A synopsis of Typhlocarcinops Rathbun, 1909 (Crustacea: Decapoda: Brachyura: Pilumnidae), with descriptions of nine new species from the Indo-West Pacific Author Ng, Peter K. L. Author Rahayu, Dwi Listyo text Zootaxa 2020 2020-06-05 4788 1 1 100 journal article 10.11646/zootaxa.4788.1.1 1175-5326 3878222 7A461DBA-00B7-48DB-9320-4775DA8F21B2 Typhlocarcinops kanashi n. sp. ( Figs. 70 , 71 ) Typhlocarcinops decrescens — Sakai 1965: 171 , pl. 84, fig. 5; text-fig. 22; 1976: 546, pl. 195, fig. 2; text-fig. 293 (not Typhlocarcinops decrescens Rathbun, 1914 ). Material examined . Holotype : male (3.9 × 3.0 mm) (NSMT-Cr 11575a), station 7, Onagawa Bay , Miyagi Prefecture , Japan , 36 m , coll. M. Takeda , 26 September 1994 . Paratypes : 1 male (3.7 × 2.9 mm ) (NSMT-Cr 11575b), same data as holotype ; 1 male (4.5 × 3.5 mm ) (NSMT-Cr 1212), Kagoshima , Japan , coll. 19 August 1975 . Diagnosis . Carapace ( Fig. 70A, B, H ) about 1.3 times broader than long, slightly narrowing on posterolateral margin, surface with tufts of short plumose setae, regions demarcated, H-shaped gastro-cardiac grooves shallow, indistinct, anterolateral margin arcuate, lined with small granules, separated by 2 broad, sharp teeth; posterolateral margin subparallel; posterolateral surface with scattered tubercles. Front bilobed ( Fig. 70B, C, H ), with shallow median cleft, margin of each lobe convex. Orbit ( Fig. 70C ) short, bulbous ocular peduncles filling orbit, immovable, cornea small, pigmented. Epistome ( Fig. 70C ) relatively broad, triangular median lobe with slight median suture. Antennal peduncles long. Third maxilliped ( Fig. 71A ) with merus broad, outer and inner margins straight, anteroexternal angle protruding, auriculiform, ischium as broad, but slightly longer than merus, inner margin subequal in length to outer margin; exopod broad, relatively stout. Chelipeds slightly unequal in males ( Fig. 70A, F ), outer surface of dactylus and fixed finger with longitudinal ridge, sparse tubercles on proximal upper outer surface of dactylus; long fine setae on upper and lower margins of dactylus and fixed finger, cutting edges with prominent broad teeth; palm with large tubercles on outer lower and upper surface, carpus and merus smooth, tufts of sparse setae on its surfaces; inner angle of carpus with low tooth ( Fig. 70E ). P2−P5 proportionally long ( Fig. 70A, G ); proximal dorsal margin of the merus of first to third ambulatory legs with 1 or 2 small sharp granules; lateral surface, dorsal and ventral margins lined with long setae; dactylus straight, relatively short; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular ( Fig. 70D ), proportionally narrow; thoracic sternites 3, 4 fused, suture discernible. Male pleon ( Fig. 71B, E ) relatively broad; telson relatively short, 1.4 times as long as somite 6, with rounded distal margin. G1 ( Fig. 71C, D ) slender, curved, upper half longer than lower half, gently sinuous, distal part bent at almost right angles, tip tapering, with setae subdistally. Females not known. Etymology . The name is derived from the classical Japanese word “kanashi, meaning pretty and beloved; alluding to the delicate features of the species. The name is used as a noun in apposition. Remarks . Typhlocarcinops kanashi n. sp . is most similar to T. diminutus n. sp . but can be separated, with the anteroexternal angle of the merus of the third maxilliped strongly produced and the ischium is relatively short ( Fig. 71A ) (versus anteroexternal angle gently produced with the ischium much longer in T. diminutus n. sp . ; Fig. 69A ); the proximal dorsal margin of the merus of the ambulatory leg has one or two small sharp granules ( Fig. 70G ) (versus dorsal margin of merus entire in T. diminutus n. sp . ; Fig. 67H ); the ambulatory dactylus is proportionately shorter ( Fig. 70G ) (versus ambulatory dactyus proportionately longer in T. diminutus n. sp . ; Fig. 67H ); male pleonal somites 4–6 are proportionately broader ( Fig. 71B ) (versus pleonal somites proportionately more narrow in T. diminutus n. sp . ; Fig. 69B ); and G1 is gently sinuous with the distal part bent at almost right angles ( Fig. 71C, D ) (versus G1 strongly sinuous with the distal part more prominently curved in T. diminutus n. sp . ; Fig. 69C, D ). FIGURE 70 . Typhlocarcinops kanashi n. sp . A–G, holotype male (3.9 × 3.0 mm) (NSMT-Cr 11575a), Japan; H, paratype male (4.5 × 3.5 mm) (NSMT-Cr 1212), Japan. A, overall habitus; B, H, dorsal view of carapace; C, frontal view of cephalothorax; D, anterior thoracic sternum and telson; E, subdorsal view of carpus of right cheliped (denuded); F, outer view of right chela; G, left fourth ambulatory leg (denuded). FIGURE 71 . Typhlocarcinops kanashi n. sp . A–D, holotype male (3.9 × 3.0 mm) (NSMT-Cr 11575a), Japan; E, paratype male (4.5 × 3.5 mm) (NSMT-Cr 1212), Japan. A, right third maxilliped; B, pleon (telson tip damaged); C, right G1 (ventral view); D, right G1 (dorsal view); E, pleonal somites 5, 6 and telson. Scales: A, C, D = 0.1 mm; B, E = 0.5 mm. Sakai (1965) reported this species as “ T. decrescens ” based on a Sagami Bay male measuring 8.0 × 6.2 mm and later reported a second specimen from Manazuru, also in Japan ( Sakai 1976 ). The carapace as figured by him has three low lobes along the anterolateral margin ( Sakai 1965 : text-fig. 22a; 1976: text-fig. 293a), and in this aspect, superficially resembles the condition in T. canaliculatus , T. decrescens and T. denticarpes . The shape of the male pleon ( Sakai 1965 : text-fig. 22c) and especially the structure of the third maxilliped ( Sakai 1965 : text-fig. 22d), with the distinctive short ischium and prominently auriculiform anteroexternal angle indicate otherwise. His specimens are here identified as T. kanashi n. sp. (cf. Fig. 71A ) instead. The anterolateral margin of the types of T. kanashi n. sp. are relatively sharper and more dentate ( Fig. 70B, H ) but they are still low and the condition figured by Sakai (1965 , 1976 ) may be due its proportionately larger carapace size. The G1 as figured by Sakai (1965 : text-fig. 22b; 1976: text-fig. 293b) agree well with what is figured for T. kanashi n. sp. ( Fig. 71C, D ). Type locality . Honshu , Japan . Distribution . Known only from Japan thus far. The types were from 36 m depth, with the material from Sagami Bay recorded by Sakai (1965 , 1976 ) collected from 65– 85 m .