A New Species of Modocia (Trilobita: Ptychoparioidea) in the Late Middle Cambrian (Guzhangian: Miaolingian) Devoncourt Limestone, Northwestern Queensland

Abstract

A new species of late middle Cambrian (Guzhangian: Miaolingian) ptychoparioid trilobite is described from the Devoncourt Limestone just west of the Burke River crossing on the Duchess to Cloncurry Road. This is an addition to the extensive study of the fossil fauna of that district in the Burke River Structural Belt and provides another link to the Georgina Basin fauna, albeit younger by one zone, about 200 km west on Mungerebar Station. Generic assignment of the new species is discussed in relation to a worldwide complex of similar solenopleurid genera with small eyes situated well forward on the cephalon. Some comments are made in relation to family placement of the species, but the question of family concepts relies heavily on revision of an extensive northern hemisphere literature on these standard trilobites; so, although placement in the Solenopleuridae is favoured, no formal family assignment is made until family groups in this large complex of genera are better defined.