Lathrobium kawamurai, Senda, 2024

Senda, Yoshihiro, 2024, Seven new species of the genus Lathrobium Gravenhorst (Coleoptera: Staphylinidae: Paederinae) from Central Honshu, Japan, with new distributional records, Zootaxa 5403 (5), pp. 501-529 : 515-516

Lathrobium kawamurai sp. nov.

( Figs. 1F , 9 , 12 )

http://zoobank.org/ urn:lsid:zoobank.org:act:C40A699A-D3FA-4AE5-884D-9E096DD4B239

Type material. Holotype: JAPAN: Honshu : ♂, “ 岐阜県ţDzmae尾水鳥 | [JAPAN; Honshu] | Neomidori (alt. 500 m) | Motosu-shi | Gifu, 10–V–2020 | Kôhei Kawamura leg.” [printed on white label], “collected from | subterranean zone” [printed on white label], “HOLOTYPE | Lathrobium kawamurai | sp. nov. | Det. Y. Senda, 2022 ” [printed on red label with black border]. (EUMJ).

Diagnosis. The new species closely resembles Lathrobium satoi Watanabe, 2003 , but is different from the latter by the following characteristics: 1) male abdominal sternite VIII without distinct posterior excision, with posterior margin very feebly emarginated asymmetrically at middle; 2) basal part of ventral process slightly convex; 3) dorsal plate of aedeagus with a small hook at apex (while in L. satoi : male abdominal sternite VIII with very shallow, but distinct triangular posterior excision; basal part of ventral process not convex; dorsal plate of aedeagus with a small hook before the acute apex). The new species is also superficially similar to preceding species, L. minoccidentale sp. nov., found same locality, but is easily distinguishable from it by the following characteristics: 1) punctures of head surface comparatively sparse; 2) male abdominal sternite VIII without distinct posterior excision, with posterior margin very feebly emarginated at middle; 3) dorsal plate of aedeagus elongate, but not twisted (while in L. minoccidentale : punctures of head surface comparatively dense; male abdominal sternite VIII with shallow, but distinct triangular posterior excision; dorsal plate of aedeagus very elongate, slightly twisted apically)

Description. Male. Colouration:Body black; antennae, mandibles, labrum, basisternum, meso- and metavantrite and abdominal sternites reddish brown; labial palpi, maxillae, legs and abdominal segment IX (apical part) and X brownish yellow; elytra dark reddish brown in sutural and apical area.

Body elongate, subparallel-sided, slightly flattened dorsally, shining. Head subtrapezoid in dorsal view, lateral sides weakly arcuate, widest at basal 1/3 of posterior part of eyes, HL/HW ≈ 0.9; surface with coarse setiferous punctures and coriaceous microsculpture; punctures of surface becoming denser and less coarse in temporal area. Eyes small, about 0.3 times as long as temple, flat.Antennae moderate in length, AL/FBL ≈ 0.6; antennomere I widest at about apical 1/3, dilated to widest point, thence weakly contracted toward apex; antennomeres II constricted at the base; III–X almost moniliform; antennomere XI fusiform, pointed at apex; length/width ratio of each antennomere I to XI as follows: 2.4, 1.1, 1.3, 1.3, 1.4, 1.2, 1.3, 1.2, 1.1, 1.3, 1.6; relative lengths of antennomeres from base to apex: 28.1: 10.0: 12.0: 12.6: 12.3: 12.2: 12.8: 11.0: 11.2: 11.9: 15.0, and relative widths: 12.8: 10.4: 10.4: 11.0: 10.0: 11.2: 11.2: 10.6: 11.6: 10.0: 10.2.

Pronotum oblong, widest about middle, PL/PW ≈ 1.6, PL/HL ≈ 1.4, PW/HW ≈ 1.2, lateral sides gently arcuate; disc sparsely covered with coarse and setiferous punctures except median smooth area; anterior margin feebly emarginate at middle, broadly rounded at corners; posterior margin almost straight, rounded at corners. Scutellar shield impunctate, covered with indistinct microsculpture, sparsely covered with fine brownish pubescence. Elytra widest just before posterior corner, expanded weak arcuately from base to posterior corner, EL/EW ≈ 0.7, EL/PL ≈ 0.6, EW/PW ≈ 1.1; disc covered with shallow punctures, sparsely covered with fine brownish pubescence. Hind wings absent. Legs, rather slender, covered with golden pubescence; protarsomeres I–IV strongly dilated.

Abdomen covered with minute punctures, densely covered with dark brownish pubescence; sternite VI ( Fig. 9A ) without median depression; sternite VII ( Fig. 9A ) with very weak median depression, which is sparsely covered with short black setae; tergum VIII weakly arcuate at posterior margin; sternite VIII ( Fig. 9A ) with weak triangular median depression, which is densely covered with short black setae, with posterior margin very feebly emarginated asymmetrically at middle; tergum IX setigerous except on basal 1/4, with posterolateral projections as long as 1/5 of tergum IX and curved dorsally from apical 1/3 to pointed apex; sternite IX elongate, widest at basal 1/4, narrowed apically, setigerous in apical 2/3, with posterior margin feebly arcuate; tergum X trapezoidal, widest at basal corners, with few setae and pores, with posterior margin arcuate.

Aedeagus ( Fig. 9B–D ) robust, 2.50 mm long, well sclerotised except membranous dorsal side; dorsal plate elongate and somewhat slender, weakly asymmetric, widest at apical 1/3, emarginately dilated to widest point, thence gently contracted toward pointed apex in dorsal view, with small hook at apex; ventral process asymmetrical, slightly curved to right, widest at basal 2/5, weakly dilated to widest point, thence gently contracted toward apex in ventral view, strongly curved ventrally in apical half, slightly convex in basal half, with fine longitudinal carina along midline in apical half. Endophallus ( Fig. 9E–F ): internal sac slightly longer than dorsal plate, simple, symmetric, without any membranous projection in everted condition, with ventrolateral teeth patch as Figs. 9E–F , with numerous minute sclerites on dorsal side of apex; copulatory piece membranous, very short, thick, tapering to round apex.

Female. Unknown.

Measurements. Male (n = 1)—BL: 6.80 mm; FBL: 3.08 mm; HL: 0.94 mm; HW: 0.99 mm; AL: 1.71 mm; PL: 1.32 mm; PW: 1.14 mm; EL: 0.82 mm; EW: 1.22 mm.

Distribution. Japan: Central Honshu (southwestern area of Gifu Prefecture) ( Fig. 12 ).

Etymology. The specific name is dedicated to Mr Kôhei Kawamura (Hashima City) who collected the type specimens and kindly offered me Lathrobium specimens collected from Gifu Prefecture.

Comments. This new species is unequivocally classified in the Lathrobium brachypterum group (sensu Senda, 2023b) based on its characteristic states.According to the collector of the holotype, it was collected from subterranean zone together with the previous species.

Figures

FIGURE 1. Holotypes of Lathrobium spp., dorsal habitus: L. oopikkarianum sp. nov. (A); L. elongatiphallus sp. nov. (B); L. tomohidei sp. nov. (C); L. pegaseion sp. nov. (D); L. minoccidentale sp. nov. (E); L. kawamurai sp. nov. (F); L. volkeri sp. nov. (G). Scale bars = 1.0 mm.

FIGURE 9. Lathrobium kawamurai sp. nov., holotype, male: apical part of abdominal sternites (A); aedeagus, ventral view (B); ditto, lateral view (C); ditto, dorsal view (D); inverted endophallus of aedeagus, ventral view (E); ditto, lateral view (F). Scale bars = 0.5 mm.

FIGURE 12. Geographical distribution of Lathrobium kawamurai sp. nov., L. volkeri sp. nov., L. satoi Watanabe and their related congeners in central Honshu, Japan.