Virtual excavation and analysis of the early Neanderthal cranium from Altamura (Italy)

Abstract

Complete Neanderthal skeletons are almost unique findings. A very well-preserved specimen of this kind was discovered in 1993 in the deepest recesses of a karstic system near the town of Altamura in Southern Italy. We present here a detailed description of the cranium, after we virtually extracted it from the surrounding stalagmites and stalactites. The morphology of the Altamura cranium fits within the Neanderthal variability, though it retains features occurring in more archaic European samples. Some of these features were never observed in Homo neanderthalensis, i.e. in fossil specimens dated between 300 and 40 ka. Considering the U-Th age we previously obtained (>130 ka), the morphology of Altamura suggests that the archaic traits it retains may have been originated by geographic isolation of the early Neanderthal populations from Southern Italy.

Fig. 1. The Altamura cranium straddles two chambers within the karstic system.

Photographic probes (a) were used to acquire photogrammetrically the basal and posterior components (BP) of the cranium (b), exposed in the Back-chamber. Its frontal and facial parts (FF) were acquired by laser scanner from the Apse (c), where also the mandible and several long bones are directly visible on the cave floor (c, d).

Fig. 2. Virtual reconstruction of the Altamura cranium.

a Homologous landmark configurations were acquired on the FF and BP of Altamura and of a reference specimen, the nearly complete Cranium 5 from the Sima de los Huesos site (SH-5); b landmark coordinates were processed separately by Generalised Procrustes Analysis (GPA); c FF and BP were aligned according to the reference specimen showing the highest morphological affinity; d–f various views of the virtual model of Altamura aligned on SH-5; g SH-5 lateral view.

Fig. 3. Principal Component Analysis comparing Altamura with crania of Neanderthal lineage and of modern humans.

a PC1 vs PC2. b PC1 vs. PC3. Full circles represent fossil specimens; orange: virtual reconstructions of Altamura based on SH-5 (Alt-SH-5), on the mean shape of the EWN sample (Alt-ENW) and on Saccopastore 1 (Alt-Scp1); blue: Mid-Pleistocene specimens (SH-5: Sima de los Huesos 5; Petr: Petralona); green: Homo neanderthalensis (Amd: Amud; Gua: Guattari 1; LaFer: La Ferrassie; LaCha: La Chapelle; Scp1: Saccopastore 1; Sha: Shanidar); grey: Homo sapiens. c Cranial morphology associated at extreme negative (−) and positive (+) values of the first three principal components; yellow and violet respectively indicate local expansion and contraction from the mean shape.

Fig. 4. Shape analysis of the occipital squama.

3D map variations of the occipital squama showing Altamura compared to the average morphology of Homo neanderthalensis (a), Mid-Pleistocene humans (b) and Homo sapiens (c). Colour maps are reported in posterior and lateral view. Warm and cold colours indicate respectively which regions in the three average morphologies are respectively locally contracted and expanded compared to Altamura.