Body-size structure of Central Iberian mammal fauna reveals semidesertic conditions during the middle Miocene Global Cooling Event

Abstract

We developed new quantitative palaeoclimatic inference models based on the body-size structure of mammal faunas from the Old World tropics and applied them to the Somosaguas fossil site (middle Miocene, central Iberian Peninsula). Twenty-six mammal species have been described at this site, including proboscideans, ungulates, carnivores, insectivores, lagomorphs and rodents. Our analyses were based on multivariate and bivariate regression models correlating climatic data and body-size structure of 63 modern mammal assemblages from Sub-Saharan Africa and the Indian subcontinent. The results showed an average temperature of the coldest month higher than 26°C for the Somosaguas fossil site, a mean annual thermal amplitude around 10°C, a drought length of 10 months, and an annual total precipitation greater than 200 mm per year, which are climate conditions typical of an ecotonal zone between the savanna and desert biomes. These results are congruent with the aridity peaks described over the middle Aragonian of Spain and particularly in the local biozone E, which includes Somosaguas. The aridity increase detected in this biozone is associated with the Middle Miocene Global Cooling Event. The environment of Somosaguas around 14 Ma was similar to the current environment in the Sahel region of North Africa, the Horn of Africa, the boundary area between the Kalahari and the Namib in Southern Africa, south-central Arabia, or eastern Pakistan and northwestern India. The distribution of modern vegetation in these regions follows a complex mosaic of plant communities, dominated by scattered xerophilous shrublands, semidesert grasslands, and vegetation linked to seasonal watercourses and ponds.

A new gigantic carnivore (Carnivora, Amphicyonidae) from the late middle Miocene of France

“…A small reorganization of the amphicyonid fauna thus occurred between MN5 and MN6. This biotic event might be related to the Middle Miocene Climatic Transition ( Steinthorsdottir et al, 2021 ), which results for instance in an increase in aridity in Spain ( Menéndez et al, 2017 ).…”

Proposal of the colour pattern reconstruction of basal cervids

“…Heteroprox, as most cervids, inhabited forested areas (López-Martínez et al 2000). While the other Eurasian Heteroprox species were known to live in humid forests, the conditions during the Middle Miocene in much of the Central Iberian Peninsula were significantly arid or even semi-desertic (Fesharaki 2016;Menéndez et al 2017). Therefore, the habitats of H. moralesi were most likely forest patches near savannas and arid environments.…”

Diggers, gliders and runners: The squirrels from the Ribesalbes-Alcora Basin (East of Spain)

“…Atlantoxerus has an extant re p resentative (Barbary ground squirrel, A. getulus) that lives in African deserts (Van Dam & Weltje 1999, Minwer Barakat 2005, GarcíaAlix et al 2008, Mansino et al 2018. According to MinwerBarakat (2005) andGarcía Alix et al (2008) these genera are associated to open and denuded environments, and Menéndez et al (2017) have reported the species H. rubricati in the semidesertic habitat of the site Somosaguas in the Madrid Basin. Aragoxerus might have shared these preferences, although there is no literature on this topic, but CuencaBescós (1988) or Denys et al (2003), among others, include this genus in the Xerini, that generally have a similar life style.…”