Subfamily Spiriniinae Gerlach & Murphy, 1965

Type genus

Spirinia Gerlach, 1963 (syn. Spira Bastian, 1865: 159).

Diagnosis [emended from Decraemer & Smol (2006)]

Body cuticle finely striated (except the genera Echinodesmodora Blome, 1982, Spirodesma and Stygodesmodora Blome, 1982). Head capsule absent (i.e., cuticle not strongly thickened) and without demarcation between labial and cephalic regions. Amphidial fovea spiral located lateral and anterior on the body, its posterior border partially or completely surrounded by cuticle striations. Buccal cavity rather small, from minute to medium-sized with dorsal tooth, two smaller ventrosublateral teeth maybe present or absent.

The main modification to the diagnosis in Decraemer & Smol (2006) is the inclusion of coarse cuticle as exception in order to accommodate the transferred genera Echinodesmodora, Spirodesma and Stygodesmodora . We also acknowledge the absence of a head capsule.