Grouvellinus macilentus, Bian & Zhang, 2023

Bian, Dongju & Zhang, Yi, 2023, Descriptions of eight new species of Grouvellinus from China (Coleoptera, Elmidae), Zootaxa 5254 (2), pp. 257-277 : 268-269

Grouvellinus macilentus sp. nov.

( Figs 4C–D , 12A–C , 16D–F )

Material examined: Holotype, male ( IAECAS): “ China: Yunnan (22) / Baoshan City / Mangkuan Town / Xinguang Villageļ 25°28′18″N 98°50′53″E / 1026 m, 2019.7.4 / Leg. Peng, Dong & Zhu” . Paratypes: 1 male ( IAECAS): “ China: Yunnan (7) / Dali City, Yongping / County , Sanjia Vill. ļ 25°17′59″N 98°36′34″E / 1517 m, 2018.10.18 / Leg. Peng, Dong, & Zhu” ; 1 male ( IAECAS): “ China: Yunnan (20) / Nujiang, Lushui, / Pianma ļ 26°0′3″N 98°39′42″E / 2392 m, 2018.10.25 / Leg. Peng, Zhu, Dong” ; 1 male ( IAECAS) “ China: Yunnan (6) / Dehong Pref. / Yingjiang County / Pingyuan Townļ 24°50′42″N 98°56′27″E / 1074 m, 2019.6.27 / Leg. Peng, Dong, & Zhu; 1 male. ( IAECAS): “ China: Yunnan / Baoshan City / Lujiang Town , Shiti Vill. ļ 24°56.87′N 98°49.78′E / 1050 m, 3. VII. 2019 / Leg. Peng et al (19) ; 4 males, 1 female ( IAECAS): “ China: Yunnan / Baoshan City / Mangkuan Town / Sandieshui falls ļ 25°26.42′N 98°50.2′E / 1135 m / 3. VII. 2019 / Leg. Peng et al. (21)” ; 1 male ( IAECAS): “ China: Yunnan (30) / Nujiang Pref. / Fugong County / Shiyueliang Townļ 27°14′2″N 98°53′25″E / 1074 m, 2019.7.8 / Leg. Peng & Dong; 3 males ( IAECAS): “ China: Yunnan / Nujiang, Fugong / Shiyueliang ļ 27°14′2″N 98°53′25″E / 1474 m / 9. VII. 2019 / Leg. Peng et al. (31)” ; 1 male ( NHMW): “ CHINA: Yunnan, Chuxiong Pref. / 15 km W Lufang / 27.11.1999, ca. 1500 m / Schönmann & Wang ( CWBS 408 )” ; 1 male, 1 female ( NHMW): “ CHINA: Yunnan, Chuxiong Pref. / Da Shui Go riv. nr. Banjiu / 10 km N Yipinglang / 27.11.1999, ca. 1700 m / Schönmann & Wang ( CWBS 409 )” .

Diagnosis. Body obovate, dorsum brown except head black and antennae yellowish brown; pronotum without median carinae or sulcus; sublateral carinae present in basal 0.3, not developed; elytra subparallel in basal 2/3, distinctly narrowed in distal 1/3; elytral intervals flat, smooth and shining; strial punctures small; prosternal process broad, nearly subquadrate, apex truncate. This species is similar to Grovellinus luciaensis Freitag et al., 2019 in habitus and similar body size, but it can be distinguished from the latter by its apex of prosternal process almost truncate, by strial punctures on elytra small and shallowly impressed and intervals on elytra flat, not elevated, and also by distal 1/5 of penis not suddenly sharpened. This species can be distinguished from Grouvellinus lubricus sp. nov. by pronotum with a pair of impressions in front of anterior angles of scutellum, and also by aedeagus smaller, distal 1/3 of penis distinctly narrowed, apex narrowly rounded.

Description. Small in size. BL 1.7 mm, BW 0.9 mm. Habitus see Figs 4C–D . Head black except mouth part and antennae yellowish brown. Dorsum brown, ventral surface brown to dark brown. Legs yellowish brown.

Head. Labrum smooth and shining, sparsely punctate and pubescent, with a group of short yellowish setae anterio-laterally. Clypeus smooth and shining, punctures denser and larger than on labrum. The punctures and pubescence on frons similar to that on the clypeus.

Pronotum ( Fig. 12A ) broadest at basal 0.4, slightly attenuated anteriorly and posteriorly, PL 0.55 mm, PW 0.7 mm. Disc smooth and shining, densely punctate and pubescent. The area near anterior and posterior angles rugulose, with a few granules. Median carina or sulcus absent. Sublateral carinae present in basal 0.3, not parallel. A groove extends from apex of carina to anterior angle on each side. A pair of small oval impressions present in front of anterior angles of scutellum.

EL 1.2 mm, EW 0.9 mm. Elytra subparallel in basal 2/3, then distinctly narrowed towards apex. Strial punctures small, separated by 2–3 times of their diameters in basal half. Punctures becoming smaller and shallower in distal half. Intervals smooth and shining, setiferous punctures more developed on intervals 1, 3, 5. Intervals 7, 8 carinate.

Prosternal process ( Fig. 12B ) broad, nearly subquadrate; lateral sides almost subparallel, apex truncate. Lateral margin distinctly rimmed; basal 3/5 smooth and shining, flat, only with few fine punctures; distal 2/5 rugulose. Metaventrite ( Fig. 12C ) with disc broadly and slightly impressed, surface rugulose, punctures sparsely distributed. Lateral area densely pubescent. Each side with a row of large punctures behind of mesocoxa, and a row of small punctures in front of metacoxa.

Ventral side. Disc of ventrites I–IV smooth and shining, sparsely punctate, lateral area of ventrites I–IV densely pubescent. Ventrite I with a pair of ad-median carinae. Disc of ventrite V smooth and shining, sparsely granulate in basal 0.7, distal 0.3 densely pubescent and granulate, lateral area densely pubescent ( Fig. 12C ).

Aedeagus ( Figs 16D–F ) 0.45 mm long. Penis is about 2 times as long as phallobase. Penis overreaching the parameres, almost subparallel in basal 2/3, then distinctly narrowed in distal 1/3, apex narrowly rounded. Parameres broad at base, distinctly narrowed in basal 0.1, then gradually narrowed to the apex, and apices rounded.

Males: BL 1.6–1.8 mm, BW 0.8–0.9 mm (n=11); females: BL 1.6–1.7 mm, BW 0.8 mm (n=2).

Distribution. China: Yunnan.

Etymology. The epithet is derived from the Latin adjective “ macilentus ” and refers to its slim body.

Figures

FIGURE 4. Habitus A–B) Grouvellinus nujiangensis sp. nov. C–D) G. macilentus sp. nov. A, C) dorsal view B, D) ventral view.

FIGURE 12. Grouvellinus macilentus sp. nov. A) anterior part of body, dorsal view; B) same, ventral view; C) posterior part of body, ventral view.

FIGURE 16 Aedeagus A–C) Grouvellinus nujiangensis sp. nov. D–F) G. macilentus sp. nov. A, D) ventral view B, E) dorsal view C, F) lateral view.