Lathrobium oopikkarianum, 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 : 502-505

Lathrobium oopikkarianum sp. nov.

( Figs. 1A , 2 , 6 )

http://zoobank.org/ urn:lsid:zoobank.org:act:6785883D-B3F7-4131-91AA-0A463BDAAD56

Type material. Holotype: JAPAN: Honshu : ♂, “ SHIZUOKA: JAPAN | Mt. Ôpikkari | Shizuoka-city Aoi-ku | 8.IV.2007 | Yûgo Satô leg.” [printed on white label], “Yûgo Satô |collection” [printed on pale blue label], “HOLOTYPE | Lathrobium oopikkarianum | sp. nov. | Des. Y. Senda, 2023” [printed on red label with black border]. (EUMJ).

Diagnosis. The new species is similar to Lathrobium pollens Sharp, 1889 , but is different from the latter by the following characteristics: 1) posterior excision of male abdominal sternite VIII wide and shallow; 2) apical projection of aedeagal ventral process comparatively long (0.35 times as long as ventral process), feebly dilated to widest point, thence contracted toward acute apex; 3) dorsal plate comparatively wide, with round apex (while in L. pollens : posterior excision of male abdominal sternite VIII wide and comparatively deep; apical projection of aedeagal ventral process comparatively short (0.25 times as long as ventral process), gently contracted from the base to apex; dorsal plate comparatively thin, with acute apex). This new species also resembles Lathrobium kusamai Watanabe, 1999 , but is distinguishable from it by the following characteristics: 1) base of parameral apical projection likely truncated; 2) dorsal plate comparatively thin in basal half, with round apex (while in L. kusamai : base of parameral apical projection acute; dorsal plate comparatively wide in basal half, with acute apex).

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

Body elongate, subparallel-sided, slightly flattened dorsally, shining. Head subtrapezoid in dorsal view, lateral sides arcuate, widest at basal 1/3 of posterior part of eyes, HL/HW ≈ 0.8; surface with coarse setiferous punctures and coriaceous microsculpture; punctures of surface becoming slightly denser and less coarse in temporal area. Eyes small, about 0.3 times as long as temple, flat. Antennae moderate in length, AL/FBL ≈ 0.7; antennomere I widest at about apical 1/3, dilated to widest point, thence contracted toward apex; antennomere 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: 2.3, 1.7, 2.7, 2.1, 2.0, 1.8, 1.7, 1.7, 1.6, 1.6, 2.2; relative lengths of antennomeres from base to apex: 26.3: 12.5: 16.9: 13.1: 12.5: 11.3: 11.3: 11.3: 10.0: 10.0: 13.8, and relative widths: 18.0: 12.0: 10.0: 10.0: 10.0: 10.0: 10.5: 10.5: 10.0: 10.0: 10.0.

Pronotum oblong, widest at anterior 1/3, PL/PW ≈ 1.2, PL/HL ≈ 1.4, PW/HW ≈ 1.0, lateral sides feebly arcuate, gently contracted from widest point to posterior corner; disc sparsely covered with coarse and setiferous shallow punctures except median smooth area; anterior margin feebly emarginate at middle, broadly rounded at corners; posterior margin feebly arcuate, rounded at corners. Scutellar shield with a few minute punctures, covered with indistinct microsculpture, sparsely covered with fine light brownish pubescence. Elytra widest just before posterior corner, expanded weakly arcuately from base to posterior corner, EL/EW ≈ 0.7, EL/PL ≈ 0.6, EW/PW ≈ 1.0; disc covered with shallow punctures, sparsely covered with fine light brownish pubescence. Hind wings absent. Basisternum asetose, slightly carinate along midline in apical half; inner coxal process short, pointed at apex. Mesoventrite asetose, microsculptured, fully carinate along midline; inner coxal process short, pointed at apex. Metaventrite sparsely pubescent, microsculptured; inner coxal process 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. 2A ) without median depression, but covered with several short black setae in posteromedial area; sternite VII ( Fig. 2A ) with triangular median depression, densely covered with short black setae, emarginate at posterior margin; tergum VIII arcuate at posterior margin; sternite VIII ( Fig. 2A ) with a median depression, which is densely covered with short black setae, with wide and semielliptical posterior excision, lateral side of posterior excision weakly produced on posterior margin; tergum IX setigerous except on basal 1/4, with posterolateral projections as long as 1/5 of tergum IX and strongly curved dorsally at apex, with pointed apex; sternite IX elongate, widest at basal 1/4, narrowed apically, setigerous in 2/3, with posterior margin arcuate; tergum X semielliptical, widest at basal corners, with few setae and pores, with posterior margin arcuate.

Aedeagus ( Fig. 2B–D ) elongate, 2.50 mm long, nearly symmetrical, sclerotised except membranous dorsal side; dorsal plate elongate and slender, symmetric, widest at apical 2/5, not curved ventrally, gently and emarginately dilated to widest point, thence gently contracted toward round apex in dorsal view; ventral process long, lamellate, gently and emarginately contracted to base of apical projection in ventral view, with longitudinal carina along midline in apical half, curved ventrally at apical half, with apical projection, which is 0.35 times as long as ventral process, feebly dilated to widest point, thence contracted toward acute apex in ventral view. Endophallus poorly developed, with simple internal sac, without teeth patch.

Female. Unknown

Measurements. Male (n = 1)—BL: 8.44 mm; FBL: 3.77 mm; HL: 1.16 mm; HW: 1.41 mm; AL: 2.62 mm; PL: 1.60 mm; PW: 1.36 mm; EL: 1.02 mm; EW: 1.38 mm.

Distribution. Japan: Central Honshu (northern area of Minobu Mountains) ( Fig. 6 ).

Etymology. The new species named after the type locality.

Comments. This new species belongs to the Lathrobium pollens group (sensu Senda, 2022) based on its characteristic states.

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 2. Lathrobium oopikkarianum sp. nov., holotype, male: apical part of abdominal sternites (A); aedeagus, ventral view (B); ditto, lateral view (C); ditto, dorsal view (D). Scale bars = 0.5 mm.

FIGURE 6. Geographical distribution of Lathrobium oopikkarianum sp. nov., L. elongatiphallus sp. nov., L. tomohidei sp. nov., L. pegaseion sp. nov. and their related congeners in central Honshu, Japan.