Parapleisticantha, Yokoya, 1933

Ng, Peter K. L., Forges, Bertrand Richer De & Lee, Bee Yan, 2023, New and rare deep-sea majoid crabs (Crustacea: Brachyura) from Papua New Guinea, Zootaxa 5318 (1), pp. 1-44 : 19-20

publication ID	https://doi.org/ 10.11646/zootaxa.5318.1.1
publication LSID	lsid:zoobank.org:pub:DB9D6B30-5A8C-486A-BF67-0965E4C026DA
DOI	https://doi.org/10.5281/zenodo.8158129
persistent identifier	https://treatment.plazi.org/id/9B094F56-FA5A-FFE9-FF20-C6B2FB5AF81F
treatment provided by	Plazi
scientific name	Parapleisticantha
status

Treatment

Parapleisticantha View in CoL aie n. sp.

( Figs. 1D View FIGURE 1 , 14–18 View FIGURE 14 View FIGURE 15 View FIGURE 16 View FIGURE 17 View FIGURE 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 GoogleMaps . 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 View Materials 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 GoogleMaps .

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 View FIGURE 14 , 15A–C View FIGURE 15 , 16A, B View FIGURE 16 ); 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 View FIGURE 15 ); interantennular spine bifid distally ( Fig. 15D View FIGURE 15 ); 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 View FIGURE 16 ). 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 View FIGURE 16 ). 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 View FIGURE 17 ). Distal margin of pleonal somite 6 deeply concave ( Fig. 16E View FIGURE 16 ). 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 View FIGURE 17 , 18A–D View FIGURE 18 ). G2 about a third length of G1, tip spatuliform ( Figs. 17F View FIGURE 17 , 18E View FIGURE 18 ).

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 View FIGURE 17 ). The vulva is large and open laterally on a raised part of sternite 6 ( Fig. 17H View FIGURE 17 ).

Colour. The carapace is pale yellow to orange with the chelipeds and ambulatory legs orangish-red with patches of white ( Fig. 1D View FIGURE 1 ).

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.

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 View FIGURE 14 , 15A, B View FIGURE 15 ; cf. Richer de Forges et al. 2013: figs. 1A, B, 3A, B); the basal antennal article is distinctly more elongate ( Fig. 16C, D View FIGURE 16 ; cf. Richer de Forges et al. 2013: fig. 1C); the third maxilliped ischium is proportionately longer ( Fig. 16F View FIGURE 16 ; 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 View FIGURE 17 , 18C, D View FIGURE 18 ) (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 View FIGURE 17 ); in adult males of Parapleisticantha , the chelae are inflated and stout ( Richer de Forges et al. 2013: figs. 2E, 5E).