Pseudatheta crenulicauda ( Bernhauer, 1907 ) Hashizume & Yamamoto & Maruyama, 2023

Hashizume, Takuto, Yamamoto, Shûhei & Maruyama, Munetoshi, 2023, Revision of the Genera Pseudatheta Cameron and Phymatura Sahlberg (Coleoptera, Staphylinidae, Aleocharinae) from Japan, Zootaxa 5319 (1), pp. 27-47 : 29-33

Pseudatheta crenulicauda ( Bernhauer, 1907) , comb. nov.

( Figs. 1A , 2C , 5A–C )

[Japanese name: Miiro-kinokotsuyakeshi-hanekakushi]

Atheta (Datomicra) crenulicauda Bernhauer, 1907: 398 (original description;

type locality: “Bukenji” [Yokohama-shi, Kanagawa-ken, central Honshu, Japan]); Sawada, 1977: 217 (as a synonym of Ph. oligotinula ).

Phymatura crenulicauda ( Bernhauer, 1907) ; Pace, 1984: 54

(transferred to the genus Phymatura from the genus Atheta ); Shibata et al., 2013: 115 (catalogue); Schülke & Smetana, 2015: 633 (catalogue).

“ Phymatura oligotinula ”: Sawada, 1977: 217 (redescription; misidentification).

“ Pseudatheta oligotinula ”: Pace, 1992: 242

(transferred to genus Pseudatheta from Phymatura ; probably based on Sawada (1977)).

Pseudatheta similis Pace, 2010: 268 (original description;

type locality: “ China: Sichuan, Ganzi Prefecture, Daxue Shan, Gongga Shan, Hailougou glacier park, 102°04’E 29°36’N, river valley, ca. 1 km above camp I, 2100 m ”); Schülke & Smetana, 2015: 634 (catalogue); Pace, 2016: 301 (Yunnan). Syn. nov.

Material examined. Type material. Atheta (Datomicra) crenulicauda : Lectotype: here designated, male “Hans Sauter 4000 / Bukenji 10 XI 05 / Unter Schilfhaufen [handwritten] // Bukenji / Japan. Sauter [handwritten] // crenulicauda / Brnh. Typ. [handwritten] // Chicago NHMus / M. Bernhauer / Collection” (abdominal segments VIII–X and aedeagus were dissected and mounted in Euparal by MM) ( FMNH).

Paralectotype: 1 female, “crenulicauda / Bernh. Cotypus [handwritten] // Unzen. 2600’ / Japan. Sauter [handwritten] // Chicago NHMus / M. Bernhauer / Collection” (abdominal segments VIII–X and spermatheca were dissected and mounted in Euparal by MM) ( FMNH) .

Additional material examined. JAPAN: [Aomori-ken]: 1 male, Yasumiya, Towada-shi , 4–5 VIII 1966, M. & M. T . Ch ̊jô leg. ( KUM) ; [Miyagi-ken]: 2 males, 1 female, Yoshida, Taiwa-chô , 20 VIII 2009, J. Aoki leg. ( KUM) ; [Fukushima-ken]: 1 male, Shitokigawa-keikoku, Iwaki-shi , 24 V 1992, K. Haga leg. ( KUM); [Tochigi-ken]: 1 male, 1 female, Watarase , 6 V 1979, M. Tao leg. ( KUM); [Gunma-ken]: 1 male, Naganohara, Naganohara-machi , 9 VIII 1997, T . Kishimoto leg. (TKc); [Saitama-ken]: 1 male, 1 female, Yoshimi-machi , 16 VII 2000, K. Toyoda leg. ( KUM) ; 3 males, 2 females, Mitsumine, Chichibu-shi , 28 V 1997, M. Maruyama leg. ( KUM); [Chiba-ken]: 1 male, Noda-shi , 17 V 1991, T . Kishimoto leg. (TKc); [Tokushima-ken]: 1 male, Shikibidani, Naka-chô , 17 VII 2010, J. Aoki leg. ( KUM) ; [Ehime-ken]: 1 male, Sara-ga-mine, 29 IV 1962, S. Hisamatsu leg. ( EUM); Komenono , 18 VII 1975, A. Yonetsu leg. ( EUM) ; 1 male, Sara-ga-mine, 27 VI 1959, M. Satô leg. ( EUM); [Kochi-ken]: 1 male, 1 female, Yusuhara-chô , 5 V 2010, T . & T . Miyata leg. ( KUM); 2 males, 1 female, Kamioriwatashi, Yusuhara-chô , 24 V 1997, M. Sakai leg. ( EUM); [Nagasaki-ken]: Tsushima Is.: 1 male, Kamiagatamachi Sasuna, Tsushima-shi , 18 VI 2022, T . Hashizume leg. ( KUM).

Redescription. Measurements (n = 5): BL ≈ 1.86–2.39; FBL, 1.00–1.22; HL, 0.34–0.38; HW, 0.38–0.44; PL, 0.35–0.42; PW, 0.50–0.59; EL, 0.38–0.48; EW, 0.60–0.73. (Lectotype of Atheta crenulicauda: BL ≈ 2.0; PL, 0.40; PW, 0.55; HTL, 0.41).

Relative length of antennomeres I–XI (n = 1): 25: 24: 21: 11: 11: 11: 11: 10: 11: 12: 37. Ratio of length/width of antennomeres I–XI (n = 1): 1.84: 2.07: 2.16: 0.88: 0.71: 0.68: 0.64: 0.55: 0.57: 0.63: 1.83.

Body ( Figs. 1A , 2C ) reddish brown; head darker; posterolateral areas of elytra darker; abdominal segments V–VII darker.

Head almost as long as wide, HW/HL: 1.11–1.26; surface densely covered with setae.Antenna with antennomeres I–III and XI longer than wide, antennomeres IV–X wider than long; antennomeres I and II with rounded distal end, antennomeres III–X strongly angulated near distal end, antennomere XI oval.

Pronotum transverse, PW/PL: 1.36–1.50, PW/HW: 1.32–1.41; surface densely covered with setae, finely punctured, without microsculpture; posterior margin slightly bisinuate. Elytra wider than long, EW/EL: 1.60–1.70, EL/PL: 1.00–1.10, EW/PW: 1.20–1.24; surface densely covered with setae and finely punctured; posterior margin sinuate near posterolateral corners. Hind wings well developed; flabellum with one seta. Mesoventrite without longitudinal carina; mesoventral process extended to slightly beyond middle of mesocoxal cavities, with pointed apex; metaventral process shorter than mesoventral process, with rounded apex; isthmus present.

Abdomen slightly narrowed posteriad; surface densely covered with setae.

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. 5A ) with a tubercle on median area; three to five processes on each side of posterior margin, outer ones slightly curved, longer and sharper than the others. Aedeagus as in Fig. 5B ; median lobe with large basal bulb; apical process broad, dilated in lateral view, apical end thin and elongated, apex pointed; flagellum moderately long.

Female. Spermatheca ( Fig. 5C ) curved twice, with a transverse band-like structure at base of distal portion; distal portion elongated, U-shaped; median portion elongated, slightly curved; proximal portion longer than wide.

Distribution. Japan (Honshu, Shikoku, Tsushima Is., Kyushu?); China (Sichuan, Yunnan).

Remarks. Sawada (1977) redescribed this species in detail as Ph. oligotinula . Based on its characteristics (e.g., small body size, absence of the longitudinal carina on the mesoventrite, and the shape of the median lobe of the aedeagus and the spermatheca), this species belongs to Pseudatheta rather than to Phymatura . The illustration of the median lobe of the aedeagus of Ps. similis , shown by Pace (2010), fully agrees with that of Ps. crenulicauda (as Ps. similis syn. nov.). Pace (2016) recorded this species from Yunnan as Ps. similis . Kim & Ahn (2014) listed Ph. crenulicauda as a Korean species, based on the record of “ Ph. japonica ” from North Korea in Paśnik (2001), but later found that the specimens examined in Paśnik (2001) were not Ph. crenuicauda ( Kim & Ahn, 2016) . While the true species identity of these specimens is unknown, we tentatively consider this record as a record of Ph. japonica from North Korea. This species can be distinguished from its congeners by the apically dilated apical process and the absence of a ventral process of the median lobe of the aedeagus. There is currently no practical key to distinguish the female of this species from the female of its allies [i.e., Ps. hilaris , Ps. taiwanensis , Ps. thailandensis , and Ph. bigranipennis (Bernhauer, 1915) ]. Thus, despite our detailed morphological observations, these species could not be distinguished based on female specimens. The paralectotype of this species was collected from Unzen, Nagasaki, Kyushu, and is the only record of this species from Kyushu; however, because it was a female, it could not be positively identified. Further study is needed to allow morphologically based species identification in Pseudatheta females, supported perhaps by DNA information (see also the remarks on Ph. hilaris ).

Figures

FIGURE 1. Habitus of Pseudatheta spp. A. Pseudatheta crenulicauda (Bernhauer, 1907), comb. nov.; B. Pseudatheta taiwanensis Pace, 2008; C. Pseudatheta hilaris (Sharp, 1888), comb. nov., lectotype of Oxypoda hiralis; D. Pseudatheta thailandensis Pace, 1992; E. Pseudatheta cooteri Pace, 1998; F. Pseudatheta elegans Cameron, 1920. Scale bars: 1.0 mm.

FIGURE 2. Habitus of Phymatura spp. and type specimens examined. A. Phymatura japonica Cameron, 1933, stat. rev.; B. Phymatura russa Assing, 2021; C. lectotype of Atheta (Datomicra) crenulicauda Bernhauer, 1907 (=Pseudatheta crenulicauda comb. nov.); D. labels of C; E. holotype of Phymatura japonica Cameron, 1933, stat. rev. Scale bars: 1.0 mm for A–B.

FIGURE 5. Pseudatheta spp. A–C: Pseudatheta crenulicauda (Bernhauer, 1907), comb. nov., D–F: Pseudatheta taiwanensis Pace, 2008. A, D. male tergite VIII in dorsal view; B, E. median lobe of aedeagus in lateral view; C, F. spermatheca. Scale bars: 0.1 mm.