Denticulobasis gen. nov.

Type species: Denticulobasis garrisoni sp. nov., by present designation.

Etymology: From the Latin denticulus – meaning diminutive of tooth and – basis, a Greek feminine noun for pedestal or foundation; a common suffix used in Coenagrionidae . The name Denticulobasis is an allusion to the presence of a plate with denticles on female sternum S8.

Distribution: Brazil and Peru (Fig. 101).

Generic characterization. Medium size damselflies (HW 18.2–19.2 mm). Top of head brown with blue postocular spots. Thorax dominantly yellow, with three longitudinal pale blue stripes: antehumeral, metepisternal, and metepimeral. S1–7 dorsally brown, laterally yellow, S8–10 dorso-laterally yellow. Frons rounded. Hind prothoracic lobe in males with very small lateral lobes, median lobe well-developed, projected caudally and two-lipped (Figs 4–6); females with well-developed lateral and median lobes (Figs 8–10), the latter single-lipped.

Male mesepisternum with an antero-medial horn with a basal smooth portion and a distal portion ridged as a screw. Female mesepisternum with an antero-medial mammiliform tubercle. Metafemoral spines on distal 1/2 as long as width of femur (Fig. 3 a); metatibial spurs shorter than intervening spaces (Fig. 3 b). Supplementary tooth of tarsal claw well-developed (Figs 3 c, d). Wings petiolated distal to Ac for a distance as long as or twice as long as Ac length (Fig. 3 e). R 3 in FW and HW originating closer to Px 6 (Fig. 3 e). Penis (Figs. 1) distal segment expanded laterally along distal 1/3 forming a large lateral terminal lobe and with two lateral lobes on each side. No terminal fold. Internal fold with a filiform process directed disto-laterally (Fig. 1). Male cercus with a dorso-lateral membranous depression at base (Figs. 12–13) and no ventral process. Cercus in lateral view subequal to S10 (excluding distal lobe). Female sternum S8 with a denticulated vulvar plate (Figs. 18, 20, 22). Ovipositor extending to about level of tip of cercus (Fig. 11). Ventral border of lateral valve of ovipositor with one row of denticles each one subrectangular, directed ventro-posteriorly and associated with a robust short truncated seta (Fig. 2 a).