Narrative

Prosopocoilini tribe contains several genera including Prosopocoelus and Cyclomnatus.

There are many different species of Cyclomnatus on the island of New Guinea. There are two groups of Cyclomnatus which have been identified by the exporters of beetles from Papua. Very rarely, if ever, are these two groups of beetles identified to the species level. The two groups are:

Cyclomnatus imperator group, which has an elongated shape
Cyclomnatus pulchellus group, which has shorter and stockier beetles
After examination of a large series of these two Papua groups, it appears that more than two species are involved. Seemingly the following species are present:

CYCLOMNATUS PULCHELLUS GROUP
Cyclomnatus pulchellus - majority from Morobe Prov
Cyclomnatus speciosa - from Solomon Islands
Cyclomnatus margaritae - similar to C. pulchellus

CYCLOMNATUS IMPERATOR GROUP
Cyclomnatus imperator - majority from Papua
Cyclomnatus spineus - light spots on topside of femurs
Cyclomnatus finschi - more delicate version of above

The various characteristics that help separate the species are as follows:
Cyclomnatus imperator does not have any teeth on the underside of the mandibles near the base of the mandibles. The femurs, when viewed from above in a mounted specimen, have generally a uniform dark color. C. imperator can reach sizes of over 8.0 cm.
Cyclomnatus spineus, especially the smaller and mid-size specimens, appears very similar to C. imperator and also has the single somewhat downward pointing tooth near the middle of the mandibles. However, upon studying the underside of this species, one will observe several spines (or teeth) on the underside of the mandibles near the base of the mandibles. Also, the femurs when viewed from above in a mounted specimen will appear to have a large patch of light coloration.
C. spineus are generally under 6.0 cm. The mandibles of C. spineus are also slightly more curved than those of C. imperator.

Taxonomy

References