Brachylicoa sp.

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), pp. 1-75 : 29-32

Brachylicoa sp. SG#1

( Figs. 14A–C )

Material examined. Station SG23: 1 specimen (CR1115-P06-02), 3 November 2015. Station SG47: 1 male (INT-0090). Station SG51: 1 ovigerous female (SEA-3483). Station SG55: 1 ovigerous female (SEA-7307). Station SG59: 1 ovigerous female (SUB-0386). Station SG63: 1 male and 1 female (ARM-0209). Station SG68: 1 damaged subadult male (SUB-1020). Station SG89: 1 incomplete manca (LAZ-PRO-02.5-TAN03). Station SG91: 1 male (SEN-PRO-0.0-TAN01), 1 incomplete female with eggs (SEN-PRO-0.0-TAN02), 1 incomplete female (SEN-PRO-0.0-TAN03), 6 incomplete specimens, including 4 adults and 2 mancae (SEN-PRO-0.0-TAN04), 1 incomplete female with eggs (SEN-PRO-2.5-TAN01), 1 incomplete adult (SEN-PRO-2.5-TAN02),1 incomplete adult (SEN- PRO-2.5-TAN03) and 1 incomplete adult (SEN-PRO-2.5-TAN04); 1 incomplete adult (SEN-PRO-07.5-TAN10); 4 incomplete adults (SEN-PRO-10.0-TAN10).

Remarks. Guţu (2006) erected the genus Brachylicoa and designated Saltipedis muelleri Guţu, 1998b as the type species. The name of the taxon refers to the shortness of the pleon, which is also characteristic of Platylicoa . These two genera can be distinguished by the presence of a dorsotransverse row of setae on pleonite- 1 in Platylicoa and the lack of it in Brachylicoa (Guţu 2006) . In the revised genus diagnosis by Morales-Núñez et al. (2017), the following generic characters were found to be useful for reliably distinguishing Brachylicoa from all other known parapseudid genera: (1) the presence of a crown of setulate spiniform, lanceolate setae near the distal margin on the propodus of pereopod-4; and (2) the presence of one or two spiniform seta on the inner distal corner of the maxilliped basis. Brachylicoa is currently represented by four species ( Anderson 2023), namely B. muelleri , B. indonesiana Guţu, 2006 , B. estasiatica Guţu, 2007 and B. lui Morales-Núñez, Ulrich & Heard, 2017 . Morales-Núñez et al. (2017) provided a key to separate these four species, mainly based on characters on the rostrum, mandible palp, pereopod-6 and pleopod-1. The distribution of Brachylicoa is restricted to the Indian and Pacific Oceans, specifically Tanzania, Malaysia, Indonesia and Hawaii, at 2.5–7 m depth where bathymetric information is available ( Guţu 1998b, 2006, 2007; Morales-Núñez et al. 2017).

Even though most of these specimens from Singapore are incomplete, they can be easily identified as Brachylicoa due to the short pleon and the absence of a dorsotransverse row of setae on pleonite-1. Brachylicoa sp. SG#1 cannot be identified as any known species based on the key in Morales-Núñez et al. (2017). The absence of ventral spiniform seta on the cheliped basis of females further distinguishes Brachylicoa sp. SG#1 from its congeners. Brachylicoa sp. SG#1 is generally large reaching up to 6.4 mm in body length, but individuals as small as 1.6 mm were found among the intertidal turf algal assemblages. This potentially undescribed species was widely distributed in the Southern Islands and vicinity (i.e., Beting Bemban Besar, Lazarus Island, Pulau Semakau, Sentosa, St. John’s Island and Terumbu Hantu) from intertidal to 15 m depth. This species was also found off East Coast along the Singapore Strait at 28–54 m depth and Punggol Point along the East Johor Strait at 11 m depth.

Genus Longiflagrum Guţu, 1995

Figures

FIGURE 14. Brachylicoa sp. SG#1, Singapore: (A) ovigerous female, SEA-3483, dorsal habitus; (B) ovigerous female, SUB- 0386, lateral habitus; (C) adult male with detached appendages, dorsal habitus, INT-0090. Scale bar = 2 mm.