Typhlocarcinops raouli, Ng & Rahayu, 2020

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2020, A synopsis of Typhlocarcinops Rathbun, 1909 (Crustacea: Decapoda: Brachyura: Pilumnidae), with descriptions of nine new species from the Indo-West Pacific, Zootaxa 4788 (1), pp. 1-100 : 50-54

publication ID	https://doi.org/ 10.11646/zootaxa.4788.1.1
publication LSID	lsid:zoobank.org:pub:7A461DBA-00B7-48DB-9320-4775DA8F21B2
persistent identifier	https://treatment.plazi.org/id/03C05222-FF93-FC39-FF35-D6A5FB57F8A7
treatment provided by	Plazi
scientific name	Typhlocarcinops raouli
status	sp. nov.

Treatment

Typhlocarcinops raouli View in CoL n. sp.

( Figs. 41–44 View FIGURE 41 View FIGURE 42 View FIGURE 43 View FIGURE 44 )

Typhlocarcinops canaliculata View in CoL ?— Serène 1964: 226, fig. 9 (not Typhlocarcinops canaliculata Rathbun, 1909 View in CoL ). Typhlocarcinops stephenseni View in CoL — Serène 1964: 226 (part) (not Typhlocarcinops stephenseni Serène, 1964 View in CoL , s. str.)

Material examined. Holotype: male (8.0 × 5.7 mm) ( MZB Cru 4806), Digul, Arafura Sea, 19 October 2002 . Paratypes: 5 males (6.4 × 4.3 mm, 4.5 × 3.0 mm, 4.7 × 3.1 mm, 4.2 × 2.7 mm, 4.0 × 2.8 mm), 4 females (4.4 × 3.0 mm, 4.7 × 3.3 mm, 5.4 × 3.5 mm, 4.1 × 2.7 mm) ( ZRC 2018.0260 View Materials ), male (7.5 × 5.5 mm) , 1 female (6.0 × 4.4 mm) ( MZB Cru 4807), same data as holotype ; 1 male (5.4 × 3.6 mm) ( ZRC 2018.0261 View Materials ), Digul, Arafura Sea, coll. 27 April 2000 ; 2 females (5.3 × 3.6 mm) (8.7 × 5.8 mm) ( ZRC 2018.0262 View Materials ), Otakwa Estuary, coll. 2 November 1999 ; 2 males (7.0 × 5.0 mm, 5.2 × 3.8 mm) ( ZRC 2018.0263 View Materials ), station MA6B, Minajerwi , 5°05’10.11’’S 137°06’54.76’’E, coll. 20 November 1999 GoogleMaps ; 2 males (7.8 × 5.5 mm, 7.6 × 5.6 mm) ( MZB Cru 4808), Kokonao Estuary, 4°48’14.81’’S 136°30’49.68’’E, coll. 7 November 2000 GoogleMaps ; 1 male (7.0 × 4.7 mm) ( MZB Cru 4808), station OT 3A, Otakwa Estuary, 5°06’57.46’’S 137°09’22.03’’E, coll. 30 November 1999 GoogleMaps ; 1 male (6.5 × 4.2 mm) ( MZB), station K6B, Kokonao Estuary , 4°50’57.87’’S 136°36’10.11’’E, coll. 1 November 1999 GoogleMaps ; 1 female (7.8 × 5.0 mm) ( ZRC 2018.0264 View Materials ), station K3A, Kokonao Estuary , 4°50’04.31’’S 136°33’51.60’’, coll. 3 November 2000 ; 1 male (9.3 × 6.1 mm) ( ZRC 2018.0265 View Materials ), Minajerwi, 5 m, coll. 26 October 2000 ; 1 male (6.5 × 4.4 mm) ( ZRC 2018.0266 View Materials ), station T3B, Timika , 4°53’14.43’’S 136°38’54.85’’E, coll. 2 November 1999 GoogleMaps ; 1 ovig. female (6.5 × 4.8 mm) ( ZRC 2018.0267 View Materials ), station Mi 6, Minajerwi, 5°02’20.19’’S 137°00’42.49’’E coll. 8 November 1999 GoogleMaps ; 1 female (6.0 × 4.0 mm) ( ZRC 2018.0268 View Materials ), station A6A, Digul , Arafura Sea, 5°00’02.62’’S 136°52’49.19’’E coll. 27 October 2000 GoogleMaps ; 1 male (4.7 × 3.5 mm), 1 female (4.4 × 3.1 mm) ( ZRC 2018.0270 View Materials ), station OT 4a, Otakwa estuary, 5°13’34.95’’S 137°02’22.66’’E, 9 November 2000 GoogleMaps ; 1 ovig. female (6.0 × 4.0 mm) ( ZRC 2018.0276 View Materials ), station CA2B, 4°58’38.26’’S 136°49’07.46’’E, Arafura Sea, coll. 27 October 2000 GoogleMaps . All locations in Papua, Indonesia. Others : 1 female (8.7 × 6.1 mm) ( ZRC 2018.0701 View Materials ), station W1, Hong Kong, coll. University of Hong Kong trawls, 16 July 2015

Diagnosis. Carapace ( Figs. 41 View FIGURE 41 , 42G, H View FIGURE 42 , 43A, B View FIGURE 43 ) 1.4−1.6 times broader than long, surface smooth, short plu- mose setae on lateral and frontal margins, regions demarcated, H-shaped gastro-cardiac grooves shallow, indistinct, anterolateral margin arcuate, lined with small granules, separated by 3 broad lobes; posterolateral margin subparallel, surface and margin with scattered tubercles. Front bilobed ( Figs. 41A, B View FIGURE 41 , 42H View FIGURE 42 , 43 View FIGURE 43 A‒C), with shallow median cleft, margin of each lobe convex. Orbit ( Figs. 42A View FIGURE 42 , 43C View FIGURE 43 ) short, bulbous ocular peduncles filling orbit, immovable, cornea small, pigmented. Epistome relatively broad, slightly triangular median lobe with median suture ( Fig. 42A View FIGURE 42 ). Antennal peduncles long. Third maxilliped ( Figs. 42E View FIGURE 42 , 44A View FIGURE 44 ) with outer surface of merus covered with small granules on distal margin, outer margin straight, anteroexternal angle rounded; ischium slightly broader, but much longer than merus, inner margin much shorter than outer margin, lower margin strongly oblique; exopod relatively slender. Chelipeds unequal in males, subequal in females ( Figs. 41D View FIGURE 41 , 42G View FIGURE 42 , 43D, E View FIGURE 43 ), fingers of major chela smooth, outer surface of dactylus with longitudinal sulcus, lower outer face of fixed finger with longitudinal rim, long fine setae on upper and lower margins of dactylus and fixed finger, cutting edges with prominent broad teeth; palm, carpus and merus smooth, sparse setae on its margin; inner angle of carpus rounded ( Figs. 41A, B View FIGURE 41 , 43E View FIGURE 43 ). P2−P5 proportionally short ( Figs. 41C, D View FIGURE 41 , 42G View FIGURE 42 ), lateral surface, dorsal and ventral margins fringe with long setae; dactylus straight; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular ( Fig. 42B, C View FIGURE 42 ), proportionally narrow; thoracic sternites 3, 4 fused, suture discernible. Male pleon ( Figs. 42B, C View FIGURE 42 , 44B View FIGURE 44 ) relatively narrow; telson relatively long, 1.9 times as long as somite 6, subtriangular. G1 ( Fig. 44 View FIGURE 44 D–F) slender, upper half shorter than lower half, distal part strongly curved downwards, hook-shaped, flared with rounded tip, directed obliquely laterally, with setae near opening. Female pleon ( Fig. 42E View FIGURE 42 ) broad, somite 1 reaching coxae of fourth ambulatory legs, tapering to pointed edge; telson subtriangular; vulva ( Fig. 42F View FIGURE 42 ) relatively broad, rounded.

Etymology. The species is named after the late Raoul Serène, for his substantial contributions to Asian carcinology.

Remarks. Dai et al. (1986) and Dai & Yang (1991) recorded T. canaliculatus from China and commented that the material reported as this species by Serène (1964) from Indonesia is not that species. The present material confirms this and they are referred to a new species, T. raouli n. sp. Typhlocarcinops raouli n. sp. differs from T. canaliculatus in possessing a transversely subrectangular carapace with the anterolateral teeth clearly marked ( Figs. 41 View FIGURE 41 , 42G, H View FIGURE 42 , 43A, B View FIGURE 43 ) (versus carapace subovate with the anterolateral margin entire or with low barely discernible lobes in T. canaliculatus ; cf. Figs. 5B, C View FIGURE 5 , 7A, D View FIGURE 7 , 8B View FIGURE 8 , 9B, C View FIGURE 9 , 10A View FIGURE 10 , 11B View FIGURE 11 ); the dorsal surface of the carapace is almost flat in frontal view ( Figs. 42A View FIGURE 42 , 43C View FIGURE 43 ) (versus dorsal surface gently convex in frontal view in T. canaliculatus ; cf. Figs. 8C View FIGURE 8 , 9D View FIGURE 9 , 11C View FIGURE 11 ,); the ambulatory legs (especially the meri) are proportionately longer ( Figs. 41C, D View FIGURE 41 , 42G View FIGURE 42 ) (versus legs proportionately shorter in T. canaliculatus ; cf. Figs. 5A View FIGURE 5 , 7A View FIGURE 7 , 8A View FIGURE 8 , 9A View FIGURE 9 , 11A View FIGURE 11 , 12A View FIGURE 12 ); the chela are smooth with the ventral margin along the propodus distinctly cristate ( Figs. 42D View FIGURE 42 , 43D View FIGURE 43 ) (versus chela prominently setose with the ventral margin along the propodus not cristate in T. canaliculatus ; cf. Figs. 5F, G View FIGURE 5 , 7B View FIGURE 7 , 8F View FIGURE 8 , 9G, H View FIGURE 9 , 10E, F View FIGURE 10 , 11E, F View FIGURE 11 ); the male anterior thoracic sternum is proportionately wider ( Fig. 42B View FIGURE 42 ) (versus thoracic sternum proportionately more narrow in T. canaliculatus ; cf. Fig. 8D View FIGURE 8 , 9E View FIGURE 9 , 10B View FIGURE 10 , 11D View FIGURE 11 ); the vulvae are relatively smaller ( Fig. 42F View FIGURE 42 ) (versus relatively larger in T. canaliculatus ; cf. Fig. 12D View FIGURE 12 ); and the distal part of the G1 is prominently fluted ( Fig. 44 View FIGURE 44 C–F) (versus distal part slender and tapering in T. canaliculatus ; cf. Figs. 13 View FIGURE 13 D–G, I–L, 14B–E, H–K, 15E‒G).

Typhlocarcinops raouli n. sp. closely resembles T. stephenseni Serène, 1964 , in having a relatively broad carapace with three broad lobes on the anterolateral margin, the male pleon with the tip of the telson rounded, and a strongly curved G1 with the tip open. Typhlocarcinops raouli n. sp., however, has a relatively broader male pleon and longer telson ( Fig. 44B View FIGURE 44 ) (1.9 versus 1.3 times as long as the somite 6 in T. stephenseni ; cf. Serène 1964: fig. 8B; present Fig. 33C View FIGURE 33 ), the distal part of G1 is distinctly more strongly curved, flared, and with rounded tip ( Fig. 44 View FIGURE 44 C–F) (versus distal part of G1 is slightly less curved and the tip is not flared in T. stephenseni ; cf. Serène 1964: fig. 8C; present Fig. 33D, E View FIGURE 33 ); and relatively shorter and broader merus of the fourth ambulatory legs (3.6 times as long as broad in T. raouli n. sp. [ Figs. 41C, D View FIGURE 41 , 42G View FIGURE 42 ] versus 4.2 times as long as broad in T. stephenseni ; cf. Serène 1964: pl. 19B; present Fig. 33A View FIGURE 33 ).

Serène (1964: 224, 226) recorded T. stephenseni from the Persian Gulf, Pakistan, India, Andamans and Vietnam, but based his description and figures on a male from India. Although T. stephenseni is similar to what is here described as T. raouli n. sp. (which Serène [1964] had identified as “ T. canaliculata ”), Serène (1964) did not compare the two species. Serène (1964) only compared T. stephenseni with Typhlocarcinus nudus Stimpson, 1858 (with which the Indian and Persian Gulf material had been confused) and Typhlocarcinus dentatus Stephensen, 1946 . On the basis of the present discussion and geography, Serène’s (1964) material from Vietnam is more likely to belong to T. raouli .

There is, however, a problem with Serène’s (1964) description of T. stephenseni . He stated that he had examined one male specimen from India from the Zoological Survey of India ( Serène 1964: 223), which he figured in his plate and presumably the same one he figured the male pleon, third maxilliped and G1 (although he did not make it clear). He discussed the taxonomy and stated that the records of “ Typhlocarcinus nudus ” recorded by Alcock (1900) and Stephensen (1946) from India and the Persian Gulf, respectively, are not that species. He also noted with doubt that what Rathbun (1910) had reported as “ Typhlocarcinus nudus ” from the Gulf of Thailand was also T. stephenseni , suggesting (without any explanation) that she may have missed the fact that her specimens of this species had an elongated male pleonal somite 1 ( Serène 1964: 224), even though she was the one who established the genus and used this character in 1909. He also noted that he had specimen(s) from Nhatrang Bay in Vietnam belonging to T. stephenseni ( Serène 1964: 226) . No types of T. stephenseni were designated, and as such, all the material of Alcock (1900) and Stephensen (1946), as well as the Vietnamese specimen(s) are syntypes.A lectotype should be selected at a later date, preferably from the Indian Ocean, to stabilize the taxonomy of the species, especially since the present study indicates that Serène’s (1964) material from Vietnam is probably not that species.

Type locality. Arafura Sea.

Distribution. Arafura Sea, Indonesia; Vietnam and Hong Kong. On soft sediments 10– 40 m.