Euryxanthops flexidentatus Garth and Kim, 1983

Alrasheedi, Sami M, Alrashdi, Mousa N, Alhumaidan, Lama S, Alkhdairi, Ahmad, Alzweihary, Ali M, Alhussaini, Omar M, Alharbi, Lama S, Albalawi, Amirah N, Almutairi, Turki F, Alharbi, Osama A G & Bashal, Afaf A M, 2024, Crabs of the Families Tetraliidae, Trapeziidae and Xanthidae (Crustacea: Decapoda: Brachyura) new to the Ogasawara Islands, Japan, Bulletin of the National Museum of Nature and Science. Series A, Zoology 50 (1), pp. 1-17 : 5

Euryxanthops flexidentatus Garth and Kim, 1983

[Jn: Usuiro-hira-ougigani]

( Fig. 2D )

Material examined. Kaikata Seamount— 486 m, 1 ♂ (NSMT-Cr 31519; cb 22.3×cl 16.4 mm), 1 ♀ (NSMT-Cr 31520; cb 17.5×cl 12.5 mm), 15-VII-1991, Shinkai 2000, #558, JAMSTEC leg.

Nikko Seamount— 460 m, 1♂ (NSMT-Cr 31521; cb 28.3×cl 19.9 mm), 19-IX-1992, Shinkai 6500, #144, JAMSTEC leg.

Remarks. This species, one of six congeners of the genus Euryxanthops Garth and Kim, 1983 , was originally described on the basis of a single male specimen from off northwestern Mindanao, the Philippines ( Garth and Kim, 1983, p. 678, fig. 3). Recently, additional specimens were recorded and remarked on the variations by Davie (1997), Ng and McLay (2007), Kuo et al. (2015), Mendoza et al. (2021), and Sato and Aiba (2022). This species is characteristic in the thin and weakly upturned anterolateral margins of the carapace, with keys prepared by Davie (1997) and Ng and McLay (2007). In these keys, the shape of the first anterolateral tooth is considered as the important criterion to distinguish the species, but Mendoza et al. (2021) showed that the original illustrations are not always accurate in the proportion and first anterolateral tooth of the carapace, and that the G1 of the holotype is damaged at its tip. The G 1 in the present specimens (NSMT-Cr 31519, 31521) agrees well with the figure of Kuo et al. (2015, fig. 2), having several long hairs at the subterminal part. Although, in the published photographs and line drawings, the carapace dorsal areolation is not always clearly shown, but it is remarked at present in all the present specimens that a deep, strongly curved gutter was engraved at each side of the transverse depression between the median gastric and cardiac regions.

Distribution. Known from the Philippines (type locality, northern Mindanao, 327.6 m), southern Taiwan (265–300 m), Indonesia (Sunda Strait and southwestern Java, 234–281 m), and Japan (Off Miyazaki Prefecture, Kyushu, 350 m). As Sato and Aiba (2022) already mentioned, Euryxanthops sp. from Sagami Bay, 220–280 m, recorded by Ikeda (1998, fig. 10) is referred to this species. Xanthidae gen. et sp. recorded by Fujikura et al. (2008, fig. 11.35) from Kaikata, Nikko, Daini-Kasuga, and Daikoku seamounts, Ogasawara-Mariana Arc, 400–500 m, is also probably referred to this species.

Figures

Fig. 2. A: Tetralia brunalineata Trautwein, juv. (NSMT-Cr 31510; cb 3.2×cl 2.7mm) from Hitomaru-jima. B: Trapezia guttata Rüppell, ♂(NSMT-Cr 31511; cb 5.7×cl 5.0mm) from Omura Beach, Chichi-jima. C: Trapezia serenei Odinetz, ovig.♀ (NSMT-Cr 31512; cb 10.3×cl 8.9 mm), from Omura Beach, Chichi-jima. D: Euryxanthops flexidentatus Garth and Kim, ♂ preserved in spirit (NSMT-Cr 31519; cb 22.2×cl 16.3mm) from Kaikata Seamount. E: Juxtaxanthias lividus (Latreille), ♂ preserved in spirit (NSMT-Cr 31527; cb 46.6×cl 31.0mm) from Futami Bay, Chichi-jima. F: Garthiella aberrans (Rathbun), ♀ (NSMT-Cr 31524; cb 8.5×cl 5.6mm) from Haha-jima. G: Lybia caestifera (Alcock), ♂ (NSMT-Cr 31535; cb 3.6×cl 3.2mm) from Ani-jima. H: Etisus odhneri Takeda, ♂ (NSMT-Cr 31514; cb 5.8×cl 4.3mm) from Ani-jima.