Cyrtodesmus humerosus is a species of millipede in the family Cyrtodesmidae that is endemic to San Vito, Costa Rica, where it was found on April 19, 1972.
The front of the head and its interantenna part is joined at the same level as its body, with the former is without raised angle next to the socket of the antennae.
The front of the interantennal ridges are low, oblique and wide, with the back part tend to be more slender, granule and flat.
It has weak and narrowly impressed vertex, with median sulcus is being present on its posterior half.
Their apex have a bifurcated branch, while their gonopod is extended beyond the coxae of adjacent legs and is hemispherical.