Canthydrus testaceus ( Boheman, 1858 )

Canthydrus testaceus ( Boheman, 1858) View in CoL

Hydrocanthus testaceus Boheman, 1858: 19 View in CoL (Type locality: “ China ”).

Canthydrus testaceus ( Boheman, 1858) View in CoL : Branden 1884: 18 (n. comb.).

Hydrocanthus ritsemae Régimbart, 1880: 213 View in CoL (Type locality: “ Sumatra, Loeboekh [Lubuk] Gadang ”); syn. nov.

Type material. Hydrocanthus testaceus : Lectotype ♀ ( NHRS), by present designation. The specimen has been dislodged from its original, small, pointed card ( Fig. 1 View FIGURES 1–2 ) to check its sex and re-glued on a new, rectangular one. It is labelled as follows ( Fig. 2 View FIGURES 1–2 ): “ China [small, printed] / Kinb. [=Hjalmar Kinberg (1820-1908); small, printed] / Typus [small, printed] / testaceus Boh. [larger, handwritten, folded paper strip] / 3390 E91 + [light blue, printed] / NHRS-JLKB 000076466 [unique specimen catalogue number]” plus our red lectotype label .

Notes on the lectotype of Canthydrus testaceus . The only known type specimen, a female ( Fig. 1 View FIGURES 1–2 ), has a rather weakly convex body (dorso-ventrally), sides of elytra (in lateral view) almost straight, very weak pronoto-elytral sinuation, and no traces of paler submedian markings on the elytra. Measurements are: total length 2.8 mm, maximum width 1.4 mm. Although the body length and maximum width are closer to the upper limit, all the other characters align fully with C. ritsemae , as defined by Toledo & Negri (2024), and exclude Canthydrus flavus (Motschulsky, 1855) as well as the two other larger, light-colored species of Canthydrus from Asia ( C. birmanicus Guignot, 1956 and C. rocchii Wewalka, 1992 ). In light of this, we confirm that Canthydrus testaceus ( Boheman, 1858) and C. ritsemae ( Régimbart, 1880) are synonyms and the first name has priority over the second.