Dental mesowear reflects local vegetation and niche separation in Pleistocene proboscideans from Britain

Abstract

Proboscideans, and elephants in particular, played a key role in Pleistocene mammal communities in Europe. The British Pleistocene fossil record provides a unique opportunity to study changes in proboscidean feeding ecology associated with environmental proxy data such as pollen records and the presence of competitors. Here we utilize a recently introduced dietary analysis method, mesowear angle analysis, for studying relationships between dietary variation in proboscideans, changes in available vegetation and the presence of sympatric proboscidean species. The method is based on recording the relief of worn molar surfaces as angle measurements, which reflect attrition‐ vs. abrasion‐dominated feeding and serve as a proxy for grazing vs. browsing diets. By comparison with pollen records, we show that blunt mesowear angles specifically reflect grass eating rather than open‐ground feeding in general. We further find that all British Pleistocene proboscidean species were relatively flexible feeders able to shift their dietary preference according to local vegetation composition. Nonetheless, when more than one proboscidean species occurred in the same environment, they always show significantly different mean mesowear signal, suggesting dietary niche separation.

Effects of climate on dental mesowear of extant koalas and two broadly distributed kangaroos throughout their geographic range

“…Instead, there are greater differences in dental mesowear between taxa with different diets than there are between conspecifics occurring in regions experiencing different climatic regimes. These data confirm patterns observed in prior studies [ 8 , 16 , 32 ], most notably that diet is the primary signal recorded via dental mesowear (i.e., it is grass not grit that is likely being recorded via dental mesowear). Of the climatic variables analyzed, only variations in temperature were shown to affect mesowear.…”

Signatures of relaxed selection in the CYP8B1 gene of birds and mammals

“…However, the possibility of independent loss of the CYP8B1 gene in these two groups cannot be ruled out. Based on dental wear and distribution of vegetation, proboscideans are thought to have had a herbivorous diet (Saarinen and Lister 2016). Similar to the dietary switch between bovids and cetaceans, the change in selection landscape within Afrotheria coincides with changes in diet.…”

The skeleton of a straight‐tusked elephant, Palaeoloxodon antiquus (Falconer and Cautley, 1847) from Selsey, England, and growth and variation in Palaeoloxodon of the European Pleistocene

“…Many populations of living elephants show clear seasonal variation in diet; for example, Asian elephants in southwestern India consume more grass during the dry season and more browse during the rainy season (Sukumar, 2003). Micro-and mesowear data on P. antiquus from other British interglacial localities indicates a generally mixed-feeding strategy, but with a higher proportion of grazing at the MIS 7 locality of Ilford than at MIS 11 or MIS 5e localities, which has been attributed to the more open environment reconstructed for the Ilford fauna (Saarinen and Lister, 2016). It is clear that the straight-tusked elephant, though in Britain an interglacial animal, consumed significant quantities of grass.…”