Geosesarma confertum ( Ortmann, 1894 )

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 : 230-235

Geosesarma confertum ( Ortmann, 1894)

( Figs. 13–15 )

Sesarma (Geosesarma) sp. De Man, 1892: 345. Sesarma (Geosesarma) nodulifera var. conferta Ortmann, 1894: 56 . Sesarma (Geosesarma) noduliferum – Serène, 1968a: 1093, text

figs. 19, 20. Sesarma (Geosesarma) noduliferum confertum – Serène, 1968b:

106. Geosesarma confertum – Ng et al., 2008: 220; Ng et al., 2015:

6, fig. 1E, F.

Material examined. West Java Province, Cianjur Regency: 2 males (9.4 × 8.5 mm, 10.7 × 9.7 mm) ( ZRC 1970.3.7.11–12), Tjibodas (= Cibodas or Gunung Gede) , west Java, don. Museum Zoologicum Bogoriense, 1960s; 5 juveniles, 20 males (6.9 × 6.6 mm – 9.8 × 9.0 mm), 21 females (8.3 × 7.3 mm – 11.5 × 10.0 mm), 5 ovigerous females (9.9 × 8.9 – 10.1 × 8.9 mm) ( MZB Cru 4797) , 2 males (9.0 × 8.2 mm, 11.1 × 10.9 mm), 1 female (10.5 × 9.6 mm) ( ZRC 2018.0292 ex-MZB Cru 4797), among watercress, at nursery, on edge of cliff, near Cibogo Waterfall, Kebun Raya Cibodas (= Cibodas Botanical Garden), 06º44′16.0″S 107º00′38.3″E, 1,286 m asl, Ds. Sindanglaya, Cipanas District , coll. D. Wowor & U. Nurhaman, 29 Mar 2011 ; 1 male (11.9 × 11.1 mm, badly damaged) ( MZB Cru 4798), S. Cibogo, walled stream with slow-moderate flow with rock and gravel substrate, canopy coverage 90%, pH 6.0, Kebun Raya Cibodas (= Cibodas Botanical Garden), 06°44′18.7″S 107°00′33.7″E, 1,303 m asl, Ds. Sindanglaya, Cipanas District , coll. D. Wowor et al., 22 July 2009 ; 1 male (9.6 × 9.0 mm), 2 females (8.8 × 7.7 mm, 13.1 × 10.9 mm), 1 ovigerous female (10.2 × 9.4 mm, eggs 1.2 mm diameter) ( MZB Cru 4799) , 1 male (9.8 × 9.0 mm) ( ZRC 2018.0293 ex-MZB Cru 4799), in grasscovered holes at water edge, small gutter, near pond, not far from entrance gate, Kebun Raya Cibodas (= Cibodas Botanical Garden), Ds. Sindanglaya, Cipanas District , coll. D. Wowor et al., 23 July 2009 ; 18 males (7.9 × 7.4 mm – 10.6 × 9.6 mm), 14 females (7.8 × 7.3 mm – 11.3 × 10.1 mm), 1 ovigerous female (10.3 × 9.3 mm, eggs 1.3 mm diameter), 8 juveniles ( MZB Cru 4961), on cliff covered with wet moss, Kebun Raya Cibodas (= Cibodas Botanical Garden), Ds. Sindanglaya, Cipanas District , coll. S. Klaus, P. Koller & D. Wowor, 31 March 2006 .

Diagnosis of male. Carapace subquadrate, wider than long, lateral margins gently sinuous, divergent ( Figs. 13A, B ); dorsal surface with regions, anterior regions with very small granules ( Fig. 13B, C ); front deflexed, frontal lobes broad with convex margins, separated by shallow median concavity; postfrontal cristae relatively sharp ( Fig. 13B, C ); external orbital tooth triangular, directed obliquely outwards, tip just reaching or extending slightly beyond anterior part of lateral carapace margin, first epibranchial tooth subtruncate, separated from margin by small cleft ( Fig. 13B ). Ischium of third maxilliped short, ovate, wide; exopod relatively slender, with long flagellum that extends just beyond merus width ( Fig. 15A ). 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 16–19 small tubercles, each with chitinous tip along length ( Figs. 13E, F ). 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 ( Figs. 13D ). Male pleon triangular; telson triangular with rounded tip, slightly wider than long; somite 6 with convex lateral margins ( Figs. 13G, H ). G1 relatively slender, short, gently curved, subdistal part of outer margin before chitinous distal part with low convexity, inner dorsal section strongly developed; chitinous distal part bent about 40º along longitudinal axis, relatively long, spatulate in lateral view, subcylindrical in mesial view; tip subtruncate when viewed dorsally ( Fig. 15 B–E).

Females. The adult female carapace is more trapezoidal in form ( Fig. 14A ). The vulvae are without a sternal opercular cover, ovate and are level with the surface of the anterior half of sternite 6, and relatively widely separated ( Fig. 14C ). The egg diameter of ovigerous females is 1.2 mm (MZB Cru 4799).

Remarks. De Man (1892: 345) recorded several small specimens from “Tjipanas” and Tjibodas from Java as “ Sesarma (Geosesarma) sp.”, noting that it was possibly G. noduliferum except that the dactylus of the male has more and closely packed tubercles. Ortmann (1894: 56) had more material from the same area, observed the same differences with G. noduliferum s. str. and decided to recognise a new variety, G. noduliferum confertum , for this material (see review in Ng et al., 2015: 6). There is a town called Tjipanas (= Cipanas) further to the west in Lebak Regency, but the “Tjipanas” cited by De Man (1892) almost certainly refers to the district of Tjipanas (= Cipanas District) which includes the highlands of Tjibodas on the slopes of Mount Gede.

See General Discussion for comparisons with allied Javan species.

Notes on habitat. It is found in holes at the edge of water of small gutter and among roots of watercress in wetland. The water is clear with a slow-moderate current. The habitat is also shadowed by trees. Sometimes it is also occurs under wet moss on cliff sides. Geosesarma confertum is a highland species, occuring above 1,280 m asl.

Life colouration. The carapace is dark brown with black eyes. The chelae are yellowish brown and the ambulatory legs are with dark brown and yellowish-brown stripes.

Distribution. The species is known only from and around the highlands of Cibodas in Cianjur Regency at the border of Mount Gede Pangrango National Park.

Figures

Fig. 13. Geosesarma confertum (Ortmann, 1894), male (9.3 × 8.6 mm) (MZB Cru 4797). A, overall dorsal view; B, dorsal view of carapace; C, frontal view of cephalothorax; D, propodus and dactylus of left first ambulatory leg; E, outer view of right chela; F, dorsal view of dactylus right chela; G, anterior thoracic sternum, telson and pleonal somites 4–6; H, posterior thoracic sternum and pleonal somites 2–6.

Fig. 14. Geosesarma confertum (Ortmann, 1894), female (11.5 × 10.0 mm) (MZB Cru 4797). A, overall dorsal view; B, anterior thoracic sternum, telson and pleonal somites 4–6; C, sternopleonal cavity showing vulvae.

Fig. 15. Geosesarma confertum (Ortmann, 1894), male (9.3 × 8.6 mm) (MZB Cru 4797). A, left third maxilliped (distal part of flagellum broken off); B, left G1 (dorsal view); C, left G1 (ventral view); D, left G1 (dorso-mesial view); E, left G1(ventro-mesial view); F, left G2. All structures denuded. Scales = 0.5 mm.