Dima guizhouensis Ruan, Kundrata & Qiu, 2018

Ruan, Yongying, Kundrata, Robin, Sormova, Eliska, Qiu, Lu, Zhang, Mengna & Jiang, Shihong, 2018, Description of two new species of Dima Charpentier, 1825 from China (Coleoptera: Elateridae: Dendrometrinae), Zootaxa 4526 (4), pp. 589-599 : 590-594

Dima guizhouensis Ruan, Kundrata & Qiu sp. nov.

( Figs. 1–3 )

Type locality. China, Guizhou Prov., Chi-shui .

Etymology. This species is named after the type locality.

Distribution. China (Guizhou Province).

Diagnosis. This species is rather distinct in Dima species by the following combination of characters: body black; pronotum strongly convex from lateral view; posterior angles almost straight, oriented backwards; mesoventrite with oblique, almost straight sides; both mesoventrite and mesanepisternum with only weakly defined procoxal rests; elytra elongate, with distinctly elevated interstriae, interstria VI ridge-like, elytral apex truncate; bursa copulatrix without any spines or sclerotized parts.

It superficially resembles D. xiaolongi Ruan, Kundrata & Qiu sp. nov. and D. tianmuensis Qiu & Kundrata in Qiu et al., 2018 , especially in the strongly convex pronotum and elongate elytra. However, it can be distinguished from the two species by the black body coloration (chestnut brown in D. xiaolongi Ruan, Kundrata & Qiu sp. nov. and D. tianmuensis ), the straight posterior pronotal angles (distinctly divergent in D. xiaolongi Ruan, Kundrata & Qiu sp. nov. and D. tianmuensis ), and the truncate elytral apex (rounded in D. xiaolongi Ruan, Kundrata & Qiu sp. nov. and D. tianmuensis ).

Description (female, holotype). Body elongate-oval, obviously constricted near posterior angles of pronotum and base of elytra. Color black to blackish brown. Head and antennae black; frontal carina brown. Pronotum black, with lateral margin somewhat dark brown. Scutellar shield and ventral surface of prothorax entirely black. Elytra black, with lateral margins reddish dark brown. Ventral surface of meso- and metathorax blackish brown to reddish dark brown, surface of abdominal ventrites blackish brown; legs dark brown. Surface of body, legs and antennae covered with long, semi-erect golden pubescence.

Body length: 8.40 mm. Body width (measured across the widest part of elytra): 3.35 mm. Width of pronotum (measured across the widest part): 2.70 mm. Pronotum width to length (measured along midline, excluding posterior angles) ratio: 1.15. Ratio of pronotum width (measured in widest area) to the distance between posterior angles: 1.17. Elytron length to width ratio: 3.70. Length of elytron to that of pronotum (measured along midline, excluding posterior angles) ratio: 2.45. Width of elytra at base (measured at lateral sides near humeri) to maximum width of elytra ratio: 0.60.

Head ( Figs. 2A , 3 A–B) flattened, prognathous. Surface of frons and vertex uneven, longitudinally impressed along middle, covered with very deep and large punctures, the intervals between punctures somewhat irregular; anterior end of frons bends downwards abruptly; frontal carina incomplete medially, sharp and raised above antennal insertions; surface of carina smooth and glabrous (especially above the insertions of antennae) ( Fig. 3 A– B). Mandible extending anteriorly, maxillary palpus moderately long, apical palpomere hatchet-shaped. Antenna long, extending beyond half of elytra; with long pubescence; first antennomere robust, remaining antennomeres slender and elongate; last antennomere pointed at apex. Distance between eyes to transverse diameter of eye ratio: 3.92. Length of antenna to that of body ratio: 0.79. Proportions of antennomere lengths as follows: 100: 54: 71: 72: 85: 85: 85: 80: 80: 75: 94.

Pronotum ( Fig. 2D ) strongly convex from lateral view. From dorsal view, lateral sides evenly rounded at middle, straight at posterior angles. Anterior angles weakly developed, oriented antero-laterally. Posterior angles almost not divergent, oriented backwards. Pronotal surface covered with strong and deep punctures, intervals between punctures about 1–2 times as the diameter of a puncture. Punctures dense and coarse on disc and anterior margin, sparse and small on lateral and basal margin, very minute and scarce near posterior angles. Basal margin sinuate and simple, without any groove or indentation. Prosternal process about twice as long as procoxal diameter, gradually narrowed towards apex; apex sharp in lateral view ( Fig. 3C ). Scutellar shield ( Fig. 2E ) transverse, elliptic, widest at middle, width to length ratio: 1.65; anterior and lateral margins rounded, hind margin very slightly protruding in middle; disc slightly convex; surface smooth. Disc and anterior half strongly and densely punctate; lateral sides of hind margin almost without punctures. Mesoventrite ( Fig. 3 C–E) with lateral sides oblique, almost straight; anterior extension protruding forward, relatively deeply incised medially; procoxal rests on anterior edge only weakly defined; mesoventral cavity elongate, shallow, widened basally. Mesanepisternum with only weakly defined lateral extensions of procoxal rests. Ventral surface of pro-, meso- and metathorax covered with dense and coarse punctures, with interstices smooth and shiny; pubescence long, semi-erect. Hind wings and humeral calli absent. Elytra narrow, long, widest near apical third; sides very slightly convex to nearly straight at basal half, convex at apical half; apex truncate ( Fig. 2F ). Elytral pubescence sparse on disc and dense on lateral sides. Elytral striae I–IV equipped with longitudinal, small and distant punctures; remaining striae equipped with circular, large and almost contiguous punctures. Interstriae strongly elevated and covered with extremely minute and distant punctures; interstria VI narrow, forming prominent ridge, sides of elytra strongly bent downwards behind ridge. Legs long and slender; length ratio of metatarsomeres I–IV: 1.00: 0.64: 0.53: 0.48. Apex of tarsomere III with poorly developed lobe; apex of tarsomere IV with lobe prominent and protruding.

Abdominal sternite VIII spoon shaped ( Fig. 1E ). Tergite VIII as long as wide, medially with obscure longitudinal groove ( Fig. 1G ). Ovipositor ( Fig. 1F ) long, parallel-sided, apical part missing (also in paratype). Bursa copulatrix ( Fig. 3 F–G) cylindrical, longitudinal, its apical part dilated, without any spines or sclerites, with minute spots scattering throughout.

Variability. Posterior angles of pronotum are apically narrowed and slightly acute in the holotype, while they are slightly rounded and more robust in the paratype. The elytral apices are more prominently truncate in the paratype.

Type material. Holotype: female ( SZPT), labels: 1) Guizhou Prov., Chi-shui, Shi Fuming leg., 2000. V.29; 2 ) Holotype Dima guizhouensis n. sp. Des. Ruan, Kundrata & Qiu 2018. Paratype: 1 female ( IZCAS), labels: 1) Guizhou Prov., Chi-shui, Shi Fuming leg., 2000. V.27 ; 2) Paratype Dima guizhouensis n. sp. Des. Ruan, Kundrata & Qiu 2018.

Figures

FIGURE 1. Dima guizhouensis Ruan, Kundrata & Qiu sp. nov. (holotype). A: habitus, dorsal view. B: habitus, ventral view. C: habitus, lateral view. D: basal half of left elytron, dorsal view. E: abdominal sternite VIII, ventral view. F: ovipositor, dorsal view. G: abdominal tergite VIII, dorsal view.

FIGURE 2. Dima guizhouensis Ruan, Kundrata & Qiu sp. nov. (holotype). A: head, dorsal view. B: right metacoxal plate, ventral view. C: left posterior angle of pronotum, dorsal view. D: pronotum, dorsal view. E: scutellar shield, dorsal view. F: apex of elytra, dorsal view.

FIGURE 3. Dima guizhouensis Ruan, Kundrata & Qiu sp. nov. A: head, fronto-dorsal view (holotype). B: head, frontolateral view (holotype). C: prosternal process and mesoventrite, lateral view (paratype). D: part of mesoventrite, ventral-lateral view (paratype). E: mesoventrite, ventral view (paratype). F, G: bursa copulatrix (paratype).