Article: Late Cambrian trilobites from the Najerilla Formation, north-eastern Spain

Six late Cambrian trilobite taxa are described from the Najerilla Formation of the Mansilla district, Sierra de la Demands, Logrono Province, northern Spain. Maladioidella colcheni sp. nov.. Langyashania felixi sp. nov., an undetermined aphelaspidine genus and species, and an undetermined genus and species probably referable to Leiostegiidae, constitute the fauna of the basal member of the Najerilla Formation; and a younger assemblage comprising an undetermined solenopleuracean genus and species resembling Lajishanaspis Chu. 1979, and a pagodiine which may represent Pagodia (Wiitekindtia) occurs at the top of member 2 of this formation. Although the available material is inadequate for the confident determination and description of all but two of the six taxa, it is important to document these assemblages because they belong to a late Cambrian biofacies from which trilobites have not been described or illustrated previously in the Mediterranean region. Earlier determinations given for some of these trilobites are unsatis factory and biochronologically misleading. This Mediterranean biofacies has little in common with the well-known Acado-Baltic biofacies of northern Europe, hut may have greater relationship with contemporaneous assemblages in central Asia and northern China,