Mineralized gutfills from the Sirius Passet Lagerstatte (Cambrian Series 2) of North Greenland

Three dimensional preservation of internal moulds of the digestive tract is a characteristic feature of many arthropods and lobopodians from the Sirius Passet Lagerstatte (Cambrian Series 2, Stage 3) of North Greenland and reflects widespread early post-mortem mineralization probably facilitated by endogenous bacteria. The mineralization also preserves pre-mortem gutfills of digestive origin, cololites, providing insight into feeding habits within the Sirius Passet biota. The cololites are described in rare specimens of the arthropods Sidneyia? sp. and Pauloterminus, the annelid worm Phragmochaeta and the palaeoscolecidan worms Chalazoscolex and Xystoscolex. Partly digested material includes fragmentary carapaces of the bivalved arthropod Isoxys volucris and shields of the armoured lophotrochozoan Halkieria evangelista, the iconic Sirius Passet fossil. The presence of sediment in cololites from the small available sample suggests that the described arthropods and worms were omnivores.