The oldest brachymetopid trilobite record from the European peri-Gondwana.

Radnoria guyi sp. nov. from the middle Berounian (upper Sandbian/lower Katian, Upper Ordovician) of the Cabeço do Peão Formation, Central Portugal is the best preserved and most completely known Ordovician species of the genus, and the stratigraphically earliest known from European peri-Gondwana. Until now, the oldest record of the genus was from the upper Sandbian/lower Katian of South China. The new Portuguese record sheds new light on our understanding of the biogeography of Radnoria, suggesting the possibility of a southern high-latitude Gondwanan origin for the genus. [ABSTRACT FROM AUTHOR]