Crustacean Research 49 KARSTARMA UMBRA, a NEW SPECIES of CAVERNICOLOUS CRAB Which Is Clearly Trapezoidal in Shape with the of K

Crustacean Research 2020 Vol.49: 73–88 ©Carcinological Society of Japan. doi: 10.18353/crustacea.49.0_73 Karstarma umbra, a new species of cavernicolous crab (Brachyura: Sesarmidae) from Vanuatu, with a key to the genus

Peter K. L. Ng

Abstract.―A new species of cavernicolous sesarmid crab is described from Vanuatu. Karstarma umbra sp. nov. belongs to a group of three species that has the chitinous distal part of the male first gonopod slender and elongate. The new species can easily be distinguished from K. balicum (from Bali, Indonesia) and K. loyalty (from Loyalty Islands) by its distinctly longer ambulatory legs and its relatively more slender male first gonopod. Karstarma umbra is morphologically closest to K. waigeo (from Indo- nesian Papua) but has proportionately longer legs and the outer margin of the male first gonopod is distinctly concave. The taxonomy of the genus is discussed and a revised key to the 18 species is provided.

LSIDurn:lsid:zoobank.org:pub:D54659BC-D9B8-43FA-ADBE-5A9324F52675

Key words: Taxonomy, Grapsoidea, South Paciﬁc, new species, key, Karstarma, species-groups

■ Introduction zontally on a level surface; the length being taken from the proximal angle with the basis- Seventeen species of the cave sesarmid ge- ischium to the distalmost margin where it artic- nus Karstarma Davie & Ng, 2007, are known ulates with the carpus; while the width is ob- from the Indian Ocean and western Paciﬁc (Ng tained at the widest point, which is usually at et al., 2008; Wowor & Ng, 2009, 2018; Husana the median point (cf. Maenosono & Naruse, et al., 2010; Poupin et al., 2018) (Table 1). A 2016). The following abbreviations are used: new species is here described from caves in G1＝male ﬁrst gonopod; G2＝male second Santo Island in Vanuatu. The taxonomy of the gonopod; P2–P5＝pereopods 2–5 (ambulatory genus is discussed and a revised key is con- legs 1–4, respectively). structed to help identify the species. Specimens are deposited in the Zoological ■ Taxonomy Reference Collection (ZRC) of the Lee Kong Chian Natural History Museum, Nation- Family Sesarmidae Dana, 1851 al University of Singapore; and the Naturalis Biodiversity Centre (ex Rijksmuseum van Karstarma Davie & Ng, 2007 Natuurlijke Historie, RMNH), Leiden, The Netherlands. Type species The terminology used follows Davie et al. Sesarmoides boholano Ng, 2002, by original (2015). Measurements provided, in millime- designation. tres, are of the maximum carapace width and length, respectively. The ambulatory merus is Remarks measured with the structure positioned hori- Although Wowor & Ng (2009) recognised

Received: 29 Feb 2020. Accepted: 14 Apr 2020. Published online: 12 June 2020. 73 PETER K. L. NG

Table 1. List of known Karstarma species

Species Distribution References

Karstarma ardea Wowor & Ng, 2009 Raja Ampat, Indonesian Papua Wowor & Ng (2009)

Karstarma balicum (Ng, 2002) Nusa Penida, Bali, Indonesia Ng (2002)

Karstarma boholano (Ng, 2002) Bohol, Philippines; Ng (2002), Ishigaki Island, Ryukyus, Japan; Naruse et al. (2005), Green Island, Taiwan Husana et al. (2010), Li et al. (2019)

Karstarma cerberus (Holthuis, 1964) Nusa Lain, west of Ambon, Indonesia Holthuis (1964), Fransen et al. (1997), present study

Karstarma emdi (Ng & Whitten, 1995) Nusa Penida, Bali, Indonesia Ng & Whitten (1995), Ng (2002)

Karstarma guamense (Ng, 2002) Tumon Bay, Guam Ng (2002)

Karstarma jacksoni (Balss, 1934) Christmas Island, Australian Indian Ocean Balss (1934), Territory Orchard (2012), Poupin et al. (2018)

Karstarma jacobsoni (Ihle, 1912) Gunung Sewu, Central Java, Indonesia Ilhe (1912), Holthuis (1964), Naruse & Ng (2007), Wowor & Ng (2018)

Karstarma loyalty (Ng, 2002) Lifou Island, Loyalty Islands, New Caledonia Ng (2002)

Karstarma malang Wowor & Ng, 2018 Malang, East Java, Indonesia Wowor & Ng (2018)

Karstarma microphthalmus (Naruse & Ng, 2007) Gua Marapetang, south Sulawesi, Indonesia Naruse & Ng (2007)

Karstarma novabritannia (Ng, 1988) Arawe Island, New Britain Ng (1988), present study

Karstarma philippinarum Husana, Naruse & Kase, 2010 Boracay and Samal Islands, Philippines Husana et al. (2010)

Karstarma sulu (Ng, 2002) Palawan, Philippines Ng (2002)

Karstarma ultrapes (Ng, Guinot & Iliffe, 1994) Florida and Malaita Islands, Solomon Islands Ng et al. (1994), Wowor & Ng (2009), Husana et al. (2010)

Karstarma umbra sp. nov. Santo, Vanuatu Present study

Karstarma vulcan Poupin, Crestey & Le Guelte, 2018 Réunion Island Poupin et al. (2018)

Karstarma waigeo Wowor & Ng, 2009 Raja Ampat, Indonesian Papua Wowor & Ng (2009) two groups of Karstarma which they deﬁned peared to be closer to species of Geosesarma by the shape of the carapace, proportions of the De Man, 1892 (see Ng & Wowor, 2019) and P3 and P4, as well as structures of the G1 and they form a third group (see also Poupin et al., vulva; three groups are actually discernible. 2018). Wowor & Ng (2018) noted that the three spe- Members of the K. ultrapes species-group cies of Karstarma from Java and Sulawesi ap- are the most distinctive, possessing a carapace

74 Crustacean Research 49 KARSTARMA UMBRA, A NEW SPECIES OF CAVERNICOLOUS CRAB which is clearly trapezoidal in shape with the of K. microphthalmus is also large, so this spe- posterior part very wide; the epigastric and cies probably has large eggs as well. This is the protogastric cristae are fused, forming a large group Wowor & Ng (2018) suggested was re- swelling that protrudes anteriorly, intruding to lated to Geosesarma as all the known Javanese the level of the frontal margin, with the frontal species in this genus have direct development region just or barely visible in dorsal view; the with the large eggs hatching into juvenile crabs cornea of the eye is not reduced; the P4 is very (Ng et al., 2015; Ng & Wowor, 2019). elongate (more than four times the carapace Species in the K. boholano species-group length); there are no prominent long tufts of se- have a subtrapezoidal to quadrate carapace tae between the coxae of P2–P4; the G1 has the with the posterior part slightly wider; the epi- chitinous distal part straight, cylindrical and gastric and protogastric cristae are separate and gently bent outwards at an angle of about distinct but do not protrude anteriorly with the 30–40° along the longitudinal axis; and the frontal region and margin distinct in dorsal vulva is formed by a large U-shaped posterior view; the cornea of the eye is not reduced; the sternal vulval cover with a prominent anterior P4 is long (less than four times the carapace cover, with both projections partially covering length); there are tufts of setae between the the prominent rounded operculum. Three spe- coxae of P2–P4 which are usually dense, long cies are in this group: K. ardea, K. philippina- and prominent; the G1 has the chitinous distal rum and K. ultrapes. No ovigerous females are part short or elongate and sharply bent out- known but on the basis of their small vulvae, wards at an angle of about 90° along the longi- their eggs are probably small and less than a tudinal axis; and the vulva has a prominent millimetre in diameter. posterior sternal vulval cover with a small an- Members of the K. jacobsoni species-group terior one, the whole structure being distinctly also have a trapezoidal carapace but the poste- elevated. Eleven species are in this group: K. rior part is proportionately less wide and the balicum, K. boholano (type species), K. cer- carapace appears more subquadrate; the epi- berus, K. emdi, K. guamense, K. jacksoni, K. gastric and protogastric cristae are lower, with loyalty, K. novabritannia, K. sulu, K. vulcan, the sharp epigastric crista protruding anteriorly and K. waigeo. The egg size of several species to some degree but not completely obscuring are known and they are all small, less than a the frontal region in dorsal view; the cornea of millimetre in diameter (see Ng, 2002; Orchard, the eye is distinctly reduced; the P4 is elongate 2012; Poupin et al., 2018; unpublished data), (less than four times the carapace length); there with Li et al. (2019) recently obtaining plank- are prominent tufts of dense, long setae be- tonic zoeae for K. boholano. Most of the spe- tween the coxae of P2–P4; the G1 has the chi- cies have a short and truncate chitinous distal tinous distal part straight, cylindrical and gen- part of the G1; only in three species is the chi- tly bent outwards at an angle of about 30–40° tinous distal part elongate and tapering̶K. along the longitudinal axis; and the vulva has a balicum, K. loyalty and K. waigeo, like in K. simple broad lateral sternal vulval cover with umbra sp. nov. the structure almost level with the sternal sur- The figures of K. cerberus and K. novabri- face. Three species are in this group: K. jacob- tannia appear to depict the two species pos- soni, K. malang and K. microphthalmus. The sessing epigastric cristae which are directed eggs of the first two species are large (ca. anteriorly and reaching the frontal margin 1.8 mm in diameter) and they almost certainly (Holthuis 1964: fig. 1, 2a; Ng 1988: pl. 1) like practice abbreviated or semi-abbreviated de- those in the K. ultrapes species-group (Fig. 6A, velopment (Wowor & Ng, 2018). The vulvae B). This is, however, not accurate as the cara-

Crustacean Research 49 75 PETER K. L. NG pace had been slightly tilted anteriorly when be regarded as stygobites. All the other species, the structure was originally drawn or photo- including K. umbra, are best described as sty- graphed. Both species actually have normal gophiles or stygoxenes, and while mainly epigastric cristae that do not protrude anteriorly found in caves, are probably found in habitats (Fig. 5A–D). These two species also have setae outside the caves as well (see Ng, 2013; Ng & between the coxae of P2–P4 but the setae are Guinot, 2014). Most of these species in fact, concentrated on the sides of these coxae, rela- are well pigmented or even dark coloured. tively shorter and less dense than those of the Karstarma jacksoni, for example, has a dark other species in the group and when viewed brown carapace and bright orange chelae (Or- ventrally, less obvious (Fig. 5F, G). This is like chard, 2012) and has been collected in caves as the condition in species of the K. ultrapes spe- well as nearby limestone formations, hiding in cies-group (Fig. 6C, D). In all the other species crevices during the day and coming to forage in the K. boholano species-group, these tufts of only at night (unpublished data). These habitats setae are dense, long and prominent in ventral are often densely vegetated so observing and view (e.g., Fig. 3A, B). In the holotype of K. collecting the crabs is difficult. novabritannia, the specimen has been denuded so there are no more setae at the base of the Karstarma umbra sp. nov. legs (Fig. 5E) but these remain visible in the (Figs. 1–4) female paratype (Fig. 5F, G). The vulvae of LSIDurn:lsid:zoobank.org:act:BFCB8970- these two species have not been described or 64A9-4551-B8FA-353EB6E82265 figured before but they are similar to the condition in other members of the group (see Fig. Material examined 5H). Holotype: male (15.0×12.7 mm) (ZRC Karstarma as it now understood (sensu Da- 2019.1834), sample SK05-Lips32, vial 2044, vie & Ng, 2007) is therefore likely to be poly- in single gallery, 60 m long, Dhevathar Cave, phyletic, with the species resembling each oth- near Port Olry, 15°02.091′S 167°3.894′E, er only because they live in caves. That being northeastern Santo, Vanuatu, coll. J Lips, 17 said, members of the K. boholano and K. ultra- August 2005. Paratypes: 1 male (14.0× pes species-groups live in coastal or anchialine 11.7 mm), 1 female (17.5×14.2 mm) (ZRC cave systems while those of the K. jacobsoni 2019.1835), same data as holotype; 1 female group live in inland limestone caves. When a (11.6×10.0 mm) (ZRC 2018.45), Loren Cave, full revision can be done, new genera can then 14°58.850′S 167°03.553′E, east coast of Cape be established. The K. jacobsoni species-group Queiros, northeastern Santo, Vanuatu, coll. F. would probably be the most difficult one to de- Bréhier, 8 September 2006. termine because it is close to Geosesarma which is a large polyphyletic genus (see Ng & Comparative material Wowor, 2019). Karstarma jacksoni (Balss, 1934): 1 male It is well known that cavernicolous taxa often (ZRC 2009.824), The Settlement, Christmas possess long ambulatory legs and paler body Island, coll. 7 December 2007; 2 males (ZRC coloration, but true stygobites invariably lose 2019.1126), on wall of Cocos Padang Lodge, all their coloration and their eyes are reduced Christmas Island, coll. 15–20 December 2000; (see Holthuis, 1986; Guinot, 1988, 1994). In 1 female (ZRC 2019.1128), Cocos Padang the case of Karstarma, only the three species Lodge, Christmas Island, coll. 15–20 Decem- now known from Java and Sulawesi (K. jacob- ber 2000; 1 male (ZRC 2019.1127), Cocos soni, K. microphthalmus and K. malang) can Padang Lodge, Christmas Island, vicinity, coll.

76 Crustacean Research 49 KARSTARMA UMBRA, A NEW SPECIES OF CAVERNICOLOUS CRAB

Fig. 1. Karstarma umbra sp. nov. A, C, holotype male (15.0×12.7 mm) (ZRC 2019.1834), Vanuatu; B, D, paratype female (17.5 ×14.2 mm) (ZRC 2019.1835), Vanuatu. A, B, overall dorsal view; C, D, dorsal view of carapace.

H. H. Tan, 16 December 2014; 1 male (ZRC male (ZRC 2017.720), Retreat, Christmas Is- 2019.416), Captain’s Retreat, in bathroom, land, coll. 26 March 2011; 1 female (ZRC Christmas Island, coll. 5 February 2012; 1 2017.717), Runaway Cave, Waterfall Road,

Crustacean Research 49 77 PETER K. L. NG

Fig. 2. Karstarma umbra sp. nov., holotype male (15.0×12.7 mm) (ZRC 2019.1834), Vanuatu. A, frontal view of cephalothorax; B, left third maxilliped; C, outer view of left chela; D, inner view of left chela; E, G–I, right P2–P5 (all to same scale); F, propodus and dactylus of P2 showing setal brush on ventral margins; J, anterior thoracic sternum and sternopleonal cavity; K, pleon.

78 Crustacean Research 49 KARSTARMA UMBRA, A NEW SPECIES OF CAVERNICOLOUS CRAB

Fig. 3. Karstarma umbra sp. nov. A, holotype male (15.0×12.7 mm) (ZRC 2019.1834), Vanuatu; B–D, paratype female (17.5× 14.2 mm) (ZRC 2019.1835), Vanuatu. A, B, anterior thoracic sternum and pleon; C, sternopleonal cavity and vulvae; D, left vulva; E, outer view of left chela.

Fig. 4. Karstarma umbra sp. nov., holotype male (15.0×12.7 mm) (ZRC 2019.1834), Vanuatu. A, left G1 (dorsal view); B, distal part of left G1 (ventral view); C, distal part of left G1 (submesial view); D, E, (ventral view at different angles); F, left G2 (dorsal view). All structures denuded. Scales: A, F＝0.5 mm; B–E＝0.2 mm.

Crustacean Research 49 79 PETER K. L. NG

Fig. 5. Karstarma novabritannia (Ng, 1988). A, C, E, holotype male (23.9×20.0 mm) (ZRC 1965.7.29.66), New Britain; B, D, F–H, paratype female (26.7×24.9 mm) (ZRC 1965.7.29.67). A, B, overall dorsal view; C, D, dorsal view of carapace; E, F, anterior thoracic sternum and pleon; G, tufts of setae between coxae of P2 and P3; H, sternopleonal cavity and vulvae.

80 Crustacean Research 49 KARSTARMA UMBRA, A NEW SPECIES OF CAVERNICOLOUS CRAB

Fig. 6. A, C, Karstarma ultrapes Ng, Guinot & Iliffe, 1994, paratype female (20.4×15.5 mm) (ZRC 1993.7200), Kwakwaru Cave, Basakana island, off northern Malaita Island, Solomon Islands; B, D, K. ardea Wowor & Ng, 2009, paratype female (35.0×29.3 mm) (ZRC 2009.766), Gua Kalepale, Waigeo, Raja Ampat Regency, West Papua Province, Indonesia. A, B, dorsal view of carapace; C, D, tufts of setae between coxae of left P2 and P3, and P3 and P4.

Christmas Island, coll. 30 January 2010; 1 Cave, 10°27.964′S 105°36.404′E, Christmas male (ZRC 2017.716), Runaway Cave, Water- Island, coll. 29 January 2010; 1 female (ZRC fall Road, Christmas Island, coll. 28 January 2019.354), in 10–15 m airpocket, in submarine 2010; 5 males, 5 females (ZRC 2017.779), cave, Thundercliff Cave, 10°27.964′S 105° Runaway Cave, Waterfall Road, coll. 26 Janu- 36.404′E, Christmas Island, coll. 16 February ary 2010; 1 female (ZRC 2019.719), Freshwa- 2012. Karstarma cerberus (Holthuis, 1964): ter Cave, Waterfall Road, Christmas Island, Holotype male (34.0×30.0 mm) (RMNH coll. 21 March 2011; 2 ovigerous females D19488), in complete darkness, cave on Nusa (ZRC 2017.715), Whip Cave, Waterfall Road, Lain island, just west of Ambon, Moluccas, coll. 30 January 2010; 1 female ZRC Indonesia, coll. F. Kopstein, 21 March 2013.1853), in 10–15 m airpocket, in subma- 1923; paratypes: 2 males, 5 females rine cave, Thundercliff Cave, 10°27.964′S 105° (RMNH D19489); Indonesia, same data as 36.404′E, Christmas Island, coll. 30 January holotype. Karstarma novabritannia (Ng, 2010; 1 female (ZRC 2017.718), in 10–15 m 1988): Holotype male (23.9×20.0 mm) (ZRC airpocket, in submarine cave, Thundercliff 1965.7.29.66), Arawe Island, New Britain, Sol-

Crustacean Research 49 81 PETER K. L. NG omon Sea, ca. 6°8′53″S 149°2′13″E, leg. P. H. onal cavity on sternite 4 subcristate (Fig. 2J); Hediger, 1933; paratype: l female (26.7× dense tufts of long, soft setae present between 24.9 mm) (ZRC 1965.7.29.67), same data as coxae of P2/P3 and P3/P4 in both sexes (Figs. holotype. Karstarma emdi (Ng & Whitten, 2J, 3A, B). Chelipeds equal, more robust in 1995): 2 males, 2 females (ZRC 2004.99), in males, all margins granulated; dactylus with cave, Nusa Penida, Bali, Indonesia, coll. A. J. 11–13 low tubercles along proximal two-thirds Whitten, August 2003. Karstarma boholano of dorsal margin, cutting edges with row of nu- (Ng, 2002): 2 females (ZRC 2011.1039), Pan- merous triangular teeth, tips chitinous (Figs. glao, Bohol, Philippines, coll. P. K. L. Ng, De- 1A, B, 2C, D); female chela with slender palm cember 2010. In addition, see material of other and elongate fingers (Fig. 3E). Ambulatory Karstarma species in Ng et al. (1994), Ng legs long, slender, P3 longest, P4 shortest (Figs. (2002), Naruse & Ng (2007), Wowor & Ng 1A, B, 2E–I); dorsal margins of meri gently (2009, 2018) and Husana et al. (2010). serrated, with short subdistal spine; ventral margins of P2 propodus and dactylus with Diagnosis dense brush-like row of short black setae (Fig. Carapace trapezoidal in shape, widest be- 2E, F); P3 and P4 meri 3.8 and 4.2 times as tween P3 and P4 bases (Fig. 1A–D); dorsal long as wide, respectively, P3 and P4 propodus surface mostly smooth except for low striae on 4.6 and 5.4 times as long as wide, respectively branchial region, with small, short tufts of se- (Fig. 2G, H). Male pleon widely triangular; so- tae evenly distributed on anterior half; external mites 1 and 2 short; somite 3 widest, with con- orbital tooth, when visible, separated from first vex lateral margins; somites 4 and 5 trapezoi- anterolateral tooth by small but distinct V- dal in shape with slightly concave lateral shaped cleft, outer margin gently convex, ca. 3 margins; somite 6 almost semicircular with times length of inner margin, sometimes with strongly convex margins; telson rounded, small shallow cleft behind first one; rest of an- slightly longer than wide (Figs. 2K, 3A). Fe- terolateral margin gently convex (Figs. 1C, D, male pleon rounded, very wide; somite 3 trape- 2A); posterolateral margin gently diverging zoidal in shape with straight lateral margins; (Fig. 1C, D); frontal margin distinctly bilobed, somites 4–6 with convex lateral margins; semi- with shallow, wide, median notch, margin of circular telson distinctly sunken into distal each lobe convex; epigastric crista distinct, margin of somite 6 (Fig. 3B). G1 relatively 4-lobed; postorbital crista very low, just visible long, slender, with small submedian hump on as slight bulges (Fig. 1C, D); gastric region outer margin, outer margin with median part well defined, median longitudinal groove pres- distinctly concave; distal part bent outwards ent along epi- and protogastric regions, diverg- approximately 90° to longitudinal axis; chitin- ing on meso- and metagastric regions and ous distal part with tip elongate, relatively surrounding gastro-cardiac groove, cervical slender, gently tapering to bifurcated tip (Fig. groove distinct (Fig. 1C, D); eyes well devel- 4A–E). G2 short, about half length of G1, with oped filling orbit, with large, pigmented cornea spatuliform tip (Fig. 4F). Vulvae widely sepa- (Figs. 1C, D, 2A). Third maxilliped with ischi- rated on anterior part of sternite 6, adjacent to um much longer than merus; slender exopod suture with sternite 5; posterior sternal vulval with long flagellum (Fig. 2B). Thoracic ster- cover expanded, joining smaller anterior ster- nites 2 and 3 fused, suture indistinct; suture be- nal vulval cover to cover opening, opening di- tween 3 and 4 visible as low ridge (Figs. 2J, rected laterally outwards (Fig. 3C, D). 3A, B); sternopleonal cavity deep, without male pleonal locking tubercle, rim of sternople-

82 Crustacean Research 49 KARSTARMA UMBRA, A NEW SPECIES OF CAVERNICOLOUS CRAB

Etymology communication; see also Lips et al., 2011). The name is derived from the Latin for spir- One paratype female was collected from Loren its in shadows, alluding to the cave habitat of Cave, which is an anchialine system about the species. The name is used as a noun. 30 m from the coastline (see Bréhier et al., 2011) and is only about 6 km to the north of Remarks Dhevathar Cave. In these cave systems, two The G1 structure of K. umbra has the distal other crabs were found: the sesarmid Labuani- chitinous part elongate and slender, and is a um trapezoideum (H. Milne Edwards, 1837) (as condition shared with K. balicum, K. loyalty “Laubuanium trapezoideum”) and the varunid and K. waigeo. Karstarma umbra can easily be Orcovita cf. mcneiceae Ng & Ng, 2002 (as distinguished from K. balicum and K. loyalty “Orcovita sp.”) (Bréhier et al., 2011: 311). by its proportionately longer ambulatory legs Labuanium trapezoideum is a semiterrestrial and the G1 being relatively more slender with species not normally found in caves but has a the chitinous distal part subtruncate. Karstarma preference for vertical walls with fast flowing umbra most closely resembles K. waigeo but waters and the Loren specimen probably entered the ambulatory legs are notably longer than K. the cave while foraging (see Jeng et al., 2003; waigeo, the meri of P3 and P4 being 3.8 and Naruse & Ng, 2020). The completely aquatic 4.2 times, respectively (Fig. 2G, H) (versus genus Orcovita is known to be a wholly anchia- meri of P3 and P4 being 3.5 and 4.0 times lon- line species and has been found in cave systems ger than wide, respectively; cf. Wowor & Ng, (see Ng et al., 1996; Davie & Ng, 2012). 2009: figs. 2A, 3A). Even more significant are the difference in proportions of the propodus of Key to species of Karstarma P3 and P4; in K. umbra, the length to width proportion of the P4 propodus is 5.4 (Fig. 2H) 1a. Ocular peduncle short, cornea reduced, whereas in K. waigeo, the length to width pro- small, eyes occupying only part of orbit portion of the same structure is 4.4 (cf. Wowor 2 & Ng, 2009: figs. 2A, 3A). Although the shape 1b. Ocular peduncle and cornea normal size, of the G1 of K. waigeo and K. umbra are su- entirely occupying orbit 4 perficially similar and both have the tip of the chitinous distal part bifurcate, that of K. umbra 2a. Lateral margin of carapace distinctly is proportionately more slender and the outer convex; P4 merus 2.5–2.7 times longer margin is distinctly more concave (Fig. 4A–E). than broad; G1 chitinous distal part relatively shorter, directed outwards at an Biology angle of about 30° [Sulawesi, Indonesia] Like other Karstarma species, K. umbra is K. microphthalmus almost certainly a semiterrestrial species, hid- 2b. Lateral margin of carapace gently ing in crevices during the day and foraging on divergent, appears almost straight; P4 karst walls at night (see Ng & Whitten, 1995; merus 3.5 times longer than broad or Ng, 2002). The types of K. umbra were all more; G1 chitinous distal part relatively collected from the karst systems on the north- long, directed outwards at angle of about eastern part of Santo. Three of specimens 45° 3 were from Dhevathar Cave near Port Olry (15°02.091′S 167°3.894′E) and were obtained 3a. Ocular peduncle distinctly more during a preliminary survey of the karst sys- swollen with distinct median ridge; P4 tems on Santo Island (L. Deharveng, personal proportionately longer ratio of total leg

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length to carapace width 2.5–2.7; G1 forming wider C-shaped bracket around relatively more robust, chitinous distal vulva [Solomon Islands] K. ultrapes part with tip relatively wider, more than 6b. Outer margin of external orbital tooth half that of main stem [Central Java, convex; posterior part of sternal vulval Indonesia] K. jacobsoni cover broad, forming U-shaped bracket 3b. Ocular peduncle relatively less swollen, around vulva [Indonesian Papua] surface smooth; P4 proportionately K. ardea shorter, ratio of total leg length to carapace width 2.1–2.6; G1 relatively 7a. Setae between coxae of P2–P4 in both more slender, width of chitinous distal sexes, not dense or long, at most with part tapering more sharply, less than half setae on sides of coxae 8 that of main stem [East Java, Indonesia] 7b. With prominent dense tufts of long setae K. malang between coxae of P2–P4 in both sexes 9 4a. Carapace shape distinctly trapezoidal, posterior part much wider than anterior 8a. Tip of external orbital tooth reaching part; epigastric and protogastric cristae just beyond level of frontal margin; male fused, swollen protruding anteriorly, telson equal in length to pleonal somite 6 intruding to level of frontal margin with [Ambon, Indonesia] K. cerberus frontal region not visible in dorsal view; 8b. Tip of external orbital tooth not reaching G1 chitinous distal part relatively long, level of frontal margin; male telson directed outwards at angle of about 45° shorter than pleonal somite 6 [New 5 Britain, Papua New Guinea] 4b. Carapace shape approximately sub- K. novabritannia quadrate, slightly trapezoidal in shape, posterior part slightly wider than anterior 9a. G1 with elongate, slender chitinous distal part; epigastric and protogastric cristae part 9 lower, separate, not protruding anteriorly, 9b. G1 with relatively short, truncate chit- not intruding to level of frontal margin inous distal part 13 with frontal region clearly visible in dorsal view; G1 chitinous distal part 10a. P4 merus 3.5–3.6 times longer than wide; relatively long, directed outwards at tip of G1 chitinous distal part subtruncate angle of about 90°, may be slightly bent 11 upwards or downwards 7 10b. P4 merus 4.0–4.2 times longer than wide; tip of G1 chitinous distal part bifurcate 5a. Ambulatory legs relatively shorter, P3 12 merus 3.3–5.1 times longer than broad [Philippines] K. philippinarum 11a. Outer margin of G1 stem with gentle 5b. Ambulatory legs extremely long, P3 submedian hump [Loyalty Islands] merus 5.4–5.5 times longer than broad K. loyalty 6 11b. Outer margin of G1 stem almost straight. [Bali, Indonesia] K. balicus 6a. Outer margin of external orbital tooth almost straight; posterior part of sternal 12a. P4 merus 4.0 times longer than wide; vulval cover relatively more narrow, P4 propodus 4.4 times longer than wide;

84 Crustacean Research 49 KARSTARMA UMBRA, A NEW SPECIES OF CAVERNICOLOUS CRAB

G1 proportionately stouter, outer margin wide; G1 chitinous distal part bent at right gently concave [Indonesian Papua] angles or slightly upwards 17 K. waigeo 12b. P4 merus 4.2 times longer than wide; 17a. P4 merus 4.1 times longer than wide; P4 P4 propodus 5.4 times longer than wide; propodus 4.2 times longer than wide; G1 proportionately more slender, outer chitinous distal part bent at right angles margin distinctly concave [Vanuatu] [Guam] K. guamensis K. umbra 17b. P4 merus 3.4–4.1 times longer than wide; P4 propodus 4.6–4.8 times longer than 13a. Clefts between external orbital tooth and wide; G1 chitinous distal part slightly anterolateral teeth shallow, second tooth turned upwards [Christmas Island, Indian absent or almost undiscernible [Réunion Ocean] Island, Indian Ocean] K. vulcan S. jacksoni 13b. Clefts between external orbital tooth and anterolateral teeth distinct, second tooth ■ Acknowledgements low but often visible 14 The author is most grateful to Louis Dehar- 14a. Dorsal margin of P2–P4 meri with sharp veng and Josiane Lips (Muséum national subdistal spine [Palawan, Philippines] d’Histoire Naturelle, Paris) for passing the K. sulu specimens to him for study. Thanks are also 14b. Dorsal margin of P2–P4 meri with sub- due to Louis Deharveng and Frank Bréhier for distal angle, dentiform but not spiniform, habitat information. Charles Fransen (RMNH) sometimes undiscernible 15 kindly allowed the author access to the specimens in RMNH used for the comparative 15a. External orbital tooth usually truncate, work. Various suggestions from two anony- outer margin straight to gently concave, mous referees are also much appreciated. separated from first anterolateral tooth by prominent, deep V-shaped notch; P4 ■ Literature Cited merus 3.7 times longer than wide; G1 chitinous distal part relatively short, Balss, H., 1934. Die Krabben der Reise J. W. subconical in shape [Bohol, Philippines; Harms’ nach der Christmas-Insel und dem southern Ryukyu Islands, Japan; Taiwan] Malaiischen Archipel. Zoologische Anzei- K. boholano ger, 106(10): 225–237. 15b. External orbital tooth not truncate, outer Bréhier, F., Eberhard, S., & Lasson, N. 2011. margin almost straight to gently convex, Focus on the Loren Cave. Pp. 310–312. separated from ﬁrst anterolateral tooth by In: Bouchet, P., Le Guyader, H., & Pascal, narrow cleft or relatively shallower notch; O. (eds.), The Natural History of Santo, P4 merus 3.4–4.1 times longer than wide; Patrimoines Naturels 70, Publications G1 chitinous distal part relatively more Scientifiques du Muséum, IRD Éditions elongate, beak like 16 & Pro-Natura International, Muséum national d’Histoire naturelle, 572 pp. 16a. P4 propodus 4.5 times longer than wide; Dana, J. D., 1851. Conspectus Crustaceorum quæ G1 chitinous distal part bent downwards in Orbis Terrarum circumnavigatione, Caro- [Bali: Indonesia] K. emdi lo Wilkes e Classe Reipublicæ Foederatæ 16b. P4 propodus 4.2–4.8 times longer than Duce, lexit et descripsit. Proceedings of the

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Academy of Natural Science of Philadel- J. Brill, Leiden, pp. 589–615. phia, 5: 247–254. Husana, D. E. M., Naruse, T., & Kase, T., 2010. Davie, P. J. F., Guinot, D., & Ng, P. K. L., 2015. A new species of the genus Karstarma Anatomy and functional morphology of (Crustacea: Decapoda: Brachyura: Sesarmi- Brachyura. In: P. Castro, P. J. F. Davie, D. dae) from anchialine caves in the Philip- Guinot, F. R. Schram, & J. C. von Vaupel pines. Raffles Bulletin of Zoology, 58(1): Klein (eds.), Treatise on Zoology–Anatomy, 51–55. Taxonomy, Biology. The Crustacea. Volume Ihle, J. E. W., 1912. Ueber eine kleine Brachy- 9C-I. Decapoda: Brachyura (Part 1), pp. 11– uren-Sammlung aus unterirdischen Flüssen 163. von Java. Notes of the Leyden Museum, Davie, P. J. F., & Ng, P. K. L. 2007. A new genus 34(3 & 4): 177–182, pl. 9. for cave-dwelling crabs previously assigned Jeng, M.-S., Liu, H.-C., Tzeng, C.-S., & Ng, P. K. to Sesarmoides (Crustacea: Decapoda: L., 2003. On the taxonomy and ecology of Brachyura: Sesarmidae). Raffles Bulletin of Labuanium trapezoideum (Decapoda, Zoology, Supplement 16: 227–231. Brachyura, Sesarmidae), a crab living on Davie, P. J. F., & Ng, P. K. L., 2012. Two new riverine cliffs in Taiwan. Crustaceana, 76(2): species of Orcovita (Crustacea: Decapoda: 227–240. Brachyura: Varunidae) from anchialine Li, J.-J., Shih, Y.-J., Ho, P.-H., Jiang, G.-C., 2019. caves on Christmas Island, eastern Indian Description of the first zoea of the cavernic- Ocean. Raffles Bulletin of Zoology, 60(1): olous crab Karstama boholano (Ng, 2002) 57–70. (Crustacea: Decapoda: Sesarmidae) from Fransen, C. H. J. M., Holthuis, L. B., & Adema, J. Taiwan, with notes on ecology. Zoological P. H. M., 1997. Type-catalogue of the Deca- Studies, 58: 36: 1–9, doi:10.6620/ZS.2019. pod Crustacea in the collections of the 58–36. Nationaal Naturhistorisch Museum, with Lips, B., Bréhier, F., Wirrmann, D., Lasson, N., appendices of pre-1900 collectors and mate- Eberhard, S., Lips, J., & Deharveng, L. rial. Zoologische Verhandelingen, Leiden, 2011. Karst and Caves. Pp. 269–277. In: 311: i–xvi, 1–344. Bouchet, P., Le Guyader, H., & Pascal, O. Guinot, D., 1988. Les crabes cavernicoles du (eds.), The Natural History of Santo, Patri- monde. Mémoires de Biospéologie, 15: moines Naturels 70, Publications Scienti- 3–40. fiques du Muséum, IRD Éditions & Pro-Na- Guinot, D., 1994. Decapoda Brachyura. In: Ju- tura International, Muséum national berthie, C., & Decou, V. (eds.), Encyclopae- d’Histoire naturelle, 572 pp. dia Biospeologica, Tome 1. Société de Bios- Maenosono, T., & Naruse, T., 2016. New records péologie, CNRS, Moulis, Ariége, France and of two sesarmid crabs (Crustacea: Decapo- Académie Roumaine, Bucarest, Romania, da: Brachyura) from Ishigakijima Island, pp. 165–179, pl. 3. Ryukyu Archipelago, Japan. Fauna Ryukyu- Holthuis, L. B., 1964. Sesarma (Sesarma) cer- ana, 28: 5–22. berus, a new cavernicolous crab from Am- Man, J. G. De, 1892 Decapoden des Indischen boina. Zoologische Mededelingen, Leiden, Archipels. Zoologische Ergebnisse einer 40(9): 66–72. Reise in Niederlandisch Ost-Indien, 2: 265– Holthuis, L. B., 1986. Decapoda. In: Botosanea- 527. nu, L. (ed.), Stygofauna Mundi. A Faunistic, Milne Edwards, H., 1837. Histoire naturelle des Distributional, and Ecological Synthesis of Crustacés, comprenant l'anatomie, la physi- the World Fauna Inhabiting Subterranean ologie et la classification de ces animaux. Waters (Including the Marine Interstitial). E. Librairie Encyclopédique de Roret, Paris, 2:

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1–532. ura, Gecarcinucidae) from eastern Borneo. Naruse, T., Nakai, H., & Tamura, H., 2005. A Zoosystema, 36: 623–629. new record of cavernicolous crab Sesar- Ng, P. K. L., Guinot, D., & Davie, P. J. F., 2008. moides boholano Ng, 2002 (Brachyura, Ses- Systema Brachyurorum: Part I. An annotated armidae) from Ishigaki Island, southern checklist of extant brachyuran crabs of the Ryukyu Islands, Japan. Biogeography, 7: world. Raffles Bulletin of Zoology, Supple- 79–84. ment 17: 1–286. Naruse, T., & Ng, P. K. L., 2007. On a new spe- Ng, P. K. L., Guinot, D., & Iliffe, T. M., 1994. cies of cavernicolous crab of the genus Ses- Sesarmoides ultrapes new species, a remark- armoides Serène & Soh, 1970 (Crustacea: able sesarmine crab from caves in the Solo- Decapoda: Brachyura: Sesarmidae) from mon Islands (Decapoda: Brachyura: Grapsi- Sulawesi, Indonesia. Raffles Bulletin of dae). Crustacean Research, 23: 12–22. Zoology, 55(1): 127–130. Ng, P. K. L., Guinot, D., & Iliffe, T. M., 1996. Naruse, T., & Ng, P. K. L., 2020. Revision of the Revision of the anchialine varunine crabs of sesarmid crab genera Labuanium Serène and the genus Orcovita Ng & Tomascik, 1994 Soh, 1970, Scandarma Schubart, Liu and (Crustacea: Decapoda: Brachyura: Grapsi- Cuesta, 2003, and Namlacium Serène and dae), with descriptions of four new species. Soh, 1970 (Crustacea: Decapoda: Brachy- Raffles Bulletin of Zoology, 44(1): 109–134. ura: Grapsoidea), with descriptions of four Ng, P. K. L., Schubart, C. D., & Lukhaup, C., new genera and three new species. Journal 2015. New species of “vampire crabs” (Geo- of Natural History, in press. sesarma De Man, 1892) from central Java, Ng, N. K., & Ng, P. K. L., 2002. Orcovita mcnei- Indonesia, and the identity of Sesarma (Geo- ceae, a new species of anchialine crab sesarma) nodulifera De Man, 1892 (Crusta- (Brachyura, Grapsidae, Varuninae) from the cea, Brachyura, Thoracotremata, Sesarmi- Loyalty Islands. Crustaceana, 75(5): 663– dae). Raffles Bulletin of Zoology, 63: 3–13. 670. Ng, P. K. L., & Whitten, A. J., 1995. On a new Ng, P. K. L., 1988. A new sesarmine crab of the cave-dwelling Sesarmoides (Crustacea: De- genus Sesarmoides Serène and Soh, 1970 capoda: Brachyura: Grapsidae) from Nusa (Crustacea Decapoda, Brachyura, Grapsi- Penida, Bali, Indonesia. Tropical Biodiver- dae) from Arawe Island, New Britain, Solo- sity, 1994, 2(3): 369–376. mon Sea, with notes on the genus. Microne- Ng, P. K. L., & Wowor, D., 2019. The vampire sica, 21(1 & 2): 181–187, pl. 1. crabs of Java, with descriptions of five new Ng, P. K. L., 2002. New species of cavernicolous species from Mount Halimun Salak National crabs of the genus Sesarmoides from the Park, West Java, Indonesia (Crustacea: western Pacific, with a key to the genus Brachyura: Sesarmidae: Geosesarma). Raf- (Crustacea: Decapoda: Brachyura: Sesarmi- fles Bulletin of Zoology, 67: 217–246. dae). Raffles Bulletin of Zoology, 50(2): Orchard, M., 2012. Crabs of Christmas Island. 419–435. Christmas Island Natural History Associa- Ng, P. K. L., 2013. Stygothelphusa cranbrooki, a tion, 287 pp. new species of cave crab from Gua Sireh, Poupin, J., Crestey, N., & Le Guelte, J.-P., 2018. Sarawak, Malaysia (Crustacea: Decapoda: Cave-dwelling crabs of the genus Karstarma Brachyura: Gecarcinucidae). Raffles Bulletin from lava tubes of the volcano ‘Piton de la of Zoology, Supplement 29: 91–97. Fournaise’, in Réunion Island, with descrip- Ng, P. K. L., & Guinot, D., 2014. A new caver- tion of a new species and redescription of nicolous species of crab of the genus Bals- Karstarma jacksoni (Balss, 1934) from siathelphusa Bott, 1969 (Crustacea, Brachy- Christmas Island (Decapoda, Brachyura,

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Sesarmidae). Zootaxa, 4497(3): 381–397. Wowor, D., & Ng, P. K. L., 2009. Two new spe- Address: cies of sesarmid crabs (Crustacea: Decapo- (PN) Lee Kong Chian Natural History da: Brachyura) associated with limestone Museum, National University of Singapore, formations in West Papua, Indonesia. Zoo- 2 Conservatory Drive, Singapore 117377, taxa, 2025: 21–31. Republic of Singapore. Wowor, D., & Ng, P. K. L., 2018. A new sesarmid crab of the genus Karstarma (Crustacea: Decapoda: Brachyura) associated with lime- E-mail address stone formations in East Java, Indonesia. (PN) [email protected] Zootaxa, 4482(2): 355–366.

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