Geosesarma sekop, 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 : 235-237

Geosesarma sekop , new species

( Figs. 16–18 )

Material examined. West Java Province, Bogor Regency: holotype: male (10.5 × 9.4 mm) ( MZB Cru 4455), Pamijahan District , Ds. Gunung Sari, Kp. Rawa Lega, on moist cliff

of S. Cimuara Herang at Curug Muara Herang in Gunung Bunder Resort , 06°42′40.8″S 106°41′03.2″E, 1,015 m asl, coll. D. Wowor et al., 3 October 2015 . Paratypes: 12 males (8.2 × 7.5 mm – 11.2 × 10.5 mm), 15 females (8.3 × 7.5 mm – 10.9 × 9.7 mm), 1 ovigerous female (9.0 × 8.6 mm, eggs 1.8 mm diameter), 15 juveniles ( MZB Cru 4654), 1 male (10.2 × 9.2 mm), 1 female (11.9 × 10.4 mm) ( ZRC 2018.0288 ex-MZB Cru 4654), same data as holotype. Sukabumi Regency : paratypes: 14 males (8.1 × 7.3 mm – 12.1 × 10.8 mm), 3 females (6.6 × 6.0 mm – 12.6 × 11.8 mm), 1 ovigerous female (10.6 × 9.5 mm, eggs 1.7 mm diameter) ( MZB Cru Cru 4466), Cidahu District, Ds. Cidahu, on moist cliff at hiking gate to Kawah Ratu Salak 1, 06°44′19.1″S 106°42′52.9″E, 1,214 m asl, coll. D. Wowor et al., 30 September 2015 .

Diagnosis of male. Carapace subquadrate, slightly wider than long, lateral margins gently sinuous, divergent ( Figs. 16A, B , 17A ); dorsal surface with regions, anterior regions with numerous small granules ( Fig. 16B, C ); front deflexed, frontal lobes broad with convex margins, separated by short, shallow median concavity; postfrontal cristae sharp ( Fig. 16B, C ); 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 small cleft ( Fig. 16B ). Ischium of third maxilliped ovate, wide; exopod relatively slender, with long flagellum that extends just beyond merus width ( Fig. 18A ). Outer surface of palm of adult male chelae with scattered low granules; inner surface granulated but without transverse comb-like ridge; dorsal margin of dactylus with 15–18 small tubercles, each with chitinous tip along length ( Figs. 16 F–H, 17C). Ambulatory legs with relatively broad meri, with sharp subdistal spine on dorsal margin, surfaces rugose; ventral margins of propodus and dactylus of first ambulatory leg with scattered stiff setae. Male pleon triangular; telson triangular with rounded tip, as long as broad; somite 6 with convex lateral margins ( Figs. 16D, E , 17B ). G1 relatively slender, subdistal part of outer margin before chitinous distal part gently curved, may be crenulate, with inner dorsal section strongly developed; chitinous distal part bent about 30° along longitudinal axis, elongate, spatulate in lateral view, narrow in mesial view; tip subtruncate when viewed dorsally ( Fig. 18 B–F, H, I).

Females. The adult female carapace is distinctly more trapezoidal in form ( Fig. 17D ). 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. 17F ). The eggs were between 1.8 mm (MZB Cru 4654) and 1.7 mm in diameter (MZB Cru Cru 4466).

Etymology. The name is derived from the Indonesian word “sekop” for spade, alluding to the structure of the G1. The name is used as a noun in apposition.

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

Notes on habitat. Moist cliffs with water seepage and moss are the preferred habitats of this species; and these are usually not far from streams. The area has canopy coverage between 70 and 80%. Geosesarma sekop , new species, lives above 1,000 m asl.

Life colouration. The carapace is dark brown with black eyes and light brown chelae ( Fig. 26B ).

Distribution. Bogor and Sukabumi Regencies in West Java Province, in Gunung Bunder and Kawahratu Resorts of Mount Halimun Salak National Park, respectively.

Figures

Fig. 16. Geosesarma sekop, new species, holotype male (10.5 × 9.4 mm) (MZB Cru 4455). 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, anterior thoracic sternum, telson and pleonal somites 3–6; F, outer view of right chela; G, dorsal view of right chela; H, dorsal view of dactylus of right chela.

Fig. 17. Geosesarma sekop, new species. A–C, paratype male (12.1 × 10.8 mm) (MZB Cru 4466); D–F, paratype female (11.9 × 10.4 mm) (ZRC 2018.0288); A, D, overall dorsal view; B, E, anterior thoracic sternum, telson and pleonal somites 4–6; C, dorsal margin of dactylus of left chela; F, sternopleonal cavity showing vulvae.

Fig. 18. Geosesarma sekop, new species. A–G, holotype male (10.5 × 9.4 mm) (MZB Cru 4455); H, I, male (12.1 × 10.8 mm) (MZB Cru 4466). A, right third maxilliped; B, H, left G1 (dorsal view); C, I, left G1 (ventral view); D, E, left G1 (ventro-mesial view); F, left G1(dorso-mesial views); G, right G2. All structures denuded. Scales: A, H, I = 1.0 mm; B–G = 0.5 mm.

Fig. 26. Colour in life. A, Geosesarma lebak, new species, male (11.3 × 10.5 mm) (MZB Cru 4553), S. Cimaja, Banten Province; B, G. sekop, new species, holotype male (10.5 × 9.4 mm) (MZB Cru 4455), Curug Muara Herang, Bogor Regency. A, photograph by R.M. Marwoto; B, photograph by R.K. Hadiaty.