Dung analysis of the East Milford mastodons: dietary and environmental reconstructions from central Nova Scotia at ∼75 ka years BP

To reconstruct a mastodon diet and provide a snapshot view of environmental conditions in eastern Canada prior to the onset of the Wisconsinan glaciation, we analysed the faunal and floral components of dung associated with juvenile mastodon remains from East Milford, Nova Scotia, dated to 74.9 +/- 5.0 ka cal BP. The diverse assemblage of pollen, nonpollen palynomorphs, plant macrofossils, and macroinvertebrate remains in the dung suggests that the mastodons lived in a spruce-dominated mixed coniferous-deciduous forest with a strong boreal aspect interspersed with wetlands rich in charophytes, sedges, cattails, bulrushes, and bryophytes. The abundance of spruce needles and birch samaras in the dung sample is consistent with an inferred browsing behaviour, having been reported for other mammutid species previously. The limited diversity and near- absence of coprophilous fungi, such as Sporormiella, in the dung could have an impact on understanding the influence of feeding strategies on the presence of coprophilous taxa in sedimentary records, and thus interpretations of megafaunal abundance. The dung also yielded the earliest known Canadian remains of the bark beetle Polygraphus cf. rufipennis, gemmulae of the freshwater sponge Eunapius cf. fragilis, and loricae of the rotifer Keratella cochlearis.

Automated summary

The juvenile mastodons in eastern Canada lived in a spruce-dominated mixed forest with wetlands rich in aquatic plants, primarily exhibiting browsing behavior. The dung sample showed limited diversity of coprophilous fungi, which may impact interpretations of feeding strategies on sedimentary records and megafaunal abundance. Additionally, the dung yielded the earliest known Canadian remains of certain insects and freshwater organisms.