Pseudatheta hilaris ( Sharp, 1888 ) 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 : 36-37

Pseudatheta hilaris ( Sharp, 1888) , comb. nov.

( Figs. 1C , 6A )

Oxypoda hilaris Sharp, 1888: 285 (original description;

type locality: “Nikko” [Nikkô-shi, Tochigi-ken, central Honshu]); Schülke & Smetana, 2015: 711 (catalogue).

Type material. Lectotype: here designated, female, “ Oxypoda hi- / laris Type / D.S. / Nikko. Japan. / 31.10.80. Lewis [handwritten, paper card] // Type [red round label pinned by a curator] // Japan. / G. Lewis. // Sharp Coll. / 1905-313.” (abdominal segments VIII–X and spermatheca were dissected and glued on paper card, and labium and maxilla were mounted in Euparal by MM). ( BMNH)

Paralectotypes: 2 females, “Kuro / matsu [handwritten, paper card, underside of label] // Japan. / G. Lewis. / 1910- 320. // Oxypoda / hilaris [handwritten]” ( BMNH). See remarks .

Redescription. Measurements of lectotype of Oxypoda hilaris: BL ≈ 2.6; PL , 0.39; PW, 0.56; HTL, 0.40.

Relative length of antennomeres I–XI (n = 1): 23: 24: 22: 10: 13: 13: 13: 12: 14: 13: 36. Ratio of length/width of antennomeres I–XI (n = 1): 1.95: 1.59: 1.96: 0.65: 0.70: 0.70: 0.67: 0.59: 0.64: 0.63: 1.64.

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

Head. 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: 1.44); surface densely covered with setae, finely punctured; posterior margin slightly bisinuate. Elytra wider than long; surface densely covered with setae and finely punctured; posterior margin sinuate near posterolateral corners.

Abdomen slightly narrowed posteriad; surface densely covered with setae.

Male. Unknown.

Female. Spermatheca ( Fig. 6A ) 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).

Remarks. This species clearly does not belong to the genus Oxypoda , judging from the shape of the spermatheca, but to the genus Pseudatheta . As the type series of Oxypoda hilaris consists only of females, there is currently no method to distinguish this species from its allies. It is unclear whether this species is identical to Ps. crenulicauda , Ps. taiwanensis , both known from Japan, or neither. There is no reason to believe that the paralectotypes are the same species as the lectotype. Since this species was described in 1888 ( hilaris is the oldest name), one or more of the similar species are likely to be junior synonyms of this species.

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 6. Pseudatheta spp. A: Ps. hilaris (Sharp, 1888), comb. nov., B–D: Ps. thailandensis Pace, 1992. A, D. spermatheca; B. male tergite VIII in dorsal view; C. median lobe of aedeagus in lateral view. Scale bars: 0.1 mm.