Revision of the Genera Pseudatheta Cameron and Phymatura Sahlberg (Coleoptera, Staphylinidae, Aleocharinae) from Japan Author Hashizume, Takuto Entomological Laboratory, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, 819 - 0395 Japan. Author Yamamoto, Shûhei 0000-0002-4162-8457 The Hokkaido University Museum, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, 060 - 0810 Japan. s. yamamoto. 64 @ gmail. com; https: // orcid. org / 0000 - 0002 - 4162 - 8457 s.yamamoto.64@gmail.com Author Maruyama, Munetoshi The Kyushu University Museum, Fukuoka, 812 - 8581 Japan. text Zootaxa 2023 2023-07-24 5319 1 27 47 http://dx.doi.org/10.11646/zootaxa.5319.1.2 journal article 10.11646/zootaxa.5319.1.2 1175-5326 8182108 45CD8E29-3320-42E2-A8A8-3A36BC0F41CE Pseudatheta thailandensis Pace, 1992 ( Figs. 1D , 6B–D ) Pseudatheta thailandensis Pace, 1992: 239 (original description; type locality: “Chiang Mai Prov., Doi Suthep”); Pace, 2004: 66 ( China , Shaanxi ); Schülke & Smetana, 2015: 634 (catalogue). Material examined. THAILAND : 2 males , 1 female , Doi Inthanon , Chaing Mai , 1560 m , 20 X 1983 , M. Sakai leg. ( EUM ) . Additional description. Measurements (n = 1): BL ≈ 2.07; FBL: 1.22; HL: 0.36; HW: 0.43; PL : 0.52; PW : 0.60; EL: 0.43; EW: 0.72. Ratios (n = 1): HW/HL: 1.18, PW / PL : 1.44, EW/EL: 1.67, PW /HW: 1.39, EL/ PL : 1.03, EW/ PW : 1.20. Relative length of antennomeres I–XI (n = 1): 20: 24: 15: 10: 12: 10: 12: 12: 12: 11: 34. Ratio of length/width of antennomeres I–XI (n = 1): 1.79: 2.36: 1.50: 0.68: 0.76: 0.65: 0.66: 0.63: 0.58: 0.55: 1.61. Male. Elytra with a pair of small tubercles at about posterior 1/3 on sutural margin. Sternite VI with small medial lobe on posterior margin. Tergite VII with a tubercle on posteromedian area. Tergite VIII ( Fig. 6B ) with a tubercle on median area; four processes on each side of posterior margin, outer ones slightly curved, longer and sharper than the others. Aedeagus as in Fig. 6C ; median lobe with large basal bulb; apical process relatively slender, narrowed apically in lateral view, apex pointed; flagellum moderately long. Distribution. Thailand , China ( Shaanxi ). Remarks. This species was described only from a female and could not be distinguished from its allied species based on the spermatheca.According to the original description by Pace (1992) , the median part of the spermatheca is short, but this description may have derived from a deformed specimen. In many aleocharine species, spermathecae are easily deformed immediately after mounting in mounting medium. Later, Pace (2004) recorded this species from China , but it was again a female specimen. In this study, we were able to examine specimens of both sexes of the genus Pseudatheta , which were similar to Ps. thailandensis collected in an area close to the type locality of Ps. thailandensis . Since there are areas where more than one species of this genus is distributed, such as Japan , whether these specimens are Ps. thailandensis is unclear. Nonetheless, since this species is the only known thailandensis -like species from Thailand , we tentatively identified the specimens as Ps. thailandensis and described the aedeagus. This species can be distinguished from its allies ( Ps. crenulicauda , Ps. taiwanensis ) by the apical process of the aedeagus, which tapers gradually toward the apex. However, Ph. bigranipennis (Bernhauer, 1915) , redescribed by Benick (1980) and Kim & Ahn (2016) , cannot be distinguished from Ps. thailandensis judging from the illustrations and description, and specimens described by the authors are considered identical. Since Benick (1980) and Kim & Ahn (2016) did not state that they examined the type specimen, we cannot rule out the possibility of a misidentification. Thus, we refrain from taxonomic treatment of Ph. bigranipennis at this time. The relationship between Ps. thailandensis and Ps. hilaris could not be determined.