Late Pleistocene/Early Holocene Evidence of Prostatic Stones at Al Khiday Cemetery, Central Sudan

Abstract

The recovery of three stone-like ovoid objects within the burial of a pre-Mesolithic (Late Pleistocene/Early Holocene) individual at Al Khiday cemetery (Central Sudan) raises the question of the nature and origin of these objects. The position in which the objects were found in relation to the human skeleton suggested a pathological condition affecting the individual, possibly urinary bladder, kidney stones or gallstones. To solve this issue, a multi-analytical approach, consisting of tomographic, microstructural and compositional analyses, was therefore performed. Based on their microstructure and mineralogical composition, consisting of hydroxylapatite and whitlockite, the investigated stones were identified as primary (endogenous) prostatic calculi. In addition, the occurrence of bacterial imprints also indicates on-going infectious processes in the individual. This discovery of the earliest known case of lithiasis extends the appearance of prostatic stones into the Late Pleistocene/Early Holocene, a disease which therefore can no longer be considered exclusive to the modern era, but which also affected prehistoric individuals, whose lifestyle and diet were significantly different to our own.

Fig 1. Calculi from Grave 188 at Al Khiday.

a) geographic location of Al Khiday sites in Sudan; b) Pre-Mesolithic Grave 188; c-d) calculi in situ.

Fig 2. Mineralogical composition.

X-ray diffraction pattern of stone S3: phase labels: Ap: apatite, Wht: whitlockite, Cal: calcite.

Fig 3. Internal structure.

μ-CT reconstructed sections of stones S1 and S2: A: lighter grey colour, outermost portions; B: darker colour, innermost portions; C: black colour, fractures within the stone; D: light grey colour, calcite filling in some of the fractures.

Fig 4. Calculi structure.

SEM backscattered electron images of the microstructure of stone S3: a) outermost portion of the stone, where ovoidal structures occur; b) detail of the ovoids surrounded by a thin shrinkage rim; c) detail of the dense packing of crystals which form micron-sized spheres in some cases with a geode type structure and (on the left) acicular crystals aggregate of apatite; d) micro-fractures crossing the stone, filled by secondary calcite; e-f) micro-pores due to bacterial attack.

Fig 5. Calculus internal portion and mineral phases.

SEM secondary electrons image of loose material from the internal portion of stone S3: coexisting crystals of apatite (tabular/prismatic crystals of hydroxylapatite forming radiating clusters) and whitlockite (rhombohedral crystals).