| Cave of Aroeira | |
|---|---|
| Gruta da Aroeira | |
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  | |
| Location | Almonda, Zibreira,Torres Novas,Santarém,Portugal |
| Coordinates | 39°30′21″N8°36′57″W / 39.5057°N 8.6157°W /39.5057; -8.6157 |
| Discovery | 2017 |
| Geology | Karst |
| Entrances | 1 |
| Cave survey | 2017 |
TheCave of Aroeira (European Portuguese pronunciation:[ɐɾuˈɐjɾɐ]) is anarchaeological andpaleoanthropological site in thePortugueseEstremadura Limestone Massif. The cave is located in the village ofAlmonda, in thecivil parish ofZibreira, in the municipality ofTorres Novas in the district ofSantarém. The cave contained stones from thePaleolithicAcheulean culture, and the skull ofHomo heidelbergensis, circa 400,000 years old. The discovery ofAroeira 3 was announced in spring 2017 - the earliest human trace in Portugal.[1][2][3][4]
The Cave of Aroeira is part of the Almonda-Karst system, This system is formed of passages excavated at different elevations whose intersections withthe 70-m-highescarpment rising above the extant spring of the Almonda River, a tributary of theTagus River, correspond to fossil outlets of its subterranean course. The entrance to the cave was completely sealed by roof collapses when the excavation began in 1998.[2]
The deposits in the cave are about four meters thick and are categorised in three stratigraphic layers, from the lowest of which the fossilAroeira 3 was salvaged. Various independent analyses revealed an age of approximately 400,000 years, due to the detection of the oxygen isotope stage MIS 11c. The most recent deposits in the cave have been dated to an age of 60,000 to 40,000 years (MIS 3c).[citation needed]
The Cave of Aroeira was first investigated from 1998–2002 revealing a rich lithic assemblage with Acheuleanbifaces associated withfaunal remains and two human teeth: Aroeira 1 (a left mandibularcanine) and Aroeira 2 (a left maxillary thirdmolar). Aroeira 1 is moderately large and Aroeira 2 is among the larger of theMiddle Pleistocene upper right third molars. They fit morphologically within the known variation of European Middle Pleistocene dentitions, although Aroeira 2 has a relatively largehypocone.[2]
The faunal remains are highly fragmented, mainly consisting of isolated teeth, phalanges, carpal/tarsal bones, and antler fragments. Identified species includedeer andequids predominantly, but alsorhinoceros,bear as well as a largebovid (Bos/Bison), acaprid, and aTestudo tortoise.[2]
Renewed fieldwork in 2013, focused on establishing the chronology of the sequence viaU-series dating of interstratified flowstone deposits, led to the discovery of a partially preserved human cranium (Aroeira 3) encased in hardbreccia toward the base of the sequence. The block containing the main portion of the cranium and the detached fragments were transported to the Conservation and Restoration Laboratory at theComplutense University of Madrid for further preparation.
The cranium was restored over a period of two years. Although the taxonomic identity is debated, some authors prefer to group Aroeira 3 with other Middle Pleistocene fossils from Africa and Asia in a separate species,Homo heidelbergensis.[2]