Size: 55 - 160 mm
Dynastes neptunus is rather similar
in form to the somewhat larger D. hercules, but its body is black
instead of brown. Also, the horns are more slender and often much
more curving than in D. hercules, and the cephalic horn is of similar
length to the thoracic one. Additionally, there are two lesser yet
very pronounced horizontal horns parallel to the base of the thoracic horn.
D. neptunus had a reputation as being a very rare beetle for many
years, but that was before it was discovered that it mainly only emerges
from hiding just before dawn, and perhaps that is why it was not frequently
seen previously. It is now known to be quite common in the rain forests
throughout much of the northwestern portion of South America.