Description of two new species of Arcania Leach, 1817, from the western Pacific Ocean and redescriptions of A. undecimspinosa De Haan, 1841, and A. elongata Yokoya, 1933 (Crustacea: Brachyura: Leucosiidae) Author Naruse, Tohru text Zootaxa 2014 3814 3 301 332 journal article 45542 10.11646/zootaxa.3814.3.1 1705c8e5-ed72-40c1-ae4f-26b058f9b8ff 1175-5326 228871 09BB2494-86F2-4C72-AF1E-DDC75D05A6C8 Arcania cornigera n. sp ( Figs. 7–11 ) Arcania undecimspinosa — Sakai 1965 : 40 (part?), fig. 6a.—Chen 1989: fig. 8, pl. 2, fig. 4.— Marumura & Kosaka 2003 : 27 . Arcania sp.— Fujii & Naruse 2013 : 3 . Material examined. Holotype . NMCR 39101, male, 27.1 × 25.7 mm , Maribojoc Bay, Bohol, Philippines , coll. J. Arbasto, Nov. 2003 to Aug. 2004 . Paratypes . Philippines : NSMT-Cr 13007, 1 male , 20.8 × 19.7, 1 female , 24.9 × 23.5 mm , Balicasag I., Bohol, coll. T. Kase, Sept. 1998 .—MNHN-IU-2013-13314, 9 males , 18.1 × 16.4—25.4 × 25.0 mm, 6 females , 22.4 × 20.7–24.5 × 23.5 mm , Balicasag Island, Bohol, 50–500 m , tangle net, coll. local fishermen, 28 Nov. 2001 .—MNHN-IU-2013-13315, 6 males , 22.3 × 21.2–25.1 × 23.9 mm , 4 females , 27.9 × 27.3–23.0 x 23.0 mm, 2 ovig. females, 25.2 × 24.8, 23.4 × 21.2 mm , Balicasag Island, Bohol, 50–500 m , tangle net, coll. local fishermen, 28 Nov. 2001 .— ZRC 2008.0098, 7 males , 24.8 × 23.5–28.9 × 28.1 mm , 2 females , 16.8 × 17.2, 20.5 × 19.0 mm, 4 ovig. females, 24.0 × 22.9–26.0 × 25.7 mm , Balicasag Island, Bohol, 200–300 m , coll. local fishermen, June 2002 .— ZRC 2012.0493, 3 males , 21.3 × 18.9–23.2 × 21.9 mm , 5 females , 24.5 × 22.1–28.5 × 26.4 mm , 6 ovig. females, 24.0 × 22.1–27.1 × 25.7, Balicasag Island, Bohol, coll. local fishermen, June 2002 .—NSMT-Cr 15794, 4 males , 20.3 × 19.3–26.0 × 23.9 mm , 2 females , 23.7 × 22.5, 25.9 × 24.8 mm , Balicasag Island, Bohol, tangle nets, coll. M. Takeda, M. Manuel-Santos & H. Komatsu, Feb. 2003 .— ZRC 2012.0620, 5 males , 21.0 × 19.8 mm , 3 females , 24.3 × 22.6–28.5 × 27.3 mm , 3 ovig. females, 24.7 × 23.8–30.3 × 29.0 mm, same data as holotype .— ZRC 2012.0507, 7 males , 19.6 × 18.2–24.7 × 23.0 mm, 4 females , 14.4 × 14.6–23.2 × 21.9 mm , 3 ovig. females, 21.4 × 20.6–25.1 × 24.1 mm , Balicasag Island, Bohol, coll. local fishermen, Nov. 2003 .— ZRC 2012.0619, 4 males , 20.6 × 19.6–24.9 x 23.2 mm , Balicasag Island, Bohol, coll. local fishermen, Dec. 2003 .— ZRC 2013.0376, 1 female , 25.0 × 24.9 mm , Balicasag Island, Bohol, Apr. 2004 .—RUMF-ZC-2355, 2 males , 22.3 × 20.0, 24.2 × 23.6 mm , 1 ovig. female, 28.0 × 25.5 mm , Balicasag, Bohol, Jan. 2004 .—RUMF-ZC-2356, 1 female , 27.5 × 25.9 mm , Balicasag, Bohol, Feb. 2004 .— ZRC 2001.0487, 2 males , 19.3 × 17.8, 21.8 × 20.0 mm, Balicasag Island, Bohol, Apr. 2004 .— ZRC 2012.0481, 1 male , 19.6 × 19.3 mm , 1 female , 22.7 × 21.5 mm , Balicasag Island, Bohol, 29 May 2004 .— ZRC 2008.0088, 1 male , 30.2 × 29.3 mm , Balicasag Island, Bohol, 29 May 2004 .— ZRC 2012.0614, 7 males , 20.4 × 18.5 mm , 4 females , 18.1 × 17.8–27.0 × 24.8 mm , Balicasag Island, Bohol, coll. local fishermen, 31 May 2004 .— ZRC 2012.0506, 2 males , 27.4 × 25.3, 27.2 × 24.3 mm , Pamilacan Island, Bohol, PANGLAO 2004, stn. P5, ca. 100 m , 3 June 2004 .— NMCR 39102, 3 males , 23.7 × 21.4–28.1 × 24.4 mm , 4 females , 23.2 × 21.6–26.2 × 24.4 mm , Balicasag Island, Bohol, coll. J. Arbasto, May 2004 .— ZRC 2012.0615, 1 male , 27.9 × 24.5 mm , Bohol Island, Cortes, PANGLAO 2004, stn. T17, 132– 137 m , 19 June 2004 .— ZRC 2012.0482, 3 males , 21.1 × 18.7–21.6 x 20.7 mm , 1 female , 21.1 × 20.0 mm, Balicasag Island, Bohol, Nov. 2004 . FIGURE 7. Arcania cornigera n. sp. Holotype. NMCR 39101, male, 27.1 × 25.7 mm, Maribojoc Bay, Philippines; a, habitus; b, cephalothorax, frontal view. FIGURE 8. Arcania cornigera n. sp. Holotype. NMCR 39101, male, 27.1 × 25.7 mm, Maribojoc Bay, Philippines; a, cephalothorax, dorsal view; b, cephalothorax, ventral view. FIGURE 9. Coloration of Arcania cornigera n. sp. RUMF-ZC-2364, male, 29.7 × 28.2 mm, Kochi, Japan. FIGURE 10. G1 and G2 of Arcania cornigera n. sp. Holotype. NMCR 39101, male, 27.1 × 25.7 mm, Maribojoc Bay, Philippines; a, left G1, mesial view; b, left G1, ventral view; c, distal part of left G1, ventral view; d, left G2. Scales = 1 mm. Additional material. Japan : KMNH IvR 400,102, 1 male , 17.6 × 17.4 mm , stn. 540, near Kyoga-saki, 123 m , 25 Aug. 1929 ; KMNH IvR 400,104, 1 male , 21.8 × 20.7 mm , stn. 451, west of Goto Islands, 187 m , 22 July 1929 .— USNM 17660, 1 female (damaged), Kagoshima Bay, Kyushu, 31.6375 130.7806, Northwestern Pacific Expedition, stn. 4944, Albatross , 17 Aug. 1906 .—NSMT-Cr 6368, 1 male , 19.8 × 19.2 mm , Kamiura, Kushimoto, Wakayama, 40–70m , dredge, coll. S. Nagai.—WMNH-Na-Cr-0186, 2 males , 21.3 × 19.9, 16.2 × 16.1 mm , Kamiura, Kii Kushimoto, 60m , coll. S. Nagai.— KMNH IvR 400,105, 1 male , 18.4 × 19.1 mm , Tosa, Kochi , coll. unknown, 16 Jan.–14 Feb. 1963 .—NSMT-Cr 13220, 2 males , 20.5 × 19.6, 22.1 × 21.3 mm , 2 females , 28.2 × 26.2, 28.4 × 26.0 mm, 2 ovig. females, 25.9 × 23.8, 34.5 × 33.0 mm, 1 juvenile , 13.2 × 13.3 mm , Saga Fishing Port, Kochi , 100–150 m , coll. T. Kubodera, 24 Nov. 1999 .—RUMF-ZC-2573, 1 female , 28.0 × 26.3 mm , Tosa-saga, Kochi , Japan , coll. D. Uyeno, 11 May 2006 .—RUMF-ZC-2364, 7 males , 20.8 × 19.9–28.6 × 26.2 mm , 5 ovig. females, 20.7 × 20.8–29.7 × 28.2 mm , Tosa-Saga Fishing Port, Kochi , coll. T. Naruse, D. Ueno & Y. Ota, 7 July 2009 . FIGURE 11. Right vulva of Arcania cornigera n. sp. RUMF-ZC-2356, female, 27.5 × 25.9 mm, Bohol, Philippines. Scale = 1 mm. Korea : KMNH IvR 400,103, 1 female , 21.3 × 20.6 mm , stn. 454, east of Jeju Island (as “Saishu-to”), 113 m , 23 July 1929 . Taiwan : NTOU B00100, 1 female , 29.2 × 28.4 mm , Dasi, Ilan, coll. H.-P. Yu, 3 Feb. 1983 .— ZRC 1997.0386, 1 male , 21.0 × 17.3 mm , Taichi fishing port, Ilan, coll. P.K.L. Ng, 3–4 Aug. 1996 .— NTOU B00101, 1 male , 19.2 × 17.3 mm , Donggang, Kaohsiung, coll. 25 Mar. 1996 .— NTOU B00102, 1 male , 20.7 × 19.8 mm , Donggang, Kaohsiung, coll. P.K.L. Ng, 30 May 1997 .— ZRC 2001.0042, 1 male , 25.6 × 22.5 mm , Donggang, Kaohsiung, coll. P.K.L. Ng, 6 Nov. 2000 . Philippines : ZRC 2009.0266, 1 male , 27.8 × 24.7 mm , Aurora, Luzon Island, stn. CC 2746, 220 m , 2 June 2007 .— USNM 1192283, 1 male , 22.3 × 21.4 mm , 1 female , 14.8 × 13.7 mm , S Calach Town, Balayan Bay, Batangas, 219– 238 m ., TR MB. acc. No. 322873, coll. 19 July 1966 . Description. Carapace rounded, with anterior half less convex anterolaterally, dorsal surface densely, uniformly covered with conical granules ( Figs. 7 , 8 a, 9); pterygostomial, subhepatic regions evenly covered with rounded granules ( Fig. 8 b). Front divided into 2 triangular lobes by acute triangular gap (gap slightly obtuse in large individuals), lobes strongly produced anteriorly, with acute tip ( Figs. 7 a, 8a, 9). Carapace with subhepatic, anterolateral, lateral, posterolateral, posterior, intestinal spines. Anterolateral spines smallest, followed in size by subhepatic spine, lateral, posterolateral, intestinal spines subequal, posterior spine longest; intestinal spine sometimes smaller than lateral-posterolateral spines, distal end of intestinal spines much shorter than distal end of posterior spines in dorsal view, small individuals with relatively longer intestinal spines, tip almost reaching tips of posterior spines in dorsal view. Posterior spines with dorsoventrally compressed, wide bases. Branchiocardiac, cardiointestinal grooves distinct. Antennular fossae oblique, basal antennular segment with acutely triangular lobe, setum on distoposterior margin. Mesial end of infraorbital margin forming sharp triangular spine. Anteromesial corner of pterygostomial region, anterolateral margin of buccal cavern forming laterally compressed triangular, sharp spines fitting distal part of exopod of closed mxp3; distance between spines moderate despite of slender mxp3 exopod. Eyes fitting within orbit, only corneal part slightly exposed. Mxp3 ( Figs. 7 b, 8b) covered with rounded granules; merus about two-fifths of ischium; ischium, merus each with longitudinal groove on mesial third, half; female merus with longitudinal row of setae along longitudinal groove. Exopod narrowed at level of proximal half of merus, gap between narrowed part of exopod, merus thus fitting triangular spine of anterolateral margin of buccal cavern. Thoracic sternites 4–7 ( Fig. 8 b) covered with rounded granules; granulation about equal to pterygostomial region. Sternal button of abdominal holding on anterior end of thoracic sternite 5 at lateral slope of thoracic cavity, button fitting proximolateral cup of somite 6. Penis coxal. Vulva on mesial end of thoracic suture 5/6, placed on somite 6, narrow, elliptical, lightly oblique, no sternal cover ( Fig. 11 ). Chelipeds ( Figs. 7 a, 9) long, subequal. Merus as long as chela, entirely covered with granules. Carpus, palm covered with minute granules, carpus without knob on external margin. Fingers slender, gape absent when closed, with 8–10 almost equidistantantly placed small teeth with much smaller teeth throughout. Ambulatory legs slender, merus longest of articles, covered with minute granules. Carpus, propodus covered with minute granules. Dactylus with low keels on mid-lines of mesial, lateral surfaces, keel on lateral surface flanked by rows of setae. Abdomen ( Fig. 8 b) with rounded granules; somites 3–5 fused, with proximolateral protuberances on external surface, each protuberance higher, slightly wider than central part between two protuberances. Lateral margins of somite 6 slightly convex. G1 ( Fig. 10 a–c) slender, straight, slightly curved dorsally in mesial view; distal part only slightly upcurved in mesial view, lateral margin wrapping onto mesial surface, distal end oblique. G2 ( Fig. 10 d) short, opening facing dorsally in situ . Variation. Carapace is slightly more rounded in large individuals, which makes carapace spines proportionally smaller than those in smaller individuals. The intestinal spine of small individuals sometimes reaching beyond the tips of posterior spines in dorsal view. Coloration. Frontal, gastric to epibranchial regions reddish, other part of carapace and chelipeds orange ( Fig. 9 ). Geographical distribution. Philippines (Bohol [ type locality]; Aurora; Batangas); Japan (Pacific coast: Kushimoto, Kochi ; Sea of Japan , Kyoga-saki; Kyushu, W Goto Islands; Kagoshima); Korea (Jeju Island); Taiwan (Dasi; Donggang). Etyomology. The species name is derived from the Latin cornigera (=horned), alluding the produced, hornlike frontal lobes. Remarks. Based on the material examined, the geographical distribution of A. cornigera n. sp. overlaps with the other three congeners studied ( A. undecimspinosa , A. elongata and A. tropicalis n. sp. ). Arcania cornigera n. sp. can be distinguished from the three species by several key characters listed in Table 1. Arcania cornigera n. sp. is best distinguished by its very sharp frontal lobes ( Figs. 7 a, 8a, 9), the proportionally long cheliped merus ( Fig. 7 a, 8; also see “Morphometric analysis”), straight G1 with sharply oblique distal end ( Figs. 10 a–c), and narrow, elliptical vulvae without sternal cover ( Fig. 11 ). Chen (1989) provided a photograph of a male “ A. undecimspinosa ” (pl. 2, fig. 4, 11.0 × 10.2 mm ). The only specimen with the size of “11.0 × 10.2 mm ” listed in her examined material was collected from the northeast of Lubang Island, Philippines . Its very sharp frontal lobes are closer to the condition of A. cornigera n. sp. , although the photographed specimen has a long intestinal spine that exceeds the level of the tip of posterolateral spines. Closer-sized small specimens of A. cornigera n. sp. (e.g. KMNH IvR 400,102, 17.6 × 17.4 mm ) tend to have relatively longer intestinal spine than in fully-grown specimens (e.g. NMCR 39101, 27.1 × 25.7 mm , Fig. 7 a). Chen (1989) also illustrated the G1 of “ A. undecimspinosa ” (without specifying the size and collection data of the specimen), and its morphology is similar to relatively small specimens of A. cornigera n. sp. (e.g. NTOU B00102, 20.7 × 19.8 mm ), which suggests that at least the illustrated specimen(s) of Chen (1989) are referable to A. cornigera n. sp. Arcania elongata Yokoya, 1933 . ( Figs. 12–17 ) Arcania undescimspinosa var. elongata Yokoya 1933 : 133 , fig. 47. Arcania undescimspinosa elongata — Sakai 1937 : 124, figs. 15b, 16; 1965: 40, fig. 6b, pl. 16, fig. 2; 1976: 91, pl. 28, fig. 2. Arcania elongata — Dai et al. 1986 : 67, fig. 34-1, pl. 8, fig. 2.— Dai & Yang 1991 : fig. 34-1, pl. 8, fig. 2.— Ng & Huang 1997 : 262, fig. 1E.— Tan 1996 : 1024 (part?).— Galil 2001 : figs. 1D, 4D (part); Marumura & Kosaka 2003 : 27. Material examined. Japan : ZRC 2005.0068, 12 males , 17.6 × 17.4–26.1 × 21.7 mm , 5 females , 23.9 × 22.0–29.3 × 22.0 mm, 4 ovig. females, 18.3 × 18.7–23.7 × 22.6 mm , Tomioka, Amakusa, Kyushu, coll. J.C.Y. Lai & S. Arakaki from local fishermen, 3 Sep. 2003 .—NSMT-Cr 3559, 1 male , 18.6 × 17.0 mm, 2 females , 20.1 × 19.3, 27.7 × 24.7 mm , Mikawa-Isshiki, coll. 9 Nov. 1962 .—NSMT-Cr 5812, 1 ovig. female, 18.7 × 17.7 mm , 1 juvenile , 7.9 × 8.2 mm , Kushimoto, Wakayama, stn. 13, coll. M. Takeda, 17 July 1978 .—NSMT-Cr 3842, 1 male , 24.4 × 22.5 mm , Tanabe Bay.—NSMT-Cr 22338, male, 30.3 × 26.4 mm , off Irino, Tosa Bay, Kochi , 50–100m , coll. I. Soyama, 29 Jan. 1988 .—NSMT-Cr 10041, 1 male , ca. 30.4 × 26.8 mm , 1 female , 31.2 × 27.4 mm , same data as NSMT-Cr 22338.—NSMT-Cr 22339, 2 males , 22.6 × 20.0, 25.5 × 23.0 mm, 4 females , 18.9 × 18.1–31.4 × 26.9 mm , Saga Fishing Port, Kochi , 100–150 m , coll. T. Kubodera, 24 Nov. 1999 .—RUMF-ZC-1100, 2 males , 21.1 × 18.7, ca. 25 × 26.5 mm , 7 females , 22.5 × 19.8–31.5 × 29.0 mm, 1 ovig. female, 31.4 × 29.7 mm , Tosa-Saga Fishing Port, Kochi , coll. T. Naruse, D. Ueno & Y. Ota, 7 July 2009 . —WMNH-Na-Cr-0187, 1 female , dry, 24.1 × 20.8 mm , off Kochi , 40m , coll. S. Nagai.—NSMT-Cr 10037, 1 ovig. female, 32.3 × 29.6 mm , East China Sea, coll. T. Miura, 3 July 1985 . Taiwan : NTOU B00108, 1 female , 28.8 × 26.4 mm , Penghu, coll. T.-Y. Chan, 9 Oct. 1984 .— NTOU B00106, 1 ovig. female, 27.4 × 25.8 mm , Dasi, Yilan, Y. Wong, 6 Apr. 1986 .— NTOU B00103, 1 male , 24.1 × 21.1 mm , Dasi, Yilan, coll. J.-F. Huang, 1 Apr. 1989 .— NTOU B00105, 1 male , 24.5 × 20.1 mm , Dasi, Yilan, coll. J. F. Huang, 24 Oct. 1992 .— NTOU B00110, 1 male , 23.4 × 20.1 mm , Dasi, coll. S.-H. Wu, 21 Aug. 1997 .— NTOU B00107, 1 ovig. female, 33.5 × 29.4 mm , Dasi, Yilan, S.-H. Wu, 4 Dec. 1997 .— NTOU B00104, 1 male , 28.4 × 23.8 mm , Dasi, Yilan, coll. C.-W. Lin, 2 Nov. 1998 .— NTOU B00109, 1 ovig. female, 32.0 × 30.3 mm , Donggang, Pingtung, coll. 18 Dec. 1999 .— ZRC 2014.0014, 1 female , 23.7 × 21.2 mm , Donggang, Pingtung, coll. P. K. L. Ng, 5 Aug. 1996 .—NMMBCD 4025, 1 male , 22.2 × 19.6 mm , Kezailiao fishing port, Kaohsiung, 25 Apr. 2013 . Redescription. Carapace elliptical, longer than wide, dorsal surface evenly covered by columnar granules ( Figs. 12 , 13 a, 14); pterygostomial, subepatic regions evenly covered with rounded granules ( Fig. 12 b). Front divided into 2 triangular lobes by obtuse triangular gap, tip of lobes moderately acute ( Figs. 12 a, 13a, 14). Carapace with subhepatic, anterolateral, lateral, posterolateral, posterior, intestinal spines. Anterolateral spines smallest, followed in size by subhepatic spine, length of other spines subequal; distal end of intestinal spines exceeding those of posterior spines. Intestinal, cardiac, branchial regions divided by shallow grooves. Antennular fossae oblique, antenna excluded from antenular fossa by triangular, thin plate. Mesial end of infraorbital margin forming dorsoventrally compressed, sharp, triangular spine. Anteromesial corner of pterygostomial region, anterolateral margin of buccal cavern forming laterally compressed triangular spines fitting closed exopod of mxp3; distance between spines relatively narrow due to slender mxp3 exopod. Eyes fitting orbit, only corneal part slightly exposed. Mxp3 ( Fig. 13 b) sparsely covered with rounded granules; merus length about two-fifths of ischium; each with longitudinal groove on mesial third, half. female merus with longitudinal row of setae along longitudinal groove. Exopod narrowed at level of proximal two-fifths of merus, gap between narrowed part of exopod, merus thus fitting triangular spine of anterolateral margin of buccal cavern. Thoracic sternites 4–7 ( Fig. 13 b) covered with rounded granules; granulation almost same as pterygostomial region. Sternal button of abdominal holding on anterior end of thoracic sternite 5 at lateral slope of thoracic cavity, button fitting proximolateral cup of somite 6. Penis coxal. Vulva on mesial end of thoracic suture 5/6, placed on somite 6, narrowed laterally, with distinct sternal cover on anterolateral corner ( Fig. 17 ). Chelipeds moderately long, subequal ( Fig. 14 ). Merus slightly slender, shorter than chela, covered by rounded granules except for distoflexor part. Carpus sparsely covered with minute granules on upper surface, without knob from external margin. Palm with scattered, minute granules on outer, inner surfaces; fingers slender, gape absent when closed, with 7–9 almost equidistantantly placed small teeth over distal three-quarters, much smaller teeth throughout. Ambulatory legs slender, merus longest of articles, covered with minute rounded granules. Carpus with granules on upper-outer, lower-outer margins. Propodus with same type of granules on outer, inner surfaces. Dactylus oblong in cross-section, low keel on lower surface, keel lined with setae laterally. FIGURE 12. Arcania elongata Yokoya, 1933 . NSMT-Cr 22338, male, 30.3 × 26.4 mm, Kochi, Japan; a, habitus; b, cephalothorax, frontal view. FIGURE 13. Arcania elongata Yokoya, 1933 . NSMT-Cr 22338, male, 30.3 × 26.4 mm, Kochi, Japan; a, cephalothorax, dorsal view; b, cephalothorax, ventral view. Abdomen ( Fig. 13 b) with sparse, rounded granules; somites 3–5 fused, with proximolateral protuberances on external surface, each protuberance not distinctly larger than central part between protuberances. Somite 6 with convex lateral margins. G1 ( Figs. 15 a–c, 16a–c) almost straight over proximal four-fifths; distal part curved laterally on distal fifth, further distal part curved anteriorly. Distal end hook-like, opening facing anteriorly. G2 ( Fig. 15 d) short, opening facing dorsally in situ . Coloration. Dorsal surface of carapace and cheliped merus bright reddish. Geographical distribution. Japan ( Pacific coast: Sagami Bay, Mikawa Bay, Kushimoto, Tanabe Bay, Tosa [ type locality]; Kyushu: Amakusa); Taiwan (Dasi; Penghu; Donggang); Coral Sea. ( Sakai 1937 ; 1965 ; 1976 ; Galil 2001 ). Remarks. Yokoya (1933) described A. undecimspinosa var. elongata from two females and one male collected from three different localities (Suruga Bay, between Kochi and Ashizuri-Misaki, and Kochi , all on Pacific coast of Japan ). A search for the type specimens at the Kitakyushu Museum of Natural History & Human History with Dr. M. Shimomura was unsuccessful, and they are most probably lost. There are good numbers of specimens that can be referable to A. elongata from Kochi , Pacific coast of Shikoku, Japan . Arcania elongata can be characterized by the ellipsoid carapace ( Figs. 12 a, 13a, 14), the proportionally shorter subhepatic and anterolateral spines ( Figs. 12 a, 13a, 14), the subdistally bent and gradually curved G1 ( Figs. 15 a–c, 16 a–c) and laterally narrowed vulva with a sternal cover arising from anteromesial corner ( Fig. 17 ). The carapace contour agrees well with Yokoya’s (1933: fig. 47) figure. Three out of four Arcania species ( A. undecimspinosa , A. cornigera n. sp. and A. elongata ) studied herein have been recorded from the type locality of A. elongata . It is also true that what Yokoya (1933) identified as A. elongata actually contained specimens of A. cornigera n. sp. (see Remarks of A. cornigera n. sp. ). The very large individuals (e.g. NTOU, ovig. female, 32.0 × 30.3 mm ) tend to have a more rounded carapace contour. FIGURE 14. Arcania elongata Yokoya, 1933 ; a, ZRC 2005.0068, female, 29.3 × 25.5 mm, Amakusa, Kyushu, Japan; b, NSMT-Cr 5812, ovig. female, 18.7 × 17.7 mm, Wakayama, Japan. FIGURE 15. G1 and G2 of Arcania elongata Yokoya, 1933 . NSMT-Cr 22338, male, 30.3 × 26.4 mm, Kochi, Japan; a, left G1, mesial view; b, left G1, ventral view; c, distal part of left G1, ventral view; d, left G2. Scales = 1 mm. The drawing of the G1 of A. elongata by Dai et al. (1986 : 67, fig. 34-1; locality not indicated), Dai & Yang (1991: fig. 34(1) ; locality not indicated) and Galil (2001a: 4D; MNHN B27450 from the Coral Sea) agree with the ventrolateral view of the G1 of the specimens examined during the present study, suggesting that they are conspecific. Campbell (1971) recorded “ A. elongata ” from southern Queensland and noted that it was closer to A. novemspinosa than to Sakai’s (1937; 1965) A. undecimspinosa . Although Campbell (1971) listed a number of characters to differentiate “ A. elongata ” from A. novemspinosa , he mentioned that “ A. elongata ” “lacks prominent proximal spine on proximal margin of arm of cheliped”. Both A. elongata and A. novemspinosa , however, possess a small but distinct proximal spine on the posterior margin of the cheliped merus ( Fig. 12 b; RUMF-ZC-1910). The identity of “ A. elongata ” from southern Queensland needs to be re-assessed. Romimohtarto (1967) identified material from the Arafura Sea as A. undecimspinosa and related it to A. elongata as well. Romimohtarto’s (1967: fig. 3) specimen, however, show subdistally curved but distally recurved G1. This condition is similar to that of A. elongata , but the G1 of A. elongata differs from the Arafura Sea species by the presence of a hook-like structure at the distal end ( Figs. 15 b, c, 16b, c). The identification of the material from the Arafura Sea needs to be confirmed.