Increase on environmental seasonality through the European Early Pleistocene inferred from dental enamel hypoplasia

Abstract

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.

An Updated Review of The Quaternary Hippopotamus Fossil Records from the Iberian Peninsula

“…The stability of these populations on a large part of the peninsula is surprising, as climatic conditions were progressively becoming harsher. These changes, known as the 'Early-Middle Pleistocene Transition', were characterized by a gradual increase in the severity and duration of glacial cycles, along with an increase in seasonality and aridity [48,49]. Equally surprising is the possibility of a very brief coexistence of H. antiquus and H. amphibius in a restricted geographical area in the mid-Middle Pleistocene.…”

The Middle Pleistocene Hippopotamus from Malagrotta (Latium, Italy): New Data and Future Perspectives

“…However, body size changes in hippopotamuses should be better investigated, and effects related with distributions of water bodies, seasonality, interspecific competition, or specifical faunal compositions should be tested in the future. The size of the m2 (L, 54.8 A study with a similar conclusion to Mazza and Bertini [23] was also carried out by Fidalgo et al [14] on the hypoplasia of hippopotamids teeth. In the Hippopotamidae representatives from Untermaßfeld, among the largest sized examples of H. antiquus ever, the dental enamel hypoplasia (DEH) reported is not severe nor prevalent [61].…”

“…The studies of Mazza and Bertini [23] and Fidalgo et al [14] confirm that there is probably a correlation in hippopotamids between size and hypoplasia, with seasonality and environmental conditions affecting them. However, further studies are needed to quantify and characterize the variability of size of hippopotamuses correlated with the different environmental conditions of Pleistocene, in particular after the Jaramillo sub-chron.…”

“…Remains from Collecurti are also poorly affected by DEH, while sites dated to ca. 0.9-0.86 Ma, characterized by a long and severe glacial phase, show a high incidence of DEH [14]. The incisor collected from Malagrotta MCZR PV 2010.2690 shows feebly transversal lines on the enamel that might be caused by hypoplasia.…”

“…Hippopotamus antiquus was a large European hippopotamus which was most likely related or evolved from the African H. gorgops [5][6][7][8]. Hippopotamus antiquus was present in almost all Europe [9][10][11][12][13][14][15][16]. The first appearance datum (FAD) of H. antiquus is still highly debated but it was firmly established in the Upper Valdarno area (Tuscany, Italy) around 1.9-1.7 Ma [17].…”