Linking “last supper” and dental microwear texture in Japanese serow: Implications for palaeodietary reconstruction and dietary stability in fossil herbivores

Dental microwear texture analysis (DMTA) is widely used to reconstruct dietary habits in extant and fossil taxa, but correspondence between dental microwear texture (DMT) and short-term dietary proxies, such as stomach contents, is often weak at the individual level in wild populations due to differences in temporal resolution. We examined the relationship between stomach contents, representing the “last supper”, and DMT in a wild population of Japanese serow ( Capricornis crispus ), a territorial and selectively foraging herbivore endemic to Japan, to evaluate how short-term dietary information is reflected in microwear patterns. Stomach contents and DMT were analyzed from 57 adults using qualitative surface observations, principal component analysis of 36 DMT parameters, linear regression, and partial least squares regression. PC1 reflected overall surface relief, and regression analyses identified graminoid consumption as the sole dietary variable significantly associated with PC1. PLS regression further showed directional covariation between graminoid-rich diets and increased surface roughness, although predictive performance was low. Thus, dietary composition explained only limited individual DMT variation, but the direction of graminoid–DMT covariation was consistent across analyses. We interpret this correspondence as reflecting relatively stable individual diets promoted by territoriality, selective foraging, and seasonally constrained resources. By linking stomach contents with DMT in a wild extant herbivore, this study provides a modern analogue for interpreting individual-level DMT variation in fossil assemblages. Such variation may help distinguish stable dietary tendencies from opportunistic or heterogeneous resource use, informing reconstructions of niche breadth, habitat heterogeneity, and resource partitioning.