Lathrobium (s.str.) viduum Eppelsheim, 1893

Ryvkin, Alexandr B., 2011, On new and poorly known Lathrobium (s. str.) species from Siberia and the Russian Far East (Insecta: Coleoptera: Staphylinidae: Paederinae), Baltic Journal of Coleopterology 11 (2), pp. 135-170 : 161-163

Lathrobium (s.str.) viduum Eppelsheim, 1893

( Figs. 9–10, 12–14)

Lathrobium viduum Eppelsheim, 1893 , Deutsche Entomologische Zeitschrift, 1893(1): 51

Lathrobium viduum ; Heyden, 1898: 34 Lathrobium (Lathrobium) viduum ; Jakobson, 1909: 492

Lathrobium (s.str.) viduum ; Tichomirova, 1973: 179

Lathrobium viduum ; Bordoni, 1980, Frustula Entomologica (Nuova Serie), 2(15): 17 Lathrobium (s.str.) viduum ; Coiffait, 1982, Nouvelle Revue d’Entomologie. Suppl., 12(4): 381 Lathrobium (s.str.) viduum ; Shavrin, 2007, Baltic Journal of Coleopterology, 7(2): 175

Material. RUSSIA: TCHITA AREA: 1 female (AVSh): near Malyie Kovali, Chichatka River. 20– 28.07.1999. A. V.Shavrin leg. [with the apex of abdomen damaged; ‘ Lathrobium brunnipes [det. Shavrin]’]— 1 female (AVSh): Uletovskiy District, 2 km S of Shelokhan, left side of Ingoda River. 07.08.2008. I. V.Enushchenko leg.— AMUR AREA: 1 male ( AR): Selemdzhinskiy District, Norskiy Nature Reserve (buffer zone), Burunda River basin near Burunda cordon, plant debris and mosses on swampy sides of flood-plain lake: Carex spp. , Poaceae gen. spp., Spiraea sp. , sparse Climacium sp. , Hypnum sp. , Sphagnum sp. , Polytrichum sp. , etc. 09.09.2004. A.B.Ryvkin leg.— 1 male ( AR): Selemdzhinskiy District, Norskiy Nature Reserve, Nora River basin near Maltsevskiy cordon, Maltsevskoye Lake, 210 m a.s.l., mosses and leaf litter on swampy lakeside with tussocks of Poaceae gen. spp., Carex spp. , Spiraea spp. , etc. 11.06.2005. E.M.Veselova & A.B.Ryvkin leg.— 1 male ( AR): same locality and collectors, mosses and leaf litter among tussocks of Carex spp. and Poaceae gen. spp. with Iris sp. , Filipendula palmata , Spiraea spp. , etc. 07.06.2005.— 1 male, 2 females ( AR):same locality and collectors, mosses and litter on swampy lakeside with tussocks of Carex spp. , Poaceae gen. spp., Spiraea sp. , Salix sp. , etc. 29.09.2008.— 1 male ( AR): same locality and collectors, mosses and litter under arborescent Salix sp. , Alnus sp. , Betula platyphylla , Populus tremula , Larix gmelinii with Poaceae gen. spp., Filipendula palmata , Carex spp. , Polytrichum sp. , Pleurozium schreberi , etc. 01.10.2008.— K H AB ARO VSK TERRITO RY: 1 male ( AR): Verkhnebureinskiy District, 4th km of Chegdomyn–Urgal road, mosses and plant debris on swampy sides of wayside lake with tussocks

Ryvkin A.B.

of Carex spp. and Poaceae gen. sp., Scirpus sp. , Comarum palustre , Ledum palustre , Chamaedaphne calyculata , Vaccinium uliginosum , V. vitis –idaea, Betula divaricata , Larix gmelinii , Sphagnum spp. , Aulacomnium sp. , Polytrichum sp. 05.10.2006. A.B.Ryvkin leg.— 1 male ( ZMMU): Maritime Area, Khabarovsk. 06.07.1911. Speshilova-Petelina leg. [‘ Lathrobium sp. n.! [A.L.Tichomirova det.]’]— 1 female ( ZMMU): Lower reaches of Amur River, Troitskoye, Torgogo village. 01.07.1910. Soldatov leg. [‘ Lathrobium sp. n.! [A.L.Tichomirova det.]’]— SAKHALIN AREA: 1 male, 1 female ( AR): Kurile Islands, Kunashir Island, near Yuzhno-Kuril’sk. 17.06.1990. K. V.Makarov leg.— MARITIME PROVINCE: 1 female ( AR): Ussuriyskiy District, near Kamenushka, on dried puddle. 06.07.1980. A.B.Ryvkin leg. [?]— 1 male (AVSh): South Primorye [=S Maritime Province], Lazovskiy District, Preobrazhenie. 12.08.2007. Yu.Sundukov leg.

Redescription. Body pitchy-black to black, pronotum and elytra with bluish metallic tint; elytral suture and posterior margin narrowly and vaguely lightened, reddish to reddish-brown; antennae, mouthparts and legs brown to yellowish-brown. Forebody distinctly, abdominal tergites fatty shining. Pubescence moderately long and dense, piceous with golden shine.

Length: 7.2–7.9 mm (the last value for the specimens with abdomen extended).

Head about as long from neck to anterior margin of front as broad across basal 1/4 (66:67), less than twice as broad as the neck constriction (67:36); posterior angles broad angularly rounded, posterior margin in the middle a bit concave to nearly straight; temples nearly straight, a bit divergent posteriorly (65:67), about 2 to 2.5 times as long as eyes (37:19 to 37:15, view from above). Puncturation fairly deep and dense laterally and in the posterior 1/3, much sparser and more irregular in the middle of disk and anteromedially; average diameter of the coarsest punctures of the disk a bit larger than 1/3 cross-section of antennal segment 2; wide interstices between median punctures 3 to 4 times as broad as diameter of punctures; the puncturation of underside moderately dense and more shallow. Fine and close cellular ground-sculpture well-developed throughout, excluding medioposterior area where is much more feeble or entirely vanishing.Antennae moderately long, scarsely reaching the basal 1/5 of pronotum, with segments 2-10 inverted conical. Length/width proportions of antennal segments 1- 11 as 23/9.5: 12/8: 14/8: 12/8: 11.5/8: 12/8: 11/8: 11/ 9: 12/9: 12/8.5: 18/8 (on the male from Nora River basin).

Pronotum moderately convex, nearly as broad as head (66:67), by about 1/5 longer than broad (80:66); lateral sides slightly convex (65:66:64); both anterior and posterior angles broadly rounded; very fine median longitudinal furrow well-developed in basal 1/5, more or less distinctly extending as a feeble stroke to the anterior 1/3 to 1/5 (in some specimens vanishes in basal 1/3). Median longitudinal impunctate strip reaching both anterior margin and posterior one, slightly raised in basal part, as broad as 1/10 to 1/11 maximum breadth of pronotum. Puncturation of disk irregular, somewhat larger on average than that of the head; interstices between punctures near the smooth longitudinal median strip evidently smaller on average than the diameter of punctures; some small smooth areas, mainly narrow and longitudinal, situated on the disk laterally. Ground-sculpture absent, the whole surface varnish shining.

Elytra moderately convex, by nearly 1/5 longer than pronotum (96:80), by nearly 1/7 to nearly 1/ 4 longer than broad (95:83 to 101:82), slightly dilated posteriorly (75:82 to 72:83) behind well developed angularly-rounded humeri. Suture a little shorter than pronotum (75:80 to 80:82), somewhat elevated throughout excluding the very base; flanked with a pair of narrow and shallow sutural impressions; humeral and lateral impressions absent; posterior margin with extremely fine edging visible only in external parts. Puncturation evidently smaller than that of pronotum, but larger on average than that on the head, less distinct, rather irregular. Very shallow irregular point-touch ground-sculpture more or

On new and poorly known Lathrobium (s.str.) species from Siberia and the Russian Far East ...

less visible between punctures at high magnification. Wings developed.

Abdominal segments 3 to 7 a bit widened posteriorly; abdominal tergites 3 to 6 moderately flattened, preapical tergites more convex. Posterior margin of tergite 7 with evident white fringe. Puncturation of fore visible abdominal tergites rather uniform, very fine and moderately dense, a bit sparser medially; tergite 7 punctured somewhat more sparsely than preceding ones; puncturation of tergites 8–9 distinctly sparser. Extremely fine and dense reticular ground-sculpture well-developed throughout but much more feeble on preapical tergites.

Male: Abdominal sternite 7 with a feeble median depression and posterior margin feebly, broadly emarginated; small medioposterior angularlyround emargination of abdominal sternite 8 nearly symmetric, flanked with two short rows of spicules, and extended with a feeble median impression reaching the basal 1/3 (fig. 12); aedeagus as in figs. 9–10.

Female: Posterior margin of abdominal tergite 8 as well as abdominal sternite 8 as in fig. 13; structure of abdominal segments 9-10 as in fig. 14.

Diagnosis. In the shape of the aedeagus, the species under consideration is closely related to L. elongatum ( Linné, 1767) and may be readily distinguished from the specimens of the latter with entirely darkened elytra by the smaller body size, the more slender body proportions, the much sparser and irregular puncturation of median parts of the head, the somewhat less coarse and dense puncturation of underside of the head, and the detailes of the aedeagus (compare figs. 10 and 8).

Remarks. L. viduum was described from eight females which had been collected by Leder in Southern Cis-Baikalia (Eppelsheim 1893: ‘OstSibirien in der Nähe der Hauptstadt Irkutsk auf dem linken Ufer des Irkut in der oberen Hälfte dieses Flusses gelegen und reicht von der

Ortschaft Tunka bis an den Munku-Sardik im Sajan’schen Gebirge [...]’). Coiffait (1982) redescribed the species from two syntypes (‘paratypes’). Bordoni (1980) also mentioned ‘due paratipi females di Baikal See coll. Reitter del Museo di Budapest: corpo di circa 7 mm, bruno nero con capo e pronoto neri, antenne ed arti testacei’. In all probability, no additional material has been published on L. viduum after the type series, and so the data above give a view of the distribution of the species. All the diagnoses existing are too brief; neither male nor female specific characters have been described by the previous writers. Therefore I think it to be useful to give a detailed description of L. viduum (see above).