An entire and fragmentary specimens ofBathynotusfrom the Northern Territory, Australia, are described and referred toB. holopygus. Entire specimens from the Kaili Formation, Guizhou, China, may also belong to this species which was widespread, inhabiting the outer shelf to slope facies of the olenellid and redlichiid (Perigondwana) faunal realms. Species based on fragmentary material may, or may not, be different. The stratigraphical range ofB. holopyguslies within the currently debated late Lower Cambrian to early Middle Cambrian transition. The cranidial morphology and macropleural eleventh thoracic segment suggests that it may belong with the Redlichioidea; the morphology appears to allow complete enrolment.