Neosarmatium asiaticum, Ragionieri & Fratini & Schubart, 2012

Ragionieri, Lapo, Fratini, Sara & Schubart, Christoph D., 2012, Revision Of The Neosarmatium Meinerti Species Complex (Decapoda: Brachyura: Sesarmidae), With Descriptions Of Three Pseudocryptic Indo-West Pacific Species, Raffles Bulletin of Zoology 60 (1), pp. 71-87 : 82-83

Neosarmatium asiaticum , new species

( Figs. 1c , 2c , 3c,g , 4c,g , 5c , 6e,f )

Sesarma tetragona: Henderson, 1893: 392 [not Cancer tetragona Fabricius, 1798: 341 ].

Sesarma meinerti: De Man, 1887: 648 (in part); Bürger, 1893: 617; Alcock, 1900: 417; Horikawa, 1940: 30; Lin, 1949: 30; Ortmann, 1894a: 720; 1894b: 56.

Sesarma (Episesarma) meinerti: De Man 1895: 166 .

Sesarma (Sesarma) meinerti: Miyake, 1938: 108 ; Tesch, 1917: 171–174 (in part).

Sesarma (Sarmatium) meinerti: De Man, 1929 : Fig 4 .

Neosarmatium meinerti ; Dai et al., 1986: 496, Fig. 280, pl. 70(3); Dai & Yang, 1991: 543–44, Fig. 280, pl. 70(3); Ng et al., 1997: 145–159, Figs. 1b , 2b,f,k , 3b , 4b , 5b,d , 6b,g , 7e,f , pl. 49 (2); Dahdouh-Guebas et al., 2011: 188.

Material examined. — Holotype: male (38.52 × 33.11 mm) ( NMNS- 6327-001 ), Tainan City, Sihcao, Dajhong Temple, Taiwan, coll. J.-H. Lee & W.-J. Wang, 23 Jan.2005 . Paratypes: TAIWAN: 1 male (37.10 × 32.15 mm) ( MZUF 2516 ), Pingtung, Kenting, Pao Li stream, coll. H. C. Liu, 14–16 Jun.1995 ; 1 male (39.40 × 30.40 mm), 1 female (31.40 × 24.70 mm) ( ZRC 1997.660 ) Pingtung County, mouth of Paoli River , coll. H. C. Liu & C. H. Wang, 15 Aug.1996 ; 1 male (38.47 × 32.83 mm) ( NCHU 13076 ), Tainan City, Sihcao, Dajhong Temple , coll. J.-H. Lee & W.-J. Wang, 18 Dec.2004 ; THAILAND: 1 female ( ZRC 2000.1899 ), Phuket, Ao Teng Khen , coll. C. D. Schubart et al., 22 Aug.1999 ; 1 male (32.90 × 28.83 mm) ( ZRC 2001.1083 ), Phuket, Thailand , coll. Yeo D. C. J. & Y. Cai, 22 Feb.2001 ; INDONESIA: 1 male (23.47 × 21.91 mm) ( MNHN-B31277 ), aquarium trade ; 1 male (34.68 × 28.15 mm) ( MNHN-B31276 ), aquarium trade (possibly Sulawesi) .

Diagnosis. — Carapace narrowing to posterior, straight borders with gentle cleft, corresponding to second anterolateral tooth ( Fig. 2c ). Male chela characterised by presence of a double line of weak tubercles along inner palm surface ( Fig. 3g ), with palm height 1.70 (± 0.12; n = 6) times maximum chelar width. Descending slope of palm (with parallel prominent ridge) at articulation with dactylus almost transverse ( Fig. 3c ). Lower margin of chela convex. Dorsal surface of dactylus covered with tubercles until tip ( Fig. 4c, g ). Male abdomen relatively more quadrate; somite 6 with proximal width 1.13 (± 0.093; n = 6) times length; telson length 1.09 (± 0.11; n = 6) times width ( Fig. 5c ).

Colour. — The most common colour morph of N. asiaticum , new species is the yellow one (mostly in East Asia), whereas specimens from Sri Lanka (S. Cannicci, pers. obs.), Thailand, and Indonesia are characterised by red-orange chelae. Ragionieri et al. (2009) did not record any genetic differences among specimens with different colour morphs.

Etymology. — Neosarmatium asiaticum , new species, is named after its distribution from South Asia ( Sri Lanka) to East Asia (Taiwan) including Indonesia.

Habitat. — Neosarmatium asiaticum , new species inhabits mangroves and estuaries with grassy banks which are under the influence of tides. In Taiwan, this species occurs sympatrically with its putative sister species N. fourmanoiri , and the land crab Cardisoma carnifex (Gecarcinidae) ( Ng et al., 1997). All specimens examined from Guam were identified as N. fourmanoiri .

Ecology. — Until now, there is limited information on the ecology of this species deduced from a paper on the herbivorous feeding habitus of Asiatic sesarmid crabs ( Ashton, 2002), but a recent study performed in Sri Lanka ( Dahdouh-Guebas et al., 2011) confirmed that the species consumes leaf litter and mangrove propagules.

Distribution. — Its distribution range extends from Sri Lanka through the Andamans, ending in Indonesia and Taiwan ( Alcock, 1900; Davie, 1994; Ng et al., 1997).

Figures

Fig. 1. Frontal view of four species of Neosarmatium: a, N. africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b, N. meinerti (De Man, 1887) paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM- W29085), Australia.

Fig. 2. Dorsal view of carapaces of four species of Neosarmatium: a, N. africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), Australia.

Fig. 3. Outer and inner surfaces of the right chelae of four species of Neosarmatium: a, e, N. africanum, new species, holotype male (42.83 × 38.33) (MZUF 678), Somalia; b, f, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60) (MZUF 2931), Seychelles; c, g, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, h, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), University of Darwin, Darwin, Australia.

Fig. 4. Dorsal view of distal chelipeds and dactyli: a,e, Neosarmatium africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b,f, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, g, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, h, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), Australia.

Fig. 5. Male abdomens: a, Neosarmatium africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; b, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; c, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; d, N. australiense, new species, holotype male (39.85 ×34.77 mm) (QM-W29085), Australia.

Fig. 6. Male left first gonopods and corresponding distal parts: a, b, Neosarmatium africanum, new species, holotype male (42.83 × 38.33 mm) (MZUF 678), Somalia; c, d, N. meinerti (De Man, 1887), paratype male (40.26 × 35.60 mm) (MZUF 2931), Seychelles; e, f, N. asiaticum, new species, holotype male (38.52 × 33.11 mm) (NMNS-6327-001), Taiwan; g, h, N. australiense, new species, holotype male (39.85 × 34.77 mm) (QM-W29085), Australia.

Fig. 7. Lectotype of Neosarmatium meinerti (De Man, 1887) (34.00 × 39.30 mm) (MNHN-IU-2011-278), Isle de France, Mauritius: a, dorsal view of carapace; b, dorsal view of left cheliped and dactylus; c, outer and inner surface of right chela; d, frontal view.