Updated key to the Brazilian species of Oocyclus Sharp

This key is adapted from Clarkson & Short (2012) and includes also an additional species from Jordão et al. (2018).

1 Prosternal carina with two or more spine-like setae (Figs. 3e, 9e)................................................ 2

- Prosternal carina without spine-like setae (see Jordão et al., (2018): Fig. 2a................................ O . pilosus

2 Posterolateral angles of pronotum usually rounded (very rarely angulate) (Figs. 2, 4); prosternum with two or more spine-like setae; elytra with or without iridescent maculae, if present, maculae never blue; elytra with or without rows of erect setae.. 3

- Posterolateral angles of pronotum weakly spinose (see Clarkson & Short, 2012: Fig. 5); prosternum always with two spine-like setae; elytra with distinctive blue maculae and a dense row of erect setae (Fig. 5)........................... O. decorus

3 Prosternal carina set with 2 spine-like setae anteriorly (Figs. 2, 7).............................................. 12

- Prosternal carina set with more than 2 spine-like setae anteriorly (usually 4–6; Figs. 3, 6)............................ 4

4 Elytral surface heavily sculptured to appear bumpy or strongly undulating; glabrous (see Clarkson & Short, 2012: Figs. 1, 3) ................................................................................................... 5

- Elytral surface smooth, without bumps or strong undulations; glabrous or set with setae............................. 6

5 Elytral surface appearing blistered (see Clarkson & Short, 2012: Fig. 3).................................. O. alterosa

- Elytral surface with irregular sculpturing, but without distinctly raised bumps (see Clarkson & Short, 2012: Fig. 1).................................................................................................... O. acuru

6 Elytra with setae between rows of systematic punctures, appearing pubescent (Fig. 12b)............................. 7

- Elytra with weak or non-existent pubescence between rows of systematic punctures (Figs. 12a, c, d)................... 8

7 Posterolateral angles of pronotum rounded. Elytra pubescence decumbent laterally and on elytral intervals, but with at least two erect rows of setae medially. Posterior margin of the elytra darkly coloured, except for the pale spot on posterior quarter (see Clarkson & Short, 2012: Fig. 9)................................................................. O. itapercori

- Posterolateral angles of pronotum angulate. Elytra pubescence decumbent; not forming distinct rows medially. Posterior margin of elytra broadly depigmented medially (see Clarkson & Short, 2012: Fig. 13)............................. O. xanthus

8 Posterolateral margins of pronotum angulate (see Clarkson & Short, 2012: Fig. 4); elytral surface with very shallowly impressed longitudinal grooves near suture.......................................................... O. caparao

- Posterolateral margins of pronotum broadly rounded; elytral surface with or without very shallowly impressed longitudinal grooves near suture.................................................................................... 9

9 Elytra with strong indentation mediolaterally (see Clarkson & Short, 2012: Fig. 7); body attenuated posteriorly.. O. fryanus

- Elytra without or with only weak indentation mediolaterally; body not attenuated posteriorly........................ 10

10 Elytra surface with shallowly impressed longitudinal grooves; (e.g. Figs. 6a–e); each elytron with two or more posterior, small rounded pale spots.......................................................................... O. lacia sp. n.

- Elytra surface without shallowly impressed longitudinal grooves or with weak undulating grooves near sutural interval; each elytron with a single posterior, rounded pale spot........................................................... 11

11. Elytra with undulating grooves near the sutural interval; TL/GW ratio = 1.65; abdominal ventrites with color strongly contrasting to the legs (e.g. Figs. 3a–e)............................................................ O. espinhacu sp. n.

- Elytra without undulating grooves near the sutural interval; TL/GW ratio = 1.80; abdominal ventrites never in strong contrast to the legs.................................................................................. O. itapecum

12 Elytra surface with fine punctures (see Clarkson & Short, 2012: Figs. 2, 6); elytral suture raised or not................. 13

- Elytra surface coarsely punctures (see Clarkson & Short, 2012: Fig. 8); elytral suture raised......................... 14

13 Posterolateral margins of pronotum angulate, but never spinose (Figs. 4c, 10c).................................... 15

- Posterolateral margins of pronotum rounded............................................................... 16

14 Elytra with large, coarse punctures coarsely punctuate and without undulating grooves; posterolateral margins of pronotum angulate...................................................................................... O. iguazu

- Elytra with moderately sized, coarse punctures and with undulating grooves; posterolateral margins of pronotum rounded (e.g. Figs. 8a–e)............................................................................ O. sulcatus sp. n.

15 Elytra with conspicuous rows of systematic punctures, row 1 bearing long, erect setae in contrast to row 2 (Figs. 10a–e, 12a); body size 4.7–5.4 mm; aedeagus as in Fig. 11i................................................ O . thysanus sp. n.

- Elytra with hardly distinguishable rows of systematic punctures, rows 1 and 2 with similar setae; body size 5.7–6.3 mm; aedeagus as in Fig. 11c (e.g. Figs. 4a–e)...................................................... O. giganteus sp. n.

16 Abdominal ventrites dark brown to black, similar in color to thoracic venter (see Clarkson & Short, 2012: Figs. 2, 6); elytral suture raised or not on posterior half; elytral margins slightly reflexed or not..................................... 17

- Abdominal ventrites uniformly pale yellow or orange, distinctly darker than thoracic venter (see Clarkson & Short, 2012: Fig. 14) and in many cases with distinct medial macula present on one or more ventrites (e.g. Fig. 5b); elytral suture not raised on posterior half; elytral margins not reflexed on posterior half.................................................. 18

17 Each elytron with one rounded pale spot on distal quarter.................................................... 21

- Each elytron with two rounded pale spots on distal quarter.................................................... 22

18 Elytra without a row of large black spots alongside the suture (e.g. Fig. 5a)...................................... 19

- Elytra with a row of large black spots alongside the suture (e.g. Fig. 6a)......................................... 20

19 Elytra surface without setae; abdominal ventrites uniformly pale from yellow to orange (see Clarkson & Short, 2012: Fig. 11).......................................................................................... O. rotundus

- Elytra surface with setae; one or more abdominal ventrites in many cases with distinct medial macula as wide as or narrower than respective ventrites (e.g. Figs. 5a–e)................................................... O. humboldti sp. n.

20 Thoracic venter and legs brown and slightly darker than abdominal ventrites (see Clarkson & Short, 2012: Fig. 12)................................................................................................. O. schubarti

- Thoracic venter and legs dark brown to black and strongly contrast to the yellow abdominal ventrites (see Clarkson & Short, 2012: Fig. 14)................................................................................. O. yubai

21 Elytral suture not raised on posterior half; elytral margins not reflexed on posterior half............................ 23

- Elytral suture raised on posterior half; elytral margins weakly reflexed on posterior half....................... O. flexus

22 Elytral intervals with dense pubescence inserted in ground punctation (Fig 12b); aedeagus with gonopore located on medial half of median lobe, basal piece tapered (Fig. 11h)........................................... O. thrixdiastematus sp. n.

- Elytral interval with weak or non-existent pubescence inserted in ground punctation (Figs. 12a, c, d); aedeagus with gonopore located at four-fifths the length of median lobe, basal piece rounded (Fig. 11a)......................... O. ecolab sp. n.

23 Metaventrite with oval, glabrous posteromedial area about half the length of metaventrite; aedeagus as in Figs. 2, 15b, in Clarkson & Short (2012) ............................................................................ O. aeneus

- Metaventrite with oval, glabrous posteromedial area about two-thirds the length of metaventrite; aedeagus as in Figs. 11f (Fig. 7a–e).................................................................................. O. ovalis sp. n.