Archaeological ostrich eggshell structure as a taxonomic and paleoenvironmental indicator

We investigated the macrostructure and pore morphology of ostrich eggshells to evaluate their potential as indicators of past ostrich taxonomy and paleoenvironmental conditions in the southern Levant. We compared pore patterns of all extant ostrich species with those observed on eggshell fragments recovered from 20 archaeological sites in Israel, dating from the late Middle Pleistocene to the late Holocene. Our analysis revealed a shift from a clustered pore pattern—resembling that of the extant Somali ostrich—to a scattered pattern characteristic of the now-extinct Syrian ostrich. This transition, which occurred approximately between 100 and 70 ka, is tentatively interpreted as evidence of a species turnover, an interpretation supported by ecological niche models, which suggest that suitable habitats for the Somali ostrich existed in the southern Levant prior to ∼100 ka, with peaks of particularly high habitat suitability around 240 ka and 120 ka. We propose that the presence of the Somali ostrich in the southern Levant possibly coincided with interglacial conditions that facilitated faunal movement through an open biogeographic corridor connecting Africa and the Levant. The entry of the Syrian ostrich into the region was associated with more arid condition. Our findings demonstrate the value of ostrich eggshells as a taxonomic biomarker and for reconstructing past environments and faunal distributions in the southern Levant and other regions.