Ensiger custoides (Bruce, 1977)

de Gier, Werner & Fransen, Charles H. J. M., 2023, Polka-dotted treasures: Revising a clade of ascidian- and bivalve-associated shrimps (Caridea: Palaemonidae), Contributions to Zoology 92 (3), pp. 179-282 : 220-223

Ensiger custoides (Bruce, 1977)

(figs. 20A–C, 21–22)

Anchistus inermis – Kubo, 1940: 48–51, figs. 15–17.

Anchistus custos – Holthuis, 1952: 106 (pro parte); Miyake & Fujino, 1968: 415–417.

Anchistus custoides Bruce, 1977a: 47 , figs. 4–6 [Type locality: north-west end, Gillett Cay, Great Barrier Reef, 21°43’S 152°25’E, in bivalve mollusk Atrina vexillum according to Springthorpe & Lowry, 1994]; Bruce, 1981c: 2-3; Bruce, 1983b: 892; Bruce, 1983c: 199 (listed); Bruce, 1990: 15, 18 (listed); Müller, 1993: 7 (listed); Bruce, 1993: 56; Chace & Bruce, 1993: 72 (listed); Fransen, 1994a: 108, 110, 111 (listed); Britayev & Fachrutdinov, 1994: 124, fig. 2D-F;

De Grave, 1999: 128, fig. 2; Li, 2000: 7, fig.7 side, depth 30 m, SCUBA diving, 3.x.1994, (listed); Hayashi, 2002: 222, figs. 432c–e, 434c, in Atrina vexillum (Born) (Ø 35 cm), coll.

d, 435c, d; Bruce, 2003b: 210 (listed); Hayashi, C.H.J.M. Fransen. – 1 ovigerous female pocl.

2006: 115; Marin & Savinkin, 2007: table 2, 3 7.5 mm ( RMNH. CRUS.D.46643), SW Sulawesi, (listed); Bruce, 2010a: 63 (listed); De Grave & Spermonde Archipelago, Barang Lompo, NW Fransen, 2011: 340 (listed); Fransen & Reijnen, side, 23.ix.1994, depth 20 m, SCUBA diving, in 2012; Gan et al., 2015:3, fig.1; Anker & De Grave: A. vexillum (Ø 25 cm), coll. B.W. Hoeksema. – 2016: 406, fig. 72; Horká et al., 2016: 6, figs. 1m, 1 ovigerous famel pocl. 5.6 mm, 1 male pocl .

2–4; Chow et al., 2021: table A.1 (listed); Idris et 2.6 mm ( RMNH. CRUS.D.53610; GenBank al., 2022: 136–148, figs. 4–5. OQ603090 ( COI)), stn TER.36, off Halmahera Material examined. INDONESIA: 1 ovi- mainland, Teluk Dodinga E, N of Pulau Jere, gerous female pocl. 9.09 mm ( RMNH. 0°50’47.8”N 127°37’48.7”, 13.xi.2009, depth 2 CRUS.D.41440), Snellius II Expedition sta. m, SCUBA diving, muddy bay shallow area 4.079, E of Komodo, Selat Linta, 8°35’S with coral cover and rubble, in A. vexillum , 119°34.2’E, 18.ix.1984, snorkeling, coastal reef coll. A. Gittenberger, fcn. CF-00123, photo flat, in large Pinna sp. (also collected). – 1 TER.36.0086-91. – 2 ovigerous females pocl.

male pocl. 5.79 mm ( RMNH. CRUS.D.41441), 5.7 and 7.0 mm, 1 male pocl. 3.9 mm ( RMNH.

Java, off Jakarta, Seribu Archipelago, Kongsi CRUS . D.53615), stn TER.38, off Halmahera Island , 26.vi.1973, sandy bottom, coll. Sapri D, mainland, Teluk Dodinga, Karang Galiasa don. PPPO . – 1 ovigerous female pocl. 6.17 mm Besar E, 0°50’45.6”N 127°35’7.4”E, 14.xi.2009, ( RMNH. CRUS.D.41442) , Java, off Jakarta, depth 2 m, SCUBA diving, exposed shal- Seribu Archipelago, Pari Island , 27.i.1973, low reefflat followed by a sloping reef with coll. Sukardi, don. PPPO . – 1 ovigerous female coral and rubble,in A. vexillum , coll. C.H.J.M.

pocl. 8.47 mm ( RMNH. CRUS.D.41443), Seram Fransen, fcn. CF-00128, photo TER.38.0048- Island, Piru Archipelago, Piru Bay , 03°04’45”S 57. – 1 ovigerous female pocl. 9.0 mm, 1 male 128°11’27”E, 10.vi.1975, coll. A.H. Banner & pocl. 3.5 mm ( RMNH. CRUS.D.49844; GenBank D.M. Banner, Rumphius II Expedition, don. OQ600398 (16S)), stn BAL.32, Bali, N side of PPPO, fcn. CM 334 . – 1 ovigerous female pocl. Nusa Penida, off Tukad Adegan, 08°40’32”S 6.49 mm ( RMNH. CRUS.D.41444), Ambon 115°31’18”E, 20.iv.2001, SCUBA diving to 30 m Island, Ambon Bay, Tantoci, 3.vi.1975, coll. depth, deep reef slope with patches of sand, M.K. Moosa, A.H. Banner & D.M. Banner, in large Atrina sp. , coll. Angus, film 32. – 1 Rumphius II Expedition, don. PPPO, fcn. male pocl. 4.6 mm, 2 ovigerous females pocl .

CM 195 . – 1 ovigerous female pocl. 9.22 mm 5.9 and 8.2 mm ( RMNH. CRUS.D.58029), stn ( RMNH. CRUS.D.8996), Kera Island near LEM.29, NE Sulawesi, Lembeh Strait, Teluk Timor , 11-13.xi.1929, Snellius I Expedition Walemetodo, 1°24’11.3394”N 125°10’20.3154”E, 1929-1930, published in Holthuis, 1952: 106 as 15.ii.2012, depth 5 m, in each pair in an A.

Anchistus custos . – 1 ovigerous female pocl. vexillum , coll. C.H.J.M. Fransen. – 1 oviger- 6.2 mm ( RMNH. CRUS.D.46640), stn SUL.10, ous female pocl. 8.4 mm, 1 male pocl. 4.5 mm

N Sulawesi, Selat Lembeh, Pulau Lembeh, ( RMNH. CRUS.D.58065), stn RAJ.08, W

W of Kelapadua, 01°26’N 125°13’E, 17.x.1994, Papua, Raja Ampat Islands, Mioskon Island , large Acropora field, scuba diving to 20 m, 00°29.808’S 130°43.623’E, 21.xi.2007, depth

in Atrina vexillum (Born) , coll. J. Goud. – 1 3 m, SCUBA diving, in A. vexillum , coll. B.W.

ovigerous female pocl. 7.4 mm, 1 male pocl. Hoeksema, fcn. CF025. – 1 ovigerous female 3.4 mm ( RMNH. CRUS.D.46641), SW Sulawesi, pocl. 5.5 Downloaded mm ( RMNH from Brill. CRUS.com. 06 D/.58066 24/2024)12,:38 stn:05 AM Spermonde Archipelago, Pulau via Badi Open, NNW Access. This SER is.24an, Java open Sea access, Kepulauan article distributed Seribu (Thousand under the terms of the CC-BY 4.0 license. https://creativecommons.org/licenses/by/4.0/ Islands), off Jakarta, Kotok Kecil Island , – 1 male pocl. 3.9 mm, 1 ovigerous female pocl .

NW-side, 5°41’20”S 106°32’01”E, 16.ix.2005, 5.3 mm ( RMNH. CRUS.D.48352), Stn CEB.12, depth 15 m, SCUBA diving, in A. vexillum , coll. Cebu Strait, W of Bohol , NE side of Sandingan C.H.J.M. Fransen, photo film 11. – 1 ovigerous Island, 9°51.53’N 123°48.81’E, 15.xi.1999, female pocl. 8.5 mm ( RMNH. CRUS.D.58067), depth 3–5 m, SCUBA diving, sand with coral

stn SER.30, Java Sea, Kepulauan Seribu patches, in A. pectinata , coll. C.H.J.M. Fransen.

(Thousand Islands), off Jakarta , Tikus Island, VANUATU: 2 males pocl. 4.7 and 4.9 mm, 3 S-side, 5°51’55”S 106°34’55”E, 18.ix.2005, females pocl. 7.8, 8.5 and 9.4 mm ( RMNH.

depth 20 m, SCUBA diving, in A. vexillum, CRUS.D. 58070), stn DR11, Aoré Island, off port

coll. C.H.J.M. Fransen, photo film 16. – 1 Lautour, 15°21’58”S 167°06’02”E, 12.ix.2006,

male pocl. 4.0 mm ( RMNH. CRUS.D.58068), SCUBA diving, hand picked, 2 pairs and a

stn SER.30, Java Sea, Kepulauan Seribu single female in 3 A. vexillum – 1 ovigerous (Thousand Islands), off Jakarta, Tikus Island, female pocl. 7.5 mm, 1 male pocl. 4.5 mm S-side, 5°51’55”S 106°34’55”E, 18.ix.2005, ( RMNH. CRUS.D.58071), stn DB13, no further depth 20 m, SCUBA diving, in A. vexillum , data, 13.ix.2006, depth unknown, SCUBA div-

coll. C.H.J.M. Fransen, photo film 16. – 1 ing, in Atrina sp. , coll. C.H.J.M. Fransen, fcn.

male pocl. 4.6 mm, 1 ovigerous female pocl. CF29, photo T.-Y. Chan. – 1 ovigerous female

7.0 mm ( RMNH. CRUS.D.58069), stn BER.06, pocl. 7.6 mm ( RMNH. CRUS.D.58072), stn

NE Kalimantan, Berau Islands, shoal between FR12, S Aoré Island, W Ratua Island , 15°22’07”S Lighthouse-2 reef and Derawan Island , 167°06’17”E, 15.ix.2006, depth 0–3 m, snor- 02°12’08.6”N 118°11’34.9”E, 5.x.2003, depth 10 keling, in A. vexillum , coll. C.H.J.M. Fransen ,

m, SCUBA diving, in A. vexillum , coll. C.H.J.M. fcn. CF51. – 2 ovigerous females pocl. 6.5 Fransen. MALAYSIA: 1 male pocl. 3.3 mm and 7.7 mm ( RMNH. CRUS.D.58073), stn H1, ( RMNH. CRUS.D.53810; GenBank JX 185712), Vanuatu maritime College, 22.ix.2006, hand

stn SEM.24, Sabah, Semporna area, Bumbun picked, intertidal, mangrove environment,

Isl., 04°26’54.1”N 118°46’31.0”E, 7.xii.2010, in 2 separate bivalves. – 1 ovigerous female depth 3 m, SCUBA diving, in A. vexillum , coll. pocl. 9.0 mm, 1 male pocl. 4.7 mm ( RMNH.

B. T. Reijnen. – 1 male pocl. 3.6 mm ( RMNH. CRUS.D.58074), stn DR68, no further data , CRUS.D.53795; GenBank JX 185710), sta. 26.ix.2006 .

SEM.22, Sabah, Semporna area, Mata Pahi Isl. , Diagnosis. Rostrum broad proximally, com- 04°27’40.7”N 118°38’09.1”E, 5.xii.2010, depth 3 pressed distally, almost triangular in dorsal

m, SCUBA diving, in A. vexillum , coll. C.H.J.M. view, strongly bent downwards (especially in Fransen.–1 non ovigerous female pocl. 3.4 mm females), reaching distal segment of anten- ( RMNH. CRUS.D.53807; GenBank OQ 603091 nular peduncle, with 4–8 obtuse dorsal dis- ( COI)) , stn SEM.56, Sabah, Semporna area, tal teeth, ventral margin unarmed, distally Silawa Isl. , 04°34’29.8”N 118°33’59.6”E, rounded, lateral carina feebly developed .

17.xii.2010, depth 4 m, SCUBA diving, in A. vex- Inferior orbital angle produced. Antennal illum, coll. C.H.J.M. Fransen. PHILIPPINES: spine present. Antero-lateral angle of the car-

1 male pocl. 3.2 mm, 1 ovigerous female pocl. apace broadly rounded, produced. Anterior

5.9 mm ( RMNH. CRUS.D.48353), Stn CEB.12, margin of carapace between ventral orbital Cebu Strait, W of Bohol, NE side of Sandingan angle and antero-lateral angle sinuate. Sixth Island , 9°51.53’N 123°48.81’E, 15.xi.1999, depth abdominal segment with posterior ven-

3–5 m, SCUBA diving, sand with coral patches, tral angle acute. Telson with dorsal spines

in Atrina pectinata (L.), coll. C.H.J.M. Fransen. at 0.75 and Downloaded 0.88 of from length Brill.. Basal com 06segment /24/2024 12of:38:05 AM via Open Access. This is an open access article distributed under the terms of the CC-BY 4.0 license. https://creativecommons.org/licenses/by/4.0/ antennular peduncle with one or two distolateral teeth, lateral margin slightly convex. Scaphocerite with convex lateral margin; shallow slit between distolateral spine and lamina. Third maxilliped with robust penultimate segment and broad antepenultimate segment. Basis and ischium of first pereiopod with row of long slender setae along their ventral margins; chela sub-cannulate, slightly sub-spatulate, palm with row of long plumose setae on opposite sides; cutting edges minutely pectinate in distal half. Second pereiopods relatively small with slender fingers; dactylus with one or two small teeth in proximal half; fixed finger with 4–7 small teeth in proximal half; palm without tympanal organ. Ambulatory pereiopods with dactylus simple, not biunguiculate; reflected margin of corpus with transverse ridges; unguis sparsely provided with small triangular flattened scale-like spinules.

Remarks. The female specimen collected at sta. 4.079 of the Snellius II expedition ( RMNH. CRUS.D.41440) shows two closely set distolateral teeth on the basal segment of the antennular peduncle (fig. 21C). The same specimen has bifurcated tips on the intermediate pair of terminal spines of the telson (fig. 21D) The specimen collected at Kongsi Island ( RMNH. CRUS.D.41441) has two teeth on the left and one tooth on the right basal segment of the antennal peduncle, while the other specimens have one distolateral tooth on both sides as described for the type material (Bruce, 1977a: 47). The second pereiopods are usually small in relation to the carapace length and subequal.

Re-examination of Snellius I material described by Holthuis, 1952 yielded one ovigerous female ( RMNH. CRUS.D.8996) identified as A. custos which belong to A. custoides .

Colour (figs. 20A–C). Specimens are translucent with numerous small red and white chromatophores all over the body, giving it an orange appearance. The cornea is strongly reflecting, colouring silver.

Hosts. Recorded from Pinnidae : Atrina vexillum (Born, 1778) (Miyake & Fujino, 1968; Bruce, 1977a, 1981c; De Grave, 1999; Hayashi, 2002, 2006; Fransen & Reijnen, 2012; Idris et al., 2022); Pinna atropurpurea G.B. Sowerby I, 1825 (Anker & De Grave, 2016); Pinna bicolor Gmelin, 1791 (Britayev & Fachrutdinov, 1994; De Grave, 1999; Hayashi, 2006; Idris et al., 2022); Pinna deltodes Menke, 1843 (Idris et al., 2022); Pinna muricata L., 1758 (Idris et al., 2022); Pinna sp. (Bruce, 1993). Also from Pteriidae : Pteria (Avicula) sp. (Bruce, 1983c). Now for the first time recorded from Atrina pectinata (L., 1767).

Distribution. Gillett Cay, Swains Reefs, One TreeIsland,CapricornGroup, Australia (Bruce, 1977a); Heron Island, Australia (Bruce, 1981c); Caroline Islands, Palau (Kubo, 1940; Miyake & Fujino, 1968); Seram Island, Indonesia (Bruce, 1983c) ; Sabah, Malaysia (Fransen & Reijnen, 2012); Johor, W Malaysia (Idris et al., 2022); Singapore (Anker & De Grave, 2016); Tre Island, Vietnam (Bruce, 1993); Hainan, China (Gan et al., 2015); Okinawa, Japan (Horká et al., 2016); Japan (Hayashi, 2002, 2006). Now recorded for the first time from various localities in Indonesia: Ambon Island, Kera Island near Timor, Selat Linta E of Komodo, the Seribu Archipelago off North Java, Bali, NE and SW Sulawesi, Teluk Dodinga (off mainland Halmahera), W Papua (Raja Ampat), and NE Kalimantan (Berau Islands). Additionally, now also newly recorded from Vanuatu and the Philippines (Cebu Strait).