Leiodes osawai Nakane 1963
Creators: name: Hoshina, Hideto
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Leiodidae
Leiodes
Leiodes osawai

description: 30. Leiodes osawai Nakane, 1963
Japanese name: Ôsawa-ô-tamakinokomushi (Figs. 1, 6, 87–90, 108)
Leiodes osawai Nakane, 1963: 41; DAFFNER (1983): 71 (redescription); PERREAU (2004): 197 (catalogue).
Type locality. Japan, Honshu, Aichi Prefecture, Nagoya, Higashiyama.
Type material examined. JAPAN: HONSHU: HOLOTYPE: ♂, Aichi Pref., Nagoya City, Higashiyama, 1.iv.1947, S. Tabuchi leg. (HUMS). ALLOTYPE: ♀, same data as the holotype.
Additional specimens examined. JAPAN: HONSHU: 1 ♀, Mie Pref., Kise Town, Nako, 19.i.1997, K. Kannô leg. (FUFJ); 1 ♂, Mie Pref., Kameyama City, Mt. Nonoboriyama, 10.iii.2002, M. Inagaki leg. (FIT) (FUFJ); 1 ♂, Yamanashi Pref., Nirasaki City, Gozaishi-onsen, 26.iii.1991, K. Hosoda leg. (KM); 2 ♂♂, 1 ♀, Kanagawa Pref., Ninomiya Town, Mt.Adumayama, 17.xii.2000. Y. Hirano leg. (FUFJ); 1 ♂, Tokyo Pref., Okutama Town, Nippara, Ogawadani (alt. 1000m), 24.iii.2007, H. Kamezawa leg. (FUFJ); 1 ♀, Tochigi Pref., Ashikaga City, Ô-numatachô, 23.–31.iii.2010, H. Ohkawa leg. (FIT) (FUFJ); 1 ♀, Tochigi Pref., Ashikaga City, Ô-numata-chô (alt. 100 m), 30.iii.–4.iv.2011, H. Ohkawa leg. (FIT) (FUFJ).
Diagnosis. Coloration. Dorsum almost bicolored (Figs. 87D, 87F) or tricolored (Figs. 87C, 87E); head brown or dark brown; pronotum brown; elytra bicolored, light brown or brown, with black stripes near elytral suture (Figs. 87C, 87D) and lateral margins (Figs. 87E, 87F); scutellum black; antennomeres 1–6 and 8 reddish brown; antennomeres 7, 9, 10, and basal 3/5 of antennomere 11 black; apical 2/5 of antennomere 11 light brown.
Body 3.8–5.1 mm long, ca. twice as long as wide, cylindrical (Fig. 87A). Head densely and minutely punctate, bearing some large punctures in some specimens (Fig. 87A); antennomeres 1–3 each longer than wide, remaining antennomeres each wider than long; antennomere 11 robust (Fig. 87G). Pronotum simply and very feebly curved at posterior margin and distinctly and densely punctate (Fig. 87A). Elytra not transversely strigose; each elytron with nine rows of punctures, bearing small number of large punctures and many very fine punctures between rows (Fig. 87H); row 9 invisible in dorsal view, subhumeral row as long as ca. 1/4 of elytral length (Fig. 87B); rows composed of punctures larger than those of pronotum (Fig. 87A); sutural stria fine, reaching from apex to ca. apical half of elytral length. Metathoracic wings fully developed. Mesoventrite with one distinct excavation between median carina and transverse carina (Fig. 87I); median carina of mesoventrite low (Fig. 87I); metaventrite sexually dimorphic. Legs showing sexual dimorphism on protarsi, mesotibiae, mesotarsi, metafemora, and metatibiae; protibiae gradually and very feebly widening from base towards apex (Figs. 89E, 89F); metafemur with a small dorsal projection posteroapically (Figs. 89G, 89H).
Male. Metaventrite pubescent on middle portion (Fig. 88A); tarsomeres 2–4 of protarsi and mesotarsi expanded (Figs. 88C, 88E); mesotibiae expanded at interoapical corner, longest spine at the corner almost straight or strongly curved inwards (Figs. 88E, 88F); metafemora feebly or strongly protuberant at about midlength of posterior margins (Figs. 89A, 89B, 89C); metatibiae almost straight or moderately to strongly curved (Figs. 89A, 89B, 89C); abdominal sternite 8 strongly curved (Fig. 90C); aedeagus as shown in Figs. 90A and 90B.
Female. Metaventrite almost glabrous on middle portion (Fig. 88B); protarsi and mesotarsi slender (Figs. 88D, 88G); mesotibiae feebly and simply widening from base to apex, longest spine at interoapical corner almost straight (Fig. 88G); metafemora slender, almost straight at posterior margins (Fig. 89D); metatibiae almost straight (Fig. 89D); abdominal sternite 8 with a spiculum ventrale at central point of anterior margin (Fig. 90D); coxites and stylus as shown in Fig. 90E.
Morphological variability. The present species shows intraspecific variation in dorsal coloration and the shape of the male mesotibiae, metafemora, and metatibiae. In the specimens collected in the western region (Mie and Aichi Prefectures, see Fig. 108), the elytra are light brown with relatively slender black stripes near the elytral suture and along the lateral margins (Figs. 87C, 87E), and the male hind legs are conspicuously curved (i.e., secondary sexual characters are well-developed (Fig. 89A)). On the other hand, specimens from the eastern region (Yamanashi, Kanagawa, and Tokyo Prefecturs, see Fig. 108) have the elytra brown with relatively broad black stripes (Figs. 87D, 87F) and the male hind legs have relatively indistinct secondary sexual characters (Figs. 89B, 89C). In contrast, the male genitalia do not show the regional variation in the specimens examined. For that reason, I do not establish any new species or subspecies and consider the observed differences as intraspecific regional variation. This needs to be confirmed by additional specimens in the future, as only nine specimens were examined for this study. One male specimen from the Tokyo Prefecture (Fig. 108) is the smallest (body length 3.8 mm) and has mesotibiae, metafemora and metatibiae similar to those of females (Fig. 89C). It is possible that those features are correlated to body size, and body size varies regionally.
Differential diagnosis. Leiodes osawai can be easily distinguished from all other Japanese species of Leiodes by having an elongate cylindrical body (Fig. 87A).
Distribution. Japan: Honshu.
Taxonomic note. DAFFNER (1983) mentioned that L. osawai is morphologically very similar to L. lucens (Fairmaire, 1855). However, this note was solely based on the original description of L. osawai by NAKANE (1963), not on the examination of type specimens. The original description of male legs of L. osawai may really resemble those of L. lucens and the original description does not include any figures. In addition, both L. osawai and L. lucens have a similar large trident sclerite in the inner sac of the aedeagus (Fig. 79A, 90A). However, L. osawai can be separated from L. lucens by having a cylindrical body (Fig. 87A), bicolored or tricolored dorsum (Figs. 87C, 87D, 87E, 87F), relatively slender metafemora (Figs. 89A, 89B, 89C, 89D), and the aedeagus feebly curved in lateral view (Fig. 90B). In contrast, L. lucens has a long oval body (Fig. 77A), unicolor dorsum, relatively robust metafemora (Figs. 78C, 78D), and the aedeagus relatively strongly curved in the lateral view (Fig. 79B).
description: Published as part of Hoshina, Hideto, 2012, Review of the tribes Sogdini and Leiodini from Japan and North Chishima Islands. Part II. Genera Hydnobius and Leiodes (Coleoptera: Leiodidae), pp. 1-168 in Acta Entomologica Musei Nationalis Pragae (suppl. 1) (suppl. 1) 52 on pages 129-134, DOI: 10.5281/zenodo.4272467