Pseudothinusa sunahama Tasaku & Maruyama, 2023

Tasaku, Yuto & Maruyama, Munetoshi, 2023, Pseudothinusa sunahama, a new genus and species of the tribe Athetini (Coleoptera, Staphylinidae, Aleocharinae) from sandy beaches in Japan, Zootaxa 5244 (1), pp. 33-40 : 37-38

Pseudothinusa sunahama Tasaku & Maruyama , sp. nov.

(Figs. 1–18)

Type material. Holotype. ♁ JAPAN: Hokkaidô, Hidaka-chô, Tomihama , 19 IV 2020, Y. Tasaku. ( KUM) . Paratypes: JAPAN: Hokkaidô: 11 exs. (one on slide). same data as holotype ( KUM); 1 ♁, 3 exs., Ishikari-shi, Atsuta-ku, mouth of Ishikari-gawa River (right bank), 21 V 2017, Y. Tasaku; 4 exs., same data, but 29 IV 2018 ; 2 exs. (one on slide) Ishikari-shi, Hamamatsu-ku, Kawashimokaihin-kôen park, 17 IV 2017 , K. Mitsuhashi; 1♀ (on slide), Otaru-shi, Zenibako , 29 IV 2019 , Y. Tasaku. Honshû: 1♁, Shimane-ken, Matsue-shi, Koura , 8–10 VI 2009, T. Hayama ( FIT). Shikoku : 3 exs., Kagawa-ken, Kan`onji-shi, Ariake-hama , 20 IV 2008 , H. Fujimoto. Kyûshû; 1♁, Fukuoka-ken, Fukuoka-shi, Nishi-ku , Nokono-shima , 23 II 1998 , H. Fujimoto; 3 exs., same data, but 13 V 1998.

Etymology. The species name sunahama means sandy beach in Japanese which is the habitat of this species.

Diagnosis. This species can be distinguished from the other Japanese coastal athetines by having the spines of the front and middle tibiae (see, also Diagnosis of the genus). If further species of Pseudothinusa are discovered, they are likely to differ in the shape of the median lobe of the aedeagus and spermatheca.

Description. Brown in ground color; head and abdomen darker, mouth parts and legs paler; integument with strong microsculpture. Head (Figs. 1–2) as long as wide; length of eyes about 0.3 times as long as tempora.Antennae (Fig. 1) almost as long as head and pronotum combined, antennomere I long; antennomere II slightly shorter than I; antennomere III slightly shorter than III; VI–X moniliform, wider than long; antennomere XI about 2 times as long as X. Pronotum (Fig. 1) oval, slightly transverse, about 1.2 times as wide as long, densely covered with thick setae toward lateral side. Elytra (Fig. 1) longer than wide, densely covered with setae. Legs (Figs. 1, 3) generalized, front and middle tibiae with spines. Abdomen (Fig. 1) oblong, parallel side, narrower than elytra; tergite VIII (Figs. 14, 16) with 5 pairs of macrosetae; sternite VIII (Figs. 15, 17) with 8 pairs of macrosetae.

Male characteristics. Median lobe of aedeagus as in Figs. 10–11. Paramere as in Fig. 13.

Female characteristics. Spermatheca as in Fig. 18.

Measurements. Body length, ca. 2.0–2.8; fore body length, ca. 1.1–1.3; head length, 0.35–0.45; head width, 0.35–0.45; pronotal length, 0.35–0.45; pronotal width, 0.40–0.50 (N = 10).

Biology. The adult beetles were found under driftwood of sandy beach ( Fig. 20 ) late winter to spring (February to May). A specimen was collected by Flight interception trap (FIT) in June in Honshû, Japan. Immature stage unknown.

Distribution. Japan: Hokkaidô, Honshû, Shikoku, Kyûshû (Nokono-shima) ( Fig. 19 ).

Figures

FIGURE 19 Known localities of Pseudothinusa sunahama sp. nov. (black circles).

FIGURE 20 Collection locality Pseudothinusa sunahama sp. nov. in Ishikari-shi, Hokkaidô, Japan.