Research Article |
Corresponding author: Tsubasa Nozaki ( dosanko.lathrobium@gmail.com ) Academic editor: Volker Assing
© 2022 Tsubasa Nozaki, Munetoshi Maruyama.
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Citation:
Nozaki T, Maruyama M (2022) Taxonomy of Homoeusa Kraatz, 1856 (Coleoptera, Staphylinidae) from the East Palearctic: I. Homoeusa rufescens (Sharp, 1874) and a new allied species. ZooKeys 1121: 39-58. https://doi.org/10.3897/zookeys.1121.85489
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There is insufficient information to identify most species of the myrmecophilous rove beetle genus Homoeusa. In this paper, after examining the type material, Homoeusa rufescens (Sharp, 1874) is redescribed in detail and its new allied species Homoeusa ovata sp. nov. is described. We also observed the behavior of these two species in the field; the behavior was similar to that reported for H. acuminata (Märkel, 1842). A checklist of Homoeusa from the Palearctic and Nearctic is also provided.
Aleocharinae, description, Dinardina, Homoeusa ovata sp. nov., Lasius, myrmecophily, new species, rove beetle
Nine species of the myrmecophilous genus Homoeusa Kraatz, 1856 (tribe Oxypodini) are known from the Palearctic region, of which eight are recorded from the East Palearctic, i.e., China, Taiwan, Far East Russia, and Japan (
Homoeusa is distinguishable from the other myrmecophilous oxypodine genera of the Palearctic by its sub-limuloid body shape and unilobed ligula; the latter distinguishes it from the similar genus Thiasophila Kraatz, 1856, which has a bifid ligula.
The material examined in this study is deposited mostly in the Kyushu University Museum (
The morphological observations and measurements were conducted using an Olympus SZX10. On the methods of dissection and preparation of permanent slides, we followed
Measurement definitions and abbreviations are shown as follows: BL, approximate body length; AL, antennal length; HW, head width; PL, pronotal length; PW, pronotal width; EL, elytral length (sutural length from apex of scutellum to posterior margin of elytra); EW, elytral width; HTL, hind tibial length. Measurements of dorsal morphology were made on 20 specimens of each species, and then the sexes were identified. Measurements of each segment of the antenna (six specimens of each species) were made on dissected specimens mounted in Euparal.
Symbiotic hosts were mostly identified by MM, F. Ito, and some by TN and K. Kinomura.
The scientific names of Lasius ants follow
The species names of symbiotic hosts are abbreviated in “Type material” and “Additional material” as follows: Lasius fuliginosus Group: LFFJ, L. fuji Radchenko, 2005; LFFL, L. fuliginosus (Latreille, 1798); LFcfF, Lasius cf. fuliginosus; LFM, Lasius morisitai Yamauchi, 1979; LFN, L. nipponensis Forel, 1912; LFO, L. orientalis Karawajew, 1912; LFS, L. spathepus Wheeler, 1910; LJ, Lasius japonicus Santschi, 1941 (the niger group).
The distribution and host ant species of each species in the checklist is a synthesis of information from mostly
Subtribe Dinardina Mulsant & Rey, 1873
Homoeusa
Kraatz, 1856: 76 (original description, type species: Euryusa acuminata Märkel, 1842, by monotypy);
Myrmobiota
Casey, 1893: 594 (original description, type species: M. crassicornis Casey, 1893, by monotypy);
Soliusa
Casey, 1900: 53 (original description, type species: S. crinitula Casey, 1900, by monotypy);
This genus is distinguished by the following combination of characteristics: body somewhat sub-limuloid; apex of ligula unilobed and round; antennae not or weekly clubbed; posterior margin of antennal insertion forming distinct latitudinal carina extending medially; spermatheca somewhat S-shaped.
As mentioned in
Thiasophila rufescens
Sharp, 1874: 5;
Homoeusa rufescens:
Lectotype
(Figs
Japan: Honshû: Fukushima-ken: 1 unsexed, Yukiwari-bashi, Nishigô-mura, 29. VII. 2000, T. Kobayashi. Ibaraki-ken: 2 unsexed, Inohana Pass, 29. V. 1994, Y. Hagino. Tochigi-ken: 1 unsexed, Tobiyama Castle, Utsunomiya-shi, 17–18. VI. 1998, M. Maruyama (LFS); 2 unsexed, 1♀, same locality, 17. VI. 1998, M. Maruyama (LFcfF); 2 unsexed, Shimokomoriya, Utsunomiya-shi, 6. VII. 1999, M. Maruyama; 3 unsexed, Sayado, Môka-shi, 15. VI. 2000, T. Kobayashi & H. Obata; 81 unsexed, Ichikai-machi, Haga-gun, 29. IV.–2. V. 2002, Seidai Nagashima. Gunma-ken: 27 unsexed, Mt. Sakurayama, Onishi-chô, 22. V. 1999, Shiho Arai (LFS); 2 unsexed, Sakurayama Park, Onishi-chô, 18. V. 1998, Shiho Arai (LFS); 26 unsexed, 7♂, 3♀, same locality, 9. V. 1998, Shiho Arai (LJ); 10 unsexed, Sakurayama, Onishi-chô, 9. V. 1998, Koji Toyoda (LFS); 5 unsexed, Nakanojo Forest Park, Nakanojô-machi, 8. VI. 2001, T. Watanabe. Saitama-ken: 15 unsexed, Shioyama, Ranzan-machi, 21. VI. 1996, Koji Toyoda; 10 unsexed, same locality, 8. VI. 1997, Koji Toyoda (LFcfF); 16 unsexed, same locality, 10. V. 1998, K. Toyoda (LFcfF); 3 unsexed, Shôgunsama, Ranzan-machi, 21. IV. 1999, K. Toyoda; 1 unsexed, Sugiyama, Ranzan-machi, 13. VII. 1998, K. Toyoda; 13 unsexed, Toki-gawa, Kamagata-mura, Ranzan-machi, 25. IV. 1999, K. Toyoda; 2 unsexed, Shiro-yama, Kamagata-mura, Ranzan-machi, 17. VI. 2000, K. Toyoda (LFcfF); 4 unsexed, Ranzan-keikoku, Kamagata-mura, Ranzan-machi, 14. V. 2000, K. Toyoda; 2 unsexed, Hashidake, Chichibu-shi, 26. IV. 1998, S. Arai; 2 unsexed, Nakano, Showa-machi, 4. V. 2002, Hiromu Kamezawa (LFS) (cKam); 1 unsexed, same locality, 26. VI. 2001, H. Kamezawa (LFcfF) (cKam); 2 unsexed, same locality, 4. V. 2002, H. Kamezawa (LFcfF) (cKam); 5 unsexed, same locality, 4. V. 2003, H. Kamezawa (LFcfF) (cKam); 1 unsexed, Yokoze-machi, Chichibu-shi, 10–11. V. 1995, Yoshinori Kaneko, Akio Ito, Satoshi Tsuboyama. Chiba-ken: 1 unsexed, Mt. Kiyosumi, Amatsukominato, 9. VI. 1991, T. Takeda; 1 unsexed, Azeta, Sakura-shi, 20. VI. 1998, M. Maruyama (LFS); 1 unsexed, 1♀, same locality, 23–24. VI. 1998, M. Maruyama (LFS); 2 unsexed, same locality, 26. VI. 1998, M. Maruyama (LFS). Tôkyô-to: 1 unsexed, Mt. Takao, 1. V. 1985, S. Nomura; 2 unsexed, same locality, 13. V. 1985, S. Nomura; 2 unsexed, Takao-san (450 m in alt.), Hachioji-shi, 4. VI. 2001, M. Maruyama (LFS); 1 unsexed, Otomeyama Park, Shinjuku-ku, 13. V. 1985, S. Kubota; 3 unsexed, Dokan-bori, Imperial Palace, 17. V. 2000, T. Shimada (NSMT); 34 unsexed, Kami-dokan-bori, Imperial Palace, 17. V. 2000, Shiho Arai (LFcfF) (MSMT). Kanagawa-ken: 2 unsexed, Kawasaki-shi, 1. V. 1985, S. Kubota; 3 unsexed, Ikuta-Ryokuchi, Kawasaki-shi, 13. IV. 2002, K. Matsumoto; 1 unsexed, Mt. Masukata, Kawasaki-shi, 15. VI. 1996, K. Kawada; 1 unsexed, Jinmu-ji, Zushi-shi, 20. VI. 2003, M. Maruyama; 1 unsexed, Mt. Tanzawa, 26. VI. 1983, Y. Hirano; 1 unsexed, Kawana, Fujisawa, 19. VI. 2000, T. Watanabe (LFS); 1 unsexed, same locality, 7. V. 2001, T. Watanabe (LFcfF); 3 unsexed, 1♂, same locality, 14. V. 2001, T. Watanabe; 6 unsexed, Toya, Tsukui, 11. V. 1976, Ryo Kiryu (SCM); 6 unsexed, same locality, 29. IV. 1977, Ryo Kiryu (SCM); 2 unsexed, Mikage, Tsukui, 18. V. 1976, Ryo Kiryu (SCM); 1 unsexed, same locality, 23. IV. 1977, Ryo Kiryu (SCM); 1 unsexed, same locality, 9. VI. 1979, Ryo Kiryu (SCM). Yamanashi-ken: 2 unsexed, Karumizu-rindô, (1400 m in alt.), Narusawa, 29. VI. 2011, T. Watanabe. Shimane-ken: 1 unsexed, Urahikimi, 6. VI. 1988, S. Nomura. Okayama-ken: 1 unsexed, Ono Shine, Kawakami, Ohara-chô, Mimasaka-shi, 7. VI. 2009, Yoshifumi Fuzitani; 5 unsexed, same locality, 5. V. 2009, Yoshifumi Fuzitani (LFS). Yamaguchi-ken: 3 unsexed, Nishimagura, (100 m in alt.), Kusunoki, 30. V.–1. VI. 2000, Toshio Kishimoto. Shikoku: Kagawa-ken: 7 unsexed, 1♂, Usa-Jinja, Nagaona, Sanuki-shi, 31. V. 2001, M. Maruyama (LFS); 11 unsexed, 1♂, 1♀, Ôtaki-san, Shionoe-chô, 2. VI. 2001, M. Maruyama (LFN); 1 unsexed, Fujio-Jinja, Nishiuta-chô, Takamatsu-shi, 31. V. 2001, M. Maruyama (LFS); 4 unsexed, same locality, 1. VI. 2001, M. Maruyama (LFN); 5 unsexed, Furodani, Miki-chô, 30. VII. 2000, K. Izawa; 1 unsexed, Kamiyama, Miki-chô, 1. VI. 2001, M. Maruyama (LFS); 4 unsexed, Ôtawa, Nagano-chô, 22. V. 2000, F. Ito; 11 unsexed, Atago-yama, Kotohira-chô, 1. VI. 2001, M. Maruyama (LFS). Ehime-ken: 1♂, Sugitate, 17. VI. 2017, Yu Hisasue. Kyûshû: Fukuoka-ken: 1 unsexed, Hikosan, Biol. Lab. KU, Soeda-machi, 8–10. V. 1957, K. Morimoto; 1 unsexed, same locality, 7. VI. 1993, S. Nomura; 3 unsexed, Hikosan, Biol. Lab. KU (750 m in alt.), Soeda-machi, 22. V. 2011, M. Maruyama (LFcfF); 1 unsexed, Kusaba, Nishi-ku, Fukuoka-shi, 28. IV. 2018, Tsubasa Nozaki; 1 unsexed, Motooka, Nishi-ku, Fukuoka-shi, 29. IV. 2020, Tsubasa Nozaki; 1 unsexed, Mt. Shioji, Otogana, Onojo-shi [33.5416°N, 130.5023°E], 28. V. 2017, Yu Hisasue (LFS). Saga-ken: 1 unsexed, Tôsen-zan, Ureshino-shi, 29. IV. 2018, Mitsuyasu Nishida (fit). Nagasaki-ken: 4 unsexed, Tanukinoo, Masuragahara-machi, Ômura-shi, 5. V. 2018, Mitsuyasu Nishida. Kumamoto-ken: 1 unsexed, Shiraga-dake, 4. XI. 1984, M. Ohara (
It is distinguished from the other species of the genus by the following combination of characteristics: body small, slender and subparallel-sided; pronotum less transverse (PW/PL, 1.38–1.47), widest near middle, posterolateral angle obtuse, posterior margin hardly sinuate; apical lobe of male aedeagus thick with round sheet-like projection; apical lobe of paramere straight; velum broad and round.
Body
(Figs
Head
(Fig.
Pronotum
(Fig.
Abdomen elongate, slightly narrowed posteriad; surface sparsely covered with short setae and each posterior margin with long stout setae; polished and weekly reticulated.
Male: 8th sternite longer than wide, weakly rounded apically. Median lobe of aedeagus (Fig.
Female: 8th sternite longer than wide, weakly rounded apically. Spermatheca (Figs
Body shape (N = 20): BL ≈ 1.6–2.7; AL, 0.64–0.75; HW, 0.41–0.47; PL, 0.44–0.50; PW, 0.61–0.70; EL, 0.38–0.44; EW, 0.65–0.73; HTL, 0.42–0.48; PW/PL, 1.38–1.49; PW/HW, 1.38–1.57; AL/HW, 1.45–1.77. Aspect ratio (length/width) of each antennal segment from I to XI (N = 6): 1.36–1.58, 1.43–1.71, 1.15–1.22, 0.63–0.77, 0.52–0.63, 0.43–0.53, 0.44–0.50, 0.39–0.49, 0.43–0.51, 0.49–0.56, 1.26–1.54.
In most individuals, the pronotum tends to be brownish red, but the color varies from brownish red to brownish black.
Japan (Honshû, Shikoku, Kyûshû).
From April to July, this species can be found in the trails of the Lasius fuliginosus species group (Fig.
Lasius cf. fuliginosus, L. morisitai, L. nipponensis, L. spathepus.
The original description suggested that the syntypes included another species (
In the original description, “Thiasophila rufescens” is “found with Formica japonica” (
Holotype. “Mt. Maruyama / Sapporo-shi / <Hokkaido, JAPAN> / 6. VI. 1988 / M. Maruyama leg. / trail of ants” (LFcfF). Paratypes. 1♂, (ex type series of “Thiasophila rufescens”), “Japan. Lewis.” / “Sharp Coll 1905-313” (no other data) (
It is distinguished from the other species of the genus by the following combination of characteristics: body subparallel-sided; pronotum convex and strongly transverse (PW/PL, 1.54–1.68), widest near middle, sides barely protrude, posterolateral angle obtuse and posterior margin hardly sinuate; apical lobe of male aedeagus S-shaped with small lanceolate sheet-like projection; apical lobe of paramere (Fig.
Body
(Fig.
Head
(Fig.
Pronotum
(Fig.
Abdomen elongate, gently narrowed posteriad; surface sparsely covered with short setae and each posterior margin with long stout setae; gently polished and weakly reticulated.
Male: 8th sternite longer than wide, rounded apically. Median lobe of aedeagus (Fig.
Female: 8th sternite longer than wide, rounded apically. Spermatheca (Figs
Body shape (N = 20): BL ≈ 1.91–2.97; AL, 0.61–0.76; HW, 0.45–0.51; PL, 0.45–0.53; PW, 0.72–0.84; EL, 0.38–0.48; EW, 0.73–0.87; HTL, 0.47–0.53; PW/PL, 1.55–1.68; AL/PL, 1.26–1.68; HTL/PL, 0.93–1.12. Aspect ratio (length/width) of each antennal segment from I to XI (N = 6): 1.29–1.67, 1.29–1.75, 0.87–1.2, 0.72–0.82, 0.50–0.55, 0.43–0.50, 0.41–0.55, 0.33–0.61, 0.38–0.48, 0.41–0.54, 1.25–1.48.
In most individuals, the pronotum tends to be darker, but the color varies from brownish red to brownish black.
Russia (Primorskyi krai), Korea, Japan (Hokkaido, Honshû, Shikoku, Kyûshû).
This species behaves almost the same as H. rufescens. It is also observed to feed on prey among ants and sometimes climbs on, and eats food carried by ants (Fig.
Photos of alive individuals of Homoeusa spp. in trails of Lasius fuliginosus species group in field environments 28, 29 H. rufescens: 28 waking on a trail of Lasius morisitai 29 feeding on food being carried by ant workers (photographed by Taku Shimada) 30, 31 H. ovata sp. nov.: 30 waking on a trail of Lasius cf. fuliginosus 31 feeding on food being carried by ant workers (photographed by Kyoichi Kinomura).
Lasius fuji, L. cf. fuliginosus, Lasius morisitai, L. nipponensis, L. orientalis, L. spathepus.
As
1. Homoeusa acuminata (Märkel, 1842): 143.
Euryusa acuminata Märkel, 1842
Homoeusa tomentosa Reitter, 1909: 38
Distribution. Azerbaijan, Austria, Belgium, Belarus, Croatia, Russia (Central European Territory), Czech Republic, France, Great Britain, Germany, Georgia, Greece, Hungary, Italy, The Netherlands, Poland, Romania, Slovakia, Spain, Russia (South European Territory), Switzerland, Russia (Far East).
Host. Lasius fuliginosus.
2. Homoeusa chinensis Pace, 1999: 150.
Distribution. China (Beijing).
Host. Unknown.
3. Homoeusa japonica Sharp, 1874: 5.
Distribution. Japan (Honshu, Shikoku, Kyushu).
Host. L. cf. fuliginosus, L. morisitai, L. spathepus.
4. Homoeusa laevigata Sharp, 1888: 283.
Distribution. Japan (Honshu).
Host. L. nipponensis.
5. Homoeusa longicornis Sharp, 1888: 283.
Distribution. Japan (Hokkaido, Honshu).
Host. L. cf. fuliginosus, L. morisitai, L. spathepus.
6. Homoeusa ovata sp. nov.
Distribution. Russia (Primorskyi krai), Korea, Japan (Hokkaido, Honshu, Shikoku, Kyushu).
Host. L. fuji, L. cf. fuliginosus, L. morisitai, L. nipponensis, L. orientalis, L. spathepus.
7. Homoeusa prolongata Sawada, 1970: 57.
Distribution. Japan (Hokkaido, Honshu, Shikoku, Kyushu).
Host. L. japonicus.
8. Homoeusa rufescens (Sharp, 1874): 5.
Thiasophila rufescens Sharp, 1874
Distribution. Japan (Honshu, Shikoku, Kyushu).
Host. L. cf. fuliginosus, L. morisitai, L. nipponensis, L. spathepus.
9. Homoeusa sibirica Rambousek, 1921: 86.
Distribution. Russia (Far East), Korea (South).
Host. Unknown.
10. Homoeusa taiwanensis Pace, 2010: 29.
Distribution. Taiwan (Kaohsiung).
Host. Unknown.
11. Homoeusa crinitula (Casey, 1900): 53.
Soliusa crinitula Casey, 1900
Homoeusa frosti (Casey, 1911): 53
Soliusa frosti Casey, 1911
Distribution. America (New York, Massachusetts).
Host. Unknown.
12. Homoeusa crassicornis (Casey, 1893): 595.
Myrmobiota crassicornis Casey, 1893
Distribution. America (Iowa).
Host. Unknown.
We would like to express our gratitude to Dr Takato Kobayashi (Yamanashi Institute of Environmental Science, Yamanashi pref., Japan), Mr Hiromichi Obata (Kanagawa pref., Japan), Dr Shuhei Nomura (NSMT), Mr Shigehisa Hori (Hokkaido Museum, Hokkaidô, Japan), Dr Fuminori Ito (Kagawa University), Mr Yasunari Kida (Maruseppu Insectarium, Hokkaidô, Japan), Mr Takashi Watanabe (Kanagawa pref., Japan), Mr Koji Arai [Koji Toyoda], Ms Shiho Arai (Ranzan-machi, Saitama pref.), Mr K. Izawa, Mr Hiromu Kamezawa (Saitama pref.), Mr Kyoichi Kinomura (Gifu pref.), Mr Yu Hisasue (Kyushu University, Fukuoka, Japan), and all other collectors for kindly offering the specimens. We would like to show our great appreciation Mr Taku Shimada (Tokyo pref.), K. Kinomura and Ms Mari Muto (Gifu pref.) for kindly allowing the use of photos of alive individuals in fields. MM thanks Dr Roger Booth (