October 2023: publication Scientific Reports
Increase on environmental seasonality through the European Early Pleistocene inferred from dental enamel hypoplasia
An in-depth study of the Early Pleistocene European remains of Hippopotamus has allowed the first detailed description of the incidence and types of dental alterations related to palaeopathologies and potentially linked to climatic and environmental factors. The results of a long-term qualitative and quantitative assessment highlight the importance of nutrient deficiencies on the development of dental enamel hypoplasia in Hippopotamus. Glacial cyclicity and the resulting changes in humidity and plant community structure conditioned the local environments critical for the survival of this taxon. Two main intervals of putative constrained nutritionally restrictions were detected at ca. 1.8 Ma and ca. 0.86 Ma (i.e., MIS63 and MIS21, respectively). Statistical comparisons show an increase in the frequency of dental hypoplasia between these two chronological periods, thus reinforcing the idea of increased seasonality in the circum-Mediterranean environments during the Early Pleistocene.
Fig. 4 – Schematic representation of the main data included in the Dental Enamel Hypoplasia (DEH) analysis of the two most representative samples. (a): Upper Valdarno (ca. 1.8 Ma), (b): post-Jaramillo Units of Vallparadis Section (ca. 0.86 Ma). a1, b1: percentage of anterior teeth with DEH. a2, b2: teeth-type distribution of the DEH. a3, b3: number of upper incisors with DEH; a4, b4: number of upper canines with DEH; a5, b5: number of lower incisors with DEH; a6, b6: number of lower canines with DEH. a7, 8: reference upper canine with Linear Enamel Hypoplasia (LEH) from Upper Valdarno (NMB Va.2518), b7, 8: reference upper canine with LEH from Vallparadís Section (IPS127141). a9, b9: boxplot of the frequency measurements of isolated episodes of LEH in upper canines, indicating significative differences between samples (Kruskal–Wallis test) with the letters a and b. The area outlined in grey represents the estimated range of annual growth in extant hippos (Hippopotamus amphibius). CGUU: Cal Guardiola Upper Unit, VEMU: Vallparadís Estacio Middle Unit. Scale bar equals 20 mm.
References
Fidalgo D., Rosas A., Bartolini-Lucenti S., Boisserie J.-R., Pandolfi L., Martínez-Navarro B., Palmqvist P., Rook L., Madurell-Malapeira J. 2023 – Increase on environmental seasonality through the European Early Pleistocene inferred from dental enamel hypoplasia – Sci Rep 13, 16941 – https://doi.org/10.1038/s41598-023-42936-y