Laccodytes

Toledo, Mario, Spangler, Paul J. & Balke, Michael, 2010, Taxonomic revision of the Neotropical diving beetles genus Laccodytes Régimbart, 1895 (Coleoptera: Dytiscidae), Zootaxa 2347, pp. 37-58 : 57

Key to species of Laccodytes

1. Posterior angles of pronotum produced backwards, acute; prosternal process with very long, needle-shaped tip, reaching caudally beyond mesocoxae for about a third of its length ........................................................................... 2

- Posterior angles of pronotum rounded; prosternal process with much shorter thorn-shaped tip, not or slightly extended caudally beyond mesocoxae .......................................................................................................................... 3

2. Dark line along suture complete, reaching the scutellum, fused laterally with humeral dark spots; subbasal band reaching the sides of elytra; dark patterns brown. Median lobe of aedeagus slender and more simple in shape........... ..................................................................................................................................................................... L. apalodes

- Dark line along suture not reaching the scutellum, ending in a lobed shape; humeral spots isolated; subbasal band not reaching the sides of elytra; dark patterns black. Median lobe of aedeagus larger and robust, more complex in shape ............................................................................................................................................................ L. rondonia

3. MR on metacoxae composed of elongate, fine longitudinal cells, visible at high magnification, punctuation not visible; elytra regularly tapering posteriourly, rounded apically ................................................................... L. americanus

- MR on metacoxae composed of rounded meshes, together with a more or less visible punctuation of fine dots; elytra rounded or truncate apically......................................................................................................................................... 4

4. Size larger (> 2 mm); Median lobe of aedeagus large and robust ........................................................ L. phalacroides

- Size smaller (<2 mm); Median lobe of aedeagus small and slender ........................................................................... 5

5. Apex of each elytron obliquely truncate, almost concave in outline; elytral patterns sharply contrasting: yellow subbasal and apical bands deeply lobate, giving to the dark markings a strongly irregular appearance ...... L. takutuanus

- Apex of each elytron not truncate, otherwise not obliquely; dark patterns less contrasting or, if so, with markings not lobate............................................................................................................................................................................. 6

6. Outer metatibial spur truncate at tip. Elytra black, with three small orange-reddish circular spots ........... L. olibroides

- Outer metatibial spur acuminate. Dark patterns of elytra brown, with a transverse sub-basal yellow band, often poorly distinct ............................................................................................................................................................... 7

7. Outer metatibial spur flat. Elytra brown with poorly distinct patterns ......................................................... L. neblinae

- Both metatibial spurs conical. Elytra with more or less distinct pale patterns, otherwise colouration dark also on head and pronotum........................................................................................................................................................ 8

8. Head and pronotum completely or mostly dark. Median lobe of aedeagus very elongate and thin in lateral view ... 9

- Head uniformly orange and pronotum of the same colour, at most with a dark basal line. Median lobe of aedeagus more robust in lateral view ....................................................................................................................... L. bassignanii

9. Dorsal colouration almost uniformly pitch-brown, with very indistinct paler patterns on elytra. Median lobe, in lateral view, visibly curved downward on apical third Male with last stenite of abdomen deeply emarginated on hind margin ..................................................................................................................................................... L. androginus

- Pronotum paler than head and elytra. Median lobe of aedeagus, in lateral view, completely straight and very thin, slightly curved on apical fifth. Male with last sternite not emarginated on hind margin ......................... L. obscuratus