Clorida albolitura Ahyong & Naiyanetr, 2000

[New Japanese name: Tosa-meboso-shako]

(Fig. 1)

Restricted synonymy.

Clorida albolitura Ahyong & Naiyanetr, 2000: 317–320, fig. 2 [type locality: Ang Sila, Gulf of Thailand].— Ahyong 2001: 217–219, fig. 105.— Ahyong et al. 2008: 79, 80, figs. 57–59.

Clorida japonica .— Okada et al. 2016: 206, 207 (part).

Material examined. SINH-CR 1447, 1 male (TL 74.0 mm, CL 13.1 mm), Susaki fishing port, Kochi Prefecture, Tosa Bay, around 50–90 m depth, bottom trawling, coll. Y. Machida, 15 Jul. 2004. SINH-CR 1455, 1 female (TL 65.3 mm, CL 13.2 mm), 22 Jul. 2004, other data same as SINH-CR 1447 .

Diagnosis. Carapace with distinct anterolateral spines (Fig. 1B). A1 somite dorsal processes with short, triangular apices (Fig. 1C). Distal margin of second segment of A2 peduncle (Fig. 1B, red arrow) extending anteriorly beyond eyes. Mandibular palp present. Raptorial claw dactylus with 5 teeth; extensor margin with basal notch (Fig. 1D). TS5 lateral process with acute spine (Fig. 1E). TS6–8 each lacking SM carinae. AS 1–6 with distinct SM carinae (Fig. 1F). Telson with long postanal carina, extending beyond half distance between anal pore and posterior margin (Fig. 1G). Eye stalk without black band dorsally (Fig. 1A–C). A2 scale without black pigments (Fig. 1A; Galil et al. 2009: fig. 1A, B). Telson median carina with large white patch in life (Ahyong et al. 2008: figs. 57, 58).

Colour. Largely faded in alcohol (Fig. 1). Eye stalks without pigmentation. Rostral plate black. Carapace marginally fringed with narrow black line. TS6–8 and AS 1–5 posterior margins each with narrow black line. Proximal segment and mesial margin of distal segment of uropodal exopod and endopod black. In life, telson with large white patch on median carina (Ahyong & Naiyanetr 2000; Ahyong et al. 2008: figs. 57, 58).

Remarks. Okada et al. (2016) recorded C. japonica from Kochi Prefecture, south Shikoku Island, on the basis of 12 specimens including three collected by bottom trawlings at around 50–90 m in depth. Remaining nine were collected by yabby pumps from tidal flats. We re-examined all of the trawls’ specimens and six of tidal flats’ specimens in Okada et al. (2016) and found they do not belong to C. japonica . Two specimens (SINH-CR 1447 and 1455) collected by trawlings (Susaki fishing port) were identified as C. albolitura based on the aforementioned diagnostic characters, whereas a single specimen (SINH-CR 1848) also obtained by a trawling (Irino fishing port) was referred to Lenisquilla lata (Brooks, 1886) . The remaining six specimens collected from the tidal flats were identified as Cloridina ichneumon (Fabricius, 1798) instead (see Remarks of Cloridina ichneumon mentioned below).

Clorida albolitura is morphologically close to C. japonica, but distinguishable by the following characters (Ahyong et al. 2008; this study): anterior part of eye peduncle stouter in C. albolitura (Fig. 1C) than C. japonica (Fig. 2D); anterolateral spines of carapace larger in C. albolitura (Fig. 1B) than C. japonica (Fig. 2A–C); teeth of raptorial claw dactylus more strongly elongated and curved appearance in C. albolitura (Fig. 1D) than C. japonica (Fig. 2E); TS5 lateral process (in posterior view) more slender and with stronger spine in C. albolitura (Fig. 1E), instead of relatively smaller and triangular lobe in C. japonica (Fig. 2F); and SM carinae on AS 1–3 distinct in C. albolitura (Fig. 1F), but absent in C. japonica .

In fresh coloration, the presence of a median white patch on the telson is a useful diagnostic character of C. albolitura . However, it should be noted that a similar white spot is also observed in C. bombayensis (Ahyong et al. 2008: figs. 60, 61) and C. japonica (Fig. 2A).

In Ahyong & Naiyanetr (2000) and Ahyong (2001), C. albolitura was reported to be distributed in Japan, but this was later turned out to be a misinterpretation (Hamano 2005: 57, his personal communication with Dr. Shane T. Ahyong). This study represents the first specimen-based record of C. albolitura from Japanese waters. The male specimen (SINH-CR 1447) is designated as the standard specimen for the new Japanese name (Tosa-meboso-shako) proposed here.

Distribution. Madagascar, eastern Mediterranean Sea (introduced), Red Sea, Andaman Sea, Gulf of Thailand (type locality), Vietnam, Taiwan and northern Australia (Ahyong & Naiyanetr 2000; Ahyong & Galil 2006; Ahyong et al. 2008; Galil et al. 2009); now from Japan. In Japan, only known from Kochi Prefecture, southern part of Shikoku Island (Fig. 11).

Ecological note. Sand and mud substrates at 31–110 m in depth (Ahyong 2001). Judging from the location of the trawler’s operation, the specimens examined were collected at depths of around 50–90 m (Y. Machida, personal communication with the third author). This is the deepest recorded species of Clorida in Japan.