[1] The species in endemic to California and found in the foothills of the Sierra Nevada mountains.

[1][2][3] Sigmocheir calaveras is the type species for the genus Sigmocheir and was described by Ralph V. Chamberlin in 1951 based on a sample collected by G. Moore from Crystal-Stanislaus Cave, Calaveras County in 1950.

[2] The paranota on S. calaveras arise high on the tergites giving the millipedes a rather flat appearance.

[2] This species occupies a central, and slightly overlapping range, with the additional representative of the genus.

It is found in the foothills of the Sierra Nevada mountains west of Stockton and Modesto[2] Individuals of the genus have been reported in Amador, Calaveras, and Tuolumne counties.