A new subspecies of the conodont genus Ozarkodina and its correlative value

A new conodont subspecies, Ozarkodina martinssoni auriformis, from the Jack Formation of the Broken River region in northern Australia is described. The taxon can also be recognised in other low diversity Late Silurian conodont faunas globally and whilst it does not provide a tightly constrained chronology for its host lithologies, it is of value as an indicator of the Late Silurian to earliest Devonian time interval spanned by the siluricus to waschmidti zones. Ozarkodina martinssoni is thus construed as a long-ranging species extending from the Wenlock to the Early Devonian, in common with other species of this genus. The range of the species as currently understood does contain some gaps, most significantly in the late Wenlock to early Ludlow, where intermediate forms between the two chronologically constrained subspecies are, as yet, unknown.