Poligarida beni Bamber & Marshall, 2013

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 : 32-33

Poligarida beni Bamber & Marshall, 2013

( Figs. 16A–B )

Poligarida beni Bamber & Marshall, 2013: 256–262 , figs. 1–4.

Material examined. Station SG25: 2 incomplete specimens (CR1209-P08-01), 3 December 2009.

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. 16B ); (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 SG25 (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.

Figures

FIGURE 2. Sampling stations in the West Johor (red), East Johor (green) and Singapore (blue) Straits, Singapore. Refer to Table 1 for details. This map was modified from nautical chart GSP1 ‘Anchorages and Aids to Navigation’ (Maritime Port Authority of Singapore 2012).

FIGURE 16. Poligarida beni Bamber & Marshall, 2013, CR1209- P08-01, from Singapore: (A, B) dorsal and ventral habitus, respectively, of non-ovigerous female, with inset showing rostrum (arrow) bearing three terminal tubercles. Scale bar = 500 µm.