Grouvellinus mediocarinatus, 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 : 133-135

Grouvellinus mediocarinatus sp. nov.

( Figures 2 C–D, 7A–C, 10A–C)

Type material: Holotype male ( IAECAS): “ CHINA: Guangdong Prov. \ 25 km SE Shixing \ 24°50′23″N 114°14′32″E \ 8.11.2001, ca. 150 m \ Jäch & Komarek ( CWBS 481 )” . Paratypes: 2 males ( IAECAS), 32 exs. ( NMW), same data as holotype ; 1 male, 1 female ( NMW): “ CHINA: Guangdong Prov. \ 50 km E Fengkai \ 23°27′36″N 111°54′36″E \ 31.10./ 2.11.2001, ca. 150 m \ Jäch & Komarek ( CWBS 455 )”; 10 exs. ( NMW): “ CHINA: Guangdong Prov. \ 35 km NE Huaji \ 24°00′25″N 112°26′09″E \ 3.11.2001, ca. 130 m \ Jäch & Komarek ( CWBS 463 )” ; 1 female ( IAECAS): “ CHINA: Guangdong Prov. \ Chebaling N.R. \ 24°42′21″N 114°14′17″E \ 7.11.2001, ca. 304 m \ Jäch & Komarek ( CWBS 476 )”; 7 exs. ( NMW): “ CHINA: Guangdong Prov. \ Chebaling N.R. \ 55 km SE Shixing \ 8.11.2001, ca. 340 m \ Jäch & Komarek ( CWBS 483 )” ; 2 males ( IAECAS, NMW): “ CHINA: FUJIAN, Longyan \ Xiaochi (20 km W Longyan) \ Meihua Shan , 650m, 30.1.1997 \ leg. Ji & Wang ( CWBS 263 )” .

Diagnosis. This species can be distinguished from Grouvellinus bishopi by the distinctly raised median pronotal carina, by the larger elytral strial punctures, by the apically rounded penis distinctly exceeding the parameres, and by the long phallobase; from G. longiusculus it can be distinguished by its smaller size, and by the apex of the penis, which is broadly rounded; from G. hongkongensis it can be distinguished by the apex of the penis being broadly rounded, and by the relative length of the phallobase; from G. robustus by its smaller and slimmer body, male metaventrite without a pair of admedian carinae, and also by the distinctly smaller aedeagus.

Description. BL ca. 1.7–1.9 mm, BW ca. 0.95 mm. Body elongate obovate.

Dorsal coloration: Dorsum dark brown to black, anterior margin of labrum yellowish, anterior margin of pronotum brown, antennae yellowish brown. Ventral surface dark brown, legs dark brown except tarsi yellowish brown.

Head: Labrum anteriorly and laterally rather densely pubescent, superficially microreticulate posteriorly. Clypeus and frons moderately pubescent; granules on frons denser than on clypeus. Frontoclypeal suture distinct.

Pronotum ( Figure 7A ): PL ca. 0.6 mm, PW ca. 0.7 mm, subparallel at basal 0.4, anteriorly distinctly attenuate, anterior margin convex. Surface rather densely microgranulate/micropunctate, moderately densely pubescent. Sublateral carinae present from base to basal 0.4, oblique impressions shallow, extending from apex of carina to anterior angles. Median carina extending from base to basal 0.8. Base with a pair of subcircular impressions in front of anterior angles of scutellum.

Elytra: EL 1.30 mm, subparallel in basal 2/3, then tapering to conjointly or separately rounded or subacuminate apex. Strial punctures large and deeply impressed, separated by 0.5 times of their diameters in basal half. Punctures becoming smaller and more widely separated (2–3 times of their diameters) in distal half. Strial intervals narrow, surface smooth and shining, sparsely punctate, with rows of setae. Pubescence on intervals 1 and 3 more distinctly developed. Intervals 3, 5, 7, 8 with finely granulate carinae. Carina of interval 3 extending from base to elytral declivity.

Prosternal process elongate, distinctly rimmed laterally; basal half of disc slightly elevated; surface sparsely granulate; posteriorly broadly rounded. Metaventrite with posterior 3/4 of disc narrowly and shallowly impressed; surface densely granulate; laterally with an oblique row of very large punctures, and with a deep transverse groove at anterior and posterior margin; sublateral portion densely granulate.

All ventrites densely granulate throughout and sparsely pubescent.

Male genitalia ( Figure 10 A–C): ca. 0.55 mm long. Slim and elongate, penis distinctly exceeding parameres, gradually narrowed from base to apex, which is comparatively broadly rounded; ventral sac weakly developed. Parameres in ventral view distinctly narrowed at basal 1/4, apices narrowly rounded; in dorsal view gradually narrowed from base to apex.

Distribution. China (Guangdong, Fujian).

Etymology. The epithet is derived from the Latin adjectives “medius”= middle, and “carinatus” = carinate, referring to the long median pronotal carina.

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 7. Grouvellinus mediocarinatus. A) anterior part of body, dorsal view; B) same, ventral view; C) posterior part of body, ventral view.

FIGURE 10. Aedeagus. A–C) Grouvellinus mediocarinatus. D–F) G. robustus. A, D) in ventral view; B, E) in dorsal view; C, F) in lateral view. Scale: 0.2 mm.