CHIN, Karen1, BLOCH, John D.2, TWEET, Justin S.3, EBERLE, Jaelyn J.1, and CUMBAA, Stephen L.4, (1) CU Museum and Department of Geological Sciences, Univ of Colorado at Boulder, UCB 265, Boulder, CO 80309, Karen.Chin@colorado.edu, (2) Dept. of Earth & Planetary Sciences, Univ. of New Mexico, Northrop Hall, Albuquerque, NM 87131, (3) Department of Geological Sciences, Univ of Colorado at Boulder, Boulder, CO 80309, (4) Canadian Museum of Nature, P.O. Box 3443, Stn D, Ottawa, ON K1P 6P4 Large accumulations of Arctic vertebrate coprolites provide clues about energy flow and feeding strategies in an Upper Cretaceous high latitude marine ecosystem. Exposures of the upper Kanguk Formation on Devon Island, Nunavut show a regressive sequence of sediments from offshore shales to nearshore glauconized sands to terrestrial silts and sands with abundant conifer wood debris. The coprolites are patchily distributed in the greensands and can be locally abundant; fossil burrows, sponges, and Lingula in the same sediments indicate a nearshore environment. Although shape and size (up to 300 ml volume) are variable, the specimens can be characterized by ground mass composition; some are largely phosphatic, whereas others contain high concentrations of greensands. Most of the phosphatic specimens are highly burrowed and indicate extensive coprophagy by benthic invertebrates. These coprolites contain surprisingly high concentrations of siliceous microfossils. The greensand-filled coprolites are cemented by phosphate and also contain microfossils, as well as crustacean fragments, tiny fecal pellets, and other invertebrate debris. The high sand content in these specimens suggests that the vertebrate fauna included at least one sizeable taxon with a sediment-ingesting feeding habit. Body fossils from the same sediments suggest that sharks, ichthyodectid fishes, and plesiosaurs were possible coprolite producers. Although Devon Island would have been subject to extreme photoperiodic seasonality in the Late Cretaceous, paleoclimatic models indicate that the climate was considerably more temperate than that of todays Arctic. The large chunks of fossil wood in the non-marine sediments show that Cretaceous terrestrial habitats differed from modern Arctic environments and suggest that marine ecosystems were also significantly different. The Devon Island coprolites provide evidence for energy flow in a productive ancient ecosystem, and demonstrate intense benthic foraging activity by invertebrate detritivores and vertebrate deposit feeders. Such feeding strategies are consistent with benthic-pelagic coupling in modern Arctic environments, where excess nutrients generated by pulses of planktonic production are transferred to the benthos where they can be exploited over a period of time.
Canadian Museum of Nature or Victoria Memorial Museum Building Scientists of the United Kingdom-based Royal Society released a paper August 1, 2008 which studied Cretaceous era fossil finds found at the northern area of Devon Island in the 1980s. ''Nunavutospongia irregulara'' is the name of the new species of sponge found, released by Proceedings B the Royal Society's biological research journal. 

Thick bones and armour-like scales have been found that are believed to belong to a new species of fish which grew up to two meters long. Thousands of fossilized feces - termed coprolites - both small and as large as an arm have been found. Coral reef fossils, conifer wood debris, fossil wood chunks and thousands of plankton and microbes have been found both at Devon Island and Beechy Island. Beechy Island is connected to Devon Island during times of low tide.

Two areas on Devon Island about 30 kilometres apart are providing Cretaceous fossil finds, and each is kilometres in length. These areas are khaki-coloured valley greensands rich in fossil beds, which provide a peek at life 73 million years ago. During the Cretaceous Devon Island was located in a position with a warmer climate, large trees grew north of Baffin Island, and plesiosaurs, ichthyodectid fish, and sharks roamed the waters of the Arctic. Devon Island was submerged under warm water in the Cretaceous period, when the island was situated hundreds of kilometres south of its current location due to continental drift. 

At the upper Kanguk Formation, the fossil finds represent offshore and near-shore sedimentary deposits on an ocean floor. The warmer temperate waters supported benthic invertebrates (organisms such as larva that live on the bottom of a water body) and large predatory vertebrates. Whereas life is currently supported by nutrients from the sea ice, Cretaceous sea life was supported by terrigenous resources from forested landscapes.

The eight-member team from the Royal Society consists of Canadian, United States and Polish researchers. The fossil specimens are held at the Canadian Museum of Nature in Ottawa on behalf of the Nunavut territorial government.