Lathrobium (Lathrobium) palanum Ryabukhin, 2015

Ryabukhin, A. S., 2015, A new species of Lathrobium Gravenhorst, 1802 (Coleoptera: Staphylinidae, Paederinae) from Kamchatka Peninsula, Far Eastern Entomologist 295, pp. 8-11 : 8-10

Lathrobium (Lathrobium) palanum Ryabukhin , sp. n.

Figs 1–7

TYPE MATERIAL. Holotype – ♂, Russia: western Koryakia (northern part of Kamchatka Peninsula), environs of Palana village , 23.VII 2009 (A.S. Ryabukhin). Paratypes – the same locality as holotype , 10.VII 2009, 3 ♂, 2 ♀ (A.S. Ryabukhin ) ; 23-24.VII 2009, 5 ♂, 1 ♀ (A.S. Ryabukhin ) ; 4-8.VIII 2009, 3 ♂, 2 ♀ (A.S. Ryabukhin ) .

DESCRIPTION. Head, pronotum and elytra reddish-brown to brown. Sutural and apical margins of elytra a little bit lighter, reddish-brown. Abdomen brown to dark-brown, or, to almost black, with apical segments sometimes more or less lightened. Mouthparts (excluding mandibles), antennae and legs yellowish-brown. Head and elytra only shining, pronotum strongly, abdomen moderately shining. Surface of head, pronotum and elytra with sparse, fine, yellowish pubescence and a few scattered brownish setae, abdomen with moderately dense yellowish pubescence. Length 3.8-4.3 mm (specimens with extended abdomen – 4.5 mm).

Head approximately as long as wide (from neck constriction to anterior margin of clypeus). Slightly convex temples approximately 4 times longer than eyes (ratio of length of temples to length of eyes on average 28: 7, see from above), gradually widened to base (ratio of width at level of eyes to maximum width 42: 46). Basal angles moderately broadly rounded, basal margin straight or feebly sinuate. Front and vertex with moderately deep and coarse irregular punctation. Distance between punctures on average 1-3 times as wide as diameter of punctures. Diameter of largest punctures a little bit less one-half that width of 3rd antennal segment. Surface with fine but distinct cellular microsculpture. Lateral parts of head somewhat denser but smaller punctated than on disk, with irregular punctation and distinct reticulate microsculpture. Distance between punctures on average 1-2 times as wide as diameter of the punctures. Antennae moderately short, extending to basal third of pronotum. Length/width proportions of 1-11 antennal segments 6; 10/6.

as 17/8; 9/6; 8/5; 7/6; 7/6; 7/6; 7/6; 6/6; 6/6; 6/ 9

Pronotum moderately convex, approximately as wide as head, sides usually parallel, sometimes very slightly narrowed to base. Length approximately 1.2 times longer than width (ratio of 1/w on average 55: 46). Basal and apical angles broadly rounded. Apical margin very slightly sinuate, basal margin usually straight, sometimes very feebly sinuate. Surface without microsculpture, densely and coarsely punctate. Distance between punctures on average 1-2 times as wide as ones. Median longitudinal impunctate strip extending to apical and basal margins, not raised above surface of pronotum. Ratio between its width to width of pronotum approximately as 10: 46. Narrow, very feeble median longitudinal furrow in basal half not extending to basal margin.

Elytra approximately as long as pronotum; conjointly on average 1.1 times broader than their length (ratio of w/l 52: 46). Apical margin obliquely truncate. Elytra distinctly shorter at sutural margin, than at lateral one (ratio 35: 46). Sides straight, gradually and evenly widened from rounded humeral angles to apex (ratio of width at humeral level to maximum width on average 43: 52). Outer apical angles broadly rounded. Suture slightly but distinctly raised. Broad, weakly indistinct impressions along each side of suture extending almost to apex and base of elytra. Surface with fine but distinct irregular hatched microsculpture. Punctation very irregular, much more indistinct than that of head and pronotum. Diameter evidently less than those on pronotum. Wings absent.

Abdomen evenly and weakly widened posteriad. Segments 6 and 7 slightly broader than others. Surface with distinct, dense, reticulate microsculpture and fairly dense, fine punctation, sparser in median parts of tergites. Diameter of punctures evidently less than on elytra. Apical margin of tergite 7 without light fringe.

MALE. Aedeagus slightly asymmetrical, median lobe without dorsal lamella. Internal sac with short, slightly curved, more or less sclerotized sclerite and ring-shaped structure. Lateral and ventral views as in Figs 1-2 respectively. Abdominal sternite 8 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 .

DISTRIBUTION. Russia: Kamchatka Peninsula.

ETYMOLOGY. The specific name is a noun in apposition taken from the type locality.

DIAGNOSIS. Lathrobium palanum sp. n. is similar to L. transsibiricum Ryvkin, 1989 from Magadan Region ( Ryvkin, 1989), L. tshucoticum Tichomirova, 1976 from Chukotka (Tichomirova) and L. ossorum Ryabukhin, 2010 from Kamchatka ( Ryabukhin, 2010). From L. transsibiricum new species differs by the rather smaller size, by longer temples and antennae, and by lighter and much longer elytra. L. palanum sp. n. differs from L. tshucoticum by the rather smaller size, by longer and much more widened basally temples, by longer pronotum, by much longer and widened apically elytra and by distinct elytral microsculpture. From L. ossorum new species differs by the smaller size, by the longer and a bit less widened basally temples, by longer antennae, by slightly shorter pronotum and by much more longer elytra. New species is distinguished from all other species of the genus Lathrobium by the shape of aedeagus.

REMARKS. Most specimens of Lathrobium palanum sp. n. have been collected by sifting and hand picking litter in the stone birch ( Betula ermanii ) forest on the gentle slope. Two samples (male and female) were collected from the ground cover and litter in the grassdwarf shrub tundra under the clumps of the dwarf birch ( Betula exilis ).

Figures

Fig. 1–7. Lathrobium (Lathrobium) palanum sp. n. 1, 2 – aedeagus: 1 – lateral view; 2 – ventral view; 3-8 – details of structure of abdominal segments without pubescence: 3 – male 8th sternite; 4 – female genital segment, dorsal view; 5 – the same, ventral view; 6 – female 8th tergite; 7 – female 8th sternite.