Cuapetes nilandensis ( Borradaile, 1915 )

Okuno, Junji & Chan, Tin-Yam, 2012, A new antipatharian-associated species of the genus Cuapetes Clark, 1919 (Crustacea: Decapoda: Palaemonidae) and a new record of C. nilandensis (Borradaile, 1915) from Japan *, Zootaxa 3367 (1), pp. 115-125 : 122-124

Cuapetes nilandensis ( Borradaile, 1915)

( Figs. 5 , 6B, C )

Periclimenes (Falciger) nilandensis Borradaile, 1915: 211 ; Borradaile 1917: 324, pl. 54, fig. 3.

Periclimenes (Ancylocaris) nilandensis — Kemp 1922: 172.

Periclimenes (Harpilius) nilandensis — Holthuis 1952: 58–60, fig. 22.

Periclimenes nilandensis — Bruce 1978: 222–227, figs. 8, 9; Bruce 1981: 18; Chace & Bruce 1993: 118–119; Bruce & Coombes 1995: 132; Li 2000: 214, fig. 278.

Kemponia nilandensis — Bruce 2004: 18 ; Li et al. 2004: 531–532 ; Li & Bruce 2006: 647–648 ; Marin & Savinkin 2007: 181–182, fig. 85D in colour.

Cuapetes nilandensis — Okuno 2009: 67.

Material examined. Kume Island. NTOU M01237 , 1 ovigerous female, CL 3.0 mm, NTOU M01384 , 1 male, 1 female, 6 ovigerous females, CL 2.5–3.0 mm, trawl 31, 75.3– 70.4 m, 26°18.785ʹN 126°53.249ʹE – 26°18.904ʹN 126°53.563ʹE, 13 November 2009 . Okinawa Island. CMNH-ZC 01969 , 1 male, 3 females, 2 juveniles, CL 0.9–2.0 mm, Seragaki, Onna Village , 48.5 m, in association with Parantipathes tenuispina Silberfeld, 1909 ( CMNH-ZG 4287 ), 13 August 2004 , coll. T. Yanagisawa; CMNH-ZC 01898 , 1 male, CL 1.4 mm, 1 female, CL 1.7 mm, CMNH-ZC 01899 , 1 female, CL 2.0 mm, Seragaki, Onna Village , 48–50 m, in association with an unidentified antipatharia, 4 May 2005 , coll. T. Yanagisawa. CMNH-ZC 02412 , 1 ovigerous female, CL 2.4 mm, RUMF-ZC- 1581, 2 females, CL 2.0, 2.4 mm, Kyoda, Nago , 30 m, in association with an unidentified antipatharian, 19 November 2010, coll. M. Tsuchiya and Y. Yamada.

Colouration ( Fig. 6B, C ). Body generally transparent. Carapace and rostrum covered with white dots; thoracic sternites vermilion; abdominal somites also with white dots, dorsal midline salmon pink, ventral midline red. Eyestalk salmon pink, cornea white. External margin of antennal scaphocerite red. All prereiopods with bases reddish, palm of second pereiopod reddish-brown.

Common name. Sabachi-tenaga-kakure-ebi (new standard Japanese name).

Distribution. Type locality: South Nilandu Atoll, Maldive Islands, Indian Ocean ( Borradaile 1915). Also known from Madagascar ( Bruce 1978; Li & Bruce 2006), Réunion ( Li & Bruce 2006), Indonesia ( Holthuis 1952), Vietnam ( Marin & Savinkin 2007), Beibu Bay, South China Sea ( Li et al. 2004), Japan (present study), Australia ( Bruce 1981; Bruce & Coombes 1995), and New Caledonia ( Li & Bruce 2006).

Remarks. The specimens examined here are identified with Cuapetes nilandensis on account of the following features: Carapace ( Fig. 5A, B ) armed with a supraorbital spine, pterygostomial margin furnished sparsely with long setae; rostrum ( Fig. 5B ) nearly horizontal but dorsally sinuous distally, slightly overreaching scaphocerite, 1.0–1.5 times as long as carapace, armed dorsally with 7–10 equidistant teeth, posterior-most tooth situated slightly posterior to orbital margin, ventrally with 3–5 teeth; fourth thoracic sternite ( Fig. 5C ) with an acute median process; second pereiopod ( Fig. 5D ) without distoventral tooth on merus, with carpus shorter than merus; ambulatory pereiopods with propodi ( Fig. 5E ) armed distoventrally with long spines, about half as long as dactylus. The long spines on the propodi are especially diagnostic, as all other congeners have markedly shorter spines.

Most species of Cuapetes are free-living, but some of them are known as to be associated with Hexacorallia: C. amymone (De Man, 1902) and C. kororensis Bruce, 1977 , are obligatory associates of scleractinian corals, whilst C. lanceolatus (see above) and C. nilandensis are associated with antipatharian corals ( Bruce 1998, 2004). The host specificity of C. nilandensis appears to be low, as it has also been recorded from Hydrozoa ( Bruce 1981) and Octocorallia, such as gorgonians ( Bruce 1978, 2004) and alcyonarians ( Marin & Savinkin 2007). Part of the present specimens catalogued as CMNH-ZC 01969 were found on Parantipathes tenuispina collected together with the pandalid shrimp, Chlorotocella gracilis Balss, 1914 (CMNH-ZC 01970, 1 female) and the trapeziid crab, Quadrella maculosa Alcock, 1898 (CMNH-ZC 01971, 1 male and 1 female).

The present specimens represent the first record of C. nilandensis from Japan, also being the northern-most limit of its known geographical range.

Figures

FIGURE 5. Cuapetes nilandensis (Borradaile, 1915). Ovigerous female, CL 2.9 mm, NTOU M01384 (A, B, D, E), female, CL 2.0 mm, CMNH-ZC 01899 (C). A, anterior part of carapace, rostrum and cephalic appendages, lateral view; B, anterior part of carapace and rostrum, lateral view; C, fourth thoracic sternite, ventral view; D, right second pereiopod, lateral view; E, propodus and dactylus of right third pereiopod, lateral view. Scale bars: A, B, D, 1.0 mm; C, 0.1 mm; E, 0.5 mm.

FIGURE 6. A, Cuapetes lanceolatus n. sp. Holotype, female (ova detached by collecting shock), CL 3.0 mm, RUMF-ZC- 01579. In situ, associated with an unidentified antipatharian at Umagai, Kume Island, 25 m, 29 October 2002 (photo T. Kawamoto). B, C, Cuapetes nilandensis (Borradaile, 1915). B, ovigerous female, CL 3.0 mm, NTOU M01237, fresh specimen, lateral view (photo T.-Y. Chan); C, in situ, associated with an unidentified antipatharian at Kyoda, Nago, Okinawa Island, 30 m, November 2010 (photo Y. Yamada).