Iberian mastodonts: Geographic and stratigraphic distribution

Abstract

The Iberian Peninsula has a complete Mio-Pliocene fossil record in which all biostratigraphic units are represented. As a consequence, there is an exceptional proboscidean record including deinotheres, mastodonts and elephants, which has increased significantly in recent years. Many of the older localities are not known in the common paleontological literature because only or mainly proboscidean remains were collected. This paper presents an overview of the localities yielding mastodont remains.Gomphotherium angustidens dispersed into Europe during late MN3. The oldest Spanish record is possibly from early MN4 (zone B of the Aragonian). There are over 125 Iberian localities. The material includes skulls and more or less complete skeletons. The youngest localities are from the lower part of MN7+8.Tetralophodon longirostris replaced Gomphotherium during the latest Aragonian. This event is well reflected in the Spanish record and the first Tetralophodon appears in localities that belong to the upper part of MN7+8. Together with other faunal changes, this event strengthens the idea that MN7 and MN8 can be recognized as separate units. The species is known from over 70 Iberian localities, some of which yielded complete skulls and relatively complete skeletons. At Crevillente II (MN11) a tetralophodont form is found with morphometric similarities to Stegotetrabelodon.Anancus arvernensis replaced Tetralophodon during the Latest Miocene (MN12). This event is well documented in the Iberian Peninsula. This species is found at over 20 localities and is particularly well represented at Las Higueruelas (MN 16; 3.1‑2.9Ma) with many skulls and abundant remains of the different parts of the skeleton. The last Iberian record is in Villarroya (MN 16) and La Florida (E Pleistocene).Zygolophodon turicensis dispersed late in MN3 into Europe, but in Spain it is known from few localities from the Middle Miocene (MN5–7). It evolved into Mammut borsoni, which in Spain is known from some Upper Miocene to Lower Pliocene localities.Overall, the Iberian mastodont record is similar to that of the rest of Europe. The bunodont and zygodont mastodonts overlapped during many millions of years, but at any moment the zygodont species were much less abundant in the Iberian record. Proboscidean dispersals from Africa towards Western and central Europe show a peculiar pattern: several dispersals occurred during the Mid-Miocene Climatic Optimum and again during the Pleistocene, but not during the long time interval between. After the optimum came the Mid-Miocene Crisis, when global temperatures dropped, which probably did not favor northward proboscidean dispersals. When, during the Late Miocene C4 grasslands spread at low latitudes, most Proboscideans adapted to grazing and may have become pre-adapted for living in the seasonal climates of the higher latitudes, and dispersed again to the north. This mirrors the hominoid dispersals from Africa to Europe, which occurred also during the Mid-Miocene and Pleistocene.