Lamiogethes sagittalis, 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 : 68-71

Lamiogethes sagittalis sp. n.

( Figs. 1c , 2 e–f, 3b, f, 5)

Diagnosis. Vaguely similar in external body shape and color to small specimens of the common Palearctic species L. brunnicornis (in the L. difficilis species group: Audisio 1993). Male genitalia distinctively shaped, with elongate, subparallel-sided and deeply incised tegmen ( Fig. 2e ), aedeagal median lobe moderately large, ca. 2.2× longer than wide, its maximum width proximad, and with arrowhead-shaped distal apex ( Fig. 2f ).

Description. Size (male holotype): body length 2.20 mm, width 1.45 mm.

Body color and pubescence: uniformly dark brown, tegument shiny. Legs brown to dark brown, with paler tarsal plates, antennae brown to dark brown with paler second and third antennomeres. Pubescence pale golden, moderately long and sparse, not concealing tegument, each individual seta ca. 0.80× as long as second antennomere ( Fig. 1c ).

Dorsal habitus: body shape ( Fig. 1c ) vaguely similar to L. brunnicornis . 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 = 0.49; ratio WPR1/LPR1 = 1.89; ratio WPR2/LPR1 = 1.80; ratio WPR2/WPR1 = 0.95; ratio LELY/WELY = 1.02; ratio WPR1/WPRA = 1.77; ratio WPR1/WELY = 0.92; ratio WPR2/WELY = 0.88.

Ventral habitus: combined outer edges of antennal grooves almost straight, parallel-sided along most of length. Prosternal process nearly as wide as antennal club, only with fine and sparse punctation. Male metaventrite markedly and widely impressed, with a rather deep semi-circular transverse impression, occupying nearly the posterior two-thirds; with two distinctly raised elongate longitudinal tubercles, nearly as long as second antennomere, placed on each side of the impression, prior to middle portion. Last visible ventrite with a large and moderately transverse shining tubercle in middle of posterior edge.

Appendages: antennae rather short ( Fig. 1c ); ratio ANLE/HWEA = 0.70; ratio CLLE/W10J = 1.20; ratio L03J/ W03J = 2.4; ratio L03J/L02J = 0.80; ratio L03J/L04J = 2.0; ratio WFTA/LFTA ≈ 0.34; ratio LETI/WITI ≈ 3.40. Pro- tibiae with a series of 3–5 moderately sharp teeth, increasing in size from the first to penultimate, shaped nearly as in the rare Caucasian endemic species L. amei Audisio & Kirejtshuk, 1988 ( Fig. 3f ). Metatibiae simple, not arcuately curved nor sinuate along their inner side, with a series of peculiarly long and slender spurs along outer edges ( Fig. 1c ).

Male genitalia: distinctively shaped, with elongate and subparallel-sided tegmen ( Fig. 2e ), widest in middle, medial distal excision deep, V-shaped (ratio DTIN/LETE ≈ 0.37), inner margins of excision simple, without projec- tion; ratio LETE/WITE ≈ 1.48. Median lobe of aedeagus large and long (ratio LEAE/WIAE ≈ 2.2; Fig. 2f ), exhibit- ing maximum width close to proximal base, with suddenly narrowed, arrowhead-shaped distal apex and slightly concave proximal apex.

Female: the only known female paratype is slightly larger than the male holotype, 2.5 mm length. Protarsal plates narrower than in male, ratio WFTA/LFTA ≈ 0.25. Metaventrite appearing simple, flattened; last abdominal ventrite without distal tubercle.

Ovipositor: mid-sized, with moderately pointed distal apex, not darkened distad, rather long subapical styli, and distinctly “V”-shaped basicoxites ( Fig. 3b ).

Variation: body size 2.20–2.52 mm (length) and 1.45–1.55 mm (width), and sexually dimorphic body size.

Examined material. Holotype, ♂: China: Shaanxi, Taibai Mts, Mei Xian, Haopingsi Natural Protection Area , ca. 2000 m a.s.l., ca. 34°2’24”N 107°25’12”E, 29.vii.2015, Huang, Liu & Cao lgt, by netting on flowering vegetation, ( NWAU) . Paratype: same data as holotype, 1 ♀ ( CAR-MZUR) .

Distribution. Central China (Shaanxi) ( Fig. 5 ).

Host-plants. Unknown, but likely among Lamiaceae .

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

Phenology. The two available specimens were collected at the end of July, which likely indicates adult activity at least from June to August.

Etymology. The specific epithet is derived from the Latin sagitta (= arrow), due to its peculiarly arrowheadshaped apex of the median lobe of the aedeagus ( Fig. 2f ), strongly resembling the condition typical of most members of the distantly related genus Sagittogethes Audisio & Cline, 2009 ( Audisio et al. 2009).

Taxonomic remarks. As reported above, this new species is vaguely similar in external shape to small specimens of L. brunnicornis from Europe (see Audisio 1993), as well as to other E Palearctic species of the genus. However, it is rather closely related to L. falcatus sp. n. and L. hastipenis sp. n. described above, sharing with them a similar body shape and size, type of punctation, and the peculiarly sword-tip-shaped or arrowhead-shaped distal apex of the median lobe of the aedeagus. Male specimens of both above-mentioned species exhibit markedly different tegmen shape and much longer and narrower median lobe of the aedeagus. We propose that L. sagittalis sp. n. belongs to the same species complex as L. ancestor mentioned above.

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.