Aparatanais 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 : 39-40

Aparatanais sp. SG#1

( Figs. 21A–B )

Material examined. Station SG 6: 1 specimen ( ZRC.1992.6636–6642). Station SG 26: 1 specimen (CR0514-PS06- 03-03), 5 May 2014; 1 specimen (CR0515-PS06-03-02), 14 May 2015; 1 damaged specimen (CR1117-PS06-02- 03), 6 November 2017. Station SG 38: 1 specimen (4412TB1-123) .

Remarks. Bird & Bamber (2013) erected the genus to accommodate five species that were previously classified in Paratanais , and designated P. spinanotandus Sieg, 1981 from Seamount Vema, South Atlantic Ocean as the type species. The split was largely based on the presence of a stout dentate or spinulate spiniform seta on the inner margin of maxilliped palp article- 2 in the females of Aparatanais . Other generic characters include the kukri-shaped spine on the cheliped palm and relatively short uropods. Aparatanais is currently represented by nine species ( Anderson 2023), which are widely distributed in the shallow waters (intertidal to 80 m depth) of the Atlantic and Pacific Oceans ( Sieg 1981; Guţu & Ramos 1995; Dojiri & Sieg 1997; Larsen 2001; Błażewicz-Paszkowycz & Bamber 2012; Larsen et al. 2012; Bird & Bamber 2013; Tzeng & Hsueh 2014b; Bird 2015; Morales-Núñez et al. 2016). The only exception is A. intermedius ( Dojiri & Sieg, 1997) , which inhabits the bathyal depths, from 98 to 591 m. Morales-Núñez et al. (2016) provided a key to the six Aparatanais species that have a long setulose seta on the epimeral margins of pleonites 1–4.

The specimens from Singapore are most similar to A. lenoprimorum Tzeng & Hsueh, 2014b , which was originally described from Taitung, Taiwan, but have (1) a wider pereopod-1 basis; (2) long seta on pereopod-1 carpus; (3) a pereopod-5 basis without plumose setae; and (4) longer propodi on pereopods 4 and 5. Based on these morphological differences, Aparatanais sp. SG#1 is a potentially undescribed species. This tanaid, measuring up to 3.7 mm in body length, is the second largest tanaidomorphan recorded from Singapore. It is a rare species and was collected only from three stations in the Southern Islands of Singapore, on sandy substrates at 13–26 m depth.

Figures

FIGURE 21. Aparatanais sp. SG#1, non-ovigerous females, Singapore: (A) dorsal habitus, CR0515-PS06- 03-02; (B) lateral habitus, 4412TB1-123. Scale bar = 500 µm.