Small size (2.7–3.2 mm) and scattered, squamiform, appressed setae on the elytron make Limnobaris albosparsa a distinctive species around the Eastern Sea (Sea of Japan). The aedeagus is identical to that of the more southern Limnobaris tibialis except for its somewhat wider base (Fig. 10 vs. Yoshihara and Morimoto 1994: 451), and the two species usually have a sharply pointed tooth on the ventral edge of the male protibia (Fig. 5). However, they are allopatric (Fig. 13) and Limnobaris tibialis has erect rather than appressed setae on the elytron. Other small species, like Limnobaris basalis, Limnobaris elliptica and Limnobaris martensi, have a blunt male protibial tooth and lack scattered squamiform setae on the elytron.

The species has been reported from Japan (Honshu), Russia (Khabarovsk and Primorsky krajs) and South Korea (Reitter 1910, Egorov 1976, Yoshihara and Morimoto 1994, Hong et al. 2000, 2011, Legalov 2009). It may occur also in the Chinese provinces Heilongjiang and Jilin (Fig. 13).

Nojima (in Yoshihara and Morimoto 1994) found specimens on Carex dickinsii Franch. and Savat. in Yoshikawa, Japan. Most known collecting dates fall between the middle of May and the end of June. Three specimens were collected in August and September (ZIN, data below) and indicate that the new generation emerges in the same year and overwinters in the adult stage.

RUSSIA. Primorsky Kraj: Golubiny Utes, 27.viii.1988 (ZIN 1); Kamen'-Rybonov 20 km NW, 26.vi.1974 (ZIN 3); Kamenushka, 12.vi.1989 (ZIN 1); Khanka Lake, 20 km W Spassk, 12.vi.1989 (ZIN 1); Provalovo, 12.ix.1982 (ZIN 2).

The Japanese Limnobaris babai is very similar to Limnobaris elliptica from Myanmar and South China. These two species can be distinguished from all others by the blunt ventromedian process on the male protibia and almost glabrous elytra. Limnobaris babai is on average larger than Limnobaris elliptica (3.5–4.5 mm vs. 3.2–3.8 mm), has shorter setae on the profemur, an apically rounded penis and the female protibia has a moderate ventromedian projection which is more subtle in Limnobaris elliptica. However, we have not compared specimens of the same size and these differences may not always hold. Limnobaris basalis, another morphologically similar species from Fujian, is smaller (2.3–3.1 mm) and has a longer rostrum.

The species occurs in Honshu and Kyushu, Japan (Yoshihara and Morimoto 1994).

Adult weevils have been collected from Carex sp. (Yoshihara and Morimoto 1994).

JAPAN. Saitama Pref., Urawa City, 23.v.1998 (JPPC 4).

Limnobaris basalis is a small species (2.3–3.1 mm) with white, squamiform setae on the elytral base. Males can be distinguished from the equally small Limnobaris albosparsa and Limnobaris tibialis by the shape and position of the ventral process on the protibia (Fig. 3). Abraded females of Limnobaris basalis and Limnobaris tibialis may be distinguished by body proportion (Limnobaris basalis is slightly stouter) and host association, Limnobaris basalis and Limnobaris albosparsa by allopatry. Other similar but allopatric species are Limnobaris babai (Japan) and Limnobaris elliptica (South China, Myanmar). They are larger, have smaller and fewer scales on the elytral base and a shorter rostrum.

The species is known from several sites in Fujian Province, China (Fig. 13).

The overwintered weevil appears on Scirpus in early April and feeds on the leaves. In late April, when the plant flowers in Fujian, we observed numerous specimens on the inflorescence. The larva develops in the culm, apparently most successfully in the basal, often submerged internode. Occupants of more distal internodes frequently were parasitized by an unidentified species of the Eupelmus (s. str.)urozonus Dalman group (Eupelmidae, Hymenoptera). Pupation starts in June and newly eclosed adults appear in July. In middle July 2013, we found mostly larvae, approximately one third pupae and one eclosed adult in the culms we dissected.

Pertorcus tibialis basalis is transferred here to Limnobaris and raised to full species rank based on plant association, molecular data and morphological details of the protibia, genitalia and vestiture.

CHINA. Fujian: 建阳坳头[?]田坵 [?tianqiu, Aotou, Jianyang], 25.iv.1965 (IZCAS 1); 建阳坳头三板桥 [Sanban Bridge, Aotou, Jianyang], 19.iv.1965, 26.iv.1965, 18.v.1991 (IZCAS 3); Daanyuan, Wuyi Mts., 24.–27.iv.2013 (BMNH 4, IZCAS 17, JPPC 11, ZIN 4), 16.–19.vii.2013 [larvae, pupae, 1 adult, parasites] (IZCAS, JPPC); Guadun, Wuyi Mts., 1.iv.1938 (PT), 2.iv.1938 (HT), 7.iv.1938 (4x), 8.iv.1938 (5x), 12.iv.1938 (2 PT), 15.iv.1938, 16.iv.1938, 19.iv.1938, 25.iv.1938 (5x), 27.iv.1938, 5.v.1938, 6.v.1938 (1 + 1 PT), 7.v.1938 (AKMB 25); 大竹栏 [Dazhulan], 4.vii.1965 (IZCAS 1); Guangze, 5.ix.1937 (AKMB 1); 建阳黄坑新历 [Xinli, Huangkeng, Jianyang], 25/27.v.1965 (IZCAS 2); 建阳黄坑 [Huangkeng, Jianyang], 10.–13.iv.1965 (IZCAS 4); 建阳将乐龙栖山 [Longqi Mts., Jiangle, Jianyang], 19.iv.1965, 3.vii.1965, 17.–19.v.1991 (6x), 1.viii.1991 (IZCAS 9); 梅花山双车村 [Shuangche Village, Meihua Mts.], 6.xi.2008 (IZCAS 1); 黄坑大竹篮先峰岭 [Xian Fengling, Huangkeng Dazhulan, Jianyang], 28.v.1960 (IZCAS 2).

Limnobaris dolorosa has characteristic ventrolateral vestiture of dense, squamiform setae, which occurs also in Limnobaris t-album and Limnobaris japonica. All three species can be distinguished from each other based on details of the male genitalia and vestiture. In addition, Limnobaris japonica is allopatric (see under this species for further details). The safest way to separate Limnobaris dolorosa from Limnobaris t-album is the short and wide penis (Figs 6, 7). Moreover, Limnobaris dolorosa has evenly dense vestiture on the entire flank, whereas Limnobaris t-album usually has less dense vestiture on the first ventrites and the metasternum.

Specimens with a dolorosa-type of aedeagus show regional variation in size, body shape, vestiture and surface sculpture. Dieckmann (1991) mentioned disjunct, aberrant populations of unusually large specimens, one of which was found on Cladium mariscus (L.) Pohl rather than Carex. This scarce material was collected at sites with mild winters and cool summers (Swedish Baltic islands and Adige River valley in South Tyrol). Our own study showed that the East Asian Limnobaris jucunda is a population with a dolorosa-type of aedeagus that is morphologically indistinguishable from European Carex-associated specimens. However, small, densely squamose specimens with the same male genitalia occur in Transbaikal, Mongolia and adjacent Northeast China. Further studies with inclusion of molecular and ecological data of geographically representative material are needed to better understand the nature of this variation. We therefore follow Dieckmann (1991) and consider Limnobaris dolorosa (and, likewise, Limnobaris t-album) as a morphologically and ecologically polytypic species.

The range of Limnobaris dolorosa extends from Western Europe (without Iberian Peninsula) to the Pacific coast (apparently without offshore islands, although Legalov (2010) reported the species from the Kuril Islands, possibly a misidentification of Limnobaris japonica). In China, the species has been found in Heilongjiang, Inner Mongolia and Jilin (Fig. 13).

Because of taxonomic confusion with Limnobaris t-album, published life history data are unreliable and need verification. Specimens of the typical size range occur on Carex rostrata Stokes ex With. in Scotland (Cawthra 1957; see Morris 2009 for weevil identification) and Northern Germany (J. Prena, unpubl. data). Palm (1957) found very large specimens (up to 7 mm) on Cladium mariscus in the Baltic islands Öland and Gotland. Hoffmann (1955) mentioned Scirpus sylvaticus L. as a host plant. In Jilin Province, we found Limnobaris dolorosa in mixed stands of Scirpus and tall Carex species (mostly Carex rhynchophysa C. A. Meyer, some Carex drymophila Turczaninow ex Steudel), occasionally in pure Carex stands. Feeding occurred on leaves of Carex rhynchophysa and Scirpus. Life history data published by Kleine (1910), Hoffmann (1955) and Cawthra (1957) on Limnobaris t-album almost certainly apply to Limnobaris dolorosa. According to Kleine (1910), the larva develops in the stem of Cladium mariscus. Cawthra (1957) reported that eggs are laid in the basal part of the leaf of Carex rostrata and that the larva bores down to the rhizome, overwinters, and pupates inside the plant in late May. Hoffmann (1955) described an almost identical development in Schoenoplectus lacustris (L.) Palla.

CHINA. Heilongjiang: 哈尔滨 [Haerbin], 31.v.1943 (IZCAS 2); 虎林 [Hulin], 9.vi.1971 (IZCAS 3); 虎林虎头 [Hutou, Hulin], 9.vi.1971 (IZCAS 2); 二層甸子 [Ercengdianzi, =Yuquan], 15.vi.1941, 30.vi.1941 (3x) (IZCAS 4). Inner Mongolia: 海拉尔嵯岗 [Cuogang, Hailaer], 22.vi.1994 (IZCAS 1). Jilin: Changbai Mts., Dongwo, 8.–11.vi.2013 (IZCAS 11, JPPC 8). MONGOLIA. Dornod Aymag: Duro-Nur Lake [Dörgön núr], 15 km W Khukh-Nur Lake, 28.vi.1976 (ZIN 1). RUSSIA. Zabajkal’skij Kraj: Darasun, 28.vi.1975 (ZIN 2); Soktuj, 23.vi.1925 (ZIN 1). Irkutskaya Oblast: Irkutsk, vii.1994 (JPPC 1). Kemerovskaya Oblast: Tyazhin, 17.vi.1958 (IZCAS 1). Republic of Buryatia: Kjakhta District, NW Kiram, 27.vi.1999 (JPPC 1); Barun-Torej Lake, Ulza River, 29.vi.1925 (ZIN 2).

Limnobaris elliptica is very similar to Limnobaris babai from Japan. These two species can be distinguished from all others by the short, curved rostrum, the blunt ventromedian process on the male protibia and almost glabrous elytra. Limnobaris elliptica is on average somewhat smaller than Limnobaris babai (3.2–3.8 mm vs. 3.5–4.5 mm), has an apically pointed penis (rounded in Limnobaris babai) and at least the males have longer setae on the underside of the profemur. Limnobaris basalis, another similar species, has a longer rostrum, larger scales on the elytral base and occurs in Fujian. The Nepalese Limnobaris martensi is slenderer and almost entirely glabrous.

The species is known from three sites west of the Gaoligong Mountains in the border region between Myanmar and Yunnan Province, China (Fig. 13).

We found larvae, pupae and freshly eclosed adults inside flowering culms of Scirpus wichurai Böckeler in late September. A few specimens already had exited the plant and one was observed on a tall Scleria species, which does not appear to be a larval host. Many larvae were killed by three to five specimens of an apparently undescribed Entedon Dalman species (Eulophidae, Hymenoptera), a large and widespread genus known to parasitize beetle larvae (C. Hansson, in litt.). The weevil overwinters and the first specimens appear on the host plant in late March.

CHINA. Yunnan: 盈江伐木場 [Famuchang (logging headquarter), Yingjiang ], 1700 m, 13.iv.1980 (IZCAS 3); Xiaozahe, Tengchong County, 1800 m, 26.ix.2013 (IZCAS 4, JPPC 4, ZIN 2). MYANMAR. Kachin: Kambaiti [Kan Paik Ti], Myitkyina District, 2130 m, 28.iii.–3.iv.1934 (3x), 14.iv.1934 (BMNH 4).

Limnobaris japonica is the only species in Hokkaido, Honshu and the Kuril Islands that has dense lateroventral vestiture. Unlike Limnobaris dolorosa and Limnobaris t-album, the two other species with this trait, Limnobaris japonica has squamiform vestiture also on the prosternum. The penis is similarly elongate as in Limnobaris t-album but apically more gradually narrowed.

The species occurs in Hokkaido and Honshu (Yoshihara and Morimoto 1994) and Sakhalin Oblast (Egorov et al. 1996) (Fig. 13).

Adult weevils have been collected from Carex thunbergii Steud. and unidentified Carex species (Yoshihara and Morimoto 1994).

JAPAN. Hokkaido, Fukushima-cho, Sengen, 13.vi.1998 (JPPC 2). RUSSIA. Sakhalin Oblast: Kunashir Island, Yushno-Kurilsk, 15.vi.1991 (ZIN 1).

Limnobaris kabakovi is a relatively large (4.1–4.6 mm) species with ventral projection on the male protibia and scattered, appressed, squamiform setae on the elytron. Similarly appressed elytral vestiture occurs also in Limnobaris albosparsa, but that species is smaller and occurs only around the Eastern Sea. At least the type series of Limnobaris kabakovi has brownish elytra.

The species is known only from the type locality, a mountain resort and national park in Northern Vietnam (Fig. 13). This is the most southern record for a species of Limnobaris.

Unknown.

VIETNAM. Tinh Vinh Phuc: Tam Dao, 25.ii.1962 (ZIN 5).

Limnobaris kumei is the only known species that has neither dense lateroventral vestiture nor a male protibial projection. Moreover, the rostrum is longer and sexually more dimorphic than in other congeners. Females have the antenna inserted in the basal half of the rostrum, a condition otherwise noticed only in Limnobaris albosparsa and Limnobaris tibialis.

The species is known from the Ryūkyū Islands (Okinawa) and Taiwan (Fig. 13).

Adult weevils were collected from unidentified Cyperaceae (Yoshihara and Morimoto 1997).

TAIWAN. [data not recorded] (BPBM 1).

Limnobaris martensi is a shiny, almost entirely glabrous species that has just a few inconspicuous setae on the ventral side and the legs (Fig. 2). The slightly bulging apical section of the tenth interstria is nearly smooth in Limnobaris martensi but more or less serrated in the other glabrous species Limnobaris babai and Limnobaris elliptica. Very slender, abraded Limnobaris tibialis can be distinguished from Limnobaris martensi by the sharply pointed, more basally inserted male protibial projection and apically round penis (Figs 8, 10).

Rostrum as long as pronotum, weakly and evenly curved, cylindrical, parallel-sided in basal 2/3, slightly dilated to apex; depression before eyes very weak but distinct. Dorsal surface of rostrum evenly convex, with short striole at level of antennal insertion; shiny, with sparse minute round punctures. Sides of rostrum at base with denser and larger elongate punctures. Antennae inserted at 0.57 × length of rostrum from base, antennal scrobe shortly continued beyond base of antenna. Ventral margin of antennal scrobe merging with lateroventral edge of rostrum at half way to eye; dorsal margin of scrobe reaching eye. Scape of antenna slender, shortly widened at apex. First segment of funicle 1.5 × as long as wide, 2nd slightly longer than wide, 3rd weakly transverse, 4–7th moderately to strongly transverse. Base of club very broadly rounded, almost truncate, but clearly separated from broad 7th funicular segment, apex of club broadly rounded. Frons weakly convex, at anterior margin as broad as base of rostrum, slightly widened posteriad, shiny, with sparse small punctures. Vertex with reticulate microsculpture. Eyes large.

Pronotum 1.1 × as wide as long, parallel-sided in basal half, then weakly narrowed to shallow apical constriction. Base of pronotum feebly bisinuate. Disc weekly and evenly convex, sub-matt due to reticulate microsculpture, with rather sparse fine, somewhat angular, round or oblong punctures, separated usually by not less than own diameter, in some places by 2–3 × diameter. Median line without microreticulation and punctures. Scutellum shiny, nearly rectangular, feebly widened at base.

Elytra 1.8 × as long as wide, with well-pronounced humeri, parallel-sided in basal half, rather narrowly rounded at apex; sutural angle slightly sinuate. Disc flattened, with fairly abrupt declivity; preapical prominences very distinct. Striae deep and narrow, intervals flat, about 4 × as wide as striae, shiny, with 1 row of small punctures and much finer microreticulation than on pronotum. Intervals in many places distinctly impressed around sparse and inconspicuous punctures in striae.

Legs slender and fairly long. Fore tibia with large tooth slightly proximal of middle of inner surface, apex of tooth blunt (Fig. 4). 1st tarsite 1.5 × as long as wide, 2nd clearly transverse, rounded at sides, 3rd in fore tarsus 1.7 × as broad as 2nd. 5th tarsite slender, weakly widened toward apex, by one-half of its length projecting beyond lobes of 3rd tarsite. Length of claw 1.5 × width of claw-segment at apex. Penis as in Fig. 8, moderately bent ventrally at base and apex, basal apodemes shorter than in other species.

Body black; scape of antenna in basal 2/3 light brown, apical third of scape, 1st and base of 2nd segments of antennal funicle, and tarsi dark brown, humeral callus brownish. Upper side bare, legs with sparse short recumbent white setae, sides of abdomen with few inconspicuous setae.

Length of body 3.2 mm, width at shoulders 1.15 mm.

The only known specimen is from Eastern Nepal (Fig. 13).

Unknown.

Holotype male: Nepal, 272, Taplejung Distr., Kabeli Khola, N Yamputhin, S-Hang, 1700–2200 m, Kulturland/Busch, 5 Sep. 1983, J. Martens and B. Daams (SMNS).

The species is named after Dr. Jochen Martens (Mainz).

Limnobaris tibialis is a small species (2.1–3.1 mm) with sparse ventrolateral vestiture and erect setae on the elytron. Males have a sharply pointed, anteriorly directed process on the ventral edge of the protibia, which is located more basally than the blunt tooth of other species (Fig. 5). Limnobaris albosparsa, the only other species with a sharply pointed process, has a slightly wider penis basally, appressed rather than erect setae on the elytron and is allopatric. The number and width of white setae on the elytral interstriae vary considerably even in series taken at the same locality. Females may be confused with sympatrically occurring Limnobaris basalis, but the latter species has white setae crowded at the elytral base and is slightly less elongate. Most female Limnobaris tibialis can be distinguished by more basally inserted antennae.

Voss (1958) distinguished a pilose “form” with slightly different protibial process. Even though the size of setae can differ noticeably between individual specimens, transitional forms occur even in the same series. Pertocus tibialis pilifer is a new junior synonym of the nominal species.

The species is known from Southeast China (Anhui, Fujian, Guizhou, Jiangxi, Zhejiang) (Fig. 13).

In Northern Fujian, we found this species on several, ca. 20–30 cm tall Carex species. The larva develops in the basal, ca. 2 mm wide section of the culm. Pupation starts in July and newly eclosed adults appear in the same month.

CHINA. Anhui: Taipingshien, x.1932 (MCZ 30+). Fujian: Guadun, Wuyi Mts., 3.iv.1938 (PT of P. t. pilifer), 5.iv.1938 (HT + 2 PT of P. t. tibialis + 1), 8.iv.1938 (4x), 18.iv.1938 (1 PT of P. t. tibialis + 1 PT of P. t. pilifer), 20.iv.1938 (HT of P. t. pilifer), 5.v.1938 (2x), 26.v.1938 (PT of P. t. pilifer) (AKMB 15); ditto, 3.iii.1938 10.iv.1938 (PT of P. t. tibialis), 10.iv.1938 (PT of P. t. tibialis) (ZIUH 2); ditto, 7.iv.1938, 18.iv.1938 (2x) (CWOB 3); Changting, Hotien, 15.iv.1941 (BPBM 1), Changteh, Talungchan, 15.iv.1941 (BPBM 1); Daanyuan, Wuyi Mts., 24.–27.iv.2013 (BMNH 4, IZCAS 21, JPPC 12, ZIN 4), 16.–19.vii.2013 [larvae, pupae] (JPPC); 将乐龙栖山余家坪 [Yujiaping, Longxi Mts., Jiangle], 11.iv.1991 (IZCAS 2); 将乐龙栖山里山 [Lishan, Longxi Mts., Jiangle], 22. iv.1991 (IZCAS 1); 建阳黄坑桂林 [Guilin, Huangkeng, Jianyang], 11.iv.1960 (IZCAS 1); 建阳 [Jianyang], 10.v.1965 (IZCAS 1); 邵武铁洋 [Tieyang, Shaowu], 9.vi.1965, 28.vi.1965 (IZCAS 2); Shaowu, Wuyi Mts., 30.iv.1943 (BPBM 1). Guizhou: 遵义市绥阳县宽阔水自然保护区香广山村[Xiangguangshan village, Kuan Kuoshui Natural Reserve, Suiyang, Zunyi], 4.vi.2010 (IZCAS 1). Jiangxi: 九连山保护区 [Jiu Lianshan Natural Reserve], 29/30.ix.1979 (IZCAS 2). Zhejiang: 临安市西天目山禅院寺[Chanyuan Temple, West Tianmu Mts., Lin’an], 22.viii.2009 (IZCAS 2); 景宁 [Jingning], 28.vii.2010 (ZAFU 1); 庆元百山祖 [Baishanzu, Qingyuan], 16.v.1994 (IZCAS 2).

Diagnostic characters for the distinction of Limnobaris t-album and two other species with dense lateroventral vestiture are given under Limnobaris dolorosa.

The squamiform setae on the first two ventrites and the metasternum vary in size and density between local populations. Specimens with nearly imbricate setae have been recognized by some authors either as a subspecies or species. Dieckmann (1991) considered them as a subspecies because he recongized (1) a continuous northern distribution of the nominal form of Limnobaris t-album and (2) a relatively narrow transitional zone to the deviating southern form. Prena (2008) rejected the subspecies because the applied name was based on an invalid lectotype designation and the transitional zone corresponds closely with the winter isotherm indicating a possible environmental effect on the scale pattern. The issue needs to be readdressed with appropriate methods in a larger context, i.e. under inclusion of the Central Asian population named Limnobaris sahlbergi and Limnobaris sculpturata. Until this is accomplished, we suggest to include all nominal taxa with a t-album-type of aedeagus under Limnobaris t-album. The type repository of Limnobaris scutellaris Reitter, described from Utsch-Dere in South Russia, remains unknown. The herein proposed synonymy with Limnobaris t-album is based on Reitter’s comparison with that species.

Limnobaris t-album is widespread in the Palaearctic Region and apparently extends further north than the other common species, Limnobaris dolorosa. In fact, Limnobaris t-album is the only baridine weevil worldwide that reaches either of the polar circles. The most eastern records are from Mongolia (ca. 95°E), Xinjiang Province, China (ca. 90°E) and the adjacent Russian territory (Legalov 2010).

Because of taxonomic confusion with Limnobaris dolorosa, published life history data are unreliable and need verification. The adult occurs on Carex acutiformis Ehrh. between middle May and early July in Northern Germany (J. Prena, unpubl. data). Carex atherodes Spreng., Carex pseudocyperus L., Carex rostrata and Scirpus sylvaticus grew occasionally nearby but received no attention by the weevil. Reports from Carex rostrata, Carex vesicaria L. and the tall sedges Cladium mariscus and Schoenoplectus lacustris (i.e., Heyden in Brisout 1870, Heyden 1877, Sahlberg 1892, Kleine 1910, Hoffmann 1955, Cawthra 1957, Scherf 1964) may apply to Limnobaris dolorosa. Associations with plants other than sedges are accidental.

CHINA. Xinjiang: 青河县达巴特新村 [Dabate, Qinghe], 7.vii.2009 (IZCAS 1); Turpan (HNHM 1). KAZAKHSTAN. Aulie-Ata [=Taraz] (HNHM 3); Wernyi [=Almaty] (HNHM 1, SFFM 6). KYRGYZSTAN. Bishkek (HNHM 2); Ketmen’tebe (HNHM 1); Tschu [Tschüi] River, Issyk-kul [Ysyk-Köl] (SDEI 1); Yssik-kul [Ysyk-Köl] (SNSD 3). MONGOLIA. Sargyn-Gobi, S Som. Sarga, Aimak Gobi Altai, 970 m, 18.–20.vi.1964 (MNKB 1). RUSSIA. Novosibirskaya Oblast: Kuibyshev Distr., Zonovo, 29.v.1961 (IZCAS 1). UZBEKISTAN. Jizzakh Prov.: Djizak [Jizzakh] (SNSD 1).