.

Description. Female. Rostrum acute, narrow in lateral and dorsal views, situated below level of dorsal carapace, as long as eyestalks. Carapace dorsally flat, as long as pleomeres 1, 2 and half pleomere 3 combined; orbital margin almost transverse; anterolateral lobes rounded; subanterolateral margin oblique; cervical groove across 0.8 length of carapace, shallow at midpoint, reaching linea thalassinica. Pleomere 1 tergite flat dorsally, wider posteriorly. Pleomere 2 about as wide as long. Pleomeres 3–5 each wider than long; pleura each with patch of plumose setae. Pleomere 6 1.15 times as long as wide, 1.3 times as long as pleomere 5; with oblique shelf protruding from posteroventral margin.

Eyestalk about as long as wide, with oblique dorsal face diverging from rostrum, anterolateral margin evenly tapering, oblique, anteromedial angle rounded in dorsal view, not reaching distal margin of antennular peduncle article 1. Cornea densely pigmented, sitting in middle of eyestalk.

Antennular peduncle reaching distal margin of antennal peduncle article 5; article 1 visible in dorsal view; article 3 about as long as articles 1 and 2 combined; articles 2 and 3 with longitudinal ventral row of long setae. Antennal peduncle article 5 0.6 length of article 4; scaphocerite comma-shaped in dorsal view.

Maxilliped 3 ischium dilating over most of length, constricted distally, 1.55 times as long as wide, crista dentata consisting of row of about 25 uneven contiguous teeth; merus half as long as ischium measured along outer margin, about 1.5 times as wide as long, with mesiodistal margin evenly convex, with sharp mesially directed tooth; carpus about as long as merus outer margin; propodus tapering, 1.6 times as long as greatest width; dactylus 0.7 length of propodus, elongate-oval, with dense row of short setae along flexor (lower) margin.

Pereopods 1 (chelipeds) unequal, dissimilar. Major cheliped carpus-palm upper margin 0.9 carapace length. Ischium expanding distally, upper margin unarmed; lower margin with 9 spines increasing in length distally. Merus as long as ischium, 2.2 times as long as wide (tooth excluded), oval; upper margin convex; lower margin with small tooth at about two thirds length. Carpus 1.4 times as long as wide. Propodus upper margin 1.15 times as long as carpus; palm 1.35 times as long as wide; upper margin convex; lateral surface smooth, convex, with concave gape; mesial surface convex; lower margin with row of setae extending onto fixed finger; fixed finger about as long as palm; cutting edge with 2 low teeth. Dactylus as long as fixed finger, curved; cutting edge with 2 low teeth.

Minor cheliped carpus-palm upper margin 0.9 carapace length. Ischium lower margin with 9 spines increasing in length distally. Merus as long as ischium; upper margin convex, smooth; lower margin with small distal tooth. Carpus dilating, 1.15 times as long as merus, 3 times as long as wide. Palm 0.6 length of carpus, twice long as wide; upper margin barely convex; lower margin carinate, with row of setae extending onto fixed finger; fixed finger longer than palm, cutting edge smooth. Dactylus longer than palm, curved distally; cutting edge smooth.

Pereopod 2 merus 3.8 times as long as wide; carpus twice as long as wide; chela subtriangular; palm 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 oval, longer than wide, with evenly curved lower margin, marginal setae evenly spaced, without gaps, with 1 short spiniform seta; dactylus 0.7 length of propodus upper margin. Pereopod 4 propodus longer than carpus, with dense grooming setae distally on lower margin, scattered stiff setae on outer surface, with short spiniform setae at base of dactylus; dactylus half as long as propodus. Pereopod 5 slender, chelate.

Pleopods 3–5 biramous, endopod 3.3 times as long as wide; appendix interna narrow, 0.25 length of endopod.

Uropod endopod and exopod well overreaching posterior margin of telson. Endopod subtriangular-oval, twice as long as wide; anterior margin slightly convex; anterodistal margin setose, with 4 subdistal spiniform setae; posterior margin with marginal setae; dorsal face with irregular row of 5 spiniform setae close to anterior margin. Exopod rectangular, truncate distally, twice as long as wide; anterior margin straight, setose; posterior margin with 5 falcate setae indistinguishably merged with densely setose distal margin; dorsal plate scarcely differentiated from distal margin, comprising about 12 short and medium stiff setae merging anteriorly with similar setae on distal margin; dorsal face with distal long seta and short spiniform seta near anterior margin.

Telson 1.15 times as wide as long, widest at strong lateral lobes at midpoint, narrowing posteriorly to rounded corner leading to transverse-convex posterior margin; posterior margin setose, with medial spine; lateral lobe with spiniform seta and long seta; transverse ridge with 1 pair of spiniform setae and long setae.

Male. Major cheliped unknown. Minor cheliped carpus-palm upper margin 0.9 carapace length. Ischium lower margin with 8 spines increasing in length distally. Merus almost as long as ischium; upper margin convex, smooth; lower margin with sharp distal tooth. Carpus 1.15 times as long as merus, 2.3 times as long as wide. Palm 0.65 length of carpus, 1.4 times long as wide; upper margin barely convex; lower margin carinate, with row of setae extending onto fixed finger; fixed finger 1.4 times as long as palm, cutting edge irregular. Dactylus longer than palm, curved distally; cutting edge smooth.

Pleopods 1 and 2 absent.

Etymology. From Mandu, a local name on Cape Range near the type locality (noun in apposition).

Distribution. Northwest Australian Shelf (Western Australia, northeastern North West Shelf to off Geraldton); 80– 200 m.

Remarks. Two species of Praedatrypaea have been recorded from the North West Shelf of Australia: Praedatrypaea praedatrix (De Man, 1905) by Sakai (1988) and P. propinqua (De Man, 1905) by Ngoc-Ho (1994); the latter was the name used erroneously in Robles et al.’s (2020) molecular study for a specimenfromthisregion.Closerstudyrevealsthatthespecimen from which tissue was taken is a new species, P. mandu , which differs from De Man’s two species in having the peduncles of the antenna and antennule of similar lengths; the peduncles of the antenna are much longer in De Man’s species. The telson of the new species is as long as wide, whereas those of De Man’s species are longer than wide. The uropodal exopod of the new species is twice as long as wide but relatively wider in the other two species. The propodus of pereopod 3 is much narrower than that of the holotype of P. propinqua figured by De Man (1928a) and of that of material from New Caledonia ( Ngoc-Ho, 1991).

The new species bears an uncanny resemblance to C. brachytelson Sakai, 2002 from the Andaman Sea, especially in the shape of the pleomere 6, telson, uropod and rostrum. Sakai’s specimens lacked all pereopods. Sakai specifically noted the absence of a tooth on the merus of maxilliped 3, a feature of P. mandu .

Figures

Figure 30. Praedatrypaea mandu sp. nov. Australia, Carnarvon Shelf. NMV J59650, holotype female, 3.3 mm: a, carapace, eyestalk, pleomeres 1, 2; b, c, anterior carapace, eyestalks, antennular, antennal peduncles (lateral, dorsal views); d, pleomere 6, telson, right uropod; e, pleomere 6, telson, uropod peduncle (left lateral view); f, uropod exopod (distal half, dorsal plate); g, pleomere 6, bases of uropod peduncles (ventral view). NMV J59276, paratype male, 3.5 mm: h, carapace, pleon, telson, uropod. Scale bars = 1 mm.

Figure 31. Praedatrypaea mandu sp. nov. Australia, Carnarvon Shelf. NMV J59650, holotype female, 3.3 mm: a, maxilliped 3 (inner view); b, maxilliped 3 merus (outer view); c, major cheliped (right, mesial view); d, minor cheliped (left, lateral view). NMV J59276, paratype male, 3.5 mm: e, minor cheliped (right, mesial view); f–i, pereopods 2–5; j, pleopod 3. Scale bar = 1 mm.