taxonID	type	description	language	source
03ED8786FFEA5554E1AEF94C7E83580B.taxon	description	(Figs. 4 A – G)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFEA5554E1AEF94C7E83580B.taxon	materials_examined	Material examined. Station SG 22: 2 males (CR 1209 - P 02 - 03), 3 December 2009; 2 non-ovigerous females and 2 males (CR 0511 - P 02 - 01 - 04), 9 May 2011; 1 damaged specimen (CR 1211 - P 02 - 03), 7 December 2011; 1 non-ovigerous female (CR 0112 - P 02 - 02 - 02), 20 January 2012; 1 damaged specimen (CR 0512 - P 02 - 01 - 01), 1 non-ovigerous female (CR 0512 - P 02 - 02) and 1 ovigerous female and two males (CR 0512 - P 02 - 03), 23 May 2012; 1 non-ovigerous female and 1 male (CR 1113 - P 02 - 03 - 02), 13 November 2013; 2 males (CR 0514 - P 02 - 03 - 02), 7 May 2014; 1 damaged specimen (CR 1114 - P 02 - 02 - 01) and 1 male (CR 1114 - P 02 - 03 - 02), 11 November 2014; 3 damaged specimens (CR 1115 - P 02 - 02 - 01) and 1 non-ovigerous female (CR 1115 - P 02 - 03 - 02), 2 November 2015; 1 male (CR 1016 - P 02 - 01) and 2 ovigerous females (CR 1016 - P 02 - 02 - 03), 5 October 2016; 4 damaged specimens (CR 1117 - P 02 - 01 - 02) and 2 damaged specimens (CR 1117 - P 02 - 02 - 02), 8 November 2017; 1 non-ovigerous female (CR 0518 - P 02 - 01), 9 May 2018; 1 ovigerous female (CR 1118 - P 02 - 02), 14 November 2018; 2 ovigerous females (CR 1219 - P 02 - 01 - 01), 1 damaged specimen (CR 1219 - P 02 - 02) and 2 ovigerous females and 1 damaged specimen (CR 1219 - P 02 - 03 - 01), 4 December 2019; 1 ovigerous female (CR 0820 - P 02 - 03), 5 August 2020. Station SG 23: 2 ovigerous female (CR 1112 - P 06 - 01), 6 November 2012. Station SG 25: 3 ovigerous females (CR 1110 - P 08 - 03 - 01), 16 November 2010; 1 male (CR 1115 - P 08 - 03 - 02), 5 November 2015. Station SG 26: 1 damaged specimen (CR 0515 - PS 06 - 02 - 02), 14 May 2015.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFEA5554E1AEF94C7E83580B.taxon	discussion	Remarks. Mendamanus Bamber, 1999 is solely represented by M. ailurostoma, which is distinguished from other apseudids by having a reduced fixed finger on the male chela (Bamber 1999). Mendamanus, together with Atlantapseudes Băcescu, 1978 a and Typhlapseudes Beddard, 1886, are the only genera within Apseudinae that lack an exopod on pereopod- 1 but possess an exopod on the cheliped (Błażewicz-Paszkowycz & Bamber 2007). The absence of a row of lanceolate spines on the propodus of pereopod- 5 is also a diagnostic character of this genus (Bamber et al. 2012). Mendamanus ailurostoma is an uncommon species as it was previously known only from the shallow subtidal (2 – 60 m) sandy bottoms of Bruneian waters (Bamber 1999; 2013 b; Bamber et al. 2012). The specimens from Singapore match the description of M. ailurostoma from Brunei (Bamber 1999) but these specimens, which include males and ovigerous females, possess hyposphenia on pereonites 2 – 6 (Figs. 4 E – F), which were not mentioned in the description by Bamber (1999). It is likely that hyposphenia are absent in the Bruneian specimens because these conspicuous structures are unlikely to be overlooked and would have been mentioned if present. It is, however, important to note that hyposphenia is rarely considered a reliable taxonomic character in apseudomorphans as it has been shown to exhibit intraspecific variations (Jóźwiak & Błażewicz-Paszkowycz 2011). The present material represents the first record of M. ailurostoma outside Brunei and was collected from silty bottoms along the Singapore Strait at 12 – 54 m depth, which is within the bathymetric range of the records in Brunei. This species is especially abundant at station SG 22, which is located at the eastern end of the Singapore Strait (Fig. 2). Genus Siegius Allsopp, 2017	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFF55557E1AEFC887DDE5AAC.taxon	description	(Figs. 6 A – D)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFF55557E1AEFC887DDE5AAC.taxon	materials_examined	Material examined. Station SG 2: 3 moulted exoskeletons (ZRC). Station SG 4: 4 females (ZRC. 1991.19205 - 19208). Station SG 5: 2 females (ZRC. 1992.5995). Station SG 6: 1 female (ZRC. 1992.6636 - 6642). Station SG 8: 2 males and 2 females (S 5 G 1); 2 females (S 6 G 5); 1 female (S 7 G 2). Station SG 10: 5 damaged specimens (276). Station SG 11: 5 damaged specimens (001). Station SG 13: 2 damaged specimens (242). Station SG 15: 1 incomplete specimen (197). Station SG 17: 1 specimen (088). Station SG 18: 1 ovigerous female, 1 male and 1 exoskeleton (083). Station SG 22: 1 specimen (CR 0112 - P 02 - 01), 20 January 2012; 2 specimens (CR 1113 - P 02 - 03 - 01), 13 November 2013; 1 specimen (CR 0514 - P 02 - 03 - 01), 7 May 2014; 1 specimen (CR 1114 - P 02 - 02 - 02), 11 November 2014; 1 specimen (CR 1115 - P 02 - 03 - 01), 2 November 2015; 2 specimens (CR 0516 - P 02 - 02), 10 May 2016; 1 specimen (CR 0517 - P 02 - 02), 17 May 2017; 1 specimen (CR 0717 - P 02 - 02 - 01), 19 July 2017; 2 specimens (CR 1117 - P 02 - 01 - 01, CR 1117 - P 02 - 02 - 01), 8 November 2017; 2 males (CR 0619 - P 02 - 02 - 01), 13 June 2019. Station SG 23: 2 damaged specimens (CR 0512 - P 06 - 01 - 01), 25 May 2012; 2 ovigerous females and 1 male (CR 1117 - P 06 - 03 - 01), 9 November 2017. Station SG 24: 1 specimen (CR 0105 - P 07 - 02) and 1 specimen (CR 0105 - P 07 - 03), 19 January 2005; 1 specimen (CR 0511 - P 07 - 02), 10 May 2011; 1 specimen (CR 0513 - P 07 - 02), 9 May 2013; 3 damaged specimens (CR 1118 - P 07 - 01), 15 November 2018. Station SG 25: 1 damaged specimen (CR 1110 - P 08 - 03 - 02), 16 November 2010; 1 ovigerous female (CR 1115 - P 08 - 03 - 01), 5 November 2015. Station SG 26: 3 specimens (CR 1113 - PS 06 - 01 - 01), 11 November 2013; 10 specimens (CR 0514 - PS 06 - 01 - 01), 3 specimens (CR 0514 - PS 06 - 02 - 01) and 1 specimen (CR 0514 - PS 06 - 03 - 01), 5 May 2014; 1 incomplete specimen (CR 1114 - PS 06 - 01), 8 November 2014; 1 ovigerous female and 1 male (CR 1114 - PS 06 - 02) and 2 males (CR 1114 - PS 06 - 03 - 02), 13 November 2014; 5 specimens (CR 0515 - PS 06 - 02 - 01) and 1 specimen (CR 0515 - PS 06 - 03 - 01), 14 May 2015; 2 specimens (CR 0516 - PS 06 - 01 - 01) and 1 specimen (CR 0516 - PS 06 - 02 - 01), 12 May 2016; 2 specimens (CR 0517 - PS 06 - 01), 15 May 2017; 5 specimens (CR 0518 - PS 06 - 01) and 2 specimens (CR 0518 - PS 06 - 03), Singapore, 7 May 2018; 1 damaged specimen (CR 1219 - PS 06 - 01 - 01), 2 December 2019. Station SG 35: 1 specimen (JS- 6065); 1 female with oostegites (JS- 6496). Station SG 39: 1 specimen (5115 TB 1 - 041). Station SG 40: 1 specimen (5113 DR 1 - 095). Station SG 43: 1 ovigerous female (4713 DR 3 - 234). Station SG 50: 1 specimen (SUB- 0074). Station SG 52: 1 specimen (SEA- 5555). Station SG 58: 1 male (SUB- 0490). Station SG 65: 3 females (SUB- 0667). Station SG 68: 1 damaged specimen (SUB- 1020). Station SG 70: 1 male (SUB- 1187). Station SG 71: 1 female (SUB- 1578).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFF55557E1AEFC887DDE5AAC.taxon	discussion	Remarks. Members of Kalliapseudinae can be easily recognised by the presence of feeding filters in the form of long plumose setae on the anterior appendages such as chelipeds, maxillipeds and mandibular palps as well as long sensory setae (aesthetascs) on the dactylus of the pereopod- 1 (Drumm & Heard 2011). This subfamily contains six genera including Phoxokalliapseudes. Drumm & Heard (2011) erected Phoxokalliapseudes and assigned Kalliapseudes gobinae Bamber, 1999 from Brunei as the type species of the genus. Phoxokalliapseudes differs from the other five Kalliapseudinae genera by the (1) lack of strong sexual dimorphism on antennule peduncle article- 1; (2) presence of ventral spines on the antennule peduncle article- 1; (3) presence of exopods on cheliped and pereopod- 1; (4) non-globose basis on pereopods 4 and 5; and (5) lack of tuft of sensory setae on the long dactylus of pereopod- 6 (Drumm & Heard 2011). This genus is currently represented by seven species (Anderson 2023), namely P. tomiokaensis (Shiino, 1966), P. gobinae, P. multiarticulus (Guţu, 2006), P. singaporensis, P. aculeatus Wi, Kang & Soh, 2017, P. cinctus Wi, Kang & Soh, 2017 and P. gibbus Wi, You & Kang, 2019, which are widely distributed in the Indian and western Pacific Oceans (Shiino 1966; Bamber 1999, 2013 b; Bamber et al. (2003), 2012; Bamber & Sheader 2005; Guţu 2006; Drumm & Heard 2011; Quan & Zhu 2013; Wi et al. 2017, 2019) but limited to the shallow subtidal waters (1 – 60 m depth). Characters uniting Phoxokalliapseudes include (1) the terminal plumose setae on the pleotelson; (2) the presence of cusps on the labrum; and (3) the large spine on the propodus of the male cheliped. Appendages including antennule, antenna, cheliped, and pereopods 1 – 3 and 6 contain important characters for distinguishing species within the genus (Wi et al. 2017, 2019). The present material matches the original description of P. singaporensis, which was based on specimens collected from an unspecified locality in Singapore (Drumm & Heard 2011). In this study, P. singaporensis was found in many stations along the Singapore Strait and the outer East Johor Strait (e. g., Pulau Tekong, Pulau Ubin and Punggol) at 5 – 75 m depth. This relatively large animal with a body length of up to 9.5 mm is one of the most common tanaids in the subtidal habitats of Singapore.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFF3555CE1AEF8C47A525A40.taxon	discussion	Remarks. The family Parapseudidae was erected by Guţu (1981) and its diagnosis later revised by Larsen (2005) and Guţu (2008). Key features of parapseudids include the (1) absence of a well-developed spiniform coxa on pereopod- 1; (2) large size of pereopod- 1, in relation to pereopods 2 and 3; and (3) small length of pereopod- 4 dactylus (smaller than some distal spines on the propodus). The family contains two subfamilies Pakistanapseudinae Guţu, 2008 and Parapseudinae Guţu, 2008, which were erected by Guţu (2008) as tribes and then promoted to subfamily rank by Błażewicz-Paszkowycz & Bamber (2012). Guţu (2008) also provided identification keys to these tribes and genera. The two subfamilies are differentiated by the relative length of the pleonites and the presence or absence of a dorsotransversal row of small setae on the first pleonite (Guţu 2008). Preserved specimens of this family are notoriously fragile and thus often incomplete (Guţu 1996, 1998 c), resulting in taxonomic difficulties.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFD555EE1AEFBD07ED55D8C.taxon	description	(Figs. 12 A – C)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFD555EE1AEFBD07ED55D8C.taxon	materials_examined	Material examined. Station SG 22: 1 incomplete female with eggs (CR 0511 - P 02 - 01 - 03), 9 May 2011; 1 incomplete specimen (CR 0112 - P 02 - 02 - 01), 20 January 2012; 1 incomplete female with eggs (CR 1113 - P 02 - 03 - 03), 13 November 2013; 1 female with oostegites (CR 1114 - P 02 - 01), 11 November 2014; 1 incomplete specimen (CR 1016 - P 02 - 02 - 02), 5 October 2016; 1 incomplete female brooding mancae I (CR 0717 - P 02 - 02 - 02), 19 July 2017; 1 incomplete specimen (CR 0619 - P 02 - 02 - 02), 13 June 2019. Station SG 23: 1 damaged specimen (CR 1112 - P 06 - 02 - 02), 6 November 2012; 1 incomplete female with oostegites (CR 1113 - P 06 - 03 - 03), 13 November 2013; 2 incomplete females, including 1 brooding embryos and 1 with empty brood pouch (CR 0514 - P 06 - 01 - 02), 1 incomplete female with eggs (CR 0514 - P 06 - 02) and 1 incomplete specimen (CR 0514 - P 06 - 03), 8 May 2014; 2 incomplete ovigerous females (CR 1114 - P 06 - 01 - 01), 12 November 2014; 1 female with brood pouch (CR 0516 - P 06 - 03), 9 May 2016; 1 incomplete specimen (CR 0717 - P 06 - 01), 20 July 2017; 1 incomplete male (CR 0619 - P 06 - 01) and 1 incomplete female with oostegites (CR 0619 - P 06 - 02), 14 June 2019; 2 females with oostegites (CR 0820 - P 06 - 01) and 1 female with oostegites (CR 0820 - P 06 - 02), 6 August 2020. Station SG 25: 2 ovigerous females and 1 female with oostegites (CR 1110 - P 08 - 02), 16 November 2010. Station SG 26: 1 incomplete female with oostegites (CR 1115 - PS 06 - 02 - 02), 5 November 2015; 1 incomplete specimen (CR 1117 - PS 06 - 02 - 01), 6 November 2017; 1 incomplete specimen (CR 1118 - PS 06 - 01 / 02), 12 November 2018.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFD555EE1AEFBD07ED55D8C.taxon	discussion	Remarks. The genus Biropalostoma was erected by Guţu & Angsupanich, 2004 a and is currently represented by two species (Anderson 2023), namely B. goofi (Bamber & Sheader, 2003) and B. spiniferum Guţu & Angsupanich, 2004 a, with the latter designated as its type species. Both species are found in the shallow subtidal habitats of Malaysia, Brunei and Thailand at up to 35 m depth (Bamber & Sheader 2003, 2005; Guţu & Angsupanich 2004 a, b; Bamber 2013). Biropalostoma is characterised by the presence of a distinctive spinose ‘ bludgeon-like’ process adjacent to the mandible palp (Guţu & Angsupanich 2004 a; Guţu 2006, 2008). Other characters shared between the two species include the (1) dorsally curved epistomal spine; (2) pereonites 3 – 6 longer than wide; (3) antenna peduncle inner margin with hook-like spines; (4) pereopod- 1 merus, carpus and propodus with short spiniform setae; and (5) pleopod exopod smaller than endopod. Like other parapseudids, B. spiniferum is a very fragile species and none of the present material examined is complete. Nonetheless, these specimens from Singapore match the diagnostic features of B. spiniferum, and these include the (1) short and ventrally curved rostral spine; (2) wider than long pereonite- 2; and (3) absence of ventrodistal spiniform setae on the cheliped merus (Guţu & Angsupanich 2004 a). This species is also similar to the sympatric Actenos sp. SG # 1 by possessing (1) a ventrally curved rostrum and a dorsally curved epistome; (2) posterolateral processes on pleonites at the location bearing pleopods. However, B. spiniferum differs from Actenos sp. SG # 1 by the (1) pereonites lacking anterolateral spines (see Fig. 11 B); (2) pereopod- 1 coxa bearing setae instead of spines; and (3) pereopod- 1 claw not bifid and bearing more (five as compared to two in Actenos sp. SG # 1) spiniform setae. Biropalostoma spiniferum was previously recorded only from its type locality in the Andaman Sea at 1.5 m depth. The Singaporean specimens were collected from sandy silt bottoms along the Singapore Strait at 14 – 54 m depth. The current record is the first for the species outside its type locality and extends its geographical distribution southwards from southwestern Thailand to Singapore. Genus Platylicoa Guţu, 2006	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFE555FE1AEF9547FF15E54.taxon	description	(Fig. 13)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFE555FE1AEF9547FF15E54.taxon	materials_examined	Material examined. Station SG 6: 1 ovigerous female and 1 female with oostegites (ZRC. 1992.6636 - 6642). Station SG 13: 1 damaged specimen (002). Station SG 14: 7 damaged and incomplete specimens (133). Station SG 15: 1 damaged specimen (129). Station SG 16: 3 damaged specimens (041); 10 damaged and incomplete specimens (220). Station SG 22: 1 incomplete and damaged specimen (CR 0511 - P 02 - 01 - 01), 9 May 2011; 1 incomplete and damaged specimen (CR 0512 - P 02 - 01 - 02), 23 May 2012; 1 incomplete male (CR 0514 - P 02 - 03 - 05), 7 May 2014; 1 incomplete specimen (CR 1114 - P 02 - 03 - 01), 11 November 2014; 1 incomplete specimen (CR 0515 - P 02 - 03), 11 May 2015; 1 incomplete specimen (CR 1016 - P 02 - 02 - 01), 5 October 2016; 2 incomplete specimens (CR 1117 - P 02 - 01 - 03, CR 1117 - P 02 - 02 - 03), 8 November 2017; 1 incomplete specimen (CR 1118 - P 02 - 01 - 02), 14 November 2018; 1 incomplete specimen (CR 0619 - P 02 - 03), 13 June 2019; 1 damaged specimen (CR 1219 - P 02 - 01 - 02), 4 December 2019; 1 incomplete specimen (CR 0820 - P 02 - 01), 5 August 2020. Station SG 23: 1 incomplete female with oostegites (CR 0513 - P 06 - 02), 9 May 2013; 1 incomplete female with oostegites (CR 1113 - P 06 - 01), 1 specimen (CR 1113 - P 06 - 02), 1 incomplete specimen (CR 1113 - P 06 - 03 - 01) and 1 incomplete specimen (CR 1113 - P 06 - 03 - 02), 13 November 2013; 1 incomplete male (CR 0514 - P 06 - 01 - 01), 8 May 2014; 2 incomplete males (CR 1115 - P 06 - 01 - 01) and 2 specimens (CR 1115 - P 06 - 01 - 02), 3 November 2015; 1 specimen (CR 1117 - P 06 - 02 - 01), 9 November 2017; 1 incomplete female with oostegites (CR 0518 - P 06 - 02), 10 May 2018; 1 incomplete specimen (CR 1219 - P 06 - 02), 6 December 2019. Station SG 24: 1 incomplete ovigerous female (CR 1115 - P 07 - 02), 3 November 2015. Station SG 25: 2 damaged specimens (CR 0609 - P 08 - 01), 8 June 2009. Station SG 36: 1 adult male (JS- 7365).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFE555FE1AEF9547FF15E54.taxon	discussion	Remarks. Guţu (2006) erected Platylicoa and assigned Pakistanapseudes pectinis Bamber, 1999 from Brunei as the type species of the new genus. The genus name refers to the great width of the pleonites (Guţu 2006). Other diagnostic features of this taxon include (1) the short pleon; and (2) the presence of plumose setae on both dorsal and ventral margins of pereopod- 6 basis (Guţu 2006). A revised diagnosis of the genus is available in Guţu (2008). Bamber (2013 b) later questioned the validity of this genus, as he observed that the dorsal row of setae on pleonite- 1 displays interspecific variation within the genus, while the setation of pereopod- 6 shows intraspecific variation in the genus. He also transferred Platylicoa from another subfamily, Parapseudinae, to Pakistanapseudinae. This genus is currently represented by three species (Anderson 2023), namely P. pectinis, P. setosa Gutu, 2006 and P. angela Bamber, 2013 b, all of which were recorded from shallow (6.5 – 180 m depth) sandy habitats in Borneo and Queensland, Australia (Bamber 1998 (1999), 2013 b; Bamber & Sheader 2005; Guţu 2006). Most of the individuals in the present material are incomplete, reflecting the fragility of the specimens as also observed by Bamber (2013 b). Nonetheless, these specimens from Singapore can be readily identified as P. angela based on the distinctive posterolateral ventral curved spiniform setae on each of pereonites 2 and 3 (Fig. 13). The body length of the current material, excluding the rostrum, reaches a maximum of 8.8 mm, which is similar to the length of the P. angela holotype at 10.5 mm including the rostrum. However, the P. angela specimens from Singapore differ from that described in Bamber (2013 b) by the presence of a large and curved spiniform seta on pereopod- 1 merus dorsodistally. Bamber (2013 b) also observed intraspecific variation in the number of setae and spines on the ventral margin of pereopod- 1 propodus of this species. Platylicoa angela was previously recorded only from its type locality in Brunei at 6.5 – 90 m depth (Bamber 2013 b). The Singaporean specimens were collected from the Singapore Strait and the outer East Johor Strait (i. e., Pulau Tekong, Pulau Ubin and Punggol) at 5 – 54 m depth.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFF5558E1AEFA727B785BD4.taxon	materials_examined	Material examined. Station SG 14: 1 specimen (133). Station SG 22: 1 incomplete male (CR 0609 - P 02 - 01), 8 June 2009; 1 incomplete specimen (CR 0511 - P 02 - 01 - 02), 9 May 2011; 3 incomplete specimens, including 1 male (CR 0513 - P 02 - 01), 8 May 2013; 1 incomplete female with oostegites (CR 1113 - P 02 - 02) and 1 incomplete male (CR 1113 - P 02 - 03 - 04), 13 Nov 2013; 2 incomplete specimens, including 1 male (CR 0514 - P 02 - 01) and 1 incomplete female with oostegites (CR 0514 - P 02 - 02) and 1 incomplete female with oostegites (CR 0514 - P 02 - 03 - 04), 7 May 2014; 16 complete specimens (CR 1114 - P 02 - 02 - 03), 11 November 2014; 1 incomplete specimen (CR 0515 - P 02 - 01), 11 May 2015; 2 incomplete specimens, including 1 female with oostegites (CR 0717 - P 02 - 02 - 03), 19 July 2017; 1 incomplete male (CR 1117 - P 02 - 01 - 04), 8 November 2017. Station SG 23: 1 damaged specimen (CR 0112 - P 06 - 03 - 02), 20 January 2011; 1 damaged female with oostegites (CR 0820 - P 06 - 03 - 02), 6 August 2020. Station SG 26: 2 incomplete specimens (CR 1114 - PS 06 - 03 - 01), 13 November 2014; 1 incomplete specimen (CR 0516 - PS 06 - 01 - 03), 12 May 2016; 1 incomplete female with eggs (CR 0517 - PS 06 - 02 - 02), 15 May 2017. Station SG 65: 1 incomplete male (SUB- 0667).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFF5558E1AEFA727B785BD4.taxon	discussion	Remarks. These pakistanapseudine individuals from Singapore could not be reliably identified to lower taxonomic levels as they are in too poor a condition. Almost all specimens are incomplete and / or badly damaged and are likely to belong to more than one species. They are similar to Actenos sp. SG # 1 and B. spiniferum specimens obtained in this study but can be easily distinguished by the minute rostrum that is not curved. They were collected from sandy silt bottoms along the East Johor and Singapore Straits at 10 – 54 m depth.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFB555BE1AEFDB17C735D16.taxon	description	(Figs. 15 A – C)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFB555BE1AEFDB17C735D16.taxon	materials_examined	Material examined. Station SG 9: 8 females (SB 28 / 5 C 10.3); 6 females (SB 28 / 5 C 10.6). Station SG 27: 77 specimens, including 31 females and 11 males (No. 5087 – 5162). Station SG 28: 1 male (No. 18006 B). Station SG 29: 2 females (No. 34152 – 34153). Station SG 31: 2 females and 1 male (No. 37002 – 37004). Station SG 37: 1 male and 2 females (JS- 7226). Station SG 84: 6 specimens, including 3 ovigerous female (20170617.028, 20170617.029 and 20170617.040), 17 June 2017. Station SG 85: 11 specimens, including 1 ovigerous female and 2 males (20170617.075).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFB555BE1AEFDB17C735D16.taxon	discussion	Remarks. Guţu (1995 b) erected the genus Longiflagrum and designated Apseudes estuarius Boesch, 1973 from Brisbane River, Queensland, Australia as the type species. Diagnostic features of the genus include the (1) equal length of the antennule flagella; (2) presence of long setae on the inner side of the antennal peduncle; (3) wide carpus of pereopod- 1; and (4) wide exo- and endopods of the pleopods (Guţu 1995 b, 2008; Angsupanich 2004). Stępień & Błażewicz-Paszkowycz (2009) provided identification keys to species of Longiflagrum, and identified the antennule, antenna and pereopods 4 and 5 as important characters. This genus is currently represented by four species (Anderson 2023), namely L. estuarius, L. koyonense Angsupanich, 2004, L. nasutus (Nunomura, 2005) and L. amphibium Stępień & Błażewicz-Paszkowycz, 2009. These Longiflagrum species were primarily recorded from intertidal estuarine habitats in the Indo-West Pacific Ocean, specifically Queensland, Port Hedland in Western Australia, Songkhla Lake in Thailand and Manko Lake in Okinawa, Japan (Boesch 1973; Angsupanich 2004; Nunomura 2005; Bamber 2008 c; Stępień & Błażewicz-Paszkowycz 2009). The present material from Singapore is the first record of L. koyonense outside its type locality in Thailand, where it was collected from 0.7 m depth. In Singaporean waters, this relatively large species, reaching 7.8 mm in body length, was confined to intertidal estuarine habitats (e. g., mudflats and mangroves) where there is a substantial freshwater influx from nearby rivers in the West Johor Strait (i. e., Lim Chu Kang, Sungei Buloh Wetland Reserve and Sungei Mandai) and Singapore Strait (i. e., Sungei Pandan).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFB5564E1AEF8DF7C0B5814.taxon	description	(Figs. 16 A – B)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFB5564E1AEF8DF7C0B5814.taxon	materials_examined	Material examined. Station SG 25: 2 incomplete specimens (CR 1209 - P 08 - 01), 3 December 2009.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFFB5564E1AEF8DF7C0B5814.taxon	discussion	Remarks. Sphyrapodids are characterised by the enlarged pereopod- 1 as well as the absence of spines on the cephalothorax, ocular lobes and pereopod coxa (Guţu 1980; Larsen 2005). Poligarida belongs to the subfamily Sphyrapodinae Guţu, 1980, which is differentiated from its sister subfamily Pseudosphyrapodinae Guţu, 1980 by the absence of the mandibular palp (Guţu 1980). This is the only sphyrapodin genus with a cephalothorax that is wider than long (Bamber & Marshall 2013) and is also characterised by the following morphological traits: (1) antennule inner flagellum with two articles; (2) antenna without squama; (3) antenna peduncle article- 2 elongate, at least four times longer than article- 3; (4) maxillule without palp; and (5) pereopods without complex setation and lack hook-like apophyses on basis (Bamber & Marshall 2013). There are only two species in the genus, and both were recorded only from shallow subtidal (20 – 90 m) sandy habitats in Brunei (Bamber & Marshall 2013). Poligarida beni can be distinguished from P. keriakis Bamber & Marshall, 2013 by (1) the presence of distal tubercles on anterior margin of rostrum (Fig. 16 B); (2) the presence of anterolateral spines on pereonite- 3; (3) the absence of a spine on the outer margin of antennule peduncle article- 1; (4) having less spiniform setae on pereopod- 1 propodus; and (5) the presence of seta on pleopod basis (Bamber & Marshall 2013). The Singaporean specimens closely resemble P. beni but differ slightly by the triangular anterolateral apophyses on pereonite- 3 being blunt instead of acute. Poligarida beni was previously recorded only from its type locality in Brunei at 20 m depth. In Singaporean waters, this species was collected only from the station SG 25 (see Fig. 2), which is located at the north of Kusu Island, at a depth of 12 – 30 m. The two specimens from this material measured 1.0 and 1.7 mm, making this species the smallest apseudomorphan in Singapore waters.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC55566E1AEFE047FF159A8.taxon	description	(Figs. 17 A – D)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC55566E1AEFE047FF159A8.taxon	materials_examined	Material examined. Station SG 86: 38 specimens, including 9 that are incomplete (HAN-EXP- 00.0 - TAN 03, HAN-EXP- 00.0 - TAN 04, HAN-EXP- 00.0 - TAN 06); 1 male, 23 adults, 9 mancae (HAN-EXP- 02.5 - TAN 04, HAN- EXP- 02.5 - TAN 05, HAN-EXP- 02.5 - TAN 07); 1 male, 22 adults, 1 manca (HAN-EXP- 05.0 - TAN 02, HAN-EXP- 05.0 - TAN 03, HAN-EXP- 05.0 - TAN 06); 36 specimens, including 10 adults and 1 manca (HAN-EXP- 07.5 - TAN 01, HAN-EXP- 07.5 - TAN 02, HAN-EXP- 07.5 - TAN 04, HAN-EXP- 07.5 - TAN 05, HAN-EXP- 07.5 - TAN 06); 1 male, 4 adults, 2 mancae (HAN-EXP- 10.0 - TAN 02, HAN-EXP- 10.0 - TAN 04, HAN-EXP- 10.0 - TAN 05, HAN-EXP- 10.0 - TAN 06). Station SG 91: 3 adults (SEN-PRO- 00.0 - TAN 07); 11 adults, 2 mancae (SEN-PRO- 02.5 - TAN 05, SEN- PRO- 02.5 - TAN 09); 1 adult (SEN-PRO- 05.0 - TAN 09); 2 adults (SEN-PRO- 07.5 - TAN 08).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC55566E1AEFE047FF159A8.taxon	discussion	Remarks. Bamber (2006) erected the genus Konarus and designated K. cheiris Bamber, 2006 as its type species. The distinctive feature of this genus is the fat antennule peduncle (Bamber 2006). Konarus is currently represented by three species (Anderson 2023), namely K. crassicornis (Stebbing, 1905), K. cheiris and K. straddi (Bamber, 2008 c), which were recorded from intertidal and shallow subtidal (10 – 40 m) habitats in the Indo-West Pacific including India, Australia (Queensland) and New Caledonia (Stebbing 1905; Bamber 2006, 2008 c; Bamber & Chatterjee 2010). All three species are very similar in general morphology (Bamber & Chatterjee 2010; Bamber 2013 a). The present material from Singapore is most similar to K. crassicornis. Even though males of K. crassicornis from the type locality remain unknown, the male specimens of K. crassicornis in this study can be easily distinguished from the males of K. cheiris and K. straddi based on their chelipeds: (1) propodus ovoid, with mid-ventral triangular apophysis and with adjacent row of one long seta and numerous short setae; (2) fixed finger absent (Fig. 17 D); and (3) movable finger shorter than propodus. Previous records of K. crassicornis occurred in the intertidal shores of India at Gulf of Mannar, Laccadive Sea (Stebbing 1905) and the Andaman Islands, Andaman Sea (Bamber & Chatterjee 2010). In Singaporean waters, this species was found only from intertidal macroalgal turfs in the Singapore Strait, on an exposed seawall at Pulau Hantu and on a sheltered seawall at Sentosa (Pulau Blakang Mati).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC05560E1AEFB687FD65FC4.taxon	description	(Fig. 19)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC05561E1AEFB1D7FF05A64.taxon	materials_examined	Material examined. Station SG 86: 1 male (HAN-EXP- 10.0 - TAN 01). Station SG 90: 1 incomplete male (SEN- EXP- 05.0 - TAN 01). Station SG 91: 1 incomplete male (SEN-PRO- 05.0 - TAN 08).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC05561E1AEFB1D7FF05A64.taxon	discussion	Remarks. Leptochelia minuta Dana, 1849 from Fiji is the type species of the genus Leptochelia, which has long been suspected to be polyphyletic (Morales-Núñez et al. 2013). Jarquiìn-Gonzaìlez et al. (2015) provided identification keys for both males and females of the genus, with the most important characters on the uropods, but the usefulness of these tools became limited after the mass transfer of 17 species to its sister genus Chondrochelia by Guţu (2016). Despite the revision, the systematics of Leptochelia still has some existing issues. Guţu (2016) included only five species in Leptochelia sensu stricto, namely L. minuta Dana, 1849, L. forresti (Stebbing, 1896), L. mirabilis Stebbing, 1905, L. afrieurina Guţu, 2016 and L. splendida, with the males characterised by possessing slender chelipeds that are at least as long as their body. In contrast, Leptochelia sensu lato currently contains 28 species (Anderson 2023), which have been recorded from intertidal and shallow subtidal (up to 62 m depth) habitats worldwide, except at the poles (Jarquiìn-Gonzaìlez et al. 2015). The present specimens composed of only males and they are most similar to the males of L. splendida based on the (1) body length of about 2 mm; (2) body length to width proportion of about 5.5; (3) large eyes; (4) elongated antennule peduncle article- 1 with length to width proportion of more than 10; (5) antennule peduncle article- 2 about half as long as article- 1; (6) slender cheliped that is longer than the body (Fig. 19); (7) uropod endopod having six articles and exopod having two articles (Fig. 19); and (8) uropod exopod longer than endopod article- 1. Leptochelia splendida was previously recorded only from its type locality in Bunaken Island, Indonesia, at 1 – 3 m depth (Guţu 2016), which is relatively close to Singapore. There are, however, some subtle differences between the males of L. cf. splendida and L. splendida such as the number of articles on antennule flagellum (7 vs. 9) and the number of processes on chela fixed finger (2 vs. 1). It remains uncertain whether the L. splendida specimens from Singapore are of the same species as those from Bunaken Island until more specimens have been examined, especially those of females, which are surprisingly absent in the present material. In Singaporean waters, L. splendida was found only from intertidal macroalgal turfs on seawalls at Pulau Hantu and Sentosa (Pulau Blakang Mati) in the Singapore Strait.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC15561E1AEFA067E155D27.taxon	description	(Figs. 20 A – C)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC15562E1AEF9BB7C375A88.taxon	materials_examined	Material examined. Station SG 7: 38 females, 3 males (ZRC. 1993.2601 – 2626, ZRC. 1993.2633 – 2648). Station SG 30: 15 females, 6 males (No. 36784 – 36809). Station SG 54: 1 specimen (SEA- 7302), 9 April 2014. Station SG 79: Hundreds of specimens.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC15562E1AEF9BB7C375A88.taxon	discussion	Remarks. Shiino (1968) erected the genus Nesotanais and designated N. lacustris from the Solomon Islands as the type species. Nesotanais is best characterised by the unusual development of the male cheliped. It has been speculated that these chelipeds are used for sound production, based on the presence of serial ridges on the inner surfaces of their propodus and dactylus (Bamber et al. 2003; Larsen 2005; Kakui et al. 2010). This genus is currently represented by four species (Anderson 2023), namely N. lacustris, N. maclaughlinae Guţu & Iliffe, 1989, N. rugula Bamber, Bird & Angsupanich, 2003 and N. ryukyuensis Kakui, Kajihara & Mawatari, 2010. Coincidently, all these species occurred in sheltered waterbodies (e. g., marine caves, lagoons, lakes, and rivers) in the Indo-West Pacific region (Shiino 1968; Guţu & Iliffe 1989; Bamber et al. (2003); Angsupanich et al. 2005; Kakui et al. 2010) and these relatively calm environments probably facilitate sound transmission. Kakui et al. (2010) provided an identification key to species of the genus, based on the pleopods, chelipeds and maxillipeds. The specimens from Singapore agree most with N. rugula, which was previously recorded only from its type locality in the Songkhla Lake, Thailand at 1 m depth (Bamber et al. 2003). In Singaporean waters, N. rugula is restricted to relatively sheltered habitats in the inner Johor Straits (i. e., Sungei Cina and Sungei Buloh Wetland Reserve). This small tanaid, of body length about 1.5 mm, can be very abundant when present in this study.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC35563E1AEF9B87FD55D94.taxon	description	(Fig. 22)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC3556CE1AEF9507C415814.taxon	materials_examined	Material examined. Station SG 86: 9 specimens, including 1 male (HAN-EXP- 00.0 - TAN 01); 4 specimens (HAN- EXP- 02.5 - TAN 09); 3 specimens (HAN-EXP- 05.0 - TAN 05); 3 specimens, including 1 female with brood pouch and 1 female with oostegites (HAN-EXP- 07.5 - TAN 08). Station SG 88: 2 adults (LAZ-EXP- 07.5 - TAN 06); 1 adult (LAZ-EXP- 10.0 - TAN 02). Station SG 89: 2 adults (LAZ-PRO- 02.5 - TAN 02); 2 adults, 1 manca (LAZ-PRO- 05.0 - TAN 04); 2 adults, 1 manca (LAZ-PRO- 07.5 - TAN 10); 1 adult (LAZ-PRO- 10.0 - TAN 09). Station SG 91: 4 adults, including 1 female with brood pouch (SEN-PRO- 00.0 - TAN 09); 3 adults (SEN-PRO- 02.5 - TAN 08); 5 adults (SEN- PRO- 05.0 - TAN 10); 4 adults, 1 manca (SEN-PRO- 07.5 - TAN 09).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC3556CE1AEF9507C415814.taxon	discussion	Remarks. Pseudotanaids can be easily recognised by their greatly reduced pereonite- 1 (Jakiel et al. 2019). Akanthinotanais, which was recently promoted from subgenus to genus rank (Jakiel et al. 2018), can be differentiated from the other four pseudotanaid genera by the presence of simple instead of blade-like seta on the carpi of pereopods 2 and 3 (Jakiel et al. 2019). This genus occurs globally from the intertidal to the abyssal zone up to 4910 m depth (Kudinova-Pasternak 1986; Błażewicz et al. 2021) and is currently represented by 14 species (Anderson 2023). The type species Akanthinotanais gerlachi was originally described from the Maldives at 5 – 32 m depth and later recorded from a coral reef in the Gulf of Mexico (Cházaro-Olvera et al. 2018). Key morphological characters of female of all Akanthinotanais species, except A. rossi Błażewicz, Jakiel, Bamber & Bird 2021, were tabulated and compared in Tzeng & Hsueh (2021). The present material from Singapore closely resembles A. gerlachi based on the following shared characters: (1) similar body length; (2) body relatively elongate (i. e., about 5 times longer than wide); (3) pereonite- 2 about twice as long as pereonite- 1; (4) antennule and cephalothorax of similar length; (5) uropod and pleotelson of similar length; (6) uropod endopod and exopod biarticulated; and (7) uropod exopod slightly shorter than endopod. Until the microstructures on the present material, especially setation on the pereopods, have been examined, it remains uncertain whether they belong to the same species as A. gerlachi. These A. cf. gerlachi specimens from Singapore are very small with body length ranging between 0.7 – 1.2 mm, making them the smallest tanaidacean species recorded from local waters. This species was found only from intertidal macroalgal turfs on seawalls at Lazarus Island, Pulau Hantu and Sentosa (Pulau Blakang Mati) in the Singapore Strait.	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFCC556DE1AEF92D7E285AD0.taxon	discussion	Remarks. The genus Zeuxo belongs to the tribe Anatanaini Sieg, 1980, which is defined by the (1) pleonite- 5 not being fused with the pleotelson; (2) labial palp not being as reduced; and (3) third pair of pleopods not being smaller than pleopods 1 – 2 (Bird 2008). Distinguishing the three genera within Anatanaini is problematic due to the overlap of diagnostic characters (Bamber 2008 c; Bird 2008; Edgar 2008). Nevertheless, Anatanais Nordenstam, 1930 is generally characterised by its relatively short antennule article- 1 that is about two times longer than article- 2 (Sieg 1980) while Zeuxoides Sieg 1980 can be differentiated by its relatively short terminal uropod article that is less than half length of the preceding article (Edgar 2008). To date, Zeuxo is represented by 40 species (Anderson 2023) that are widely distributed in shallow habitats (intertidal to 52 m depth) of the world’s oceans, except at the poles (Larsen 2014; Kakui & Shimada 2022). Zeuxo westwoodiana Templeton, 1840 from Mauritius is the type species of the genus. This increasingly species-rich genus Zeuxo is possibly polyphyletic (Bird 2008), and the taxonomic difficulties associated with this taxon have been discussed extensively (Larsen 2014; Larsen et al. 2014; Bird 2019). Keys to identify Zeuxo species are available but only for a small number of species (Sieg 1980; Edgar 2008; Wi et al. 2016).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFCD556EE1AEF9157DE95880.taxon	description	(Figs. 23 A – C)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFCD556EE1AEF9157DE95880.taxon	materials_examined	Material examined. Station SG 42: 1 ovigerous female (SA 11 - 003). Station SG 46: 1 male (SS- 6291). Station SG 60: 2 females (INT- 1181). Station SG 67: 2 females (1 with oostegites) (INT- 0890).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFCD556EE1AEF9157DE95880.taxon	discussion	Remarks. The present material resembles Z. coralensis in having (1) three aesthetascs on the antennule terminal article; (2) plumose lateral setae on pleonites 1 – 3 and simple lateral setae on pleonites 4 – 5; and (3) three articles on the uropod endopod. However, these Singaporean specimens are much smaller than Z. coralensis (1.4 – 1.8 mm vs. 3 – 4.5 mm) that was originally described from the Maldives at 4 m depth (Sieg 1980). While body length is mostly conservative in Zeuxo species, large intraspecific variation in body size has been demonstrated in at least one species. For example, Z. beringi Kudinova-Pasternak, 1989 has a size range of 1.8 – 4.9 mm. However, the Singaporean specimens have dotted pigmentation throughout the body (Figs. 23 A – C), a condition that is not shared with Z. coralensis. This pattern has been documented in only one congener, namely Z. nannioggae Bamber, 2005 from the Great Australian Bight but this species bears one aesthetasc on the antennule terminal article and four articles on the uropod endopod (Bamber 2005). The usefulness of pigmentation pattern as a taxonomic character for distinguishing Zeuxo species has been embraced by several workers (Edgar 2008; Bamber et al. 2012; Okamoto et al. 2020; Okamoto & Kakui 2022) but also dismissed by Larsen et al. (2014). Until the type specimens of Z. coralensis have been examined, it remains uncertain whether the Singaporean specimens belong to the same species as the ones from the Maldives. It is important to note that the original description of Z. coralensis also included material from Japan (Kakui 2017). Subsequent observations of this species were recorded from mangroves, rocky shores, marine caves, and ship hulls in the Atlantic Ocean: Spain (Sánchez-Moyano & García-Gómez 1998; Navarro-Barranco et al. 2015), Brazil (Masunari & Sieg 1980; Pires 1980; Tararam et al. 1996; Aviz et al. 2012; Bueno et al. 2015; García et al. 2015), Mexico (Winfield et al. 2013, 2017) and Florida, USA (Camp 1998). The wide geographical distribution of Z. coralensis suggests that it is either a cosmopolitan species or a species complex. In Singaporean waters, Zeuxo cf. coralensis was collected from the intertidal coral reefs of the Southern Islands (i. e., Lazarus Island, Pulau Biola, Pulau Sudong and St. John’s Island).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC85574E1AEFAD57AB05FCC.taxon	description	(Figs. 26 A – B)	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC85574E1AEFAD57AB05FCC.taxon	materials_examined	Material examined. Station SG 74: 1 manca (BNC- 002). Station SG 75: 2 mancae (BNC- 046). Station SG 76: 2 non-ovigerous females, 1 male (BNC- 070). Station SG 77: 2 females (BNC- 085, 089). Station SG 78: 8 females, 1 male, 9 mancae (BNC- 205, 206, 207, 209, 214 and 221).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
03ED8786FFC85574E1AEFAD57AB05FCC.taxon	discussion	Remarks. Xenosinelobus is a monotypic genus (Anderson 2023). It is very similar to its sister genus Sinelobus but can be easily distinguished by the (1) unusually short antenna article- 5; (2) presence of a spiniform seta on pereopod- 1 coxa and; (3) complete row of dorsotransverse setae on pleonites 1 and 2 (Chim & Tong 2019). Xenosinelobus balanocolus is a small species with body length barely more than 2 mm. It is the first tanaid species to be recorded from the inside of barnacles (Chim et al. 2016). Pigmentation on its cephalothorax is similar to that of Zeuxo sp. SG # 1 but with honeycomb pattern instead of a band between the eyes. Xenosinelobus balanocolus is known only from the inside of dead Tetraclita barnacles on the rocky shores and seawalls of Singapore Southern Islands (i. e., Lazarus Island and St. John’s Island).	en	Kong, Chim Chee (2024): A synopsis of the Tanaidacea (Crustacea: Peracarida) of Singapore, with a review of tanaidacean diversity in Southeast Asia and the South China Sea. Zootaxa 5451 (1): 1-75, DOI: 10.11646/zootaxa.5451.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5451.1.1
