Liparocephalus tokunagai Sakaguti, 1944

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 : 256-257

Liparocephalus tokunagai Sakaguti, 1944

[Japanese name: Oozu-umi-hanekakushi]

( Figs. 2A, C ; 3B, C, F & G ; 4 )

Liparocephalus tokunagai Sakaguti, 1944: 20 (original description); Ahn, 1997: 89 (redescription of adult and description of larva; diagnosis); Senda, 2012: 187 (rediscovery from Shikoku; biological notes).

Material examined. Japan: Honshû: Kanagawa-ken: 6 males, 6 females, Miura-shi, Aburatsubo, 19. V . 1985, Y. Shibata ( KUM) ; 2 males, 1 female, ditto, 3. VII . 1985, Y. Shibata ( KUM) ; Hiroshima-ken: 37 unsexed, Edashima-shi, Nômi-shima, Iwane , 19. IX. 2021, H. Yoshigou (cYT) ; Yamaguchi-ken: 2 females, Shimonoseki-shi, Chôfusangen’ya-kaigan, 7. IV . 2015, M. Matsuda (cYT). Shikoku: Ehime-ken: 1 female, Nagahama-chô, Kushû, 21. V . 1978, M. Sakai ( KUM) ; 1 male, 1 female, Matsuyama-shi, Katsuoka, Shiraishi-no-hama, 10. V . 2009, Y. Senda (cYT); 7 males, 9 females, Matsuyama-shi, Hojô-ôura, 15–16. IV . 2010, M. Maruyama et al. ( KUM) . 3 males, 5 females, Iyo-shi, Kônogawa-kaigan, 29. IV . 2017, M. Motonaga ( KUM) . Kyûshû: Fukuoka-ken: 5 males, 2 females, Munakata-shi, Kôno minato, 22. V . 2016, N. Tsuji ( KUM) ; 3 males, 3 females, Fukuoka-shi, Shika-no-shima, 17. VI . 2022, Y. Tasaku (cYT); Ôita-ken: 1 female, Ôita-shi, Seki, Kuro-ga-hama, 20. VII . 2012, M. Maruyama ( KUM) .

Diagnosis. This species can be easily distinguished from all other Japanese species of the tribe Liparocephalini by its large, broad and reddish body ( Figs. 3B & C ). This species, along with L. cordicollis LeConte, 1880 , exhibits significant sexual dimorphism in head size, whereby males possess larger head with larger mandibles compared to females.

Remarks. It is noteworthy that this species exhibits a coiled spermatheca ( Fig. 3G ), a unique feature not observed in other species of the genus. It remains uncertain whether this species truly belongs to the same genus as L. litoralis and its allies, as the delimitation of the genus is currently under revision (Tasaku et al, in prep.).

Biology. This species exclusively inhabits the intertidal rocky zone, particularly in areas abundant with seaweeds. In Japan, seaweeds are facing a serious decline on rocky coasts, and as a result, this species has been classified as an “Endangered species (EN)” in “The 4 th Version of the Japanese Red Lists” ( Ministry of the Environment, Japan, 2020). Notably, in recent years, this species has not been observed in Kanagawa Prefecture in the eastern Honshû, where it was previously recorded. Due to its distinctive ecological traits, its life history has been extensively studied (e.g., Matsuda, 2021; Motonaga, 2019). These beetles exhibit activity for merely one or two hour during low tide, specifically around spring tide, from the moment the rocks are exposed until the tide starts to rise ( Motonaga, 2019).

Distribution. Japan: Honshû, Shikoku, Kyûshû.

Figures

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 3 Habitus and genitalia of Liparocephalus. A–C, habitus (A, L. litoralis female; B, L. tokunagai, male; C, L. tokunagai, female); D & F, median lobe of aedeagus (D, L. litoralis; F, L. tokunagai); E & G, female spermatheca (E, L. litoralis; G, L. tokunagai). Scale bars: 1.0 mm for A–C; 0.1 mm for D–G.

FIGURE 4 Mouth parts of Liparocephalus tokunagai. A, mentum; B, labrum (right side, dorsal view; left side, ventral view (epipharynx)); C, labium; D, maxilla; E, right mandible. Scale bar: 0.1 mm.