Chiasognathus sombrus, 2010

Paulsen, M. J. & Smith, Andrew, 2010, Revision of the genus Chiasognathus Stephens of southern South America with the description of a new species (Coleoptera, Lucanidae, Lucaninae, Chiasognathini), ZooKeys 43 (43), pp. 33-63 : 41

Key to Adults of Chiasognathus Species

1. Apex of elytra spinose. Males with large tooth projecting ventrally from each mandible, females with ridge or large tubercle in the same spot ... C. grantii Stephens

– Apex of elytra not spinose, either subdentate or rounded. Males and females at most with small ventral tooth at base of mandible.................................. 2

2. Epipleuron strongly concave in basal third of elytra. Elytral apex with beaded margins to just before apex......................................................................... 3

– Epipleuron more or less flat in basal third of elytra. Elytral apex thickened, with margin lacking bead........................................................................... 4

3. Prothorax with lateral margin obsolete anteriorly. Elytra distinctly shiny; surface glabrous in males, with long scattered bristles in females ......... C. impubis Parry

– Prothorax with lateral margin strongly indicated throughout, crenulate. Elytra usually densely squamose (rarely abraded).... C. mniszechii Thomson

4. Dorsal surface entirely squamose with short scales....... C. jousselinii Reiche

– Dorsal surface (especially pronotum) more or less glabrous ........................ 5

5. Mesotibia thickened (Fig. 10). Specimens known only from Ñuble Province (VIII Región del Biobío, Chile) .......... C. sombrus Paulsen & Smith , sp. n.

– Mesotibia not thickened (Fig. 11). Specimens from farther south.............. 6