Key to the species of Atlanticolycus gen. nov.

1. Maxillary palpomere 2 almost twice longer than 3. Phallus curved in lateral view, sharp dorsoapical projections slightly curved............................................................................................. 2

- Maxillary palpomere 2 longer than twice the length of palpomere 3. Phallus with dorsoapical sharp projections strongly curved subapical or several dorsally oriented projections............................................................ 3

2. Pronotum with median longitudinal carina in anterior 1/3 with areola mostly in posterior 2/3, connected to the basal margin by a very short carina (Figs. 1–2). Male genitalia with phallus strongly curved and parameres medially constricted in ventral view (Figs. 7–8)...................................................................... A. camposgerais sp. nov.

- Pronotum with median longitudinal carina bifurcating in anterior 1/4 forming areola in almost basal 3/4, connected directly to the posterior margin. (Fig. 5). Male genitalia with phallus slightly curved and parameres slightly tapering towards the apex in ventral view (Figs. 13–14)............................................................... A. ilhabela sp. nov.

3. Maxillary palpomere 2 much longer than palpomere 3, elytra with yellow median transversal band increasing in thickness towards marginal costae (Fig. 6), phallus apically presenting projections with several thorns, parameres medially constricted in ventral view bearing ventral and lateral thorns.............................................. A. morretes sp. nov.

- Maxillary palpomere 2 slightly longer than palpomere 3...................................................... 4

4. Pronotum with areola connected to the posterior margin by basal carina (Fig. 3), phallus strongly bent dorsally, apex slightly ventrally bent, and dorsally oriented apical projections hooked, parameres with ventral subapical thorns..... A. japi sp. nov.

- Pronotum with areola connected to the posterior margin by a very short carina (Fig. 4), phallus curved basally with 2/3 straight in lateral view,presenting double dorsoapical projections and apex ventrally bent, parameres with ventral subapical and apical thorns................................................................................ A. itatiaia sp. nov.