Geosesarma cikaniki, Ng & Wowor, 2019

Ng, Peter K. L. & Wowor, Daisy, 2019, The vampire crabs of Java, with descriptions of five new species from Mount Halimun Salak National Park, West Java, Indonesia (Crustacea: Brachyura: Sesarmidae: Geosesarma), Raffles Bulletin of Zoology 67, pp. 217-246 : 237

Geosesarma cikaniki , new species

( Figs. 19–21 )

Material examined. West Java Province, Bogor Regency: holotype: male (8.9 × 8.7 mm) ( MZB Cru 4649), Nanggung District , Ds. Malasari , 4th tributary from Cikaniki Research Station , at trail between Cikaniki Research station and Kp. Citalahap Sentral, in the forest, above 1,108 m asl, coll. D. Wowor et al., 5 July 2017 . Paratypes: 5 males (11.9 × 11.0 mm [post molt], 9.0 × 8.2 mm – 9.5 × 9.2 mm), 2 females (8.4 × 7.6 mm, 10.4 × 9.3 mm), 1 ovigerous female (10.1 × 9.2 mm, eggs 1.5 mm diameter), 12 juveniles ( MZB Cru 4650), same data as holotype ; 5 females (6.8 × 6.2 mm – 10.7 × 8.9 mm), 1 juvenile ( MZB Cru 4619), Nanggung District, Ds. Malasari, 4th tributary from Cikaniki Research Station , at trail between Cikaniki Research station and Kp. Citalahap Sentral, in the forest, above 1,108 m asl, coll. D. Wowor et al., 11 May 2016 ; 8 males (6.7 × 6.3 mm – 10.0 × 9.3 mm), 2 females (6.6 × 6.4 mm, 10.2 × 9.2 mm), 7 juveniles ( MZB Cru 4651), Nanggung District, Ds. Malasari, 5th tributary from Cikaniki Research Station , at loop trail between Cikaniki Research Station and Kp. Citalahap Sentral, in the forest, above 1,108 m asl, coll. D. Wowor et al., 5 July 2017 ; 1 young (5.9 × 5.3 mm) ( MZB Cru 4652), 1 male (11.1 × 9.1 mm) ( ZRC 2018.0289 ex-MZB Cru 4652), Nanggung District , Ds. Malasari, about 30 m down of the 4th tributary from Cikaniki Research Station , coll. D. Wowor et al., 5 July 2017 ; 3 males (6.9 × 6.6 mm – 7.4 × 6.9 mm), 2 females (5.9 × 5.4 mm, 7.3 × 6.7 mm), 1 juvenile ( MZB Cru 4653), 2 males (9.2 × 7.9 mm, 11.6 × 10.2 mm), 1 female (10.2 × 9.2 mm) ( ZRC 2018.0290 e×- MZB Cru 4653), Nanggung District , Ds. Malasari , a tributary (= S. Malajegang ), on the road to Cikaniki Research Station , 6°44′55.4″S 106°32′26.1″E, 1,093 m, coll. D. Wowor et al., 5 July 2017 .

Diagnosis of male. Carapace subquadrate, slightly wider than long, lateral margins gently sinuous, slightly divergent ( Figs. 19A, B , 20A ); dorsal surface with regions, anterior regions with numerous small granules ( Figs. 19B, C , 20A ); front deflexed, frontal lobes broad with convex to subtruncate margins, separated by short, shallow median concavity; postfrontal cristae sharp ( Figs. 19B, C , 20A ); external orbital tooth triangular, directed obliquely outwards, tip not extending beyond anterior part of lateral carapace margin, first epibranchial tooth subtruncate, separated from margin by distinct cleft ( Figs. 19B , 20A ). Ischium of third maxilliped ovate, wide; exopod relatively slender, with long flagellum that extends just beyond merus width ( Fig. 21A ). Outer surface of palm of adult male chelae with small granules; inner surface granulated but without transverse comb-like ridge; dorsal margin of dactylus with 15–18 small tubercles, each with chitinous tip along most of length except distal part ( Figs. 19E, F , 20C ). Ambulatory legs with relatively broader, shorter meri, with sharp subdistal spine on dorsal margin, surfaces rugose; ventral margins of propodus and dactylus of adult first ambulatory leg with dense comb-like setae. Male pleon triangular; telson triangular with rounded tip, as long as broad; somite 6 with convex lateral margins ( Figs. 19D , 20B ). G1 relatively slender, short, gently curved, subdistal part of outer margin before chitinous distal part very low with inner dorsal section strongly developed; chitinous distal part bent about 40° along longitudinal axis, short, spatulate in lateral view, narrow in mesial view; tip subtruncate when viewed dorsally ( Fig. 21 B–D).

Females. The adult female carapace is distinctly more trapezoidal in form ( Fig. 20D ). The vulvae are without a sternal opercular cover, ovate and are level with the surface of the anterior half of sternite 6, and relatively more widely separated ( Fig. 20F ). The egg diameter is 1.5 mm (MZB Cru 4650).

Etymology. The species is named after the site where it was first collected, Cikaniki. The name is used as a noun in apposition.

Remarks. See General Discussion for comparisons with allied Javan species.

Notes on habitat. It lives under pebbles with coarse sand substrate. The substrate is always wet due to water seepage. The habitat is in the middle of highland rain forest with almost totally under canopy coverage ( Fig. 25E ). Geosesarma cikaniki , new species, lives above 1,000 m asl. A new genus and new species of gecarcinucid, Occulthusa halimun Ng & Wowor, 2018 , was recently described from the same area as this Geosesarma species ( Ng & Wowor, 2018).

Life colouration. The carapace is dark brown with black eyes and purplish brown chelae.

Distribution. Bogor Regency in West Java Province, in Cikaniki Resort of Mount Halimun Salak National Park.

Figures

Fig. 19. Geosesarma cikaniki, new species, holotype male (8.9 × 8.7 mm) (MZB Cru 4649). A, overall dorsal view; B, dorsal view of carapace; C, frontal view of cephalothorax; D, anterior thoracic sternum, telson and pleonal somites 4–6; E, outer view of left chela; F, dorsal view of dactylus of left chela.

Fig. 20. Geosesarma cikaniki, new species. A–C, paratype male (11.9 × 11.0 mm) (MZB Cru 4650); D–F, paratype female (9.9 × 8.9 mm) (MZB Cru 4619). A, D, overall dorsal view; B, E, anterior thoracic sternum, telson and pleonal somites 4–6; C, dorsal margin of dactylus of right chela; F, sternopleonal cavity showing vulvae

Fig. 21. Geosesarma cikaniki, new species, holotype male (8.9 × 8.7 mm) (MZB Cru 4649). A, left third maxilliped; B, left G1 (dorsal view); C, left G1 (ventral view); D, left G1(dorso-mesial views); E, left G2. All structures denuded. Scales = 0.5 mm.

Fig. 25. Habitats. A, Geosesarma noduliferum habitat, stream at Tenjolaya District, Bogor Regency; B, G. lebak, new species, edge of S. Cimaja in Banten Province; C, G. sukabumi, new species, cliff face above S. Cirendang, Sukabumi Regency; D, G. robustum, new species, head water of S. Ciampea, Bogor Regency; E, G. cikaniki, new species, moist forest in Cikaniki Research Station, Bogor Regency.