Rotundicephala koheii Tasaku, Ono & Maruyama, 2023

Tasaku, Yuto, Ono, Hiroki & Maruyama, Munetoshi, 2023, Review of the intertidal rove beetle tribe Liparocephalini Fenyes (Coleoptera, Staphylinidae, Aleocharinae) from Japan, Zootaxa 5383 (3), pp. 251-296 : 274

Rotundicephala koheii Tasaku, Ono & Maruyama , sp. n.

[Japanese name: Sawada-umi-hanekakushi]

( Figs. 1C ; 2G ; 14D ; 15E, F & I ; 16 ; 25A & B )

Type material. Holotype. Male, “Kanaya, Futtsu-shi, / Chiba-ken / 9. IV. 2007 / Hiroki ONO leg.” ( Fig. 14D ) ( KUM) . Paratypes. Japan: Honshû: Chiba-ken: 1 male, 1 female, 23 unsexed, same data as holotype, 9. IV. 2007, H. Ono ( KUM) ; 3 unsexed, Tateyama-shi, Sunosaki, Sunosaki-kaigan , 15. VI. 2007, H. Ono ( KUM) ; 1 unsexed, ditto, 15. IV. 2008, H. Ono ( KUM) ; 1 unsexed, ditto, 12. II. 2009, H. Ono ( KUM) ; 2 unsexed, Shirahamamachi, Nemoto , 1. IV. 2005, H. Ono (cHO) ; 1 unsexed, ditto, 26. III. 2007, H. Ono (cHO); 1 unsexed, ditto, 18. IV. 2008, H. Ono (cHO) ; Tôkyô-to: 1 male, Izu-ôshima, Okada, Noda-hama, 15. VII. 2022, Y. Tasaku (cYT) ; Kanagawa-ken: 1 male, 23 unsexed, Manazuru-machi, Manazuru-misaki, 15. IV. 2003, M. Maruyama ( KUM) ; 5 unsexed, Yokosuka-shi , Wada-naga-hama (Nahama), 24. III. 2007, I. Kawashima ( KUM) ; 1 unsexed, ditto, 1. IV. 2007, I. Kawashima ( KUM) ; 1 male, 5 unsexed, ditto, 20. IV. 2007, M. Asano ( KUM) ; 1 unsexed (abdomen lost), Manazuru Pen. Banbaura-kaigan , 5. V. 2002, S. Arai ( KUM) ; 1 male, Yokosuka-shi, Nagai, Arasaki-kôen, 24. IX. 2021, K. Chiyoda (cYT); Shizuoka-ken: 1 unsexed, Shimoda-shi, Taraimisaki , 21. IV. 2003, M. Moriguchi ( KUM) ; 2 unsexed, Shimoda-shi, Tsumeki-zaki , 21. VI. 2003, M. Maruyama ( KUM) .

Diagnosis. This species similar to R. pacifica comb. n. and previously confused (e.g., Sawada, 1971;Ahn, 1996) (we call them as the R. pacifica species-complex) but, can be distinguished by the combination of the following characteristics: head and pronotum slightly convex ( Fig. 14D ); segments IV–IX of antennae as long as wide ( Fig. 15I ). Also, this species can be easily distinguished from R. koreana comb. n. by the short antennae not reaching elytra.

Description. Body small, robust, shining ( Fig. 14D ). Ground color reddish blown, abdominal segments VI–VII usually almost black, legs and month parts slightly paler.

Head slightly convex, almost circular, as long as wide (MHL/MHW = 0.95) ( Fig. 1C ); eyes small; antennae almost as long as head and pronotum combined, segments IV–X as long as wide, segment XI oval and longer than X ( Fig. 15I ). Labrum transverse, anterior margin rounded, with about 20 setae; epipharynx with 6 lateral setae ( Fig. 16A ). Mandibles almost symmetric, right median tooth larger than left one ( Fig. 16E ). Mentum almost trapeziform, anterior margin deeply emarginated with about 15 setae ( Fig. 16B ). Pronotum convex, as long as wide. Tarsal formula 3-3-4. Abdomen oblong oval.

Male: apical lobe of median lobe bent almost at right angle ( Fig. 15E ).

Female: spermatheca short, coiled one time at base ( Fig. 15F ).

Measurements. (N = 20): BL, 1.87–2.63 mm; FBL, 0.82–1.01 mm; HW, 0.34–0.42 mm; PL, 0.37–0.43 mm; PW, 0.34–0.40 mm; EW, 0.34–0.42 mm.

Etymology. This species is named after Dr. Kohei Sawada, who contributed greatly to the elucidation of the Japanese coastal Staphylinidae fauna.

Habitat. This species is found from the crevices of rock and around the holdfast of seeweeds (e.g., Monostroma nitidum Wittrock ) on the intertidal zones ( Fig. 25B ).

Distribution. Japan: central Honshû ( Fig. 25A ).

Figures

FIGURE 1 Definitions of measurements of body parts. A, adult of Diaulota; B, head of Diaulota aokii, dorsal view; C, head of Rotundicephala koheii sp. n., dorsal view.

FIGURE 2 Aedeagal parameres of Liparocephalus, Diaulota and Rotundicephala gen. n. spp. A & D, parameres of aedeagus (A, L. tokunagai; D, D. aokii); B, C, E, F & G, apical lobe of parameres (B, L. litoralis; C, L. tokunagai; E, D. aokii; F, D. uenoi; G, R. koheii sp. n.). Scale bars: 0.1 mm.

FIGURE 14 Habitus of Rotundicephala gen. n. spp. A, R. pacifica comb. n.; B, ditto, female; C, R. koreana comb. n.; D, R. koheii sp. n., male (holotype). Scale bar: 1.0 mm.

FIGURE 15 Genitalia and antenna of Rotundicephala gen n. A, B & G, R. pacifica comb. n. (A, median lobe of aedeagus; B, spermatheca; G, right antenna); C, D & H, R. koreana comb. n. (C, median lobe of aedeagus; D, spermatheca; H, right antenna); E, F & I, R. koheii sp. n. (E, median lobe of aedeagus; F, spermatheca; I, right antenna). Scale bars: 0.1 mm.

FIGURE 16 Mouth parts of Rotundicephala koheii sp. n.A, labrum (right side, dorsal view; left side, ventral view (epipharynx)); B, mentum; C, labium; D, maxilla; E, right mandible. Scale bar: 0.1 mm.

FIGURE 25 Distribution and habitat of Rotundicephala gen. n. spp. of Japan. A, known localities in Japan (red circle, R. pacifica comb. n. (red ring, type locality)); blue square, R. koheii sp. n.; yellow triangle, R. koreana comb. n.); B, habitat of R. koheii sp. n. (Kanagawa-ken, Japan); C, habitat of R. pacifica comb. n. (Tsushima, adults of Diaulota submarina was collected same time).