Aulonothroscus longulus ( Weise, 1879 )

Seung, Jinbae, Han, Taeman, Lee, Seunghyun, Lee, Minhyeuk & Lee, Seunghwan, 2024, Taxonomic review of the family Throscidae Laporte, 1840 (Coleoptera: Elateroidea) in Korea, the description of a new species with new generic and species records, Zootaxa 5432 (2), pp. 267-278 : 271

Aulonothroscus longulus ( Weise, 1879)

Trixagus longulus Weise, 1879: 148 .

Aulonothroscus nipponicus Cobos, 1969: 50 .

Diagnosis. Frons a paired frontal keel; frontoclypeus almost straight at apical margin; pronotum about 1.5 times as wide as long; length from anterior margin of pronotum to elytral apex about 2.4–2.5 times in male and 2.5–2.6 times in female as long as maximum width; prosternal process with marginal carinae laterally, almost reaching anterior margin of prosternum; aedeagus about 5.4 times as long as wide; phallobase deeply emarginate at middle on basal half, about 2.9 times as long as wide; parameres slender, widest at base, gradually narrowed apically, laterally evenly covered with short pubescence throughout; median lobe elongate, about 0.9 times as long as length of parameres.

Redescription ( Fig. 2 ). Male. Body ( Figs. 2A, C–D ) 2.5–2.8 mm long and 1.0– 1.1mm wide; elongate and convex; widest at base of pronotum and elytra, length from anterior margin of pronotum to elytral apex about 2.4–2.5 times as long as maximum width; surface coloured dark red-brown, densely covered with recumbent golden setae. Head ( Fig. 2E ) deeply inserted into prothorax, coarsely punctate; frons with a pair of frontal keels between compound eyes, divergent posteriorly; anterior margin of frontoclypeus almost straight; compound eyes complete, without emargination; antennae ( Fig. 2F ) 11-segmented, with 3-segmented antennal club; scape stout; pedicel almost square, as long as wide; flagellomeres 3–8 subequal, adjacent to each other; flagellomeres 9 and 10 about 1.2 and 1.5 times wider than long, respectively; apical flagellomere asymmetrical, about 1.6 times longer than wide. Pronotum subtrapezoidal, subparallel-sided at basal two-fifths, then gradually narrowed anterad; about 1.4 times as wide as long; anterior margin weakly arcuate; disc evenly covered with deep punctures, slightly larger and sparser than those of head, becoming coarser, larger, and denser basally; intermingled with sparse microscopic punctures between coarse punctures. Scutellar shield subtriangular, gradually narrowed posterad; about 1.1 times wider than long; covered with fine punctures and setae. Elytra subparallel-sided, weakly narrowed posterad from basal half; about 1.9 times as long as wide; elytral stria complete; interstriae subflattened, mostly with single rows of punctures. Prosternum subparallel-sided, weakly arcuate laterally; anterior margin weakly trilobate; prosternal process with marginal carinae laterally, almost reaching anterior margin of prosternum; hypomeron with transverse impression connected with lateral margin of prosternum, forming deep cavity anteriorly and posteriorly; anterior cavity connected with anteriorly open notosternal groove to receive antennae; posterior cavity housing prothoracic leg. Metasternum covered with deep punctures, coarser, larger, and denser laterally and basally; sparsely scattered with microscopic punctures between deep punctures; oblique mesotarsal groove ( Figs. 2C–D ) deep, well-developed, extending from underneath mesocoxa to posterior angle of metasternum. Abdomen with five abdominal ventrites, strongly connated; covered with large and shallow puncture than those of metasternum, becoming coarser, larger, and denser laterally; densely setose; ventrite 5 broadly rounded at apex, laterally smooth. Aedeagus ( Figs. 2J–O ) trilobed, about 5.4 times as long as wide; phallobase deeply emarginate at middle on basal half, about 2.9 times as long as wide; parameres slender, widest at base, gradually narrowed apically, laterally evenly covered with short pubescence throughout; median lobe elongate, about 0.9 times as long as length of parameres. Legs moderately long, slender; mesotarsi ( Fig. 2H ) short, about 0.6 times as long as midtibia; tarsomere 1 about 1.5 times longer than 2–3 combined. Female ( Fig. 2B ) mostly similar to males, except for the following characters: length from anterior margin of pronotum to elytral apex about 2.5–2.6 times as long as maximum width; antennal club ( Fig. 2G ) less developed, smaller than those of male; flagellomeres 9 and 10 about 1.1 and 1.4 times wider than long, respectively; apical flagellomere asymmetrical, about 1.5 times longer than wide; mesotarsi ( Fig. 2I ) rather long and slender than male, tarsomere 1 about 1.2 times longer than 2-3 combined; genitalia shown as Figs. 2P–Q .

Material examined. (11) 2 females. Republic of Korea, Beopheung-ri, Mureungdowon-myeon, Yeongwol-gun , Gangwon-do , 04–18. VI.2015, Seung et al. leg., by flight intercept trap (SNU) ; 1 male and 2 females. Republic of Korea, Deoksu-ri, Danwol-myeon, Yangpyeong-gun , Gyeonggi-do, 23. VI –06.VII.2016, Seung et al. leg., by flight intercept trap (SNU) ; 1 female. Republic of Korea, Jeongbae-ri, Seojong-myeon, Yangpyeong-gun , Gyeonggi-do, 05–18. VI.2022, Seung et al. leg., by flight intercept trap (SNU) ; 2 males and 3 females. Republic of Korea, Sanga-dong, Andong-si , Gyeongsangbuk-do, 27. V –10. VI.2022, Seung et al. leg., by flight intercept trap (SNU) .

Distribution. Korea (New record), Japan, Russia (Far East).

Remarks. Its elytron is prominently longer than other Palaearctic Aulonothroscus species. The ratio of ‘length pronotum + elytra’ to ‘maximum width’ is quite variable in this species, even among individuals of the same sex: 2.42–2.53 in males, 2.47–2.63 in females.

Figures

FIGURE 2. Aulonothroscus longulus (Weise, 1879) A, C–F, H, J–O, male; B, G, I, P–R, female A–B, dorsal habitus; C, ventral habitus; D, lateral habitus; E, frons; F–G, antenna; H–I, midleg; J–L, aedeagus (dorsal-ventral-lateral); M–O, male genitalia (dorsal-ventral-lateral); P–R, female genitalia (dorsal-ventral-lateral)(scale bars for A–D: 1mm; E–R: 0.5mm)