Biostratigraphy and taxonomy of polymerid trilobites of the Manuels River Formation (Drumian, middle Cambrian), Newfoundland, Canada

Newfoundland’s middle Cambrian fine-clastic Manuels River Formation is renowned for its well-preserved trilobite fauna. Here we present a newly collected assemblage of 1184 specimens from the type locality at Conception Bay South, Newfoundland, Canada. The faunal assemblage comprises detailed information about the accurate ranges of each species. Thus, the polymerid Paradoxides davidis and Paradoxides hicksi zones previously established for the region and the globally recognised agnostid Tomagnostus fissus, Hypagnostus parvifrons, Ptychagnostus atavus, and Ptychagnostus punctuosus zones are now precisely correlated. The polymerid fauna is comparable with that of other regions of Avalonia, Baltica, and partly with Gondwana. Our analysis of the faunal assemblage demonstrates that there is a need for comprehensive revisions of Cambrian trilobite faunas, including important and well-known taxa such as Agraulos Hawle & Corda, 1847, and Paradoxides sensu lato. Sao hirsuta Barrande, 1846, was earlier documented from the Czech Republic, Spain and Germany, and is now first described from western Avalonia, while Bailiella aequalis (Linnarsson, 1882) was already mentioned for eastern Newfoundland and is now illustrated for the first time. The specimens presented here were assigned to the orders Ptychopariida, Redlichiida and Corynexochida and include Agraulos ceticephalus (Barrande, 1846); Jincella? applanata (Hicks in Salter & Hicks, 1869); Sao hirsuta Barrande, 1846; Bailiella aequalis (Linnarsson, 1882); Bailiella tenuicinta (Linnarsson, 1879); Meneviella venulosa (Hicks, 1872); Paradoxides davidis Salter, 1863; Plutonides hicksii (Salter, 1866b); Clarella venusta (Billings, 1872); and Acontheus inarmatus Hutchinson, 1962.