Campsurus molinerii sp. nov. (Figures 3–15) Materials examined. Holotype: ♂ imago (genitalia and wings on slide), BRAZIL, Mato Grosso, Ribeirão Cascalheira, Fazenda Campina Verde, Rio Suiá-miçu, 28-30.xi.2006, S12˚48.591 W52˚06.925, A. R. Calor, R. Silva & S. Mateus cols (MZUESC-EPH0640). Paratypes: 27 ♂ imagos, same data as holotype (10 in MZUESC- EPH0641; 10 in UFVB; 07 in MZUSP). Diagnosis. The male imago of Campsurus molinerii sp. nov. can be separated from the other congeners by the following combination of characters: 1) male abdominal sternum IX posterior margin truncate to slightly concave, microlepides 3- to 6-pointed; 2) pedestals of each side almost touching basally, and parastylus wide at base and abruptly narrowed in distal half; 3) outer projection of pedestal with apical condyle process-like projection; 4) main lobe of penis expanded laterally, slightly curved ventrally and with acute apex curved ventrally outwards, apical portion almost cylindrical with apex in ventral view pointed, secondary membranous lobe cylindrical and relatively long; 5) small size (length of male fore wings 5.0– 5.8 mm). Description. Male imago (n=10). Lengths (mm): body, 5.3–6.6; forewings, 5.0–5.8; hind wings, 2.0–2.5; forelegs, 2.4–2.8; cerci, 15.0–16.8. General coloration: yellowish white. Head. Yellow shaded with blackish grey on dorsum; antennae: scape and pedicel yellowish, flagellum hyaline. Ocelli white surrounded with black. Thorax. Pronotum translucent, shaded with brownish laterally; meso- and metanotum yellowish-brown with sutures well marked (Figure 5). Mesonotum shaded with black marks on median zone of scutum and darker between posteroscutal protuberances; pleura and sterna pale yellowish white. Forelegs with femur shaded with gray; tibiae with posterior black marks; vestigial middle and hind legs yellowish. Wings translucent whitish, shaded with gray on subcostal distal area (Figures 3–4). Abdomen. Whitish translucent; all terga gradually shaded with gray, becoming darker on VIII–X (Figures 5–6). Sternum IX brownish with truncate to sinuous hind margin and covered with 3- to 6-pointed microlepides (Figure 11). Genitalia. (Figures 7–15) Yellowish white. Forceps whitish translucent; pedestals of each side almost touching basally, inner corner short and not projected, parastylus wide at base and abruptly narrowed in distal half, outer projection of pedestal with apical condyle process-like projection (Figures 7, 9 and 13). Main lobe of penis expanded laterally, rounded but not ear-like, slightly curved ventrally and with acute apex curved ventrally outwards, apical portion almost cylindrical with apex in ventral view pointed; secondary membranous lobe of penis cylindrical and almost reaching apex of main lobe (Figures 7–8, 10, 14–15). Paracercus whitish and short, cerci whitish translucent. Female imago. Unknown. Nymph. Unknown. Etymology. The specific name, molinerii (masculine, noun in the genitive case singular), is dedicated to our colleague Carlos Molineri for his contribution to the knowledge of neotropical mayflies.

Published as part of Cabral, Jeniffer, Salles, Frederico F. & Mariano, Rodolfo, 2022, A new species of Campsurus Eaton, 1868 (Ephemeroptera: Polymitarcyidae) from Brazil, pp. 236-242 in Zootaxa 5213 (3) on pages 239-241, DOI: 10.11646/zootaxa.5213.3.2, http://zenodo.org/record/7359891