Grouvellinus longiusculus, Bian & Jäch, 2019

Bian, Dongju & Jäch, Manfred A., 2019, Revision of the species Grouvellinus Champion, 1923 (Coleoptera: Elmidae) with long median pronotal carina, including descriptions of four new species from China, Zootaxa 4586 (1), pp. 127-140 : 132-133

Grouvellinus longiusculus sp. nov.

( Figures 2 A–B, 6A–C, 9D–F)

Type material: Holotype male ( IAECAS): “ CHINA: Jiangxi, Jiuling Shan \ 18km NW Shangfu, 12.11.1997 \ env. Jiu Xian, 650m \ leg. Schönmann ( CWBS 303 )” . Paratypes: 5 males (1 IAECAS, 4 NMW) , 16 females (2 IAECAS, 14 NMW): same data as holotype, but six specimens labelled “leg. M. Wang ” instead “leg. Schönmann ” ; 1 female ( NMW) : “ CHINA: Jiangxi, Jiuling Shan \ 18km NW Shangfu, 12.11.1997 \ env. Jiu Xian, 700 - 800m \ leg. Schönmann ( CWBS 302 )” .

Diagnosis. This species can be distinguished from G. bishopi by the stronger median pronotal carina, by the larger strial elytral punctures; from G. mediocarinatus it can be distinguished by its larger size, by the penis being distinctly longer than the phallobase, and by the more distinctly acuminate apex of the penis; from G. hongkongensis it can be distinguished by the longer aedeagus, which is more distinctly curved in lateral view; from G. robustus by its slimmer body, more distinctly acuminate apex of the penis, and also by the mesal margin of the parameres being emarginate in ventral view

Description. BL ca. 2.0– 2.2 mm, BW ca. 1.0 mm. Body elongate obovate.

Dorsum more or less black, anterior margin of labrum brown, anterior rim of pronotum sometimes reddish brown; ventral surface testaceous brown to dark brown. Legs dark brown, antennae yellowish brown.

Head: Labrum pubescent anteriorly, smooth and shining, superficially microreticulate posteriorly. Clypeus and frons densely microgranulate and sparsely pubescent.

Pronotum ( Figure 6A ): PL ca. 0.65 mm, PW ca. 0.75 mm, broadest at basal 2/5, anteriorly distinctly attenuate. Disc rugosely micropunctate/microgranulate, moderately densely pubescent. Sublateral carina present at basal 0.4, adjoined by mesal groove, median carina present in basal 0.9.

Elytra: EL ca. 2.1 mm, subparallel in basal 2/5, then tapering to apex. Strial punctures very large and deeply impressed in basal half, about 0.5–1.0 times of their diameters, punctures becoming smaller and more widely separated in distal half, separated by 2–4 times of their diameters. Sutural interval with a short row of granules at basal 0.3. Intervals 3, 5, 7, 8 with finely crenulated carinae; interval 3 especially strongly elevated subbasally. Remaining intervals flat, smooth and shining, sparsely micropunctate and pubescent.

Prosternal process slightly elevated. Surface granulate throughout, sparsely pubescent. Disc of metaventrite broadly impressed in males, narrowly impressed in females, coarsely granulate and sparsely pubescent; sublateral portion densely granulate; laterally with an oblique row of very large punctures, and with deeply impressed groove at anterior and posterior margin.

All ventrites densely granulate and sparsely pubescent.

Male genitalia ( Figure 9 D–F): ca. 0.70 mm long. Penis distinctly longer than phallobase, slightly exceeding parameres, distinctly narrowed from base to apex, apex narrowly rounded; ventral sac weakly developed. Parameres in ventral view distinctly narrowed from basal 0.1 to basal 0.3, then gradually narrowed towards apex, lateral edges incurved at distal 0.1.

Distribution. China (Jiangxi).

Etymology. The epithet is derived from the Latin adjective “longiusculus” and refers to the fact that the penis is distinctly longer than the phallobase.

Figures

FIGURE 2. Habitus. A–B) Grouvellinus longiusculus, holotype male; C–D) Grouvellinus mediocarinatus, holotype male. A, C) in dorsal view; B, D) in ventral view.

FIGURE 6. Grouvellinus longiusculus. A) anterior part of body, dorsal view; B) same, ventral view; C) posterior part of body, ventral view.

FIGURE 9. Aedeagus. A–C) Grouvellinus hongkongensis; D–F) G. longiusculus; A, D) in ventral view; B, E) in dorsal view; C, F) in lateral view. Scale: 0.2 mm.