Lathrobium (Lathrobium) kamenum Ryabukhin, 2018

Ryabukhin, A. S., 2018, A new species of the genus Lathrobium Gravenhorst, 1802 (Coleoptera: Staphylinidae, Paederinae) from the northern part of Kamchatka kray, Far Eastern Entomologist 354, pp. 15-18 : 15-18

Lathrobium (Lathrobium) kamenum Ryabukhin , sp. n.

Figs 1–7

TYPE MATERIAL. Holotype – ♂, Russia: Kamchatka Kray, environs of Kamenskoe village , 11.VII 2011 (A.S. Ryabukhin ) . Paratypes – the same locality as holotype, 15–31.VII

2011, 12 ♂, 10 ♀ (A.S. Ryabukhin ).

DESCRIPTION. Head, pronotum and elytra reddish-brown to dark-brown, sometimes head darker, to almost black. Anterior margin of front lighter, light-brown to brown. Sutural and apical margins of elytra usually lightened. Abdomen dark-brown to piceous-black, apical part of segment 8 and segment 9 more or less lightened, dark reddish-brown to brown. Mouthparts yellow to light-brown. mandibles darker, light-brown to brown. Antennae and legs yellowish-brown to light-brown. Head, pronotum and elytra distinctly, abdomen moderately shining. Surface of head, pronotum and elytra with short, sparse, yellowish pubescence and a few scattered brownish setae. Abdomen with moderately long and dense yellowish pubescence with golden shine. Length 3.7–4.2 mm, specimens with extended abdomen – 4.4 mm.

– ventral view; 3–8 – details of structure of abdominal segments without pubescence: 3 –

male 8th sternite, ventral view; 4 – female genital segment, dorsal view; 5 – the same,

ventral view; 6 – female 8th tergite, dorsal view; 7 – female 8th sternite, ventral view.

Head approximately as long from neck to anterior margin of front as wide across basal

1/4 (on average 44: 44). Slightly convex temples approximately 3,5 times longer than eyes

(ratio on average 25: 7), widened to base (ratio of width at level of eyes to maximum width on average 42: 44). Basal angles broadly rounded; basal margin scarcely emarginated or,

sometimes, about straight. Punctation irregular, moderately deep and coarse. Average diameter of largest discal punctures approximately equal to one-half that width of 3rd antennal segment. Distance between punctures on average 1-3 times as wide as diameter of punctures.

Surface with fine but distinct cellular or reticulate microsculpture. Punctation of temples more feeble than that of disc. Antennae moderately short, almost reaching basal third of pronotum.

Length/width proportions of 1-11 antennal segments as 15/7; 7/5; 6/5; 6/5,5; 6/5,5; 6/6; 6/6;

6/6; 6/6; 6/6; 10/6.

Pronotum moderately convex, narrower than head (on average 41:44). Length approximately 1.2 times longer than width (ratio of 1/w on average 51: 41). Lateral sides parallel,

apical and basal margins straight, or, sometimes, very feebly sinuate. Basal and apical angles broadly rounded. Surface without microsculpture. Punctation irregular, more or less coarse,

vary in density. Distance between punctures on average 1-3 times as wide as ones. Median longitudinal impunctate strip reaching apical and basal margins, not raised above surface.

Ratio between its width to width of pronotum approximately as 8: 41 to 10: 41. Narrow,

more or less visible median longitudinal furrow in basal part usually reaches the middle of length of pronotum, but not extending to basal margin.

Elytra moderately flattened, approximately 1.2 times shorter than pronotum (on average

44: 51); conjointly on average 1.2 times broader than length (52: 44), distinctly shorter at sutural margin, than at lateral one (32: 44). Sides straight, gradually and evenly widened from rounded humeral angles to apex (ratio of width at humeral level to maximum width on average 41: 52). Apical margin obliquely truncate. Outer apical angles broadly rounded.

Suture slightly elevated posteriorly. Broad and shallow indistinct impressions along each side of suture extending to base and almost to apex of elytra. Punctation irregular, much more indistinct than that of pronotum and head. Diameter of punctures usually evidently less than those on pronotum, although some single punctures may be quite distinct and equal or even greater than on pronotum. Surface with fine but distinct irregular hatched or shagreen microsculpture. Wings absent.

Abdomen evenly and weakly widened posteriad. Segment 6 and base of segment 7 slightly broader than others. Apical margin of tergite 7 without light fringe. Punctation fine, shallow,

moderately dense, sparser in median parts of tergites. Diameter of punctures evidently less than that on elytra. Surface with well-developed, distinct, dense, reticulate or reticulate-waved microsculpture.

MALE. Aedeagus with ring-shaped structure and long, curved, strongly sclerotized sclerite.

Lateral and ventral views as in Figs 1-2 respectively. Abdominal sternite 8 with a more or less developed shallow, oval-shaped apico-median impression. Posterior margin of abdominal sternite 8 with moderately broad and deep angularly rounded emargination as in Fig. 3 .

FEMALE. Dorsal and ventral views of genital segment as in Figs 4 and 5 respectively.

Abdominal tergite 8 as in Fig. 6 . Sternite 8 as in Fig. 7 .

DIAGNOSIS. Lathrobium kamenum sp. n. is most similar to L. ossorum Ryabukhin, 2010

from Kamchatka Kray, and also to L. mentitum Ryabukhin, 1993 and L. tshucoticum Tichomirova, 1976 from Chukotka ( Tichomirova, 1976; Ryabukhin, 1993 , 2010), but differs from the first species in most cases by the smaller body size, darker coloration of pronotum and elytra, lighter coloration of mouthparts, antennae and legs, as well as in the head which is approximately as long as wide and less widened to base, and the longer temples and sparser punctuation of head. New species also differs from L. ossorum by narrower, than head, shorter pronotum and less distinct median longitudinal furrow; and by microsculpture of elytra.

From L. mentitum new species differs by smaller body size, longer temples and sparser its punctuation, by pronotum, narrower, than head, its parallel lateral sides, straight apical and basal margins and more sparser punctuation, and by more widened apically elytra and distinct elytral microsculpture.

New species differs from L. tshucoticum by rather smaller body size, less distinct median longitudinal furrow of pronotum, by longer and more widened apically elytra, and by more distinct elytral microsculpture.

A new species can be distinguished from all other species of the genus Lathrobium by the shape of aedeagus.

DISTRIBUTION. Russia: Kamchatka Province.

ETYMOLOGY. The specific name is derived from the village name “Kamenskoe”, in the environs of which the holotype and paratypes were collected.

REMARKS. The specimens of Lathrobium kamenum sp. n. have been collected by sifting and hand picking ground cover, moss and litter in the moss-grass-dwarf shrubs tundra with sparse alder, willow and birch scrub.

Figures

Figs. 1–7. Lathrobium (Lathrobium) kamenum sp. n. 1, 2 – aedeagus: 1 – lateral view; 2