Late Silurian trilobites from central western New South Wales, with revision of Batocara rothwellae (Encrinuridae) and Denckmannites rutherfordi (Phacopidae)

Trilobites occurring uncommonly in late Silurian (late Pridoli) strata of the Hanover Formation at a locality in the Cumnock district of central western New South Wales include the cheirurid Crotalocephalina? sp., the encrinurid Batocara rothwellae, the phacopid Denckmannites rutherfordi and an indeterminate phacopid. The specimens of B. rothwellae and D. rutherfordi are preserved as typical moult ensembles. The previously poorly known B. rothwellae is revised on the basis of the specimens from Cumnock, which are better preserved and more numerous than those from the type locality in the Yass–Bowning district. The reassignment of D. rutherfordi to Lochkovella by some authors is rejected, and the original generic assignment supported; owing to the limited material available from Cumnock, the species is revised on the basis of specimens from the type locality near Cheesemans Creek, west of Orange. The mode of moulting in D. rutherfordi changed during ontogeny, from the Ductina mode in small holaspides to the Salterian mode in larger specimens when the posterior branch of the facial suture became fused. Based on other occurrences of B. rothwellae and D. rutherfordi in New South Wales, the Hanover Formation at the Cumnock locality is correlated with the lower part of the Wallace Shale in the Cheesemans Creek district, the lower part of the Elmside Formation in the Yass–Bowning district and the upper part of the Cardinal View Formation in the Bungonia district.