taxonID	type	description	language	source
CF079C1BFF9EFFC1FF5E2A679349FA30.taxon	description	Sesarma (Holometopus) obtusifrons — Rathbun 1906: 840; 1907: 35. — Tesch 1917: 179. — Edmondson 1946: 306, fig. 183 e; 1959: 185, figs. 13 c, 17 c. Chiromantes obtusifrons — Ng & Liu 1999: 230. — Castro 2011: 120. “ Chiromantes ” obtusifrons — Ng et al. 2008: 220, 224 (part).	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF9EFFC1FF5E2A679349FA30.taxon	materials_examined	Material Examined. ZRC 2002.0220, 2 males (16.8 × 12.9, 19.7 × 14.7 mm), Malaikahana, O‘ahu, Hawaiian Is., C. M. Cooke et al., 0 8.07.1916 [ex. BPBM- 266]. — UFUF- 14837, male (17.7 × 13.2 mm), female (15.7 × 11.6 mm), 21.2833 ° N, 157.667 ° E, Coco Head, O‘ahu, Hawaiian Is., G. Paulay et al., 10.2006.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF9EFFC1FF5E2A679349FA30.taxon	diagnosis	Diagnosis. Carapace transversely rectangular, c. 1.3 times broader than long; dorsal carapace, lateral branchial regions weakly convex, not prominently swollen; exorbital tooth with outer margin broadly convex so greatest carapace width clearly posterior to exorbital tooth; front c. 0.65 times carapace width, margin broadly convex in frontal view with medial part relatively straight in dorsal view, beaded with row of small but distinct granules, with pair of low lateral swellings behind margin; supraorbital margin entire, semicircular; dorsal surface of cheliped carpus covered in small but conspicuous granules; walking legs relatively short; P 4 merus c. 2.2 times longer than wide; P 5 merus c. 2.3 times longer; P 5 propodus c. 2.2 times longer; male abdomen moderately broad; somite 6 with distolateral margins strongly divergent, relatively straight over distal two-thirds; somite 3 width 2.9 times basal width of telson; G 1 (Fig. 11 D – G) relatively slender, weakly tapering to obtusely angled subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process long, with slender narrow apex, dorsal margin slightly concave. Redescription. Carapace transversely rectangular, c. 1.3 times (range 1.30 – 1.34) broader than long; surface bare, lacking setal tufts; anterior half conspicuously granular, granules become minute posterior, arranged into inconspicuous striae; mesogastric regions well defined; lateral carapace surface generally without obvious discrete oblique striae, except for strong, concave epibranchial sulcus beginning just behind exorbital tooth. Dorsal carapace, lateral branchial regions weakly convex. Exorbital tooth triangular, pointed, outer margin broadly convex so that greatest carapace width clearly posterior to exorbital tooth, margin not constricted behind (except on one side of larger male, but probably result of damage) so that entire lateral border appears convex, no trace of second anterolateral tooth. Postfrontal lobes well demarcated but relatively low, rounded, separated by broad grooves, median lobes similar in width to lateral lobes. Front c. 0.65 times carapace width, markedly deflexed, margin broadly convex in frontal view, but medial part relatively straight in dorsal view; laterally triangular, bluntly pointed; frontal margin emarginated, beaded with row of small but distinct granules; surface concave behind rim, but with pair of low lateral swellings behind frontal margin. Supraorbital margin entire, semicircular but oblique medial section somewhat straight; secondary rim formed either side making smooth, broadly triangular, deflexed central plate behind ocular peduncle. Eye not extending beyond exorbital tooth. Frontal plate protruding as shelf; medial septum broad, largely covering anterior half of anterior half of epistome; antennae, antennules much reduced in size, lodged under overhanging front; basal antennular segment not much swollen; antennal, antennular basal segments adjacent, not separated by septum. Antennal flagellum distinctively short, entering orbit. Third maxilliped ischium subequal to merus in length; ischium with shallow longitudinal, curved, median sulcus. Inner margins of merus, ischium with long setae, proximal outer margin of ischium, base of exopod with dense setae; outer margin of merus with short scattered setae only. Exopod slender, hidden behind ischium, merus except near base, tip reaching half length of outer margin of merus, flagellum long, slender. Chelipeds subequal, robust. Merus trihedral; posterior border broadly convex, emarginated, minutely granular, without indication of subdistal spine or lobe; inner anterior border with conspicuous row of pointed granules, broadly triangular; outer surface broadly convex, with fine transverse striae but appearing almost smooth. Carpus subquadrilateral, inner angle moderately produced, apically granular; outer margin, dorsal surface covered in small but conspicuous granules. Dorsal surface of palm slightly striated along superior margin, with scattering of moderate sized granules, otherwise smooth, punctate. Palm outer surface broadly rounded, smooth; no indication of subventral longitudinal ridge. Inner face of palm of males smooth except for curved projecting crest of large tubercles posterior to gape (Fig. 6 A, B). Cutting margin of fixed finger typically with 3 or 4 blunt teeth, proximal 3 similar in size, distal-most larger, rounded, conical, placed medially; dactylus with 2 teeth proximally, distalmost large, third much smaller, blunt tooth slightly distal of medial tooth of ventral finger. Dorsal surface of dactylus smooth. Fingers with chitinous tips; adult males with narrow but distinct gape when fingers closed. Walking legs relatively short, broad, flattened; second, third pairs sub-equal, longer than other walking legs. Without setae except for scattering of short dark bristles on dactyli, ventral face of propodi. Dorsal margin of meri with blunt subdistal shoulder, otherwise unarmed; outer surfaces of meri with minutely granular transverse striae. P 4 merus c. 2.2 times longer than wide; P 5 merus c. 2.3 times longer. Carpi with 2 well-developed accessory carinae on outer surface. Dorsal surfaces of carpi, propodi conspicuously granular. P 4 propodus c. 2.1 times longer than wide; P 5 propodus c. 2.2 times. Dactyli 0.8 times length of propodi, slightly recurved, terminating in acute chitinous tip. Thoracic sternites (Fig. 9 A, B) smooth, mostly bare of setae except for few scattered bristles; abdominal cavity reaching to thick transverse setal fringe at junction of sternites 3, 4. Male abdomen (Fig. 11 C) moderately broad; telson broadly rounded apically, 1.1 times longer than wide, slightly longer than somite 6 (1.15 times); somite 6 c. 2.0 times wider than long, distolateral margins strongly divergent, relatively straight over distal two-thirds; somites 3 – 5 trapezoidal, lateral margins of somites 4, 5 relatively straight, lateral margins of somite 3 convex; somite 3 width 2.9 times basal width of telson; somites 1, 2 transversely narrower, longitudinally narrow. G 1 (Fig. 11 D – G) relatively slender, almost straight, weakly tapering to obtusely angled subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process long, with slender narrow apex, dorsal margin slightly concave. G 2 short, as for the genus. Females. Chelipeds slightly smaller, less robust than in males; lacking raised granular row on inner face of chela. Vulval morphology without clear species-specific characters.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF9EFFC1FF5E2A679349FA30.taxon	description	Colour in life. Colour photographs taken from fresh specimens are given in Fig. 1. Background colour of carapace, legs fawn to bluish gray, covered in fine darker speckling with scattering of slightly larger irregular spots. Legs with darker, broad transverse bands that are more noticeable on the carpi and meri. Chelipeds dorsally similar in colour to carapace and legs but becoming greyish white in frontal and ventral view. Ocular peduncles and corneas pale, similar to carapace in colour.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF9EFFC1FF5E2A679349FA30.taxon	discussion	Remarks. Chiromantes obtusifrons was originally described by Dana (1851) from Maui, Sandwich Archipelago [= Hawaiian Is.], and since then it has been reported from a number of Indo-West Pacific localities stretching as far west as Christmas Island in the Indian Ocean (Davie 2002). Like most of Dana’s specimens, the type material is now considered lost, and so, to be certain of its identity we obtained topotypic material from the Hawaiian Is. for redescription and refiguring. Although we have concluded that C. obtusifrons sensu lato consists of at least five sibling species, we feel confident that each can be reliably recognised based on differences in the morphological characters given here for the Hawaiian populations. We therefore do not consider it necessary to designate a neotype at this time, especially because it appears that most of the species have relatively narrow distributions, and this will make it unlikely that there will be future taxonomic confusion. Chiromantes obtusifrons can be identified using the characters given in Table 1. Of all the members in the species-complex it has the most conspicuously granular carapace (over anterior half), frontal margin and claws; and the carapace is more flattened and less convex longitudinally.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF9EFFC1FF5E2A679349FA30.taxon	description	C. obtusifrons C. garfunkel C. silus C. leptomerus C. eurymerus Carapace dorsal Weakly convex Prominently convex Prominently convex Prominently convex Prominently convex surface (Fig. 10 A) (Fig. 10 B) ...... continued on the next page C. obtusifrons C. garfunkel C. silus C. leptomerus C. eurymerus We have included previous reports of C. obtusifrons by other authors under the synonymies of our new species as appropriate, however the record of De Man (1895, 1898) from the southern coast of Sumatra must remain incertae sedis until his material can be reexamined. It occurs relatively close to Christmas I., but we believe it to be different from C. garfunkel sp. nov., and probably represent a yet undescribed species (see Remarks for C. garfunkel).	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF9EFFC1FF5E2A679349FA30.taxon	distribution	Distribution. Only known from the Hawaiian Islands. Ecology. Edmondson (1959) noted that C. obtusifrons was found intertidally and “ even above the high water mark ”, and Paulay & Starmer (2011: 11) reported finding it living in a supratidal boulder field on O‘ahu. Paulay & Starmer (2011: 11) nevertheless also suggested that this species may not be as terrestrial as Chiromantes silus sp. nov. (see below), which they had observed in Micronesia, but indicated that additional observations on its ecology in the Hawaiian Is. would be useful.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF99FFCAFF5E2E9292E3F996.taxon	description	Sesarma obtusifrons — Gibson-Hill 1947: 44. — Tweedie 1947: 33. — George 1978: 13 (unnumbered pages). — Hicks et al. 1984: 22, 65 including colour picture. Chiromantes obtusifrons — Davie 2002: 221.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF99FFCAFF5E2E9292E3F996.taxon	materials_examined	Material Examined. HOLOTYPE: QM-W 29172, male (17.0 × 13.0 mm), Greta Beach, Christmas Island, H. H. Tan, 0 8.12.2007. PARATYPES: ZRC 2012.0776, female (13.3 × 12.0 mm), station CI- 33, Greta Beach, 10 ° 30.127 ' S, 105 ° 40.475 ' E, 27.03.2011. — ZRC 2012.0777, male (13.9 × 10.6 mm), station CI- 12, Greta Beach, 10 ° 30.127 ' S, 105 ° 40.475 ' E, limestone cliff, sandy beach, limestone bedrock, 24.01.2010. — ZRC 2012.0778, 4 males (13.5 × 10.2, 15.2 × 11.6, 18.2 × 14.7, 17.9 × 14.0 mm), 4 females (13.0 × 9.6, 14.3 × 10.8, 14.7 × 11.2, 17.5 × 13.6 mm), station CI- 06, The Grotto, Waterfall Road, 10 ° 25.386 ' S, 105 ° 42.127 ' E, weathered cave, tidal sump, 23.01.2010. — ZRC 2012.0779, 2 males (10.8 × 9.8, 14.5 × 13.2 mm), station CI- 07, Waterfall Bay, Christmas Island Resort, 10 ° 27.54 ' S, 105 ° 42.30 ' E, freshwater stream, sandy beach, limestone base rock, 23.01.2010. — ZRC 2012.0780, female (12.1 × 9.1 mm), station CI- 04, Merrial Beach, 10 ° 28.455 ' S, 105 ° 33.551 ' E, sandy beach, beach forest, limestone base rock, 20.03.2011. — ZRC 2012.0781, male (13.5 × 10.2 mm), station CI- 09, Ethel Beach, 10 ° 27.805 ' S, 105 ° 42.443 ' E, sandy beach, beach forest, limestone base rock, 21.03.2011. — ZRC 2012.0782, female (11.1 × 8.3 mm), station CI- 01, Flying Fish Cove, 10 ° 25.815 ' S, 105 ° 40.180 ' E, rocky, gravel beach, 22.01.2010. — ZRC 2012.0783, 1 ovig. female (11.4 × 8.6 mm), station CI- 01, Flying Fish Cove, 10 ° 25.815 ' S, 105 ° 40.180 ' E, rocky, gravel beach, 22.01.2010. — ZRC 2012.0784, male (14.0 × 10.8 mm), Flying Fish Cove, 10 ° 25.815 ' S, 105 ° 40.180 ' E, rocky, gravel beach, 22.01.2010. — ZRC 2012.0785, female (10.8 × 8.2 mm), station CI- 0 2, Lily Beach, 10 ° 28.011 ' S, 105 ° 42.688 ' E, sandy beach, beach forest, limestone base rock, 22.01.2010. — ZRC 2012.0786, female (11.6 × 8.6 mm), station CI- 02, Lily Beach, 10 ° 28.011 ' S, 105 ° 42.688 ' E, sandy beach, beach forest, limestone base rock, 22.01.2010. — QM-W 29173, male (18.2 × 13.8 mm), 3 females (12.8 × 9.8, 16.5 × 12.7, 16.6 × 12.7 mm), 31.03.2011, The Blowholes, 10 ° 30.861 ' S, 105 ° 37.358 ' E, under limestone rocks adjacent vegetation at back of limestone terrace, P. Davie. — ZRC 1965.7.29.153, male (13.7 × 10.4 mm), 1932, no specific location. — ZRC 1965.7.29.154 - 163, 2 males (larger 11.5 × 8.8 mm), 7 females (largest 20.4 × 16.2 mm), M. W. F. Tweedie, shore terrace along east and north coasts, and Isabel Beach, 0 2.03.1932. All localities Christmas I.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF99FFCAFF5E2E9292E3F996.taxon	diagnosis	Diagnosis. Carapace transversely subovate, c. 1.3 times broader than long; dorsal carapace, lateral branchial regions prominently swollen; exorbital tooth at widest point only projecting slightly more than exorbital tooth; front c. 0.6 times carapace width, margin broadly convex in dorsal view, appearing smooth but microscopically granular, with pair of weak lateral swellings behind margin; supraorbital margin entire, straight, obliquely sloping posteriorly; outer surface of cheliped carpus moderately granular; walking legs relatively short; P 4 merus c. 2.3 times longer than wide; P 5 merus relatively narrower than P 4 merus, c. 2.6 times longer; P 4 propodus c. 2.8 times longer than wide; P 5 propodus c. 2.7 times longer; male abdomen (Fig. 12 A) moderately broad; somite 6 with lateral margins diverging, slightly concave over distal half, more subparallel over proximal half; somite 3 width 3.0 times basal width of telson; G 1 (Fig. 12 B – E) relatively slender, weakly tapering to prominent subdistal shoulder; terminal process long, with slender narrow apex, dorsal margin slightly sinuous.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF99FFCAFF5E2E9292E3F996.taxon	description	Description. Carapace transversely subovate, c. 1.3 (range 1.26 – 1.35) times broader than long; surface bare, lacking setal tufts; covered with fine, but distinct low granules becoming arranged into short striae posteriorly; mesogastric regions well defined; lateral carapace surface generally without obvious discrete oblique striae, except for strong, concave epibranchial sulcus beginning just behind exorbital tooth. Dorsal carapace, lateral branchial regions relatively weakly convex, not prominently swollen (Fig. 10 A, B). Exorbital tooth triangular, pointed, outer margin long, slightly convex, at widest point only projecting slightly more than exorbital tooth; margin constricted behind, but no trace of second anterolateral tooth. Postfrontal lobes strongly demarcated, separated by broad grooves, median lobes similar in width to lateral lobes. Front c. 0.6 times carapace width (0.63 in holotype), markedly deflexed, margin broadly convex in dorsal view; laterally triangular, bluntly pointed; frontal margin emarginated, minutely granular (Fig. 8 D); surface somewhat concave behind frontal margin, but with pair of weak lateral swellings. Supraorbital margin entire, straight, obliquely sloping posteriorly at about 45 ° angle; secondary rim sloping obliquely inwards, downwards to form smooth, broadly triangular, deflexed plate behind ocular peduncle. Eye not extending beyond exorbital tooth. Frontal plate protruding as shelf; medial septum broad, largely covering anterior half of anterior half of epistome; antennae, antennules much reduced in size, lodged under overhanging front; basal antennular segment not much swollen; antennal, antennular basal segments adjacent, not separated by septum. Antennal flagellum conspicuously short, entering orbit. Third maxilliped ischium, merus subequal in length; ischium with shallow longitudinal, curved, median sulcus. Merus, ischium inner margins with long setae, ischium proximal outer margin, base of exopod with dense setae; merus outer margin with short scattered setae only. Exopod slender, hidden behind ishium, merus except near base, tip reaching half length of outer margin of merus, flagellum long, slender. Chelipeds subequal, robust. Merus trihedral; posterior border broadly convex, emarginated, minutely granular, without indication of subdistal spine or lobe; inner anterior border minutely granular, broadly triangular; outer surface broadly convex, with fine transverse striae but appearing almost smooth. Carpus subquadrilateral, inner angle moderately produced, apically granular; outer margin, dorsal surface moderately granular. Palm dorsal surface slightly striated along superior margin, with scattering of moderate sized granules, otherwise smooth, punctate. Palm outer surface broadly rounded, smooth; no indication of subventral longitudinal ridge. Inner face of palm in males smooth except for curved projecting crest of large tubercles behind gape (Fig. 6 F), but prominence variable. Cutting margin of fixed finger with 3 or 4 blunt teeth (Fig. 5 F), proximal 3 similar in size, distalmost larger, rounded, conical, placed medially; dactylus with 2 proximal teeth, distalmost large, third much smaller blunt tooth slightly distal of medial tooth of ventral finger; teeth on both fingers can vary in prominence. Dorsal surface of dactylus smooth. Fingers with chitinous tips; adult males with narrow but distinct gape when fingers closed. Walking legs relatively short, broad, flattened; second, third pairs sub-equal, longer than other walking legs. Without setae except for scattering of short dark bristles on dactyli, ventral face of propodi. Dorsal margins of meri with blunt subdistal shoulder, otherwise unarmed; outer surfaces of meri with minutely granular transverse striae. P 4 merus c. 2.3 times longer than wide; P 5 merus relatively narrower than P 4 merus, c. 2.6 times longer. Carpi with 2 accessory carinae on outer surface but not strongly marked. P 4 propodus c. 2.8 times longer than wide; P 5 propodus c. 2.7 times. Dactyli 0.8 times length of propodi, slightly recurved, terminating in acute chitinous tip. Thoracic sternites (Fig. 9 F) smooth, mostly bare of setae except for few scattered bristles; abdominal cavity reaching to thick transverse setal fringe at junction of sternites 3, 4. Male abdomen (Fig. 12 A) moderately broad; telson broadly rounded apically, 1.1 times longer than wide, slightly longer than somite 6; somite 6 c. 1.8 times wider than long, lateral margins divergent, slightly concave over distal half, but more subparallel over proximal half; somites 3 – 5 trapezoidal, lateral margins of somites 4, 5 relatively straight, lateral margins of somite 3 convex; somite 3 width 3.0 times basal width of telson; somites 1, 2 transversely, longitudinally narrow. G 1 (Fig. 12 B – E) relatively slender, straight, weakly tapering to prominent subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process long, with slender narrow apex, dorsal margin slightly sinuous. G 2 short, as for the genus. Females. Chelipeds slightly smaller, less robust, lacking raised granular row on inner face of chela. Vulval morphology without clear species-specific characters. Colour in life. Colour photographs taken from fresh specimens are shown in Fig. 2. Carapace and legs of adults rich, dark purple to maroon; without prominent speckling or splotching. Legs uniform in colour, without transverse banding. Chelipeds relatively uniform in colour, not clearly darker dorsally; off-white to white porcelain in adults, markedly contrasting with purple carapace. Ocular peduncles same as carapace in colour; corneas bright yellow (Fig. 2 A – D). Female specimens from more exposed supralittoral areas behind beaches can be paler in coloration, with the carapace and legs beige with streaks of purple and brown (Fig. 2 E, F). Their eyes, however, are still bright yellow.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF99FFCAFF5E2E9292E3F996.taxon	discussion	Remarks. This species was first recorded from Christmas Island by Balss (1934) as Sesarma obtusifrons. It was subsequently listed by Gibson-Hill (1947 a, b) and Tweedie (1947) who reported on comparisons with specimens from the Hawaiian Islands made by F. A. Chace (in litt. to M. Tweedie). Chace noted (Tweedie, 1947: 34) that the Christmas I. specimens had more slender legs but felt that it was within the possible range of variation. It was pictured by Hicks et al. (1984: 65), who gave a short account and gave it the name “ Yellow-eyed Crab ” (Sesarma obtusifrons) because “ Bright yellow eyes peering from a pock-mark in the seacliff are all you normally see of this shy little crab ”. They further commented: “ Yellow-eyed crabs live high on the seacliff, beyond tidal or salt spray influences, and have been recorded all around the coast. ” Tweedie (1947) considered the record of Sesarma obtusifrons by De Man (1895, 1898) from Atjeh, Sumatera, Indonesia as being conspecific with his Christmas I. samples. We disagree and consider that the identity of these specimens must remain unresolved at this time. From De Man’s figure (1898: pl. 29, fig. 31) the abdomen appears significantly narrower than in C. garfunkel and the legs are relatively shorter, both characters that are useful in separating other species in the group. Furthermore, the live colouration was well described by De Man and this does not agree with the colour of the Christmas I. species. De Man (1895: 161 – 165) described the colour as “ The surface of the carapace has an olive-green base color [purple in C. garfunkel] and transmits some symmetrically arranged dark brown patches of irregular shape. The lower frontal border, the orbital margins, and the lateral margins are yellowish, as are the depressions of the hepatic regions immediately behind the external orbital angle. The claws are yellowish, turning reddish-yellow dorsally, the legs are brownish in color with purple transverse bands. The numerous features that distinguish this species from its closest congeners are given in Table 1.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF99FFCAFF5E2E9292E3F996.taxon	etymology	Etymology. Named for Art Garfunkel, who sang “ Bright Eyes ” for the soundtrack of the 1978 animated film Watership Down. Like the rabbit to which the song alludes, the new crab species also lives in holes, and is remarkable for its brightly shining eyes. The name is used as a noun in apposition.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF99FFCAFF5E2E9292E3F996.taxon	distribution	Distribution. Only known from Christmas Island, eastern Indian Ocean. Ecology. Gibson-Hill (1947 b: 44) noted that: “ Yet another species, Sesarma obtusifrons, is fairly plentiful in the pock-marks and crevices at the top of the sea cliff. It is particularly common in Flying Fish Cove and behind Greta and West White Beaches. It also occurs up on the shore terrace proper, at the base of the inland cliff, and during the rainy season can occasionally be found in the open. Females with spawn (a crab with a carapace width of 18 mm carrying about 5500 eggs) are most frequent from January to April. The spawn is taken to the sea and deposited, at low tide, on the edges of the rock pools on the uncovered portions of the fringing reef. ” George (1978) largely repeated the earlier notes made by Gibson-Hill (1947 a, b). Hicks et al. (1984: 65) stated: “ Yellow-eyed crabs live high on the seacliff, beyond tidal or salt spray influences, and have been recorded all around the coast. ” Our personal observations agree entirely with these earlier authors.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF92FFD7FF5E2D3D90E4F870.taxon	materials_examined	Material Examined. HOLOTYPE: ZRC 2012.0787, male (16.3 × 12.8 mm), Tanguisson, Guam, 10 – 20 m from shore, 5 – 8 m elevation, under limestone rocks, G. Paulay, 0 5.10.1997. PARATYPES: ZRC 2012.0788, data as for holotype, male (15.1 × 11.3 mm), female (14.9 × 11.2 mm). — UFUF- 122, 3 males (16.3 × 13.2, 15.9 × 11.9, 13.6 × 10.5 mm), Tanguisson, 10 – 20 m from shore, 1 m from forest, under rocks, G. Paulay, 05.10.1997. — ZRC 2001.0742, male (15.7 × 11.7 mm), Haputo Beach, P. K. L. Ng, 3.08.2001. — ZRC 2001.0743, ovigerous female (15.2 × 11.6 mm) (with zoea 1), Haputo Beach, P. K. L. Ng, 04.08.2001. — ZRC 2000.0573, female (15.2 × 11.2 mm), Pago Bay, outside of University of Guam Marine Laboratory, P. K. L. Ng & C. H. Wang, 15 – 18.04.2000. — UFUF- 90, 2 females (19.1 × 13.6, 19.0 × 13.7 mm), Tagachang, near shore, karst rubble, under 15 m overhang, G. Paulay, 29.09.1996. All localities Guam.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF92FFD7FF5E2D3D90E4F870.taxon	diagnosis	Diagnosis. Carapace transversely subovate, c. 1.3 times broader than long; dorsal carapace, lateral branchial regions markedly swollen; exorbital tooth weakly oblique, forming rounded obtuse angle posteriorly marking widest point of carapace, especially in larger specimens; front c. 0.65 times carapace width, margin straight or slightly concave in dorsal view, appearing smooth but microscopically granular, with pair of low lateral swellings behind margin; supraorbital margin entire, semicircular; dorsal surface of cheliped carpus conspicuously granular; walking legs relatively short; P 4 merus c. 2.3 times longer than wide; P 5 merus similar, 2.4 times longer; P 4 propodus c. 2.6 times longer than wide; P 5 merus c. 2.3 times; male abdomen (Fig. 13 A) moderately broad, somite 6 with lateral margins broadly divergent with margins relatively evenly convex, somite 3 width 3.2 times basal width of telson; G 1 (Fig. 13 B – E) relatively slender, weakly tapering to broadly convex subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process long, with dorsal margin concave, apically pointed.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF92FFD7FF5E2D3D90E4F870.taxon	description	Description. Carapace transversely subovate, c. 1.3 (range 1.27 – 1.36) times broader than long; surface bare, lacking setal tufts; covered with fine, but distinct low granules arranged into short striae that become longer posteriorly; mesogastric regions well defined; lateral carapace surface generally without obvious, discrete oblique striae except for strong, concave epibranchial sulcus beginning just posterior to exorbital tooth. Dorsal carapace, lateral branchial regions markedly swollen. Exorbital tooth triangular, pointed, outer margin long, weakly oblique, forming rounded obtuse angle posteriorly marking widest point of carapace, especially in larger specimens; margin markedly constricted posteriorly, but no trace of second anterolateral tooth. Postfrontal lobes strongly demarcated, separated by broad grooves, median lobes similar in width to lateral lobes. Front c. 0.65 times carapace width, markedly deflexed, margin straight or slightly concave in dorsal view; laterally triangular, bluntly pointed; frontal margin emarginated, appearing smooth but microscopically granular (Fig. 8 B); frontal surface somewhat concave medially but with pair of low lateral swellings posterior to frontal margin. Supraorbital margin entire, semicircular but oblique medial section somewhat straight; secondary rim formed either side making smooth, broadly triangular, deflexed central plate posterior to ocular peduncle. Eye not extending beyond exorbital tooth. Frontal plate protruding as shelf; medial septum broad, largely covering anterior half of anterior half of epistome; antennae, antennules much reduced in size, lodged under overhanging front; basal antennular segment not much swollen; antennal, antennular basal segments adjacent, not separated by septum. Antennal flagellum very short, entering orbit. Third maxilliped ischium, merus subequal in length; ischium with shallow longitudinal, curved, median sulcus. Inner margin of merus, ischium with long setae, proximal outer margin of ischium, base of exopod with dense setae; outer margin of merus with short scattered setae only. Exopod slender, hidden behind ishium, merus except near base, tip reaching half length of outer margin of merus, flagellum long, slender. Chelipeds subequal, robust. Merus trihedral; posterior border broadly convex emarginate, minutely granular, without indication of subdistal spine or lobe; inner anterior border armed with small pointed granules, broadly triangular; outer surface broadly convex, with fine transverse striae but appearing almost smooth. Carpus subquadrilateral, inner angle moderately produced, apically granular; outer margin, dorsal surface conspicuously granular. Palm dorsal surface slightly striated along superior margin, with scattering of moderate sized granules, otherwise smooth, punctate. Palm outer surface broadly rounded, smooth; no indication of subventral longitudinal ridge. Palm inner face of males smooth except for curved, projecting crest armed with large tubercles posterior to gape (Fig. 6 C), but which can vary in prominence among specimens. Cutting margin of fixed finger with 3 or 4 blunt teeth, proximal 3 similar in size, distalmost larger, rounded, conical, placed medially; dactylus with 2 teeth proximally, distalmost large, third much smaller blunt tooth slightly distal of medial tooth of ventral finger. Dorsal surface of dactylus smooth. Fingers with chitinous tips; adult males with narrow but distinct gape when fingers closed. Walking legs relatively short, broad, flattened; second, third pairs sub-equal, longer than other walking legs. No setae except for scattering of short dark bristles on dactyli, ventral face of propodi. Dorsal margins of meri with blunt subdistal shoulder, otherwise unarmed; outer surfaces of meri with minutely granular transverse striae. P 4 merus c. 2.3 times longer than wide; P 5 merus similar, c. 2.4 times longer. Carpi with 2 accessory carinae on outer surface but not strongly marked. P 4 propodus c. 2.6 times longer than wide; P 5 propodus 2.3 times longer than wide. Dactyli 0.8 times length of propodi, slightly recurved, terminating in acute chitinous tip. Thoracic sternites (Fig. 9 C) smooth, mostly bare of setae except for few scattered bristles; abdominal cavity reaching to thick transverse setal fringe at junction of sternites 3, 4. Male abdomen (Fig. 13 A) moderately broad; telson broadly rounded apically, 1.1 times longer than wide, only slightly longer than somite 6; somite 6 c. 1.9 times wider than long, lateral margins broadly divergent with margins relatively evenly convex; somites 3 – 5 trapezoidal, lateral margins of somites 4, 5 relatively straight, lateral margins of somite 3 convex; somite 3 width 3.2 times basal width of telson; somites 1, 2 transversely, longitudinally narrow. G 1 (Fig. 13 B – E) relatively slender, almost straight, weakly tapering to broadly convex subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process long, with dorsal margin concave, apically pointed. G 2 short, as for the genus. Females. Chelipeds slightly smaller, less robust, lacking raised granular row on inner face of chela. Vulval morphology without clear species-specific characters. Colour in life. Colour photographs taken from fresh specimens are shown in Fig. 3 A – C. Background colour of carapace typically maroon, with coarse paler orange to yellow-green blotching. Legs speckled with some indication of transverse banding. Legs and chelipeds dorsally reddish brown to dark orange, becoming paler orange in frontal and ventral view. Ocular peduncles speckled similar to carapace; corneas darker.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF92FFD7FF5E2D3D90E4F870.taxon	discussion	Remarks. The numerous features that distinguish this species from all others in the genus are given in Table 1. The greater marked constriction of the carapace behind the epibranchial teeth, the shape of the tip of the G 1, the relatively straight frontal margin, the abdominal proportions, and the colour of the live crabs are all important characters to help identify this species.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF92FFD7FF5E2D3D90E4F870.taxon	etymology	Etymology. The name silus is Latin for “ pug-nosed ” in reference to the broad, flattened frontal plate that the new species shares with congeners.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF92FFD7FF5E2D3D90E4F870.taxon	distribution	Distribution. So far only known from Guam. Ecology. Reported to live “ under rocks and in karstic crevices in sparsely vegetated coastal platforms, up to ca. 50 m inland and ca. 10 m elevation ” (Paulay & Starmer 2011: 11); and this is confirmed by personal observations of the second author.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8DFFD3FF5E2BF09539FC85.taxon	materials_examined	Material Examined. HOLOTYPE: NMNS- 7028 - 001, male (16.8 × 12.7 mm), Pingtung County, Hsiang Chiaowan, Taiwan, H. - C. Liu, 25.08.1999. PARATYPES: ZRC 2000.1860, 2 males (13.4 × 10.3 mm, 16.4 × 12.7 mm), west coast of Lanyu Island, Taiwan, calcareous rock terraces, spray zone, C. D. Schubart & H. - C. Liu, 20 – 21.09.1999. — QM-W 25699, male (16.2 × 12.4 mm), female (18.1 × 13.4 mm), data as for ZRC 2000.1860. NMMBA- 3504 a, 2 males (23.0 × 18.3 mm, 16.7 × 13.0 mm), Hsiang-Chiau-Wan, Kenting, Pingtung County, Taiwan, C. C. Li, 23.08.2012. — ZRC 2012.0958, 2 females (21.0 × 15.7, 20.0 × 14.9 mm), Siatanzai, Kenting, Pingtung County, Taiwan, 21 ° 55 ’ 55.8 ” N 120 ° 44 ’ 37.4 ” S, J. - H. Lee & W. - J. Wang, 6.08.2012. — NMNS, male (17.1 × 13.0 mm), female (20.5 × 15.6 mm), Siatanzai, Kenting, Pingtung County, 21 ° 55 ’ 36.6 ” N 120 ° 44 ’ 21.8 ” S, Taiwan, J. - H. Lee & W. - J. Wang, 17.08.2012. — ZRC 2012.0959, male (18.1 × 13.9 mm), Siatanzai, Kenting, Pingtung County, 21 ° 55 ’ 36.6 ” N 120 ° 44 ’ 21.8 ” S, Taiwan, J. - H. Lee & W. - J. Wang, 31.08.2012. — ZRC 2012.0960, male (17.8 × 13.9 mm), ovigerous female (18.8 × 14.2 mm), Siatanzai, Kenting, Pingtung County, 21 ° 55 ’ 36.6 ” N 120 ° 44 ’ 21.8 ” S, Taiwan, J. - H. Lee & W. - J. Wang, 31.08.2012. — ZRC 2012.0961, female (22.3 × 16.6 mm), Hsiang- Chiau-Wan, Kenting, Pingtung County, Taiwan, P. K. L. Ng & C. - W. Lin, 1.10.2012. NON-TYPE: RUMF-ZC- 1351, male (16.1 × 12.4 mm), Gazuda Beach, Hateruma I., Ryukyu Is., Japan, Y. Fujita, 2.05.2009. — RUMF-ZC- 1386, 2 males (15.5 × 11.1, 13.2 × 9.9 mm), beside Hateruma Port, Hateruma I., Ryukyu I., Japan, Y. Fujita, 19.04.2009. — RUMF-ZC- 2075, male (16.9 × 13.0 mm), Dannu Beach, Yonagun Island, Ryukyu Islands, Japan, Y. Fujita, 15.11.2007. — RUMF-ZC- 2076, male (19.7 × 14.6 mm), Honba Coast, Minamidaito Island, Japan, Y. Fujita, 2.09.2008. — RUMF-ZC- 2077, male (18.5 × 13.9 mm), Honba Coast, Minamidaito Island, Japan, Y. Fujita, 2.09.2008. — RUMF-ZC- 2078, male (10.9 × 8.2 mm), Ubama Beach, Yonaguni Island, Ryukyu Islands, Japan, Y. Fujita, 16.11.2007. — RUMF-ZC- 2079, male (17.2 × 12.8 mm), Dannu Beach, Yonaguni Island, Ryukyu Islands, Japan, Y. Fujita, 15.11.2007. — RUMF-ZC- 2080, male (12.5 × 9.5 mm), Dannu Beach, Yonaguni Island, Ryukyu Islands, Japan, Y. Fujita, 15.11.2007. — RUMF-ZC- 2082, female (16.9 × 12.9 mm), Shimoji Island, Miyako Group, Ryukyu Islands, Japan, Y. Fujita, 23.09.2012. — RUMF-ZC- 2083, female (15.6 × 12.1 mm), Shimoji Island, Miyako Group, Ryukyu Islands, Japan, Y. Fujita, 23.09.2012. — RUMF-ZC- 2089, female (18.0 × 13.1 mm), Giza Banta, Okinawa Island, Ryukyu Islands, Japan, T. Maenosono, 2007. — RUMF-ZC- 2090, 2 males (16.0 × 12.2, 14.1 × 11.0 mm), female (14.8 × 11.6 mm), Kori Island, off Nakijin Village of Okinawa Island, Ryukyu Islands, Japan, T. Maenosono, 9.06.2010. — RUMF-ZC- 2104, 2 males (17.5 × 13.7, 17.4 × 12.9 mm), female (15.7 × 12.1 mm), Muigah, Miyako Island, Ryukyu Islands, Japan, Y. Fujita, 4.05.2005. — ZRC, 6 males (largest 18.9 × 14.5 mm, smallest 14.3 × 10.8 mm), 5 females (largest 15.2 × 11.3 mm, smallest 8.3 × 7.1 mm), Muigah, Miyako Island, Ryukyu Islands, Japan, Y. Fujita, 4.07.2005. — RUMF-ZC- 819, female (15.7 × 12.0 mm), Giza Banda, Yaese Town, Okinawa I., Ryukyu Is., Japan, T. Maenosono, 22.05.2007.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8DFFD3FF5E2BF09539FC85.taxon	diagnosis	Diagnosis. Carapace transversely subovate, c. 1.3 times broader than long; dorsal carapace, lateral branchial regions markedly swollen; exorbital tooth moderately oblique, forming slight angle posteriorly marking widest point of carapace, most prominent in larger specimens; front c. 0.6 times carapace width, margin slightly to broadly concave in dorsal view, appears smooth but microscopically granular, with pair of prominent lateral swellings behind margin; supraorbital margin entire, semicircular; dorsal surface of cheliped carpus conspicuously granular; walking legs relatively short; P 4 merus c. 2.3 times longer than wide; P 5 merus similar, 2.2 – 2.3 times longer; propodus P 4 propodus c. 2.8 times longer than wide; P 5 propodus 2.4 times; male abdomen (Fig. 13 F) moderately broad; somite 6 with divergent lateral margins, margins relatively evenly convex; somite 3 width 2.8 times basal width of telson; G 1 (Fig. 13 G – J) relatively slender, weakly tapering to broadly convex subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process long, with dorsal margin concave, apex slightly flanged.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8DFFD3FF5E2BF09539FC85.taxon	description	Description. Carapace transversely subovate, c. 1.3 times (range 1.26 – 1.35) broader than long; surface bare, lacking setal tufts; covered with fine, but distinct low granules becoming arranged into short striae posteriorly; mesogastric regions well defined; lateral carapace surface generally without obvious discrete oblique striae, except for strong, concave epibranchial sulcus beginning just behind exorbital tooth. Dorsal carapace, lateral branchial regions markedly swollen. Exorbital tooth triangular, pointed, outer margin long, moderately oblique, forming slight angle posteriorly marking widest point of carapace, most prominent in larger specimens; margin constricted behind, but no trace of second anterolateral tooth. Postfrontal lobes strongly demarcated, separated by broad grooves, median lobes similar in width to lateral lobes. Front c. 0.6 times carapace width (0.66 in holotype), markedly deflexed, margin slightly to broadly concave in dorsal view; laterally triangular, bluntly pointed; frontal margin emarginate, microscopically granular (Fig. 8 C); surface somewhat concave behind but with pair of prominent lateral swellings behind frontal margin. Supraorbital margin entire, semicircular; secondary rim formed either side making a smooth, broadly triangular, deflexed central plate behind ocular peduncle. Eye not extending beyond exorbital tooth. Frontal plate protruding as a shelf; medial septum broad, largely covering anterior half of anterior half of epistome; antennae, antennules much reduced in size, lodged under overhanging front; basal antennular segment not much swollen; antennal, antennular basal segments adjacent, not separated by septum. Antennal flagellum very short, entering orbit. Third maxillipeds with ischium, merus subequal in length; ischium with shallow longitudinal, curved, median sulcus. Inner margin of merus, ischium with long setae, proximal outer margin of ischium, base of exopod with dense setae; outer margin of merus with short scattered setae only. Exopod slender, hidden behind ishium, merus except near base, tip reaching half length of outer margin of merus, flagellum long, slender. Chelipeds subequal, robust. Merus trihedral; posterior border broadly convex emarginate, minutely granular, without indication of subdistal spine or lobe; inner anterior border minutely granular, broadly triangular; outer surface broadly convex, with fine transverse striae but appearing almost smooth. Carpus subquadrilateral, inner angle moderately produced, apically granular; outer margin, dorsal surface conspicuously granular. Palm dorsal surface slightly striated along superior margin, with scattering of moderate sized granules, otherwise smooth, punctate. Palm outer surface broadly rounded, smooth; no indication of subventral longitudinal ridge. Palm inner face of males smooth except for curved projecting crest of large tubercles behind gape (Fig. 6 D). Cutting margin of fixed finger with 3 or 4 blunt teeth, proximal 3 similar in size, distalmost larger, rounded, conical, placed medially; dactylus with 2 teeth proximally, distalmost large, third much smaller blunt tooth slightly distal of medial tooth of ventral finger. Dorsal surface of dactylus smooth. Fingers with chitinous tips; adult males with narrow but distinct gape when fingers closed. Walking legs relatively short, broad, flattened; second, third pairs sub-equal, longer than other walking legs. Without setae except for scattering of short dark bristles on dactyli, ventral face of propodi. Dorsal margins of meri with blunt subdistal shoulder, but otherwise unarmed; outer surfaces of meri with minutely granular transverse striae. P 4 merus c. 2.3 times longer than wide; P 5 merus similar, 2.2 – 2.3 times longer. Carpi with 2 accessory carinae on outer surface but not strongly marked. P 4 propodus c. 2.8 times longer than wide; P 5 propodus 2.4 times longer than wide. Dactyli 0.8 times length of propodi, slightly recurved, terminating in acute chitinous tip. Thoracic sternites (Fig. 9 D) smooth, mostly bare of setae except for few scattered bristles; abdominal cavity reaching to thick transverse setal fringe at junction of sternites 3, 4. Male abdomen (Fig. 13 F) moderately broad; telson broadly rounded apically, 1.1 times longer than wide, only slightly longer than somite 6; somite 6 c. 1.8 times wider than long, lateral margins divergent with margins relatively evenly convex; somites 3 – 5 trapezoidal, lateral margins of somites 4, 5 relatively straight, lateral margins of somite 3 convex; somite 3 width 2.8 times basal width of telson; somites 1, 2 transversely, longitudinally narrow. G 1 (Fig. 13 G – J) relatively slender, almost straight, weakly tapering to broadly convex subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process long, with dorsal margin concave, apex slightly flanged. G 2 short, as for the genus. Females. Chelipeds slightly smaller, less robust, lacking raised granular row on inner face of chela. Vulval morphology without clear species-specific characters. Colour in life. (Fig. 3 D – H). Carapace background colour of adult males varying from pale brown to a darker grey-green; females and smaller males mottled greyish white, sometimes yellowish. Upper surface of carapace and legs with some course blotches and streaks; a distinctive pattern of large dirty yellow to green blotches across anterior part of carapace. Chelae of adult males reddish-pink to purplish red overall, especially on dorsal surfaces and dactylus; smaller males and females with palm whitish to whitish-pink, dactylus always clearly tinged with red to pink in part or whole. Ocular peduncles similar to carapace; corneas light green to yellowish green.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8DFFD3FF5E2BF09539FC85.taxon	discussion	Remarks. Easily separated from its sympatric Taiwanese congener, Chiromantes eurymerus, by its relatively narrower legs, but also by its more slender G 1 with its markedly elongated tip, and other differences discussed further under that species account. The numerous features that distinguish this species from all other presently known species in this sibling complex are given in Table 1. Specimens from the Ryukyu Is. seem to show some minor variability in the proportions of the leg segments, with the meri of some individuals appearing a little broader than typical, and almost approaching the C. eurymerus condition. However, in all other characters, including the form of the thoracic sternum and G 1, they appear to be typical C. leptomerus. Their live colours are also similar. Perhaps this could indicate some incipient population separation taking place between Taiwan and Japan, as has been observed for the mitten crab Eriocheir japonica (Varunidae), with crabs from Okinawa proving to be genetically distinct from Taiwanese and Chinese populations (Xu et al. 2009). Twin species-pairs on either side of the deep-water strait between Taiwan and the Yaeyama Islands has now been observed for several crabs including Tmethypocoelis ceratophora and T. choreutes (Dotillidae) (Davie & Kosuge 1995), and Mictyris guinotae and M. brevidactylus (Mictyridae) (Davie et al. 2010). While we cannot discern any clear morphological grounds for separating the Japanese and Taiwanese populations of C. leptomerus for the moment, it will be interesting if future genetic studies may show some level of evolutionary divergence reflecting that observed for other populations and species between these two areas.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8DFFD3FF5E2BF09539FC85.taxon	etymology	Etymology. Derived from the Greek leptos meaning “ thin ” and meros meaning “ thigh ”, and refers to the relatively more slender legs of this species compared to the other sympatric Taiwanese species, C. eurymerus sp. nov. It is used here as a noun in apposition.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8DFFD3FF5E2BF09539FC85.taxon	distribution	Distribution. Only known from Taiwan and the Ryukyu Islands, southern Japan. Ecology. Supratidal; calcareous rock terraces, spray zone. Found comingled with C. eurymerus sp. nov. in the same shore habitat; the nature and extent of niche separation has not been determined.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8BFFD0FF5E283D9539FD5D.taxon	materials_examined	Material Examined. HOLOTYPE: NMNS- 7028 - 002, male (18.7 × 14.8 mm), west coast of Lanyu Island, Taiwan, calcareous rock terraces, spray zone, C. D. Schubart & H. - C. Liu, 20 – 21.09.1999. PARATYPES: ZRC 2000.1823, Pingtung County, Hsiang Chiaowan, Taiwan, H. - C. Liu, 25.08.1999, male (18.2 × 14.0 mm), 2 females (17.0 × 13.2, 19.9 × 15.0 mm). — ZRC 2000.1822, male (13.3 × 10.2 mm), Pingtung County, Hsiang Chiaowan, Taiwan, H. - C. Liu, 5.07.1999. — QM-W 29171, male (20.0 × 15.4 mm), west coast of Lanyu Island, Taiwan, calcareous rock terraces, spray zone, C. D. Schubart & H. - C. Liu, 20 – 21.09.1999. NMMBA- 3504 b, male (19.3 × 14.8 mm), female (22.6 × 16.7 mm), Hsiang-Chiau-Wan, Kenting, Pingtung County, Taiwan, C. C. Li, 23.08.2012. — NMNS, 2 males (17.5 × 13.4, 16.7 × 12.3 mm), Siatanzai, Kenting, Pingtung County, Taiwan, 21 ° 55 ’ 36.6 ” N, 120 ° 44 ’ 21.8 ” S, J. - H. Lee & W. - J. Wang, 17.08.2012. — ZRC 2012.0956, male (15.4 × 12.3 mm), ovigerous female (18.0 × 13.4 mm), Siatanzai, Kenting, Pingtung County, 21 ° 55 ’ 36.6 ” N, 120 ° 44 ’ 21.8 ” S, Taiwan, J. - H. Lee & W. - J. Wang, 31.08.2012. — NMNS, female (18.8 × 13.6 mm), same data as ZRC 2012.0956. NON-TYPE: ZRC 2012.0957, dried female exuvium (24.8 × 18.7 mm), Dingtanzai, near nuclear power station, Kenting, Pingtung County, Taiwan, P. K. L. Ng, 4.10.2012.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8BFFD0FF5E283D9539FD5D.taxon	diagnosis	Diagnosis. Carapace transversely subovate, c. 1.3 times broader than long; dorsal carapace, lateral branchial regions markedly swollen; exorbital tooth with outer margin broadly convex marking widest point of carapace; front c. 0.65 – 0.7 times carapace width, margin broadly convex in frontal view, but medial part relatively straight in dorsal view, appears smooth but microscopically granular, with pair of low lateral swellings behind margin; supraorbital margin entire, semicircular; dorsal surface of carpus of cheliped covered in small granules; walking legs relatively short; merus of P 4 c. 2.0 times longer than wide; that of P 5 similar at 2.0 – 2.1 times longer; propodus of P 5 also 2.1 – 2.2 times; male abdomen (Fig. 14 C) moderately broad; somite 6 with distolateral margins relatively straight, strongly divergent, margins convex overall; somite 3 width 3.1 times basal width of telson; G 1 (Fig. 14 E, G, H) markedly stout, with margins subparallel to obtusely angled subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process short, not projecting past line of gonopod shaft, moderately tapering.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8BFFD0FF5E283D9539FD5D.taxon	description	Description. Carapace transversely subovate, c. 1.3 times (range 1.29 – 1.32) broader than long; surface bare, lacking setal tufts; covered with fine, but distinct low granules becoming arranged into short striae posteriorly; mesogastric regions well defined; lateral carapace surface generally without obvious discrete oblique striae, except for strong, concave epibranchial sulcus beginning just behind exorbital tooth. Dorsal carapace, lateral branchial regions markedly swollen. Exorbital tooth triangular, pointed, outer margin broadly convex marking widest point of carapace, margin not constricted behind (sometimes slightly flattened) such that entire lateral border appears convex, no trace of second anterolateral tooth. Postfrontal lobes well demarcated but relatively low, rounded, separated by broad grooves, median lobes similar in width to lateral lobes. Front c. 0.65 – 0.7 times carapace width (0.65 in holotype), markedly deflexed, margin broadly convex in frontal view, but medial part relatively straight in dorsal view; laterally triangular, bluntly pointed; frontal margin emarginate, microscopically granular but appearing relatively smooth; surface relatively flat behind, but with pair of low lateral swellings behind frontal margin. Supraorbital margin entire, semicircular but oblique medial section somewhat straight; secondary rim formed either side making a smooth, broadly triangular, deflexed central plate behind ocular peduncle. Eye not extending beyond exorbital tooth. Frontal plate protruding as a shelf; medial septum broad, largely covering anterior half of anterior half of epistome; antennae, antennules much reduced in size, lodged under overhanging front; basal antennular segment not much swollen; antennal, antennular basal segments adjacent, not separated by septum. Antennal flagellum very short, entering orbit. Third maxillipeds with ischium, merus subequal in length; ischium with shallow longitudinal, curved, median sulcus. Inner margin of merus, ischium with long setae, proximal outer margin of ischium, base of exopod with dense setae; outer margin of merus with short scattered setae only. Exopod slender, hidden behind ishium, merus except near base, tip reaching half length of outer margin of merus, flagellum long, slender. Chelipeds subequal, robust. Merus trihedral; posterior border broadly convex emarginate, minutely granular, without indication of subdistal spine or lobe; inner anterior border minutely granular, broadly triangular; outer surface broadly convex, with fine transverse striae but appearing almost smooth. Carpus subquadrilateral, inner angle moderately produced, apically granular; outer margin, dorsal surface covered in small granules. Palm dorsal surface slightly striated along margin, with scattering of moderate sized granules, otherwise smooth, punctate. Palm outer surface broadly rounded, smooth; no indication of subventral longitudinal ridge. Inner face of palm of males smooth except for curved projecting crest of large tubercles behind gape (Fig. 6 E). Cutting margin of fixed finger typically with 3 or 4 blunt teeth, proximal 3 similar in size, distal-most larger, rounded, conical, placed medially; dactylus with 2 teeth proximally, distal-most being large, third much smaller blunt tooth slightly distal of medial tooth of ventral finger. Dorsal surface of dactylus smooth. Fingers with tips chitinous; adult males with narrow but distinct gape when fingers closed. Walking legs relatively short, broad, flattened; second, third pairs sub-equal, longer than other walking legs. Without setae except for scattering of short dark bristles on dactyli, ventral face of propodi. Dorsal margins of meri with blunt subdistal shoulder, but otherwise unarmed; outer surfaces of meri with minutely granular transverse striae. Merus of P 4 c. 2.0 times longer than wide; that of P 5 similar at 2.0 – 2.1 times longer. Carpi with 2 accessory carinae on outer surface but not strongly marked. Propodus of P 4 c. 2.1 – 2.2 times longer than wide; that of P 5 also 2.1 – 2.2 times. Dactyli 0.8 times length of propodi, slightly recurved, terminating in acute chitinous tip. Thoracic sternites (Fig. 9 E) smooth, mostly bare of setae except for a few scattered bristles; abdominal cavity reaching to thick transverse setal fringe at the junction of sternites 3, 4. Male abdomen (Fig. 14 C) moderately broad; telson broadly rounded apically, 1.2 times longer than wide, markedly longer than somite 6 (1.4 – 1.5 times); somite 6 c. 2.3 times wider than long, distolateral margins relatively straight, strongly divergent, margins convex overall; somites 3 – 5 trapezoid, lateral margins of somites 4, 5 relatively straight, lateral margins of somite 3 convex; somite 3 width 3.1 times basal width of telson; somites 1, 2 transversely, longitudinally narrow. G 1 (Fig. 14 E, G, H) markedly stout, relatively straight, with margins subparallel to obtusely angled subdistal shoulder; distally slender, strongly bent to 45 ° angle; terminal process short, not projecting past line of gonopod shaft, moderately tapering. G 2 short, as for the genus (Fig. 14 F). Females. Chelipeds slightly smaller, less robust, lacking raised granular row on inner face of chela. Vulval morphology without clear species-specific characters. Colour in life. Carapaces of adult males and females are generally pale grey and white to yellowish-brown to yellowish-grey; with chelae of both sexes, notably dactylus, white, without obvious pink or red; eyes blue to bluish-green (Fig. 3 I, J).	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8BFFD0FF5E283D9539FD5D.taxon	discussion	Remarks. Chiromantes eurymerus sp. nov. is separated from its sympatric Taiwanese congener, C. leptomerus sp. nov., by its obviously broader legs, and by its stouter G 1 with its much shortened tip, a unique character within the species-group, and which easily separates it from all other species described here. Numerous other features that distinguish C. eurymerus from other related species are given in Table 1. Chiromantes leptomerus sp. nov. is similar to C. obtusifrons sp. nov. in having the outer margin of the exorbital tooth broadly convex, and in not having the carapace laterally constricted behind the exorbital tooth. It differs from that species by having a less conspicuously granular carapace and claws, and by the stouter G 1 already mentioned. Both species also appear to be distinctively coloured. In C. leptomerus, corneas are typically light green to yellowish green (Fig. 3 G, H), whereas in C. eurymerus, the eyes are blue to bluish-green (Fig. 3 J). The colours of the carapace and chelae also appear different, although the reliability of these characters will need to be tested with more specimens. The carapace background colour of adult males of C. leptomerus varies from pale brown to a darker grey-green (Fig. 3 D – H); whereas in C. eurymerus adult males (and females) are generally pale grey and white to yellowish-brown to yellowish-grey (Fig. 3 I, J). Finally, in C. leptomerus the chelae of adult males are often reddish-pink to purplish red overall, especially on the dorsal surfaces and dactyli (Fig. 3 H); whereas in C. eurymerus the chelae of both sexes, and notably the dactyli are yellowish to off-white, without any obvious pink or red tinging (Fig. 3 J).	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8BFFD0FF5E283D9539FD5D.taxon	etymology	Etymology. Derived from the Greek eury meaning “ broad ”, and meros meaning “ thigh ”, and refers to the relatively shorter and stouter legs of this species compared to the other sympatric Taiwanese species, C. leptomerus sp. nov. It is used here as a noun in apposition.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
CF079C1BFF8BFFD0FF5E283D9539FD5D.taxon	distribution	Distribution. So far only known from Taiwan. We are pleased to thank Peter Castro for his careful and constructive criticism of the manuscript. Ecology. Supratidal; calcareous rock terraces, spray zone. Found comingled with C. leptomerus sp. nov. in the same shore habitat; the nature and extent of niche separation has not been determined.	en	Davie, Peter J. F., Ng, Peter K. L. (2013): A review of Chiromantes obtusifrons (Dana, 1851) (Decapoda: Brachyura: Sesarmidae), with descriptions of four new sibling-species from Christmas Island (Indian Ocean), Guam and Taiwan. Zootaxa 3609 (1): 1-25, DOI: 10.11646/zootaxa.3609.1.1
