A. californiense is generally distributed around the world and it is frequently found on dung and in soil near the entrances of animal burrows.
[1] As one of the first species selected in the genus Auxarthron, A. californiense was first isolated from pack rat dung in 1963, at California.
Although this feature may not be significant for distinguishing new genera, the genus Auxarthron could also be identified on the basis of the presence of wall thickenings in the vicinity of septa which they called "knuckle joints".
[1][3] The genus Auxarthron is related to Amauroascus and Arachnotheca, but differs from these two genera in possessing dark ascomata with distinct appendages.
[4] Auxarthron species, like most Onygenaceae, have usually been isolated from strongly anthropized soil, enriched with human or animal keratinaceous remnants.
[7] In 1998, A. californiense was isolated on the veil, tunic and wood fragments on the remains of a ninth century Longobard abbess at Pavia, Italy.