Pagurapseudes 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 : 22-23

Pagurapseudes sp. SG#1

( Figs. 9A–C )

Material examined. Station SG66: 1 male and 1 female inside cerithiid gastropod shells (ARM-0622). Station SG82: 1 specimen (TR-2521). Station SG83: 1 lost specimen (TR-2516).

Remarks. Members of the subfamily Pagurapseudinae are known to inhabit gastropod shells, in much the same way as hermit crabs ( Bird & Webber 2015). Pagurapseudes can be distinguished from its sister genera Macrolabrum Băcescu, 1976b and Pagurotanais Bouvier, 1918 by possessing a combination of the following characters: (1) the presence of an exopod on pereopod-1; (2) the presence of well-developed pleopod rami, both of subequal length and linguiform; and (3) the epistome not exceeding the anterior margin of the cephalothorax. All 13 Pagurapseudes species occur in shallow waters of the Indo-West Pacific ( Whitelegge 1901; Brown 1956; Băcescu 1976a, b; Guţu 1992, 1997; Kazmi & Siddiqui 2001; Bamber 2007, 2009; Błażewicz-Paszkowycz & Bamber 2012), except for Pagurapseudes inquilinus Bamber, 2007 , which was found in the bathyal depths of 440–450 m in New Caledonia ( Bamber 2007). Guţu (1997) provided identification key to nine species of the genus, primarily based on characters on the antennule, cephalothorax, pereopod-1 basis and pereopod-2 propodus.

These specimens from Singapore are most similar to P. dentatus ( Brown, 1956) from South Africa based on the (1) setation and spination on the lateral margins of the cephalothorax, the inner margin of the antennule peduncle article-1 and the ventrodistal margin of pereopod-1 propodus; and (2) number of articles on the antennule and the antenna. However, the rostrum of Pagurapseudes sp. SG#1 is elongated, a condition that is present in only one congener, which is P. tricoliae Băcescu, 1976a from Tanzania. Pagurapseudes sp. SG#1 is a different species as P. tricoliae as the lateral margins of the cephalothorax of P. tricoliae bear spiniform setae as well as more plumose setae. This potentially undescribed species was collected from hard substrates (e.g., corals and rocks) around offshore islands (e.g., Pulau Salu, Pulau Satumu and St. John’s Island) in the Singapore Strait at 5–43 m depth.

Figures

FIGURE 9. Pagurapseudes sp. SG#1, Singapore: (A, B) adult males, dorsal and lateral habitus, respectively; (C) tanaidacean (arrow) inside gastropod shell. A: TR-2521; B–C: ARM-0622. Scale bar = 1 mm.