49,000-year-old Neanderthal remains found in Asturias cave

The Sidrón Cave, located in Piloña, Asturias, Spain, is a 3,700-meter-long non-carboniferous limestone karst system, declared a 'Partial Natural Reserve' in 1995. It is home to five bat species and two species of Coleoptera (beetles). The cave gained recognition in 1994 when human remains were found. These remains, initially suspected to be from the Spanish Civil War, were eventually identified as Neanderthals. The remains of several Neanderthals were recovered from a single layer, Stratum III.

Researchers estimate that the juvenile specimen El Sidrón J1 was between 7 and 8 years old at the time of death. Researchers sequenced the partial nuclear genomes of several individuals from the cave, and while two of these Neanderthals (1253 and 1351c) have the same mutations at position A-911, G-977 in exon 7 of the FOXP2 gene as found in present-day humans, El Sidrón J1 exhibits many traits of delayed maturation. However, some paleoanthropologists have cautioned against interpreting the brain size as a sign of delayed maturation because of the small case number and lack of statistical evidence.

His estimated cranial capacity is 1,330 cm³, around 87% of an average adult Neanderthal cranial capacity. At a comparable age, typical modern human juveniles reach around 95% of the average adult human cranial capacity. Additionally, El Sidrón J1's neurocentral synchondrosis between his thoracic and C1 vertebrae had not yet fused, a feature usually found in modern humans two years earlier. The exceptional preservation of the remains, with very limited erosion and no major carnivore tooth marks, suggests that these Neanderthals did not die in this spot but at an exterior location.

The bones were found mixed into a jumble of gravel and mud in the Ossuary Gallery, a 28-meter-long space. A number of scenarios for how these 'members of an extended family' might have ended up in this room-sized space include flooding, cave collapse, and disposal by cannibals. Evidence for cannibalism includes the presence of cut marks, flakes, percussion pitting, conchoidal scars, and adhering flakes. Researchers suppose they may have been dropped into the cave in a single event via a collapse of nearby fissures or an influx of stormwater.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons