Praedatrypaea lobetobensis (De Man, 1905 ) 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 : 207-210

Praedatrypaea lobetobensis (De Man, 1905) comb. nov.

Figures 1d , 28 , 29

Callianassa lobetobensis De Man, 1905: 607 .— Sakai, 1999: 48.— Tudge et al., 2000: 143.— Sakai, 2005: 91.

Callianassa (Cheramus) lobetobensis . —De Man, 1928b: 26, 93, 98, 137, pl. 13 fig. 20, pl. 14 fig. 20a–d.

Cheramus lobetobensis .— Sakai, 2011: 368.

Pugnatrypaea lobetobensis .— Poore et al., 2019: 138, 143.

Material examined. Australia, NT, Arafura Sea , 9° 12.331' S, 133° 38.903' E, 158 m, mud ( CSIRO stn SS05/2005/032/ BS006 ), AM P.74439 (ovigerous female, 5.3 mm, antennules missing; female, 3.2 mm). WA, North West Shelf, 16° 73.25' S, 119° 24.68' E, 695 m ( CSIRO stn SS05/2007/73), NMV J60024 (juvenile, 1.6 mm); 16° 37.03' S, 120° 34.02' E, 410 m ( CSIRO stn SS05/2007/12), NMV J6002 (juvenile, 1.5 mm); 9° 24.141' S, 134° 14.268' E, 97 m, muddy silt ( CSIRO stn SS05/2005/014/GR023), AM P.74445 (damaged); 9° 7.587' S, 133° 25.289'E, 199 m ( CSIRO stn SS05/2005/041/GR066), AM P.74470 (female, 3.0 mm) . Papua New Guinea, Bismarck Sea , 03° 32' S, 148° 06' E, 540–586 m ( MADEEP stn DW4248 ), MNHN IU-2015-109 # (male, 3.3 mm) .

Diagnosis. Antennular peduncle reaching distal margin of antennal peduncle article 4. Maxilliped 3 ischium about twice as long as wide; merus oval, about 1.5 times as wide as long, with tooth on oblique margin. Chelipeds meri upper margins each with subproximal spine. Major cheliped merus lower margin with spine at midpoint, or with 4 teeth over proximal half; carpus about as long as wide, or about twice as long as wide; palm about as long as or 1.5 times as long as carpus, 1.2 times as long as wide or about twice as long as wide; fingers, cutting edges with obsolete teeth. Uropod endopod 1.8 times as long as wide; anterior margin straight, with 2 small teeth, with 4 distal spiniform setae; distal-posterior margin strongly convex distally; dorsal face without facial setae. Uropod exopod rectangular, truncate distally, twice as long as wide; anterior margin straight, not setose. Telson 1.4 times as long as wide, widest at strong lateral lobes at one fifth length; posterior margin with 2 semicircular lobes separated by narrow notch filled by medial spine; with 2 pairs of spiniform setae on posterolateral margins. Male pleopod 1 2-articled; pleopod 2 biramous.

Supplementary description. Female. Rostrum laterally compressed, situated below upper level of carapace, with ventral convex keel-like carina, three quarters length of eyestalks. Carapace dorsally flat, as long as pleomeres 1–3 combined; orbital margin almost transverse; anterolateral angle projecting, rounded; subanterolateral margin oblique; cervical groove across 0.7 length of carapace, reaching linea thalassinica. Pleomere 1 tergite waisted in dorsal view. Pleomere 6 about as long as wide, with ventrolateral projection.

Eyestalk 1.25 times as long as wide, with flat dorsal face, with sharp ventrolateral margin, anterolateral margin convex in dorsal view, not reaching distal margin of antennular peduncle article 1. Cornea terminal, occupying middle third of distal margin of eyestalk, darkly pigmented.

Antennular peduncle reaching distal margin of antennal peduncle article 4; article 1 clearly visible in dorsal and lateral views; article 2 shorter than article 1; article 3 as long as articles 1 and 2 combined; articles 2 and 3 with longitudinal ventral row of sparse long setae. Antennal peduncle article 5 0.6 length of article 4; scaphocerite minute, spiniform.

Maxilliped 3 ischium slightly tapering, 2.1 times as long as wide, crista dentata consisting of row of about 20 strong erect spines, stronger distally, overlapping distal margin; merus about 0.7 length of ischium measured along outer margin, about 1.45 times as long as wide, wider than ischium, with triangular tooth on mesiodistal margin; carpus slightly shorter than merus; propodus tapering, 1.9 times as long as wide; dactylus digitiform, 0.7 length of propodus, with long setae concentrated distally and along flexor margin.

Pereopods 1 (chelipeds) unequal, similar. Major cheliped linear, carpus-palm upper margin about as long as carapace length. Ischium slightly expanding distally, upper margin straight, unarmed; lower margin with row of 8 spines. Merus about as long as ischium, 3 times as long as wide (spines excluded), slightly tapering distally; upper margin with 1 spine about one third way along; lower margin with oblique tooth near midpoint. Carpus 2.7 times as long as wide, elongate-triangular; upper margin smooth; lower margin convex. Propodus upper margin 0.9 length of carpus; palm slightly expanding distally, 1.9 times as long as wide; upper margin carinate; lateral surface smooth; mesial surface slightly convex; lower margin sharply carinate, with row of setae extending onto fixed finger; fixed finger 0.75 times length of palm, slightly depressed; cutting edge obscurely denticulate proximally. Dactylus as long as fixed finger, slightly curved; upper margin with few tufts of long setae; lateral surface with few tufts of long setae along cutting edge; cutting edge smooth.

Minor cheliped similar to major but more slender; carpus-palm upper margin slightly shorter than carapace length. Ischium upper margin smooth, lower margin with row of 9 spines. Merus about as long as ischium; with teeth as in major. Carpus 5 times as long as wide, elongate-triangular. Propodus upper margin 0.35 times as long as carpus; palm slightly expanding distally, 1.9 times as long as wide; upper margin carinate; lateral surface smooth; mesial surface slightly convex; lower margin sharply carinate, with row of setae extending onto fixed finger; fixed finger as long as palm, not depressed; cutting edge smooth. Dactylus as long as fixed finger, slightly curved; cutting edge smooth.

Pereopod 2 merus with almost parallel margins, 4.1 times as long as wide; carpus subtriangular, 1.9 times as long as wide; chela subtriangular; palm twice as wide as upper margin; dactylus 3.3 times as long as palm upper margin. Pereopod 3 carpus subtriangular, twice as long as wide; propodus oval with slight produced lower proximal margin, upper margin 1.2 times width, lower margin convex; dactylus nearly straight, 0.75 length of propodus upper margin. Pereopod 4 coxa flattened ventrally, immovable; basis and ischium partially fused, extended posterolaterally; merus 1.2 times as long as ischium; carpus 0.65 length of merus; propodus as long as carpus, with dense grooming setae distally on lower margin, scattered stiff setae on outer surface; dactylus slightly curving, half as long as propodus. Pereopod 5 slender, with chela longer than carpus, slightly curving.

Female pleopod 1 of 2 articles. Female pleopod 2 subequally biramous; peduncle almost straight; exopod tapering distally, endopod of 2 articles. Pleopods 3–5 biramous, rami broad (endopod twice as long as wide); appendix interna slender, rod-like, projecting well beyond mesial margin of endopod, bearing coupling hooks on apical margin.

Uropod exopod only overreaching posterior margin of telson. Endopod about 1.6 times as long as wide, oval with straight anterior margin bearing 2 minute teeth, with 4 distal spiniform setae; upper surface without slender or spiniform setae; posterodistal margin convex, with fringe of setae. Exopod rectangular, with convex truncate distal margin, 1.7 times as long as wide, exceeding endopod by about one third length; anterior margin almost straight, without setae; posterior margin with numerous slender setae, with 10 blade-like distal setae, indistinguishably merged with distal margin; upper surface with 1 long seta; dorsal plate shorter than half exopod width, with row of about 6 stiff setae grading into/ separated from setal row of distal margin.

Telson suboval, 1.4 times as long as wide, broadest anterior to anterolateral lobes, narrowing posteriorly to pair of posterior lobes separated by deep notch including median spine; dorsal surface with few medial setae anterior to midlength; posterolateral margin with 2 prominent curved spiniform setae.

Male. Rostrum not as deep as in female. Pereopods 1 (chelipeds) unequal, similar. Major cheliped linear, carpus-palm upper margin little shorter than carapace length. Ischium slightly expanding distally, upper margin straight, unarmed; lower margin with row of 8 spines, increasing in size distally. Merus about as long as ischium, 2.5 times as long as wide (spines excluded), slightly tapering distally; upper margin with 1 spine about one third way along; lower margin with oblique tooth near midpoint, smaller ones proximally. Carpus 1.7 times as long as wide, elongate-triangular; upper margin smooth; lower margin convex. Propodus upper margin 0.8 length of carpus; palm widest at midpoint, 1.3 times as long as wide; upper margin carinate; lateral surface smooth; mesial surface slightly convex; lower margin sharply carinate, with row of setae extending onto fixed finger; fixed finger 0.7 length of palm, straight; cutting edge smooth. Dactylus as long as fixed finger, slightly curved; cutting edge smooth. Minor cheliped as in female. Pleopod 1 2-articled. Pleopod 2 biramous; endopod half as long as exopod.

Distribution. Western and Eastern Coral Triangle, Sahul Shelf, Northwest Australian Shelf ( Papua New Guinea, Bismarck Sea; Indonesia, Banda Sea [type locality: Savu Sea, 8° 27' S, 122° 54.5' E, 247 m]; Australia, NT and WA, Arafura Sea to North West Shelf); 158– 695 m.

Remarks. The holotype of Praedatrypaea lobetobensis is an ovigerous female with a more robust major cheliped than the females examined here; the lower margin of the merus of the major cheliped has four teeth along its proximal half, whereas these specimens have a single spine. These differences are attributed to larger size (cl. 5.9 mm) and maturity than the females examined here.

Praedatrypaea lobetobensis is one of two species in the genus with a tooth on the upper margin of the merus of both chelipeds, the other being P. intermedia (De Man, 1905) . Both were described from eastern Indonesian deep water. They differ in the shape of the telson, that of P. lobetobensis having convex lateral margins converging on a pair of lobes (each as long as wide) separated by a narrow median notch, while that of P. intermedia has straight lateral margins converging on a pair of lobes (each shorter than wide) separated by a concave median notch.

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 28. Praedatrypaea lobetobensis (De Man, 1905). Australia, Arafura Sea. AM P.74439, ovigerous female, 5.3 mm: a, carapace, pleomeres 1, 2; b, anterior carapace, eyestalk, antennal peduncle; c, carapace, eyestalks, left antennal peduncle; d, pleomere 6, telson, right uropod; e, maxilliped 3; f, major cheliped (right, mesial); g, minor cheliped (left, mesial); h–k, pereopods 2–5. Scale bars = 1 mm.

Figure 29.Praedatrypaea lobetobensis (De Man, 1905). Australia, Arafura Sea. AM P.74439, ovigerous female, 5.3 mm: a–c, pleopods 1–3. Papua New Guinea, MNHN IU-2015-109, male, 3.3 mm: d, e, anterior carapace, eyestalk, antennular, antennal peduncles (lateral); f, major cheliped (left mesial); g, minor cheliped (right, mesial); h–j, pleopods 1–3. Scale bars = 1 mm.