Grouvellinus denticulatus, Bian & Jäch, 2018

Bian, Dongju & Jäch, Manfred A., 2018, Revision of the Chinese species of the genus Grouvellinus Champion, 1923 (Coleoptera: Elmidae). The G. acutus species group, Zootaxa 4387 (1), pp. 174-182 : 176

Grouvellinus denticulatus sp. nov.

( Figs 3–4 , 12–14 )

Type material: Holotype ( IAECAS), male: “ CHINA: Yünnan, Xishuangbanna \ ca . 50km SSE Menglun, Mengyüan \ 8.11.1999, ca. 700 m \ leg. Jäch, et al. ( CWBS 361 )”. Paratypes: 33 exs ( IAECAS: 3, NMW: 30), same label data as holotype; 2 exs ( NMW): “ CHINA: Yünnan, Xishuangbanna \ ca . 15 km W Menglun \ 5.11.1999, ca. 700–800m \ leg. Jäch, et al. ( CWBS 354 )”; 1 ex ( NMW): “ CHINA: Yünnan, Xishuangbanna \ ca . 15km W Menglun \ 5.11.1999, ca. 700m \ leg. Jäch, et al. ( CWBS 355 )”; 34 exs ( IAECAS: 1, NMW: 33): “ CHINA: Yünnan, Xishuangbanna \ ca . 10km NW Menglun \ 7.11.1999, ca. 700 m \ leg. Jäch, et al. ( CWBS 359 )”; 5 exs ( NMW): “ CHINA: Yünnan, Xishuangbanna \ ca . 10km NW Menglun \ 7.11.1999, ca. 700–800m \ leg. Jäch, et al. ( CWBS 360 )”; 4 exs ( NMW): “ CHINA: Yünnan, Xishuangbanna \ ca . 50km NW Menglun \ 9.11.1999, ca. 800 m \ Jäch & Schönmann ( CWBS 369 )”; 9 exs ( IAECAS: 4, NMW: 5): “ CHINA: Yünnan, Simao Pref. \ 54km SW Simao, Jian Shan riv. \ 15.11.1999, ca. 1000 m \ Schönmann & Wang ( CWBS 387 )”.

Diagnosis. Yellowish-brown elytral markings on average more extended than in the other Chinese species; metaventrite broadly impressed medially, without carinae; ejaculatory duct with denticulations.

Description. Head black, pronotum dark brown, elytra brown, each with two large yellowish-brown spots at base and near apex; yellowish colouration sometimes covering most of the elytra, with darker color confined to suture and transverse median band; spots sometimes broadly connected between interval 2 and 5. Ventral surface dark brown. Antennae and legs yellowish-brown.

BL: 1.40–1.75 mm, BW: 0.80–0.90 mm. Body obovate ( Figs 3–4 ).

Head densely granulate and sparsely pubescent. Surface of clypeus similar to that of frons. Labrum smooth and shining, sparsely and finely punctate, densely pubescent laterally.

PL: 0.42–0.50 mm, PW: 0.58–0.64 mm, broadest at basal 2/5, distinctly convex. Pronotal disc smooth and shining, finely punctate, moderately densely pubescent; in basal half granules densely arranged along midline, almost resembling a low median carina. Sublateral area densely granulate. Sublateral carina present on basal 1/3, an oblique impression extending from apex of carina toward anterior angles. Base with a pair of very small oval impressions in front of anterior angles of scutellum.

EL: 0.98–1.25 mm, subparallel on basal 2/3, then tapering towards conjointly rounded, sometimes somewhat acuminate apices. Strial punctures moderately large on basal half, separated by 0.5–1.5 times of their diameters. Punctures becoming smaller on distal half. Non-carinate intervals slightly convex or almost flat, each with a row of setae.

Prosternal process subquadrate, apex truncate, distinctly rimmed laterally, disc densely granulate and sparsely pubescent. Metaventrite broadly and deeply impressed along midline, disc shagreened, sparsely pubescent, sublateral areas densely granulate and sparsely pubescent, with an oblique row of very large sublateral punctures. Disc of ventrite I smooth and shining, sparsely granulate and pubescent, remaining ventrites densely granulate and pubescent. Hind tibia without obvious sexual dimorphism.

Aedeagus ( Figs 12–14 ): 0.50 mm long. Penis almost parallel-sided in basal half, then distinctly narrowed towards apex, ventral sac well developed, ejaculatory duct denticulate in basal half. Parameres slim and elongate, with moderately long setae in distal half.

Female: Elytral apices usually more acuminate than in male.

Distribution. So far known only from Yünnan ( China).

Etymology. The epithet is derived from the Latin adjective “ denticulatus ” (denticulate) and refers to the denticles of the ejaculatory duct.

Figures

FIGURES 1–4. Habitus, 1–2 dorsal and ventral view of Grouvellinus acutus sp. nov., male, holotype; 1a G. acutus sp. nov., hooked apical appendage on male hind tibia; 3–4 dorsal and ventral view of G. denticulatus sp. nov., male, holotype. Scale bar= 0.5 mm.

FIGURES 9–14. Male genitalia of 9–11 Grouvellinus acutus sp. nov., holotype; 12–14 G. denticulatus sp. nov., holotype. 9, 12 ventral view; 10, 13 dorsal view; 11, 14 lateral view. Scale bar = 0.1 mm.