The Buen Formation (Cambrian Series 2) biota of North Greenland

The diverse metazoan fauna from the upper member of the Buen Formation of North Greenland is described as a complement to published descriptions of the exceptionally preserved fauna of the Sirius Passet Lagerstäatte which occurs in the lowest beds of the formation. Considered together with organic-walled microfossils, which are absent from the Sirius Passet Lagerst€atte on account of regional metamorphism, the fauna from the upper member provides an extended picture of the Buen Formation biota (Cambrian, Series 2, Stages 3–4; Montezuman–Dyeran of Laurentian usage). Although dominated numerically by specimens of the olenelline trilobites Limniphacos and Mesolenellus, the oldest assemblages (Montezuma–Dyeran boundary) from the upper member of the Buen Formation are characterized by a high diversity of hyoliths which often occur as partial association of conch, operculum and helens in the dark mudstones; hyoliths are rare in the Sirius Passet Lagerstäatte. Sponges are rare in the upper Buen Formation but diverse at Sirius Passet. Unlike the Sirius Passet Lagerstäatte, fossil remains of nonmineralized metazoans with limbs and other details of internal anatomy do not occur in the upper Buen Formation, although organic tubes assigned to a new selkirkiid stem group priapulid (Sullulika) are common. New taxa: Alutella siku sp. nov., Sullulika broenlundi gen. et sp. nov., Nevadotheca boerglumensis sp. nov., Kalaallitia myliuserichseni gen. et sp. nov., Nasaaraqia hyptiotheciformis gen. et sp. nov., Trapezovitus malinkyi sp. nov., Decoritheca? hageni sp. nov.