Galería del Osario

The primary gallery of interest at the Sidron cave is the Ossuary Gallery or Tunnel of Bones (Galería del Osario), where the remains of several Neanderthals were found. The Galería del Osario was excavated from 2000 to 2013.^[4] The Neanderthal remains were all recovered from a single layer, Stratum III.^[3]

The associated archaeological assemblage consists of 53 stone tools; nonhuman bones are very scarce. The only other species present of similar size is red deer. The remains of a few small mammals and gastropods were also found.^[5]

Samples

Source:^[9]

Morphology

Morphologically, the El Sidrón humans show a large number of Neanderthal lineage-derived features even though certain traits place the sample at the limits of Neanderthal variation. Integrating the El Sidrón human mandibles into the larger Neanderthal sample reveals a north–south geographic patterning. The cave is in the northern portion, southern Neanderthals show broader faces with increased lower facial heights.^[10]

Ontogeny

The relatively well-preserved specimen of a juvenile Neanderthal recovered from the Galería del Osario, El Sidrón J1, allowed researchers to study the ontogeny of Neanderthals. By analyzing its dentition, researchers estimate that El Sidrón J1 was between 7 and 8 years old at the time of death. Around 36% of the juvenile specimen's remains was recovered, including key cranial, dental and vertebral column elements. 138 fossil elements were recovered, including 30 dental elements and a complete mandible. Based on the robustness of the specimen, researchers guess that the specimen was likely male.^[4]

El Sidrón J1 exhibits many traits of delayed maturation. At the time of death, El Sidrón J1's brain was likely not yet fully developed. El Sidrón J1's estimated cranial capacity is 1,330 cm³ (81 cu in), which is around 87% of the average adult Neanderthal cranial capacity (1,520 cm³ (93 cu in)). At a comparable age, typical modern human juveniles reach around 95% of the average adult human cranial capacity. Additionally, the juvenile specimen exhibits an unusual developmental feature; the neurocentral synchondrosis between his thoracic and C1 vertebrae had not yet fused; typically, this fusion occurs around 2 years earlier in modern humans.^[4]

Other paleoanthropologists like Marcia Ponce de León and Christoph Zollikofer have cautioned to interpret the brain size as sign of delayed maturation, because of the small case number and lack of statistical evidence and Tanya Smith noted that the assumption depends on the accuracy of the tooth's age^[11]

Archaeogenetics

Ancient Neanderthal mtDNA was partially sequenced in HVR region for three distinct Neanderthals from El Sidrón cave (441, 1253, and 1351c).^[12][13] Researchers also sequenced the partial nuclear genomes from several individuals from the cave.^[14] 1253 and 1351c have the same mutations at position A-911, G-977 in exon 7 of FOXP2 gene, known as the "language gene", as found in present-day humans.^[15]

In 2017, researchers successfully sequenced DNA from soil samples taken from Stratum III at El Sidrón. They were able to identify Neanderthal mtDNA sequences; the results suggested that the sequenced mtDNA belonged to more than one individual. ^[16]

Diet

Recent research investigating the Neanderthals remains recovered from El Sidrón have provided evidence that their diet would have consisted primarily of pine nuts, moss and mushrooms. This is contrasted by evidence from other European locations which point to a more carnivorous diet.^[18]