A poorly diversified trilobite association from the lower Emsian (Lower Devonian) in the Sankt Vith area (East Belgium)

1. Introduction Contrary to the situation in South Belgium where Devonian trilobites have been the focus of numerous contemporary studies, only few papers have dealt with taxa from East Belgium (Franke, 2006; Hellemond et al., 2019; van Viersen, 2013; van Viersen & Prescher, 2009). Nearly a century ago Asselberghs (1923) reported a poorly diversified, Early Devonian trilobite association from an outcrop near Breitfeld (Sankt Vith (Saint Vith in French) area, East Belgium). Although Asselberghs described and illustrated only one trilobite species, Homalonotus maillieuxi Asselberghs, 1923, he mentioned the occurrences of several others. The present paper aims to document the Breitfeld trilobite association fully, and to discuss its potential for biostratigraphic correlations of Emsian trilobites in the Ardenno-Rhenish Mountains as well as its palaeobiogeographic affinities. 2. Geological context Locality B-117 (“Pl. Saint-Vith 1” on the field maps of Maillieux that are kept by the Institut royal des Sciences naturelles de Belgique in Brussels (IRSNB)), southwest of the village centre of Breitfeld, East Belgium (Figs 1, 2); probably lower part of the Our Formation (lower Emsian). Figure 1. Geographic map of the studied area with the Breitfeld locality (B-117) indicated. The black dotted line indicates part of the former Vennbahn railway line. Figure 2. A. Overview geological map of southeast Belgium, northern France, Luxemburg and western Germany with key localities and Lochko