New and rare deep-sea majoid crabs (Crustacea: Brachyura) from Papua New Guinea Author Ng, Peter K. L. Author Forges, Bertrand Richer De Author Lee, Bee Yan 0000-0002-5806-6999 beeyan06@gmail.com text Zootaxa 2023 2023-07-18 5318 1 1 44 http://dx.doi.org/10.11646/zootaxa.5318.1.1 journal article 10.11646/zootaxa.5318.1.1 1175-5326 8158079 DB9D6B30-5A8C-486A-BF67-0965E4C026DA Parapleisticantha aie n. sp. ( Figs. 1D , 14–18 ) Type material . Holotype : male (cl 18.7 mm , pcl 16.5 mm , cw 12.4 mm , pcw 11.5 mm ) (MNHN-IU-2014-18677a), stn CP 4502, New Ireland , 02°32’S 150°44’E , 193–206 m , coll. N.O. Alis , KAVIENG 2014 expedition, 7 September 2014 . Paratypes : 1 female (cl 14.9 mm , pcl 12.6 mm , cw 10.0 mm, pcw 9.2 mm ) (MNHN-IU-2014-18677b), same data as holotype; 1 ovigerous female (cl 17.7 mm , pcl 15.4 mm , cw 12.9 mm , pcw 12.2 mm ) ( ZRC 2022.73 ex MNHN-IU-2014-10019), stn DW 4415, New Ireland , 02°31’S 150°38’E , 212–214 m , coll. N.O. Alis , KAVIENG 2014 expedition, 27 August 2014 . All specimens from Papua New Guinea . Diagnosis. Small-sized species (ovigerous female less than 17 mm long); regions well defined; base of epigastric region with 2 short spines, meso- and metagastric regions with 1 median spine each, protogastric spines with 1 short oblique spine, cardiac region with 2 laterally positioned short spines, intestinal region with 2 short spines, branchial region with 1 prominent anterior spine and 1 short posterior spine, lateral branchial margin with 7–9 larger spines and many smaller ones, hepatic region with 2 strong spines; rest of carapace covered with short spinules and sharp granules ( Figs. 14 , 15A–C , 16A, B ); pseudorostral spines clearly diverging, forming V-shape, each spine relatively short, with 4 lateral accessory spines; ventral surface with 2 spines; distal border of antennular fossa with strong distal anteriorly directed spine; supraorbital eave relatively low, narrow, preorbital tooth long, margin of eave with 5 spines, proximal one small, no obvious large antorbital spine; intercalated spine distinct, smaller than prominent postorbital spine ( Fig. 15A–D ); interantennular spine bifid distally ( Fig. 15D ); basal antennal article long with 2 distal spines, one larger, outer margin with 3 spines, inner margin with 1 short spine, first article with prominent lateral spine ( Fig. 16C, D ). Third maxilliped pediform: ischium with 2 longitudinal rows of sharp granules on outer surface, lateral row with 8 tubercles, mesial row with 5 tubercles; merus subtriangular, longer than broad, with 4 sharp tubercles on outer surface, exopod with row of 9 tubercles or granules ( Fig. 16E, F ). Cheliped palm not inflated; propodal margin below articulation of dactylus and pollex with low subtruncate granulated process; cutting edge fingers with evenly sized teeth, those on proximal part of dactylus slightly larger ( Fig. 17B ). Distal margin of pleonal somite 6 deeply concave ( Fig. 16E ). G1 relatively slender, slightly curved along basal two-thirds, distal part bent outwards, forming ca. 60° angle, distal part elongate, with small subdistal process ( Figs. 17C–E , 18A–D ). G2 about a third length of G1, tip spatuliform ( Figs. 17F , 18E ). Female. The females agree well with the male in all non-sexual aspects. The female pleon has somites 1–5 free (each with a median tubercle), with somites 1–3 relatively narrow and somites 4–6 increasingly wider; somite 6 is functionally fused to the telson although the suture is still visible; the structure appearing almost round in ventral view, prominently dome-shape with the telson semicircular ( Fig. 17G ). The vulva is large and open laterally on a raised part of sternite 6 ( Fig. 17H ). Colour. The carapace is pale yellow to orange with the chelipeds and ambulatory legs orangish-red with patches of white ( Fig. 1D ). Etymology. The name is derived from the French word “aie” for an exclamation of pain, alluding to the prickly features of the species. The name is used as a Latin noun in apposition. FIGURE 14. Parapleisticantha aie n. sp. A, holotype male (pcl 16.5 mm) (MNHN-IU-2014-18677a), New Ireland; B, paratype ovigerous female (pcl 15.4 mm) (ZRC 2022.0073), New Ireland. Overall dorsal views. Remarks. The present new species is closest to P. japonica , known from only a few specimens, all from Japan ( Yokoya 1933: 140 , text-fig. 50; Takeda & Miyake 1969: 494 , pl. 18, fig. A, text-fig. 9c, d; Sakai 1976: 174 ; Sakai 1986: 238 ; 1940: 55; Richer de Forges et al. 2013: 17 , figs. 1–3, 6A–E). Parapleisticantha aie n. sp. , however, differs from P. japonica in having the carapace proportionately longer ( Figs. 14 , 15A, B ; cf. Richer de Forges et al. 2013 : figs. 1A, B, 3A, B); the basal antennal article is distinctly more elongate ( Fig. 16C, D ; cf. Richer de Forges et al. 2013 : fig. 1C); the third maxilliped ischium is proportionately longer ( Fig. 16F ; cf. Richer de Forges et al. 2013 : fig. 2C); and most significantly, the G1 has the distal part less distinctly curved with the tapering tip more elongate and there is a small subdistal fold ( Fig. 17C–E , 18C, D ) (versus G1 distal part curving at almost right angles with the tip shorter and there is no trace of a subdistal flap in P. japonica ; cf. Richer de Forges et al. 2013 : fig. 6A–D). The holotype male is not fully mature as its chelae are still relatively slender ( Fig. 17B ); in adult males of Parapleisticantha , the chelae are inflated and stout ( Richer de Forges et al. 2013 : figs. 2E, 5E).