Grouvellinus acutus, 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 : 175

Grouvellinus acutus species group

Members. Grouvellinus acutus sp. nov., G. denticulatus sp. nov., G. fujianensis sp. nov.

Diagnosis. The Grouvellinus acutus species group is characterized by the following features: 1) ovoid, small (BL less than 2.0 mm); 2) elytra with yellowish-brown or dark reddish markings of variable size; 3) pronotum pubescent and partly densely granulate (at least along midline in basal half), without prominent median carina, and without prescutellary pair of carinae; 4) intervals 3, 5, 7, 8 carinate, each carina with a row of granules, carina of interval 3 present only on basal 1/3, carina of interval 5 reaching middle of declivity, carinae on intervals 7 and 8 almost reaching elytral apex; 5) ventrite I with well developed pair of admedian carinae.

Distribution. China (Fujian, Guangxi, Yunnan), northern Thailand (several undescribed species of the G. acutus group from northern Thailand are deposited in the NMW).