taxonID	type	description	language	source
D65A2A57FFDAFF925FA7FBD1FC7BFBE6.taxon	description	(Figs. 1 a, 3 – 5)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925FA7FBD1FC7BFBE6.taxon	materials_examined	CMBS material. 1 female (23 / 5.3) (ZRC 2017.0947) [DNA voucher GenBank MN 237905, MN 237707, MN 238386, MN 238112], sta. TB 096, Straits of Singapore near E Bunkering A, 1 ° 18.140 ′ N 104 ° 04.221 ′ E, clay, beam trawl, 22.4 – 25.1 m, coll. B Richer de Forges et al., 29 May 2013 (SS- 3222); 1 female (18 / 4.5) (ZRC 2018.0560), sta. TB 120, Straits of Singapore, NE of Sentosa Cove, MPA grid 5115, beam trawl, 7.2 – 18.0 m, coll. TMSI team, 21 March 2013 (5115 TB 1 - 120).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925FA7FBD1FC7BFBE6.taxon	description	Description. See Liu & Liu (2010 a).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925FA7FBD1FC7BFBE6.taxon	distribution	Distribution. Beibu Gulf, South China Sea (type locality, Liu & Liu, 2010 a), Tonkin Gulf, Vietnam (Sakai, 2010 a), Singapore (this study). Habitat. Muddy sand at depth of 27 – 50 m (Liu & Liu, 2010 a); clay at depth of 7 – 25 m (this study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925FA7FBD1FC7BFBE6.taxon	discussion	Remarks. Four Indo-Pacific species of Gourretia possess a strong curved spine or projection on the ventro-proximal surface of the third maxilliped ischium, viz. G. manihinae Sakai, 1984 b, G. sinica Liu & Liu, 2010 a, G. zarenkovi (Sakai, 2010 a) and G. qeshmensis Sepahvand, Pouyani & Momtazi, 2016. This character was variable in the present material, with one female (ZRC 2017.0947) bearing this spine on only one side (Fig. 3 a, b). The second female (ZRC 2018.0560) lacks one of the third maxillipeds, but the attached one does have this spine, suggesting that it may be the more typical condition in the species. The CMBS material is tentatively assigned to G. sinica because of the strong spines on the cutting edges of the second pereopod (Figs. 4 g, 5 e) (lacking in G. manihinae). However, it differs from both G. manihinae and G. sinica by the presence of a setal row on the anterior carapace (Fig. 3 a) and a spiniform seta on the propodus of the third pereopod (Fig. 3 g). The species is recorded from Singapore for the first time. There is apparently no difference between G. sinica and G. zarenkovi except for the male first pleopod, consisting of 2 or 4 articles in the former taxon, according to Liu & Liu (2010 a) and Sakai (2017), respectively, vs. 3 articles in the latter taxon (Sakai, 2010 a). A male first pleopod consisting of 3 or 4 articles is certainly an artefact as K. Sakai often misinterpreted folds as articulations (see Felder & Dworschak, 2015; Poore & Dworschak, 2017). Since G. sinica has priority by two months (14 October 2010 vs. 13 December 2010), G. zarenkovi is herein synonymised with the former taxon.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925C2EFB71FBADF7DC.taxon	materials_examined	CMBS material. 1 ov. female (24 / 5.7) (ZRC 2017.0957) [DNA voucher GenBank MN 238003, MN 237806, MN 238459, MN 238241], sta. DR 235, east of Pulau Tekong, MPA grid 0524, sand-mud, rectangular dredge, 13.1 – 14.7 m, coll. TMSI team, 11 May 2013 (SEA- 1943). Comparative material. Michaelcallianassa indica Sakai, 2002: 1 male, 1 female (NHMW 24989), Iran, Persian Gulf, Bandar-Khamir, coll. V. Sepahvand, 2009.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925C2EFB71FBADF7DC.taxon	description	Description. See Liu & Liu (2009).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925C2EFB71FBADF7DC.taxon	distribution	Distribution. Beibu Gulf, South-China Sea (Liu & Liu, 2009), Singapore (this study). Habitat. “ Sediment ” at depth range of 31 – 50 m (Liu & Liu, 2009); sand-mud bottom, 13 – 15 m (this study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDAFF925C2EFB71FBADF7DC.taxon	discussion	Remarks. The present specimen represents a new record of Mi. sinica for Singapore.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDBFF965FF0F93AFE94FA79.taxon	description	(Fig. 1 b)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDBFF965FF0F93AFE94FA79.taxon	materials_examined	CMBS material. 1 female (32 / 7.6) (ZRC 2018.0526), sta. SW 117, St John’s Island, DRTech, north lagoon, 1 ° 13.116 ′ N 103 ° 51.079 ′ E, silt / sand, in burrows, yabby pump, 0 – 0.5 m, coll. PKL Ng, JC Mendoza, R Tan, 31 May 2013 (SS- 3269); 1 female (44 / 9.6) (ZRC 2018.0525), sta. YB 188, same locality, coll. A Anker, 6 June 2013 (SS- 4528).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDBFF965FF0F93AFE94FA79.taxon	description	Description. See Dworschak (2008).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDBFF965FF0F93AFE94FA79.taxon	distribution	Distribution. Indo-West Pacific from India to Thailand and eastern Australia (Dworschak, 2008). b, c, g a, d – f Habitat. Firm sand bottoms near mangroves (Dworschak, 2008); silt-sand bottoms in the intertidal zone or very shallow water, 0 – 0.5 m (present study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDBFF965FF0F93AFE94FA79.taxon	discussion	Remarks. Dworschak (2008) synonymised Neocallichirus kempi with N. karumba. Sakai (2011 a) considered both again as different species, however, his arguments are not convincing. The shape of the male first and second pleopods are subject to maturity as outlined by Dworschak (2008), whereas the differences in the telson shape are not obvious, as this character is quite variable (see Kemp, 1915: fig. 5; Poore & Griffin, 1979: fig. 30 c; Sakai, 1999: fig. 24 b; Dworschak, 2008: figs. 1 a, 3 a). A recent molecular study, however, indicates that two species are involved in what is identifiable as K. karumba, one from Singapore and a second one from Taiwan (Robles et al., 2020), thus requiring further study.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF965F9EF93DFC58FAD9.taxon	description	(Fig. 1 c)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF965F9EF93DFC58FAD9.taxon	materials_examined	CMBS material. 1 ov. female (28 / 5.6) (ZRC 2017.0948) [DNA voucher GenBank MN 237904, MN 237706, MN 238111], sta. SW 117, St John’s Island, DRTech, north lagoon, 1 ° 13.116 ′ N 103 ° 51.079 ′ E, silt / sand, in burrows, yabby pump, 0 – 0.5 m, coll. PKL Ng, JC Mendoza, R Tan, 31 May 2013 (SS- 3267).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF965F9EF93DFC58FAD9.taxon	description	Description. See Sakai (2002).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF965F9EF93DFC58FAD9.taxon	distribution	Distribution. Andaman Sea (Sakai, 2002), Singapore (this study). Habitat. Sand or mud with shell fragments at depths of 17 to 73 m (Sakai, 2002); sand / silt in the intertidal or very shallow water, 0 – 0.5 m (this study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF965F9EF93DFC58FAD9.taxon	discussion	Remarks. The present ovigerous female from St John’s Island represents a new record of Aqaballianassa brevirostris for Singapore.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF995CD8F9BDFF62F98E.taxon	description	(Figs. 2 a, b, 7)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF995CD8F9BDFF62F98E.taxon	materials_examined	CMBS material. 1 male (19 / 5.7) (ZRC 2018.0548), sta. DR 031, Straits of Singapore outside Marina Bay, 1 ° 16.415 ′ N 103 ° 52.838 ′ E, mud, gravel, rectangular dredge, 19.4 – 19.6 m, leg. B Richer de Forges et al., 23 May 2013 (SS- 1578); 1 ov. female (21 / 6.1) (ZRC 2018.0563), 1 male (14 / 4.0) (ZRC 2018.0568), sta. SB 249, off Small Sister I., scuba diving, hand collection, <10 m, coll. J Teo, 26 December 2013 (SUB- 0046, 0047); 1 male (21 / 6.3) (NHMW 26035), sta. SW 001, Pulau Ubin, OBS Camp 1, 1 ° 25 ′ 15.77 ″ N 103 ° 55 ′ 57.00 ″ E, near brackish stream in secondary forest, low tide, coll. PKL Ng, JC Mendoza, HH Tan et al., 16 October 2012 (JS- 0211); 1 male (23 / 6.6) (NHMW 26034), sta. SW 032, Pulau Ubin, N side of Chek Jawa, 1 ° 24 ′ 44.5 ″ N 103 ° 59 ′ 43.2 ″ E, sand and mud flat, beach seine, 0 – 1 m, coll. R Tan, B Ludt et al., 19 October 2012 (JS- 1386); 1 ov. female (22 / 6.0) (ZRC 2018.0539), sta. SB 146, W of Pulau Hantu, coral rubble brushing, 5 – 7 m, coll. HH Tan, S De Grave et al., 2 June 2013; 1 ov. female (17 / 4.7) (ZRC 2018.0537), 1 female (22 / 5.9), 1 male (15 / 4.4) ZRC 2018.0553, sta. TB 172, Straits of Singapore near Kusu Island, 1 ° 12.180 ′ N 103 ° 52.125 ′ E, consolidated marine clay, 94.5 – 100 m, coll. B Richer de Forges et al., 5 June 2013 (SS- 4521, SS- 4522). Comparative material. 3 males (CL 6.6 – 12.0) 2 females (CL 11.4 – 12.0) (NHMW 19590), Australia, Queensland, Mossman, Cooya Beach, muddy reef at low tide, coll. P. Dworschak & A. Anker, 19 – 20 July 2001; 1 female (21 / 6.1) (NHMW 26544), 1 female (20 / 6.1) (NHMW 26545), 1 female (18 / 5.3) (NHMW 26546), 1 male (17 / 5.3) (NHMW 26547), Indonesia, Lombok, coll. A. Anker, DL Rahayu et al., May 2014.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF995CD8F9BDFF62F98E.taxon	diagnosis	Diagnosis. Lateral ridges of gastric region projecting forward. Linea thalassinica (with interruption) reaching to posterior end of carapace. Rostrum longer than eyestalks, with 4 frontal teeth. Ocular spine present. Antennal peduncle longer than antennular peduncle. First pereopod usually subchelate; ischium with strong lower spine; merus with lower spines decreasing in size distally, with proximal upper spine; carpus with strong upper, moderate median and small lower spine mesially; propodus with spines on lower mesial face and proximal spine on upper border; dactylus with small tubercles proximally on mesial face, tip corneous. Second pereopod merus with proximal upper spine; propodus 1.5 – 1.9 times as long as high. Third pereopod merus with lower spines proximally. Pleomere 6 without lateral spines; posterior border smooth. Uropodal endopod acutely triangular. Telson 0.8 – 0.9 times as long as maximal width, with smooth inverted U-shaped carina. First maxilliped with epipod. Third maxilliped without epipod; exopod flagellate. Arthrobranchs of type C.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF995CD8F9BDFF62F98E.taxon	distribution	Distribution. Distributed in the Indo-Pacific, from the Red Sea to northern Australia (Sakai, 2006). Habitat. In sand, mud, coral rubble and consolidated clay from the intertidal to 100 m depth (this study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFDEFF995CD8F9BDFF62F98E.taxon	discussion	Remarks. The type material of U. carinicauda from Hong Kong is no longer extant, most probably destroyed during the Great Chicago Fire of 1871 (Evans, 1967). Stimpson’s (1860) description is rather short and points to the following characters: 1) the ventral margin of the palm of the first pereopod bears a spine at the base of the fixed finger; 2) the cutting edge of the fixed finger is denticulate; and 3) the dorsal surface of the telson has a sharply elevated transverse carina near the proximal margin. Sakai (1982) considered this sufficient to differentiate it from other species known from southern China at that time. Subsequently, the species has been reported by Miers (1884) from Thursday Island, northern Australia. Part of the type material of U. barbata (Strahl, 1862) belongs to U. carinicauda as do the subsequent records of U. barbata by Ortmann (1891, 1894) (see Sakai, 1982). De Man (1928) observed some variation in 18 specimens collected during the Siboga Expedition: 1) the ocular spine is sometimes very small; 2) the spine on the first pereopod palm near the base of dactylus is sometimes absent; and 3) the dactylus is only slightly longer than the fixed finger, especially in small specimens. Ngoc-Ho (1979) compared in detail the Indian species U. kempi Sankolli, 1972 with U. carinicauda and synonymised the former with the latter. This synonymisation was followed by Sakai (1982) and Sakai & Takeda (1995). Later, Sakai (2006) considered U. kempi as a valid species, with U. foresti Ngoc-Ho, 1989 as its junior synonym, because both show a spine on the upper border of the second pereopod merus, which according to the author was absent in U. carinicauda. Later, U. foresti was again considered a valid species by Sakai & Türkay (2014). De Man (1928: 65), Ngoc-Ho (1977: fig. 4 e, as U. darwini), Poore & Griffin (1979: fig. 46 f, as U. darwinii) and Ngoc-Ho (2008: fig. 8 F), however, indicated such a spine on the second pereopod merus for U. carinicauda (see comments in Ngoc-Ho, 2008: 159). In addition, U. rupicola Komai, 2005 has been synonymised with U. carinicauda by Sakai (2006), but considered as valid by Ngoc-Ho (2008) and Sakai & Türkay (2014). Another species, different from, but similar to U. carinicauda, is U. saintlaurentae Ngoc-Ho, 2008; however, two of the three characters given to discriminate the two species from each other are quite variable in the former. The material of the CMBS attributed here to U. carinicauda show most of the above-mentioned variations. Consistent characters are: 1) the rostrum with four dorsal spines; 2) the prominent smooth carina on the telson; 3) the presence of a spine on the upper border of first and second pereopod merus; 4) the linea thalassinica reaching to the end of the carapace; 5) the fixed finger with a serrated cutting edge proximally; and 6) the first pereopod dactylus with a corneous tip. On the other hand, the following characters are variable: 1) the development of the ocular spine (present in 6 of the 9 specimens); 2) the presence of either one or two spines on the mesial face of the cheliped propodus (4 of 9 specimens); 3) the chelipeds clearly subchelate with the dactylus twice as long as the fixed finger (5 specimens), barely subchelate with the dactylus only slightly longer than the fixed finger (2 specimens), or chelate with the fingers almost of the same length (2 specimens); 4) the upper border of the cheliped propodus serrated (3 specimens) or smooth; and 5) the lower border of the third pereopod with (5 specimens) or without (4 specimens) spines. The basal antennular article with a ventral spine was figured by de Man (1928: pl. 3 fig. 6 c), but either not mentioned in subsequent descriptions (e. g., Sakai, 1982; Ngoc-Ho, 2008) or described as unarmed (Sakai & Takeda, 1995: 206). Ngoc-Ho (2008) mentioned a ventral spine on the antennal peduncle. Most specimens from Singapore lack spines on the antennular and antennal peduncle, except for two specimens with the more chelate first pereopod, which possess a ventral spine on the antennular peduncle. The specimens from Australia (NHMW 19590) and Lombok (NHMW 26544 – 26547) have a spine on the antennal peduncle, but not at the antennular peduncle.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD1FF9B5E44F929FAC7FF25.taxon	description	(Figs. 2 c, d, 8)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD1FF9B5E44F929FAC7FF25.taxon	materials_examined	CMBS material. 1 male (43 / 12.7) (ZRC 2018.0561), 1 ov. female (47 / 13.4), 1 male (23 / 7.0) (ZRC 2018.0562), sta. DR 246, north-west of Pulau Sudong, MPA grid 4213, sand, small rocks, rectangular dredge, 22.0 – 25.2 m, coll. TMSI team, 12 December 2013 (SEA- 2684, 2581); 1 male (40 / 12.0) (NHMW 26037), ov. female (44 / 12.6) (NHMW 26038), sta. TB 069, Straits of Singapore near Pulau Sudong and Pulau Semakau, 1 ° 13.155 ′ N 103 ° 43.880 ′ E, sandy bottom, beam trawl 17.9 – 18.9 m, coll. B Richer de Forges et al., 26 May 2013 (SS- 1654); 1 male (46 / 13.1) (NHMW 26039), 1 ov. female (35 / 10.1) (NHMW 26040), sta. TB 072, Straits of Singapore, 1 ° 13.227 ′ N 103 ° 45.313 ′ E, mud, sand, beam trawl, from Xestospongia testudinarium, 23.1 – 23.6 m, coll. B Richer de Forges et al., 26 May 2013 (SS- 0384); 1 male (39 / 11.1) (ZRC 2018.0550), sta. TB 187, Straits of Singapore near Raffles Lighthouse, 1 ° 09.239 ′ N 103 ° 44.674 ′ E, sponges, rocks, gravel, beam trawl 39.5 – 40.2 m, coll. B Richer de Forges et al., 6 June 2013; 1 ov. female (44 / 12.4) (ZRC 2018.0529), sta. TB 73, Straits of Singapore south of Pulau Semakau, 1 ° 11.282 ′ N 103 ° 46.6321 ′ E, sandy bottom, beam trawl 24.6 – 29.8 m, coll. B Richer de Forges et al., 26 May 2013 (SS- 0385); 1 ov. female (30 / 8.6) (ZRC 2018.0535), 1 male (31 / 8.7) (ZRC 2018.0536), sta. DW 027, Pulau Ubin, off eastern coast of Chek Jawa, 1 ° 24.927 ′ – 1 ° 25.273 ′ N 103 ° 59.980 ′ – 103 ° 59.692 ′ E, mud, window pane shells, beam trawl 9.9 – 19.1 m, coll. B Richer de Forges et al., 19 October 2012 (JS- 1385).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD1FF9B5E44F929FAC7FF25.taxon	diagnosis	Diagnosis. Lateral ridges of gastric region projecting forward. Linea thalassinica not reaching posterior end of carapace. Rostrum longer than eyestalks, with 4 frontal teeth. Ocular spine absent. Antennal peduncle longer than antennular peduncle. First pereopod chelate; ischium with few lower spinules; merus with small lower spines, without proximal upper spine; carpus with moderate upper spine, but without median and lower spines; propodus smooth on lower mesial face and upper border; dactylus with row of tubercles on mesial face and prominent rounded tooth proximally; fixed finger with serrated cutting edge. Second pereopod merus without proximal upper spine; propodus 2.1 – 2.5 times as long as high. Third pereopod merus with smooth lower border, without proximal upper spine. Pleomere 6 without lateral spines; posterior border minutely tuberculated. Uropodal endopod triangular. Telson 0.8 – 1.0 as long as maximal width; inverted U-shaped carina with tubercles. Third maxilliped exopod flagellate, no epipods on first and third maxilliped. Arthrobranchs of type A. Embryos 570 – 860 µm in diameter.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD1FF9B5E44F929FAC7FF25.taxon	distribution	Distribution. Distributed in the Indo-Pacific, from the Red Sea to northern Australia (Sakai, 2006). Habitat. In sand, silt, coral rubble, gravel, from the intertidal zone to 50 m; often found in sponges (Dworschak, 2000; Sepahvand et al., 2013; this study); occasionally boring in corals (Scoffin & Bradshaw, 2000).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD1FF9B5E44F929FAC7FF25.taxon	discussion	Remarks. The syntype series of U. darwinii consists of 3 males and 3 females from Darwin, Australia (NHMUK 1882: 7) and a male-female pair from Singapore (NHMUK 1882: 24) (Ngoc-Ho, 1977). A male from Darwin with TL 20 mm was selected by Sakai (1982: 20) as lectotype, while he excluded the specimens from Singapore from the type series and attributed them to U. ancylodactyla de Man, 1905 (see below). Later, Sakai (2006: 94, 101, 113) attributed the Singaporean material to U. barbata, listing the specimens figured by Ngoc-Ho (1977) partly under U. darwinii (Sakai, 2006: 94) and as a synonym of U. ancylodactyla (Sakai, 2006: 91). It seems that the current taxonomic confusion of this species complex can only be solved by a more comprehensive revision, integrating both morphology and DNA.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD3FF9D5CF9FEB1FB73FA66.taxon	description	(Figs. 2 e, f, 9)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD3FF9D5CF9FEB1FB73FA66.taxon	materials_examined	CMBS material. 2 females (17 / 5.1, 17 / 4.9) (NHMW 26048), sta. DR 001, Straits of Singapore near Raffles Lighthouse, 1 ° 10.125 ′ N 103 ° 45.419 ′ E, gravel, shells, rectangular dredge, 38.3 – 38.5 m, coll. B Richer de Forges et al., 21 May 2013 (SS- 0313); 1 female (20 / 5.7), 1 male (15 / 5.3) (ZRC 2018.0566), sta. DR 013, between Pulau Hantu and Pulau Semakau, MPA grid 4513, rectangular dredge, in sponge (DR 13 _ 016), 21.1 – 21.9 m, coll. TMSI team, 3 July 2013 (DR 13 _ 027, DR 13 _ 028); 1 ov. female (22 / 6.1), 1 male (25 / 7.6) (NHMW 26042), sta. DR 111, Straits of Singapore outside Eastern Boarding Ground A, 1 ° 12.989 ′ N 103 ° 53.062 ′ E, mostly rock bottom, rectangular dredge, 125 – 136 m, coll. B Richer de Forges et al., 30 May 2013 (SS- 3265); 1 ov. female (25 / 8.3), 1 male (22 / 6.8) (NHMW 26041), sta. DR 112, Straits of Singapore, Southern Fairway south of Sister Islands, 1 ° 12.024 ′ N 103 ° 50.170 ′ E, broken shells, rubble, rectangular dredge, 33.6 – 34.4 m, coll. B Richer de Forges et al., 30 May 2013 (SS- 2943); 1 male (16 / 5.3) (ZRC 2018.0567), sta. DR 114, north of Pulau Tekong, MPA grid 0226, rectangular dredge, 6.4 – 8.7 m, coll. TMSI team, 7 October 2013 (SEA- 1276); 1 female (21 / 6.3), 1 male (17 / 5.1) (ZRC 2018.0541), 1 male (19 / 5.9) (ZRC 2018.0542), sta. DR 125, Straits of Singapore, near Sister Islands, 1 ° 12.416 ′ N 103 ° 49.858 ′ E, laterite gravel, sand, rectangular dredge, 25.3 – 30.8 m, coll. B Richer de Forges et al., 31 May 2013 (SS- 4002); 1 ov. female (21 / 6.3), 1 male (20 / 5.9) (ZRC 2018.0565), sta. DR 222, east of Pulau Pawai, MPA grid 4411, rectangular dredge, 17.3 – 18.7 m, coll. TMSI team, 21 October 2013 (SEA- 1613); 1 juvenile (7 / 2.3) (ZRC 2018.0569), sta. DR 239, south of Pulau Bukom, MPA grid 4613, rectangular dredge, 24.3 – 27.6 m, coll. TMSI team, 11 December 2013 (SEA- 2058); 1 juvenile (8 / 2.3) (ZRC 2018.0570), sta. DR 241, north of Pulau Bukom, MPA grid 4614, rectangular dredge, 17.5 – 17.8 m, coll. TMSI team, 11 December 2013 (SEA- 2089); 1 female (14 / 4.5) (ZRC 2018.0571), sta. DR 257, off southwestern tip of Jurong Island, MPA grid 4013, clay, mud, rocks, rectangular dredge, 19.4 – 22.5 m, coll. TMSI team, 19 December 2013 (SEA- 3209); 1 male (24 / 7.0) (ZRC 2018.0564), sta. RF 353, Pulau Senang, east of jetty, intertidal, rocks, rubble, hand collection, coll. TMSI team, 30 March 2014 (INT- 0849); 1 ov. female (22 / 6.4), 2 males (17 / 5.0, 18 / 5.0) (NHMW 26043), 1 ov. female (28 / 7.7) (NHMW 26045), 1 ov. female (25 / 7.1) (NHMW 26046), 1 male (23 / 7.0) (ZRC 2018.0557), sta. SB 067, Pulau Hantu, western patch reef, 1 ° 13.6 ′ N 103 ° 44.8 ′ E, coral rubble brushing 15.7 m, coll. HH Tan, S De Grave et al., 26 May 2013 (SS- 1658, SS- 1659, SS- 1647); 1 female (27 / 7.6) (NHMW 26044), 1 ov. female (27 / 8.0) (ZRC 2018.0538), sta. SB 146, west of Pulau Hantu, coral rubble brushing, 5 – 7 m, coll. HH Tan, S De Grave et al., 2 June 2013 (SS- 2979); 1 ov. female (20 / 6.0), 1 male (168 / 5.9) (NHMW 26047), sta. TB 003, Straits of Singapore near Raffles Lighthouse, Gusong Boarding Ground, 1 ° 10.653 ′ N 103 ° 46.772 ′ E, 40.7 – 40.9 m, coll. B Richer de Forges et al., 21 May 2013 (SS- 0310); 1 male (14 / 4.0) (ZRC 2018.0559), sta. TB 071, Straits of Singapore, south-west of Eastern Holding A, Singapore port limit, MPA grid 5414, beam trawl, 61.7 – 66.8 m, coll. TMSI team, 13 May 2013 (5414 TB 2 - 071); 1 male (18 / 5.7) (ZRC 2018.0540), sta. TB 073, Straits of Singapore south of Pulau Semakau, 1 ° 11.282 ′ N 103 ° 46.6321 ′ E, sandy bottom, beam trawl, 24.6 – 29.8 m, coll. B Richer de Forges et al., 26 May 2013; 1 ov. female (19 / 5.7), 1 male (16 / 4.7) (ZRC 2018.0545), sta. TB 091, Straits of Singapore, Southern Fairway near St. John’s Island, 1 ° 12.926 ′ N 103 ° 51.647 ′ E, beam trawl, 39.5 – 49.9 m, coll. B Richer de Forges et al., 28 May 2013; 1 male (19 / 6.0) (ZRC 2018.0527), sta. TB 113, Straits of Singapore, Southern Fairway south of Sister Islands, 1 ° 12.001 ′ N 103 ° 50.261 ′ E, silt with rocks, beam trawl, 29.3 – 30.5 m, coll. B Richer de Forges et al., 30 May 2013; 1 female (15 / 4.6), 1 male (12 / 4.0) (ZRC 2018.0558), sta. TB 128, Straits of Singapore beside Eastern Boarding Ground A, 1 ° 12.889 ′ N 103 ° 52.460 ′ E, mostly rock bottom, beam trawl, 75.2 – 83.7 m, coll. B Richer de Forges et al., 31 May 2013 (SS- 3995); 1 ov. female (20 / 6.0) (ZRC 2018.0544), sta. TB 185, Straits of Singapore near Pulau Senang, 1 ° 09.942 ′ N 103 ° 43.458 ′ E, thick smelly mud, laterite rocks, gravel, beam trawl, 24.3 – 24.5 m, coll. B Richer de Forges et al., 6 June 2013; 1 male (16 / 5.1) (ZRC 2018.0534), sta. TB 186, Straits of Singapore off Raffles Lighthouse, 1 ° 09.318 ′ N 103 ° 44.200 ′ E, gravel, rocks, sponges, beam trawl, 35 – 38 m, coll. B Richer de Forges et al., 6 June 2013; 1 ov. female (17 / 5.1), 1 male (14 / 4.1) (ZRC 2018.0552), sta. TB 187, Straits of Singapore near Raffles Lighthouse, 1 ° 09.239 ′ N 103 ° 44.674 ′ E, sponges, rocks, gravel, beam trawl, 39.5 – 40.2 m, coll. B Richer de Forges et al., 6 June 2013.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD3FF9D5CF9FEB1FB73FA66.taxon	diagnosis	Diagnosis. Lateral ridges of gastric region projecting forward. Linea thalassinica not reaching posterior end of carapace. Rostrum rounded, as long or slightly longer than eyestalks, with 6 or more frontal teeth. Postocular spine absent. Antennal peduncle longer than antennular peduncle. First pereopod chelate; ischium smooth or with few spinules; merus with small lower spines proximally, without proximal upper spine; carpus with small upper and several small median spines, without lower spine mesially; propodus smooth on lower mesial face and upper border; dactylus with row of tubercles on mesial face and prominent rounded tooth proximally; fixed finger with serrated cutting edge proximally. Second pereopod merus without proximal upper spine; propodus 2.5 – 3.1 times as long as high. Third pereopod merus with smooth lower border, without proximal upper spine. Pleomere 6 with prominent lateral spines; posterior border denticulated. Uropodal endopod squarish. Telson 0.8 – 1.1 times as long as maximal width; inverted U-shaped carina with tubercles. First and third maxillipeds without epipods. Third maxilliped exopod flagellate. Arthrobranchs of type B. Embryos 550 – 750 µm in diameter.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD3FF9D5CF9FEB1FB73FA66.taxon	distribution	Distribution. Known with certainty from Thursday I., Torres Strait, northern Australia (type locality), Philippines (Dworschak, 2019), Singapore (this study), Indonesia, India (Komai et al., 2020), Red Sea and Persian Gulf (Ngoc-Ho, 1990). Exact distribution (especially in Australia) uncertain due to confusion with U. darwinii (see below). Habitat. Sand, silt, mud, gravel and rubble bottoms from the intertidal zone to 84 m; often associated with sponges (Komai et al., 2020; this study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD3FF9D5CF9FEB1FB73FA66.taxon	discussion	Remarks. Upogebia hexaceras was described based on two specimens (sex not given) from Thursday Island (Torres Strait) (Ortmann, 1894). De Man (1928: 83) studied the “ single type specimen, a male ” (24 / 8.3) deposited in what is now the Phyletisches Museum in Jena, Germany (PMJ), and provided a complementary description of the species. One specimen is still extant in the PMJ collections; however, it is a female with cl 9 mm, with the pleomere 6 bearing lateral projections and its posterior border denticulated (R. Beutel, pers. comm., 25 March 2014). Upogebia hexaceras was treated as a valid species by Sakai (1982), although he concluded that it showed no differences from U. darwinii. Ngoc-Ho (1990) considered it as valid and outlined the differences between the three similar species, viz. U. darwinii, U. hexaceras, and U. octoceras (Nobili, 1904). Sakai (1993, 2006) considered U. hexaceras again as a synonym of U. darwinii, which was later rebutted by Ngoc-Ho (2008). Most recently, Dworschak (2019) and Komai et al. (2020) considered U. hexaceras a valid species. The material of U. hexaceras from CMBS is very consistent in its morphological characters. All specimens display strong, sharp, lateral projections on the sixth pleomere and its posterior border is strongly denticulate. The rostrum is short, rounded, with 6 – 12 spines (see below), whereas the lateral projections of the carapace are prominent. It differs clearly from the CMBS material herein identified as U. darwinii (see above). The number of the rostral spines is quite variable in the present material of U. hexaceras, with 2 specimens armed with 6 spines, 12 with 8, 1 with 9, 13 with 10, 1 with 11, and 7 with 12. These numbers exceed the range of the rostral spines (6 – 9) in the diagnosis of U. hexaceras provided by Ngoc-Ho (1990: table 1) and also that of U. octoceras (6 – 10, idem). None of the CMBS specimens, however, has a distomesial spine on the first pereopod propodus near the articulation with the dactylus, a feature typical of U. octoceras (Ngoc-Ho, 1990: fig. 9 g, f).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD5FF9F5CFFFA71FBC8FC06.taxon	description	(Figs. 2 g, h, 10)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD5FF9F5CFFFA71FBC8FC06.taxon	materials_examined	CMBS material. 1 ov. female (17 / 5.3), 1 male (17 / 5.1) (ZRC 2018.0547), sta. DR 174, Straits of Singapore near Kusu Island, 1 ° 12.202 ′ N 103 ° 52.178 ′ E, reddish marine clay, gravel, shells, rectangular dredge, 79.6 – 135 m, coll. B Richer de Forges et al., 5 June 2013; 1 ov. female (23 / 6.4), 1 male (22 / 6.6) (NHMW 26052), sta. IT 103, Terumbu Pempang Tengah, 01 ° 13.758 ′ N 103 ° 43.736 ′ E, intertidal, coll. CS Tan, D Uyeno et al., 30 May 2013 (SS- 3231); 1 male (15 / 4.9) (NHMW 26049), 1 ov. female (29 / 8.3) (NHMW 26050), 1 ov. female (25 / 7.7) (ZRC 2018.0530), 1 male (26 / 6.9) (ZRC 2018.0531), 1 male (27 / 8.0) (ZRC 2018.0532), 1 ov. female (24 / 6.9) (ZRC 2018.0533), 1 ov. female (18 / 5.1), 1 male (16 / 5.1) 1 exuvia (17 / 5.3) (NHMW 26054), sta. IT 120, Pulau Hantu, intertidal, coll. KS Koh, TS Ahyong, K Tilbrook et al., 31 May 2013 (SS- 2946, SS- 2949); 1 male (26 / 7.7) (ZRC 2018.0528), sta. IT 122, Terumbu Raya, intertidal, coll. CS Tan et al., 31 May 2013 (SS- 2948); 1 male (20 / 6.0) (ZRC 2018.0556), sta. IT 124, Terumbu Pempang Laut, 01 ° 13.912 ′ N 103 ° 43.402 ′ E, intertidal, coll. YL Lee, I Kwan et al., 31 May 2013 (SS- 3981); 1 ov. female (16 / 5.1), 2 males (24 / 7.1, 18 / 5.1), 1 female (16 / 5.0) (NHMW 26053), sta. IT 140, Tekukor, 1 ° 13.899 ′ N 103 ° 50.265 ′ E, intertidal, coll. YL Lee, SK Tan et al., 1 June 2013 (SS- 4012); 1 male (16 / 4.9) (ZRC 2018.0555), sta. SB 146, west of Pulau Hantu, coral rubble brushing, 5 – 7 m, coll. HH Tan, S De Grave et al., 2 June 2013 (SS- 2979); 1 male (29 / 8.4) (ZRC 2018.0549), 1 female (40 / 11.3) (ZRC 2018.0551), sta. SD 056, southern Pulau Jong, 1 ° 12.55 ′ N 103 ° 47.2 ′ E, silty rubble, hand collection by scuba diving 17 m, coll. C Messing, S De Grave, HH Tan et al., 25 May 2013 (SS- 1623, SS- 1624); 1 male (11 / 3.5) (ZRC 2018.0543), sta. SW 024, Pulau Sekudu, 1 ° 24.263 ′ N 103 ° 59.241 ′ E, sand, mud, rocks, hand and yabby pump, 0 m, coll. R Tan, M Ng et al., 18 October 2012; 1 ov. female (27 / 7.7), 1 male (27 / 8.1) (NHMW 26051), sta. SW 026, Tuas, West Drive 60, 1 ° 19 ′ 45.9 ″ N 103 ° 37 ′ 50.9 ″ E, intertidal, sand-mud, some corals, hand collection and beach seine, 0 – 0.5 m, coll. HH Ng, H Wong et al., 18 October 2012 (JS- 1152); 1 ov. female (16 / 4.4) (ZRC 2018.0554), sta. TB 172, Straits of Singapore near Kusu Island, 1 ° 12.180 ′ E 103 ° 52.125 ′ E, consolidated marine clay, 94.5 – 100 m, coll. B Richer de Forges et al., 5 June 2013 (SS- 4522).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD5FF9F5CFFFA71FBC8FC06.taxon	diagnosis	Diagnosis. Lateral ridges of gastric region not projecting forward. Linea thalassinica not reaching end of carapace. Rostrum longer than eyestalks, with 4 frontal teeth. Postocular spine absent. Antennal peduncle as long as antennular peduncle. First pereopod chelate, sexually dimorphic, twisted by 45 ° laterally; ischium with small lower spine; merus with small lower spines decreasing in size distally, without proximal upper spine; carpus with moderate upper spine, but without median and lower spines mesially; propodus smooth on lower mesial face and upper border, slender (3 times as long as high) in females, very robust (less than 2 times as long as high) in males; fingers slender in females, dactylus with rounded tooth proximally, stout (as long as high) in males. Second pereopod merus without proximal upper spine; propodus 2.1 – 3.0 as long as high. Sixth pleomere without lateral spines; posterior border smooth. Uropodal endopod rectangular. Telson 0.7 to 1.0 as long as wide; inverted U-shaped carina with tubercles. First and third maxillipeds without epipods. Third maxilliped exopod flagellate. Arthrobranchs of type B. Embryos 750 – 1430 µm in diameter.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD5FF9F5CFFFA71FBC8FC06.taxon	distribution	Distribution. Ranging in the Indo-West Pacific, from the Red Sea to northern Australia (Sakai, 2006). Habitat. Sand, mud, coral rubble and consolidated clay from the intertidal to 100 m (this study); also reported from coral rocks (Ngoc-Ho, 2008).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD5FF9F5CFFFA71FBC8FC06.taxon	discussion	Remarks. De Man (1905) did not specify how many specimens were available to him from “ Baingsisi, Samau- Island, near Timor ”, now Semau Island. Sakai (1975) first considered U. ancylodactyla as a junior synonym of U. amboinensis (de Man, 1888), but later (Sakai, 1982) corrected the identification of an illustrated specimen from Fiji Islands (Sakai, 1975: fig. 2), describing it as U. fijiensis Sakai, 1982. The type material of U. darwinii and U. barbata also contained specimens of U. ancylodactyla according to Sakai (1982: 27). The egg diameter in gravid females of U. ancylodactyla seems to be somewhat variable. According to Sakai (1982), based on de Man (1928), the egg size is 0.9 mm. Ngoc-Ho (2008) listed 1.10 – 1.30 mm for specimens from Singapore and 1 – 1.1 mm for specimens from Aden; however, she earlier mentioned that the latter material, listed as U. ancylodactyla by Sakai (1982), was actually U. barbata (see also above).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD7FF825CE0FC51FA3BFB5E.taxon	description	(Figs. 1 d, 11, 12)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD7FF825CE0FC51FA3BFB5E.taxon	materials_examined	CMBS material. Holotype: female (16 / 5.4) (ZRC 2017.0951), sta. IT 120, Pulau Hantu, intertidal, coll. KS Koh, TS Ahyong, K Tilbrook et al., 31 May 2013 (SS- 3982). Paratypes: 1 female (13 / 4.8) (ZRC 2017.0952), 1 juvenile (12 / 3.9) (ZRC 2017.0950), sta. SB 055, Kusu Island, coral rubble brushing, ~ 4 m, coll. HH Tan, S De Grave et al., 25 May 2013 (SS- 1631); 1 juvenile (11 / 3.6) (ZRC 2017.0953), sta. TB 172, Straits of Singapore near Kusu Island, 1 ° 12.180 ′ N 103 ° 52.125 ′ E, consolidated marine clay, 94.5 – 100 m, coll. B Richer de Forges et al., 5 June 2013 (SS- 4522). Comparative material. Upogebia srilankaensis Sakai, 2006, holotype, male (24 / 7.4) (SMF 30213), Sri Lanka, Matara, Weligama Bay (5 ° 59.074 ′ N 80 ° 19.695 ′ E), coll. O. Löw-Beer, 3 December 1912.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD7FF825CE0FC51FA3BFB5E.taxon	diagnosis	Diagnosis. Rostrum elongate, with four strong dorsal spines, without infrarostral spine. Lateral ridges of gastric region weakly developed, with obtuse distal tooth and posterior to that tooth 9 – 11 tubercles. Postocular spine absent. Pleonal sternites unarmed. First pereopod chelate, merus lacking subdistal dorsal spine and bearing row of obtuse ventral teeth; carpus bearing 1 strong distoventral and 1 strong distodorsal spine. Meri of third to fifth pereopods unarmed.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD7FF825CE0FC51FA3BFB5E.taxon	description	Description of female holotype. Rostrum (Fig. 11 a, b) elongate, twice as long as broad at base, setose on dorsal surface, bearing 1 pair of distal and 1 pair of subdistal dorsal spines, lacking infrarostral spine; lateral ridges of gastric region slightly protruding laterally, bearing row of 8 – 9 unequal tubercles; mid-dorsal area of gastric region with scattered tubercles. Cervical groove lacking spines. Postocular spine absent. Eyestalk stout, reaching to midlength of rostrum, unarmed. Linea thalassinica reaching to posterior end of carapace. Antennular peduncle (Figs. 11 a, 12 a) shorter than antennal peduncle; articles unarmed, second article short, third article elongate; flagella of same length, dorsal thicker than ventral, as long as peduncle. Antennal peduncle (Figs. 11 a, 12 b) overreaching rostrum by distal margin of penultimate article; articles unarmed; scaphocerite weakly developed. Epistome (Fig. 11 a) rounded, unarmed. Mandible (Fig. 12 c, d) without mesio-anterior tooth. First and second maxilla as illustrated (Fig. 12 e, f). First maxilliped (Fig. 12 g) without epipod. Second maxilliped (Fig. 12 h) with epipod. Third maxilliped (Fig. 12 i) without epipod; exopod simple (without flagellum) distally, reaching almost to end of endopodal merus. First pereopod (Fig. 11 c – f) chelate; coxa and basis unarmed. Ischium bearing 1 subterminal spine on ventral margin. Merus bearing row of 13 – 14 obtuse thick spines on ventral margin, increasing in size to mid-length of merus, distal ones diminishing in size; dorsal margin unarmed. Carpus triangular, lateral surface bearing longitudinal ventral carina; 1 strong, mesially directed dorsal spine, 1 small median spine, and 1 prominent dorsal spine present on distal margin; 6 small spines present on mesial surface. Palm 2.1 times as long as high; upper border unarmed, with several low tubercles on inner dorsal surface; lower border keeled with 7 – 8 tubercles proximally; 3 tubercles present on lower inner surface proximally. Fixed finger 0.3 times length of palm, with low denticles on cutting edge. Dactylus (Fig. 11 d, f) with proximal tooth on cutting edge. Second pereopod (Fig. 11 h) unarmed; merus 5.3 times as long as wide; propodus 2.8 times as long as wide. Third and fourth pereopods (Fig. 11 i, k) simple; dactylus with comb on lower border and 5 spaced corneous spines on upper border (Fig. 11 j, l). Fifth pereopod (Fig. 11 m) subchelate; dactylus curved, with corneous tip (Fig. 11 n). Telson (Fig. 11 p) slightly longer than maximal width; dorsal surface with U-shaped concavity, latter with denticulate transverse carina. Uropodal endopod broadened, about as long as telson, with somewhat truncate, slightly convex distal margin; uropodal exopod broadened, about as long as endopod, with prominent spine proximally (Fig. 11 o). Arthrobranchs of type A, one pair each on third maxilliped, and first to fourth pereopods. Variations. The number of spines on the lower border of the first pereopod merus ranges from 9 (juvenile 11 / 3.6) to 15 (female 13 / 4.8) on the right side and between 9 and 14 on the left side. The teeth on the lower border of first pereopod propodus differ between sides and range from 3 to 8.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD7FF825CE0FC51FA3BFB5E.taxon	etymology	Etymology. Named after the type locality, the Straits of Singapore.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD7FF825CE0FC51FA3BFB5E.taxon	distribution	Distribution. Only known from the Straits of Singapore. Habitat. Upogebia singaporensis, new species, has a wide bathymetric distribution: one female (16.1 / 5.42) was collected in the intertidal zone at Pulau Hantu (together with U. ancylodactyla); two specimens came from coral brushings at 4 m depth at Kusu Island, and one from consolidated clay at a depth of 94.5 – 100 m.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFD7FF825CE0FC51FA3BFB5E.taxon	discussion	Remarks. The new species is similar to Upogebia srilankaensis Sakai, 2006 in possessing a long rostrum with two pairs of prominent dorsal spines (1 distal and 1 subdistal pair); in the shape of the spines on the lower border of the first pereopod merus; in having upper and lower spines on the first pereopod carpus; and in the general shape of telson and uropods. However, U. singaporensis, new species, differs from U. srilankaensis (characters in parentheses) by 1) the absence of a ventral spine on the first article of the antennal peduncle (present); 2) the slightly produced lateral ridges of the gastric carapace region (not protruding); 3) the dorsal spine on the mesial surface of the first pereopod carpus prominent (much smaller); 4) the ventral margin of the first pereopod propodus with several tubercles proximally (without tubercles); and 5) the fixed finger of the first pereopod entire (with a deep concavity on the occlusal margin). A re-examination of the holotype of U. srilankaensis (Fig. 13) revealed some inconsistencies and omissions in the original description by Sakai (2006): 1) the antennal peduncle has a distinct, acute scaphocerite; 2) the first pereopod palm has a row of three tubercles proximally on the lower mesial surface (only one visible in lateral view in Sakai, 2006: fig. 23 D); 3) there are two spines on the upper mesial face of the first pereopod carpus; 4) the left first pereopod has two spines ventrally on the ischium; and 5) the third and fourth pereopod dactyli have a comb on the lower border and a row of corneous spines on the upper border, as in the present new species (not illustrated nor mentioned by Sakai, 2006).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCAFF845CB5FB19FE04FEE6.taxon	type_taxon	Type species. Upogebia (Neogebicula) alaini Sakai, 1982.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCAFF845CB5FB19FE04FEE6.taxon	diagnosis	Diagnosis. Rostrum triangular with rounded tip, longer than wide. First pereopod simple or subchelate, slender, fixed finger in females very small. Pleomere 6 longer than wide, longer than pleomere 2. Uropodal rami slender, leaf-like; exopod 3 – 4 times as long as wide, 2 – 3 times as long as telson.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCAFF845CB5FB19FE04FEE6.taxon	discussion	Remarks. The differences between Neogebicula and Paragebicula as given by Sakai (2006, 2010 b, 2011 b) and Liu & Liu (2010 b) are not observable over the range of morphologies of the species included and we consider Paragebicula a synonym of Neogebicula. Species included. Neogebicula alaini (Sakai, 1982), N. berggreni (Sakai, 2015), N. bijdeleyi (Liu & Liu, 2010), N. bussarawiti (Sakai, 2015), N. contigua (Božic & de Saint Laurent, 1972), N. edentata (Lin, Ngoc-Ho & T. Y. Chan, 2001), N. fallax (de Man, 1905), N. gracilis (Ngoc-Ho, 1990), N. holthuisi Liu & Liu, 2010, N. johorensis, new species, N. leptomorpha (Sakai, 2006), N. lipkei (Sakai, 2010), N. monochela (Sakai, 1967), N. oleseni (Sakai, 2015), N. orlik (Sakai, 2011), N. setaerostrata (Sakai, 2015), N. vietnamensis (Sakai, 2011), N. waikuli (Sakai, 2015), and N. wistari Ngoc-Ho, 1995.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCCFF865FB7FEF1FD62F946.taxon	description	(Figs. 1 e – h, 14, 15)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCCFF865FB7FEF1FD62F946.taxon	materials_examined	CMBS material. Holotype: male (18 / 5.6) (ZRC 2017.0956), sta. DR 001, eastern Straits of Johor, W of Pulau Pengerang, MPA grid 0422, rectangular dredge, 6.7 – 7.6 m, coll. SC Lim, A Anker, H Wong, CK Chim et al., 25 March 2014 (0326 DR 1 - AA 01). Paratypes: 1 ov. female (21 / 6.3) (ZRC 2017.0955), sta. DR 108, eastern Straits of Johor, beside E Pulau Tekong and Pulau Pengarang, MPA grid 0422, rectangular dredge, 11.9 – 12.0 m, coll. SC Lim, A Anker, H Wong, CK Chim et al., 25 March 2014 (0422 DR 2 - A 108); 1 ov. female (21 / 6.6) (ZRC 2017.0959), sta. DR 235, east of Pulau Tekong, MPA grid 0524, rectangular dredge 13.1 – 14.7 m, coll. TMSI team, 5 November 2013 (SEA- 1944); 1 male (14 / 3.9) (ZRC 2017.0958), sta. DR 264, Straits of Johor off Punggol, near Punggol jetty, MPA grid 5425, sandmud, rectangular dredge, 11.2 – 11.3 m, coll. TMSI team, 16 January 2014 (SEA- 3482); 1 female (19 / 5.3 left first pereopod missing) (ZRC 2017.0954), sta. DR 333, W Straits of Johor, between Tuas and Pulau Merambong, MPA grid 3718, rectangular dredge, 7.2 – 7.5 m, coll. TMSI team, 11 February 2014 (SEA- 4248).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCCFF865FB7FEF1FD62F946.taxon	diagnosis	Diagnosis. Rostrum long. Lateral ridges of gastric region strongly projecting forward. Linea thalassinica extending to end of carapace. Ocular spine present, with or without hepatic spines. Proximal antennular peduncle article with ventral spine. Antennal peduncle with articles 3 and 4 each with ventral spine. Upper border of first pereopod propodus with several spines. Sixth pleomere as long as wide. Telson with small median spine.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCCFF865FB7FEF1FD62F946.taxon	description	Description. Rostrum long, triangular, 1.7 times as long as wide at base, twice as long as eyestalks, reaching to end of fourth article of antennular peduncle, narrowing anteriorly, rounded distally (Figs. 14 a, b, i, k, 15 a, b); dorsal surface of rostrum and gastric region with shallow median groove and low tubercles, extending onto gastric region of carapace, covered with short serrulate setae. Ventral surface of rostrum unarmed. Carapace with lateral ridges of gastric region strongly projecting forward, almost reaching end of eyestalks, anteriorly acute, separated from median gastric region by distinct longitudinal grooves; median gastric region setose, with low tubercles, diverging posteriorly; linea thalassinica extending well beyond cervical groove, reaching posterior border of carapace; anterolateral border of carapace with prominent ocular spine (may be absent in juveniles); cervical groove with (Fig. 14 a, b, i, k) or without (Fig. 15 a, b) hepatic spine. Antennule (Fig. 15 c) with first article of peduncle armed with distoventral spine; second article short; third article as long as first. Dorsal flagellum longer and thicker than ventral flagellum, as long as length of second and third article combined. Antenna (Fig. 15 d) with acute scaphocerite; second article of peduncle with ventral spine; third article fused with second one; fourth article with median ventral spine. Epistome (Figs. 14 a, j, 15 a) with 2 – 3 spines. Mandible (Fig. 15 e, f) with large mesio-anterior tooth. First and second maxilla as illustrated (Fig. 15 g, h). First maxilliped (Fig. 15 i) with small epipod. Second maxilliped (Fig. 15 j) with small epipod; exopod simple. Third maxilliped (Fig. 15 k) without epipod; exopod without flagellum, reaching mid-length of endopod merus; ischium with single spine proximally on mesial face (not shown). Arthrobranchs of type C; one pair each on third maxilliped, and first to fourth pereopods. First pereopods (Figs. 14 c, d, k – m, 15 l, m) subchelate, equal in size and shape, sexually dimorphic. Ischium with distoventral spine. Merus about 4.4 times as long as wide, with 5 spines on lower border in proximal 0.6 of meral length, and 1 dorsodistal spine. Carpus triangular, with 3 strong distal spines, 1 dorsal, 1 mesial, and 1 ventral, 1 small spine present dorsal to strong ventral spine; mesial face with 1 small spine. Propodus 2.6 (male) or 4.6 (females) times as long as wide; ventral border unarmed; dorsal border with 2 (male) or 4 (females) spines; fixed finger small in females (Figs. 14 l, m, 15 l, m), distinctly larger in males (Fig. 14 c, d); dactylus 0.6 – 0.7 times as long as propodus, with 1 low proximal tubercle on ventral border and 2 tubercles on mesial face in males only, with dorsolateral plate in males and females. Second pereopod (Figs. 14 e, 15 n) with median spine on coxa; ischium unarmed; merus 4.4 times as long as wide, with 1 proximal and 1 median spine on ventral border, as well as 1 distal spine on dorsal border; carpus with 1 distal spine on ventral border, and 1 median and 1 distal spine on dorsal border; propodus unarmed, 2.3 as long as wide; dactylus 0.7 length of propodus, narrowing distally. Third pereopod (Figs. 14 f, 15 o) with ischium armed with distal spine ventrally; merus 3 times as long as wide, with 3 strong spines on ventral border; carpus with 1 strong distal spine ventrally and 1 small spine dorsally; propodus twice as long as wide, unarmed; dactylus as long as propodus, slender. Fourth pereopod (Fig. 15 p) simple, unarmed. Fifth pereopod (Fig. 15 q) subchelate, unarmed. Sixth pleomere (Fig. 14 g) slightly longer than wide; telson broader than long, lateral margin broadest at proximal third; distal margin broadly truncate, with median spine; dorsal surface with longitudinal median groove in distal 0.6 of segment length. Pleopod 1 absent in males, uniramous in females. Uropodal protopod (Figs. 14 g, h, 15 r, s) with stout spine; exopod 1.8 times as long as broad, bearing sharp proximal spine, with truncate distal margin; endopod about twice as long as broad, shorter than exopod. Embryos 570 – 640 µm in diameter. Variations. The number of spines on the upper border of the first pereopod propodus ranges from 2 to 4, one male (ZRC 2017.0958) lacks postocular spines, whereas two specimens (ZRC 2017.0954 and ZRC 2017.0958) lack the hepatic spines. One ovigerous female (ZRC 2017.0955) shows a male gonopore on the coxa of the left fifth pereopod, whilst another female (ZRC 2017.0954) has a male gonopore on the right side.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCCFF865FB7FEF1FD62F946.taxon	etymology	Etymology. The new species is named after the type locality, the Straits of Johor between Singapore and Johor, Malaysia.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCCFF865FB7FEF1FD62F946.taxon	distribution	Distribution. Presently only known from the type locality. Habitat. Sand-mud bottoms at depths of 6.7 – 14.7 m.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCCFF865FB7FEF1FD62F946.taxon	discussion	Remarks. Neogebicula johorensis, new species, is most similar to N. leptomorpha (Sakai, 2006) from the Persian Gulf, with respect to the general shape of the rostrum and lateral ridges of the gastric region. The new species differs from N. leptomorpha (characters in parentheses) by 1) the presence of only one postocular spine (two postocular spines); 2) the proximal article of the antennular peduncle having a ventral spine (without spine); 3) the third and fourth articles of the antennal peduncle each armed with a ventral spine (unarmed); and 4) the posterior margin of the telson with a small median spine (without spine). The new species also shows some similarities with the eastern Atlantic N. contigua (Božić & de Saint Laurent, 1972), differing from it (characters in parentheses) in 1) the presence of a large mesio-anterior tooth on the mandible (absent); 2) the antennular acicle being simple distally (with bifid tip); 3) the presence of several spines on the upper border of the first pereopod propodus (only one distal spine); and 4) the sixth pleomere being as long as wide (1.2 times longer than wide). In addition, both N. leptomorpha and N. contigua lack hepatic spines, whereas in N. johorensis, new species, they are present in three out of five specimens of the type series.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865CE0FD31FA19FA5F.taxon	materials_examined	CMBS material. 1 male (24 / 6.7) (ZRC 2017.0949), sta. M 04, Pulau Ubin, between OBS Camp Jetty 1 and OBS Camp Jetty 2, off reservoir, near mangrove, muddy intertidal, coll. KS Tan et al., 6 March 2012.	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865CE0FD31FA19FA5F.taxon	description	Description. See Sakai (1982) and Ngoc-Ho (1994).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865CE0FD31FA19FA5F.taxon	distribution	Distribution. Vietnam; Java, Indonesia; Darwin, Australia (Sakai, 2006); newly recorded from Singapore (this study). Habitat. Intertidal, in mangrove mud (Ngoc-Ho, 1994; this study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865CE0FD31FA19FA5F.taxon	discussion	Remarks. Sakai (1982: fig. 18 g) showed no median spine on the telson of W. inermis, in contrast to Sakai (1993: fig. 12 C). The telson was not figured nor described by Ngoc-Ho (1994). Nevertheless, the Singaporean specimen has a blunt median spine on the telson, as figured by Sakai (1993).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865FB5F951FBACFDA6.taxon	description	(Fig. 1 i, j)	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865FB5F951FBACFDA6.taxon	materials_examined	CMBS material. 1 male (15 / 4.6) (ZRC 2018.0546), sta. SW 126, Sungei Buloh, 1 ° 27.064 ′ N 103 ° 43.319 ′ E, mangrove, in mud, beach seine and hand nets, intertidal (low tide), coll. KS Koh, YL Lee et al., 30 October 2012 (JS- 2695); 1 male (37 / 10.3) (NHMW 26036), sta. SW 137, Pulau Ubin, OBS Camp 1, 1 ° 25 ′ 15.77 ″ N 103 ° 55 ′ 57.00 ″ E, near brackish stream in secondary forest, low tide, coll. R Lasley, JC Mendoza, 31 October 2012 (JS- 3001).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865FB5F951FBACFDA6.taxon	description	Description. See Sakai (1982) and Ngoc-Ho (1994).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
D65A2A57FFCEFF865FB5F951FBACFDA6.taxon	distribution	Distribution. Phuket, Thailand (Sakai, 1982, type locality); Can Gio, Vietnam (Marin, 2021); Singapore (Ngoc-Ho, 1994); Sumatra, Indonesia (Sakai & Türkay, 2014). Habitat. Intertidal, in thick mangrove mud (Ngoc-Ho, 1994; Marin, 2021; this study).	en	Dworschak, Peter C., Anker, Arthur (2022): Axiidea (Crustacea: Callianassidae, Callichiridae and Ctenochelidae) and Gebiidea (Upogebiidae) collected during the Comprehensive Marine Biodiversity Survey of Singapore. Raffles Bulletin of Zoology 70: 108-133, DOI: 10.26107/RBZ-2022-0008
