Lamiogethes falcatus, Liu & Yang & Huang & Cline & Sabatelli & Audisio, 2020

Liu, Meike, Yang, Xingke, Huang, Min, Cline, Andrew Richard, Sabatelli, Simone & Audisio, Paolo, 2020, Five new species of Lamiogethes Audisio & Cline from China (Coleoptera Nitidulidae: Meligethinae), Zootaxa 4728 (1), pp. 63-76 : 64-65

Lamiogethes falcatus sp. n.

( Figs. 1a , 2 a–b, 3a, d, i, 5)

Diagnosis. Elongate, rather markedly transversely convex, medium-sized (2.5–2.6 mm) ( Fig. 1a ). Vaguely similar in external body shape and color to the rare Palearctic species Lamiogethes buyssoni ( Brisout de Barneville, 1882) (in the L. difficilis species group: Audisio 1993). Dorsal surface closely and markedly punctate (spaces between pronotal and elytral punctures ca. 1.2–1.6× diameter), with smooth and shining interspaces; elytra together 1.1× wider than pronotum, without distinguishable traces of transverse strigose sculpturing. Pronotum with vaguely trapezoidal shape, and rather straight lateral sides, at least in posterior two-thirds ( Fig. 1a ). Pubescence on pronotum and elytra sparse, golden-yellowish, distinct, each individual seta distinctly shorter (ca. 0.80×) than antennomere 2. Body uniformly dark brown; legs uniformly orange-brown, antennae brown, with first and second antennomeres slightly paler, orange-yellowish. Male protarsi wider than in any other known Lamiogethes , ca. 1.3× wider than maximum width of antennal club ( Figs. 1a , 3d ), ratio WFTA/LFTA ≈ 0.40. Male metatibiae peculiarly shaped, markedly ar- cuately sinuate along inner edge, more than in any other known Lamiogethes ( Figs. 1a , 3i ) and sickle-shaped even along outer edge. Male genitalia distinctively shaped, with elongate, subparallel-sided and deeply incised tegmen ( Fig. 2a ), aedeagal median lobe peculiarly large,>3× longer than wide, maximum width proximad and peculiar, finely acute at distal apex ( Fig. 2b ), only similar to that of L. hastipenis sp. n. Female unknown with certainty (but see comments below in “Examined material”).

Description. Size (male holotype): body length 2.6 mm, width 1.45 mm.

Body color and pubescence: uniformly dark brown, tegument shining. Legs orange-brown with darker tarsal plates. Antennae brown to dark brown with pale brown first and second antennomeres. Pubescence golden, rather long and sparse, not concealing tegument, each individual seta ca. 0.80× as long as second antennomere ( Fig. 1a ).

Dorsal habitus: body shape ( Fig. 1a ) vaguely similar to Lamiogethes brunnicornis ( Sturm, 1845) . Clypeus with truncate anterior margin. Dorsal punctures on pronotum rather fine and deep, each puncture separated from another by ca. 1.2–1.6 diameter; space between punctures smooth and shining. Dorsal punctures on elytra rather large, separated by ca. 1.2–1.5 diameter; space between punctures smooth and shining. Ratio LPR1/LELY = 0.50; ratio WPR1/LPR1 = 1.79; ratio WPR2/LPR1 = 1.72; ratio WPR2/WPR1 = 0.96; ratio LELY/WELY = 1.03; ratio WPR1/WPRA = 1.66; ratio WPR1/WELY = 0.90; ratio WPR2/WELY = 0.86.

Ventral habitus: combined outer edges of antennal grooves almost straight, parallel-sided along most of length. Prosternal process nearly as wide as length of antennal club, punctation fine and sparse. Male metaventrite flattened posterior to midlength, with wide but shallow mediolongitudinal impression, occupying nearly posterior two-thirds, with a barely impressed but distinct, narrow median longitudinal stripe, encompassing three-quarters of the metaventrite length. Last visible ventrite simple, without tubercles or ridges.

Appendages: antennae short ( Fig. 1a ); ratio ANLE/HWEA = 0.75; ratio CLLE/W10J ≈ 1.30; ratio L03J/W03J = 2.20; ratio L03J/L02J = 0.92; ratio L03J/L04J = 2.38; ratio WFTA/LFTA ≈ 0.40 ( Fig. 3d ); ratio LETI/WITI ≈ 2.90. Protibiae with a series of 3–4 moderately sharp teeth, increasing in size from the first to the penultimate, shaped nearly as in the common Palearctic species L. brunnicornis ( Fig. 3d ). Male metatibiae peculiarly shaped, markedly arcuately sinuate along inner edge ( Figs. 1a , 3i ), and sickle-shaped along outer edge.

Male genitalia: distinctively shaped, with elongate and subparallel-sided tegmen ( Fig. 2a ), widest in middle, medial distal excision deep, narrowly V-shaped (ratio DTIN/LETE ≈ 0.44), inner margins of excision without any projection; ratio LETE/WITE ≈ 1.65. Median lobe of aedeagus large and long, ratio LEAE/WIAE>3× longer than wide ( Fig. 2b ), exhibiting maximum width close to proximal base, with suddenly narrowed, acute distal apex.

Female: The only female referred to this species (see below) exhibits protarsi markedly narrower than in male (ratio WFTA/LFTA ≈ 0.25), and simple (not arcuate) metatibiae. Metaventrite almost flat, with a barely distinct but long longitudinal impressed stria, as in male.

Ovipositor: moderately large, with blunt apex, moderately sclerotized, not darkened distad ( Fig. 3a ). Styli peculiarly small, barely distinct, positioned at apex and slightly oriented posteriad. Preapical area of coxites bearing a couple of long sensorial setae ( Fig. 3a ). Basal portions of gonocoxites obliquely oriented distad and V-shaped, apices laterally directed and bluntly rounded. The only available female exhibits a folded, poorly sclerotized, and partially damaged ovipositor, whose drawing ( Fig. 3a ) has been in part assembled based on four renderings of the different sections of the same structure. For this reason the biometric measurements have not been recorded, and await better-preserved material.

Variation: body size 2.5–2.6 mm (length) and 1.35–1.45 mm (width), and sexually dimorphic protarsal shape.

Examined material. Holotype, ♂: China: Sichuan, Kangding, W portion of the town, 2770 m a.s.l., 30°0’36”N 101°34’12”E, 21.vi.2017, Audisio, Liu & Huang lgt, sparsely forested and bushy area, beating flowering Rubus sp. ( Rosaceae ), (NWAU). Paratype: same data as holotype, 1 ♂ (CAR-MZUR). Additional material that may be referred to the same species: same locality, 8.v.2017, Chen lgt, by beating low vegetation, 1 ♀ (NWAU).

Distribution. SW China (Sichuan) ( Fig. 5 ).

Host-plants. Unknown, but certainly Lamiaceae based on placement in the genus and species complex host preferences. The above cited Rubus sp. ( Rosaceae ) was likely an occasional food-plant before or after the flowering season of the species’ larval host. Some other Chinese species of the moderately related Lamiogethes kasparyani ( Kirejtshuk, 1984) and L. forcipenis ( Liu, Huang, Cline & Audisio, 2017) groups appear to be associated as larvae with Lamium spp. ( Lamiaceae ) and related genera ( Audisio et al. 2005; Liu et al. 2017 and unpublished data).

Habitat. Locality data indicate this species prefers the edges of high altitude sparsely forested and bushy areas.

Phenology. The few available specimens were collected in middle June and probably also occur in early May, which indicates adult activity at least from late April to July.

Etymology. The specific epithet is derived from the Latin falcatus (= sickle-shaped), due to its peculiarly sickle-shaped male metatibiae ( Figs. 1a , 3i ).

Taxonomic remarks. As reported above, this new species is vaguely similar in external shape to L. buyssoni from Europe (see Audisio 1993), as well as to other E Palearctic species of the genus; however, it is probably more closely related to L. hastipenis sp. n. described below, sharing with the latter a similar overall body shape, type of punctation, and peculiarly sword-tip-shaped distal apex of the large and long median lobe of the aedeagus. Male specimens of the latter species are markedly different in having straight metatibiae, simple and narrower protarsi, more deeply impressed metaventrite, posterior edge of last abdominal ventrite with small shining tubercle, and differently shaped tegmen. We hypothesize that L. falcatus sp. n., L. hastipenis sp. n., L. sagittalis sp. n., and L. unditibiis sp. n. belong to the same species complex as Lamiogethes ancestor ( Kirejtshuk, 1980) (comb. n.) from Hua Mts. (E Shaanxi), known to the authors only based on the original description. This species was correctly placed by Kirejtshuk (1980) within the previous “ Meligethes ” (s.l.) difficilis species group, all other species of which have been later transferred to Lamiogethes by Audisio et al. (2009). In that paper, we tentatively and erroneously attributed L. ancestor to the unrelated genus Sagittogethes Audisio & Cline ( Audisio et al. 2009), due to the convergent shape of the distal apex of the aedeagus. Lamiogethes ancestor and the five new species described herein all share a rather peculiar shape of the distal portion of the aedeagus, distinctly sword-tip-shaped like in most species of Sagittogethes , a trait unknown in any other described Lamiogethes . As discussed above, all these species are probably not distantly related from L. kasparyani and other taxa of NE and Central China ( Audisio et al. 2005).

Figures

FIGURE 1. Habitus of Lamiogethes spp.: a, L. falcatus sp. n. male from China, Sichuan; b, L. hastipenis sp. n., male from China, Hubei; c, L. sagittalis sp. n., male from China, Shaanxi; d, L. unditibiis sp. n., male from China, Chongqing; e, L. limaelytralis sp. n., male from China, Sichuan. Scale bar: 0.5 mm (Figs. a–e).

FIGURE 2. Male genitalia (tegmen and median lobe of aedeagus, dorsal view) of Lamiogethes spp.: a–b, L. falcatus sp. n., male from China, Sichuan; c–d, L. hastipenis sp. n., male from China, Hubei; e–f, L. sagittalis sp. n., male from China, Shaanxi; g–h, L. unditibiis sp. n., male from China, Chongqing; i–j, L. limaelytralis sp. n., male from China, Sichuan. Scale bar: 0.2 mm (Figs. a–j).

FIGURE 3. Female genitalia (ovipositor, ventral view) of Lamiogethes spp. (a–c): a, L. falcatus sp. n. from China, Sichuan (female not selected as paratype); b, L. sagittalis sp. n., female from China, Shaanxi; c, L. unditibiis sp. n., female from China, Chongqing. Protibiae of Lamiogethes spp. (d–h): d, L. falcatus sp. n., male from China, Sichuan; e, L. hastipenis sp. n., male from China, Hubei; f, L. sagittalis sp. n., male from China, Shaanxi; g, L. unditibiis sp. n., male from China, Chongqing; h, L. limaelytralis sp. n., male from China, Sichuan. Metatibiae of Lamiogethes spp. (i–j): i, L. falcatus sp. n., male from China, Sichuan; j, L. unditibiis sp. n., male from China, Chongqing. Scale bar: 0.2 mm (Figs. a–j).

FIGURE 5. Distribution map of Chinese Lamiogethes treated herein.