Leucosia rubripalma, Mizutani & Yanagisawa & Ichikawa & Nishio & Sakai & Nonokawa & Makino & Suzuki & Ichimiya & Uchida & Watanabe & Kanashiro & Iwawaki & Kondo & Shibata & Inden & Murohara, 2025

Thranita cerasma ( Wee and Ng, 1995) View in CoL

genus Leucosia to four species, L. craniolaris (Linnaeus, 1758) , L. moresbiensis Haswell, 1880 , L. punctata Bell, 1855 , and L. rubripalma sp. nov., by having the male first gonopod with screw-like coiled shaft. The four species share a pair of dark spots at the posterior part of the carapace dorsal surface ( Fig. 1A, C View Fig ). The specimen examined is a female and therefore cannot be comparable with the known species on the male first gonopod characters, but the other morphological features such as the laterally bulged branchial regions of the carapace ( Fig. 1A View Fig ), the distinctly tridentate front ( Fig. 1A View Fig ), the carapace posterior margin expanded laterally to form a

( Fig. 2 View Fig )

Thalamita cerasma Wee & Ng, 1995 View in CoL , pp. 11 (in key), 62, figs. 30–32. — Takeda & Marumura, 1997, p. 16, fig. 1C–D. — Ng et al., 2008, p. 168 (in list).

Thalamita cerasma rectifrons Crosnier & Moosa, 2002, p. 395 View in CoL View Cited Treatment , figs. 6–7.

Thalamita cerasma cerasma View in CoL : Naruse & Shokita, 2003, p. 44, figs. 2–3.

Thranita cerasma View in CoL : Evans, 2018, p. 43 (in list). — Takeda et al., 2019, p. 41 (in discussion). — Huang & Shih, 2021, pp. 6 (in Table 1), 28, figs. 4E, 17; 2023, pp. 39 (in Tables 1–3), 67, figs. 8A–B, 9A–B.

Material examined. Ose-zaki, Suguga Bay, 7.5 m depth, 1 Ə (cb 64.2 mm, cl 42.1 mm), NSMT-Cr 32423, 7-X-2023, coll. H. Takakura.

Remarks. The present male specimen from Suruga Bay has morphological characters typical for the genus Thalamita s.l. as follows: the flattened carapace dorsal surface covered thickly with short setae ( Fig. 2E View Fig ), the six lobed, subtruncated carapace frontal margin ( Fig. 2A View Fig ), the remarkably developed inner lobe of the supraorbital margin ( Fig. 2B View Fig ), the five strong carapace anterolateral teeth each tipped with a horny spine ( Fig. 2B View Fig ), the fourth anterolateral tooth distinctly smaller than the others ( Fig. 2B View Fig ), and the concave carapace posterolateral margin retreating rapidly towards the carapace posterior margin ( Fig. 2E View Fig ).

The specimen examined is identified as T. cerasma by having the following characters used in the key prepared to the species of the genus Thalamita of Wee and Ng (1995): 1) frontal border cut into more than two lobes excluding inner supraorbital lobes, 2) frontal border cut into six teeth excluding inner supraorbital lobes, 3) anterolateral border cut into five teeth, last not the smallest; frontal and mesogastric ridges present, 4) basal antennal segment with several sharp spines. Thalamita cerasma is placed close to T. spinimana Dana, 1852 , T. prymna (Herbst, 1803) and T. pelsarti Montgomery, 1931 , but the morphological differences among these species are distinct and the details are referred to the accounts given by Wee and Ng (1995). The characters of the frontal lobes, carapace anterolateral teeth, basal antennal segment and male pleon agree well with the line drawings of T. cerasma in the original description and the additional notes by Takeda and Marumura (1997). Some minor differences are present in the present specimen, including the stronger carapace dorsal ridges, the granulated outer and inner surfaces of the cheliped palm, and the slightly flared distal part of the male first gonopod, which is considered to be not interspecific, but intraspecific vari- ations.

Thalamita cerasma rectifrons ( Crosnier and Moosa, 2002) View in CoL , reported from French Polynesia was considered to be synonymous with the nominate subspecies by Naruse and Shokita (2003) and approved by Ng et al. (2008). Another close relative, T. rubridens Apel and Spiridonov, 1998 View in CoL from the Arabian Gulf ( Apel and Spiridonov, 1998; Naderloo and Ţrkay, 2012; Naderloo, 2017) was compared with T. cerasma View in CoL as for the morphological characters of the carapace and chelipeds as well as the color in life by Naruse and Shokita (2003). The validity of this Arabian Gulf species seems to be not always clear as far as the literature concerned.

The color of the present male from Suruga Bay ( Fig. 2E View Fig ) was mostly brick red and marginally pale yellowish, being quite similar to two photographs of a male from off Shirahama, Kii Peninsula given by Takeda and Marumura (1997: fig. 1C–D) and somewhat different from a photograph of a female from the Ryukyu Islands, in which the carapace dorsal surface is basically bright olive, with the vermilion margins and ridges (Naruse and Shokita, 2013: fig. 2a). Based on the color in life, Huang and Shih (2021) doubted the identification of Thalamita cerasma View in CoL by Takeda and Marumura (1997) and suggested that the species from Japan is similar to Thranita rubridens ( Apel and Spiridonov, 1998) View in CoL from the Arabian Gulf.

Thalamita cerasma View in CoL has been designated as the type species of a new genus Thranita View in CoL established by Evans (2018) with the results of the molecular analysis. The known 17 Thranita species hitherto been referred to the Thalamita prymna View in CoL group by Stephenson and Hudson (1957) attain the big size, having the six-lobed frontal margin and the long and tapering G1. Poore and Ahyong (2023) mentioned that the genera Thalamonyx A. Milne-Edwards, 1873 View in CoL , Thranita Evans, 2018 View in CoL , and Trierachus Evans, 2018, are as junior synonyms of Thalamita View in CoL without any comments, but in this paper, the genus Thranita View in CoL is considered as valid based on the combination of the morphological characters absent in the other Thalamita View in CoL clade, and therefore this species is referred to Thranita View in CoL as mentioned in Takeda et al. (2019).

Distribution. Pacific Ocean, 10– 30 m. — French Polynesia; Singapore (type locality); Ryukyu Islands, off Kii Peninsula and Suruga Bay, Japan.