Lathrobium tomohidei, 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 : 507-509

Lathrobium tomohidei sp. nov.

( Figs. 1C , 4 , 6 )

http://zoobank.org/ urn:lsid:zoobank.org:act:F5AAEF5C-48BC-48FB-B3EF-14C2FC2FB0A7

Type material. Holotype: JAPAN: Honshu: ♂, “Yagai Center | Inabu C. | 29 IV 1968 ” [handwritten on white label], “HOLOTYPE | Lathrobium tomohidei | sp. nov. | Des. Y. Senda, 2023” [printed on red label with black border]. (EUMJ). Paratypes: 2♀♀, Takadoya, Otagi-chô, Toyota-shi, 28.IV.2022, T. Ôno leg. (EUMJ)

Diagnosis. The new species is very similar to Lathrobium kusamai Watanabe, 1999 , but distinguishable from it by the following characteristics: 1) male abdominal sternite VIII without distinct median depression, but with very shallow semielliptical posterior excision; 2) aedeagal dorsal plate comparatively wide in apical half, somewhat gently contracted from widest point to apex; 3) aedeagal ventral process with longitudinal carina along midline in apical 2/5; 4) apical projection of aedeagal ventral process very short (while in L. kusamai : male abdominal sternite VIII with distinct triangular median depression and shallow semielliptical posterior excision; aedeagal dorsal plate thin, significantly contracted from widest point to apex; aedeagal ventral process with longitudinal carina along midline in apical half; apical projection of aedeagal ventral process short).

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

Male. Body elongate, subparallel-sided, slightly flattened dorsally, shining. Head subquadrate in dorsal view, lateral sides gently arcuate, widest at the half of posterior part of eyes, HL/HW ≈ 1.0; 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 moderately 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: 2.9, 1.8, 2.8, 1.9, 2.0, 2.0, 2.0, 1.8, 1.6, 1.5, 2.5; relative lengths of antennomeres from base to apex from base to apex: 27.5: 13.8: 15.6: 11.9: 11.3: 11.3: 11.3: 11.3: 10.0: 10.0: 16.9, and relative widths: 16.7: 13.3: 10.0: 11.1: 10.0: 10.0: 10.0: 11.1: 11.1: 12.2: 12.2.

Pronotum oblong, widest at anterior 1/4, PL/PW ≈ 1.2, PL/HL ≈ 1.2, PW/HW ≈ 1.0, lateral sides arcuately 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, rounded at the corners; posterior margin almost straight, broadly rounded at corners. Scutellar shield impunctate, covered with indistinct microsculpture, sparsely covered with fine brownish pubescence. Elytra widest just before posterior corner, slightly expanded almost straightly 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 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. 4A ) without median depression, but covered with several short black setae in posteromedial area; sternite VII ( Fig. 4A ) with very weak median depression, which is sparsely covered with short black setae, feebly emarginate at posterior margin; sternite VIII ( Fig. 4A ) without distinct median depression, sparsely covered with short black setae in posteromedial area, with very shallow semielliptical posterior excision, lateral side of posterior excision not produced on posterior margin; tergum IX setigerous except on basal 1/4, with posterolateral projections as long as 1/5 of tergum IX and somewhat curved dorsally from apical 1/3 to pointed apex; sternite IX elongate, widest at basal 1/4, narrowed apically, setigerous in 2/3, with posterior margin feebly arcuate; tergum X subtrapezoidal, widest at basal corners, with few setae and pores, with posterior margin arcuate.

Aedeagus ( Fig. 4B–D ) elongate, 1.71 mm long, sclerotised except membranous dorsal side; dorsal plate elongate and slender, almost symmetrical, widest at apical half, feebly curved ventrally in apical 1/5, emarginately and somewhat strongly dilated to widest point, thence gently contracted toward acute apex in dorsal view; ventral process long, lamellate, gently and arcuately contracted to base of apical projection in ventral view, with longitudinal carina along midline in apical 2/5, gently curved ventrally, with very short apical projection, which is approximately 0.04 times as long as ventral process. Endophallus poorly developed, with simple internal sac, with roundly sclerites on dorsal side.

Female. Similar to male in general appearance. Length/width ratio of each antennomere I to XI as follows: 2.7, 1.9, 2.0, 1.8, 1.7, 1.6, 1.6, 1.6, 1.5, 1.8, 2.4; relative lengths of antennomeres from base to apex: 26.7: 11.7: 14.4: 12.2: 11.1: 10.6: 10.6: 10.6: 10.0: 10.0: 12.2, and relative widths: 20.0: 12.2: 14.4: 13.3: 13.3: 13.3: 13.3: 13.3: 13.3: 11.1: 10.0. HL/HW ≈ 1.0; AL/FBL ≈ 0.6; PL/PW ≈ 1.2; PL/HL ≈ 1.1; PW/HW ≈ 0.9; EL/EW ≈ 0.7; EL/PL ≈ 0.6; EW/PW ≈ 1.0.

Tergum VIII subtruncated at middle of posterior margin ( Fig. 4E ); sternite VIII ( Fig. 4F ) produced at middle of posterior margin, which is arcuate and fringed with micropubescence; tergum IX ( Fig. 4E & F ) similar to male, but with thicker posterolateral projections; tergum X ( Fig. 4E ) similar to male. Gonocoxites ( Fig. 4F ): lateral gonocoxal plate (distal and proximal gonocoxites fused) elongate, setigerous, with few setae in apical area, with rounded apex.

Measurements. Male (n = 1)—BL: 8.06 mm; FBL: 4.08 mm; HL: 1.41 mm; HW: 1.40 mm; AL: 2.41 mm; PL: 1.66 mm; PW: 1.37 mm; EL: 1.01 mm; EW: 1.36 mm.

Female (n = 2)—BL: 9.92 & 10.04 mm; FBL: 4.31 & 4.32 mm; HL: 1.51 & 1.52 mm; HW: 1.56 & 1.56 mm; AL: 2.77 & 2.78 mm; PL: 1.71 & 1.68 mm; PW: 1.45 & 1.46 mm; EL: 1.10 & 1.12 mm; ELW:1.54 & 1.52 mm.

Distribution. Japan: Central Honshu (northeastern area of Aichi Prefecture) ( Fig. 6 ).

Etymology. The specific name is dedicated to Mr Tomohide Ôno (Ôbu City) who collected the type specimens and kindly offered me Lathrobium specimens collected from Aichi Prefecture.

Comments. This new species belongs to the Lathrobium pollens group (sensu Senda, 2022) based on its characteristic states. The type locality “Yagai Center” probably means the Nagoya City Inabu Outdoor Education Center, which is located at Tominaga, Toyota-shi (before Inabu-chô).

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 4. Lathrobium tomohidei sp. nov., male (A–D) and female (E–F): apical part of abdominal sternites (A, F); aedeagus, ventral view (B); ditto, lateral view (C); ditto, dorsal view (D); apical part of abdominal terga (E). 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.