Molecular and morphological analyses of avian eggshell excavated from a late thirteenth century earth oven

Using ancient DNA (aDNA) extracted from eggshell of the extinct moa (Aves: Dinornithiformes) we determined the species composition and number of eggs found in a late thirteenth century earth oven feature at Wairau Bar (South Island, New Zealand) – one of New Zealand’s most significant archaeological sites. Mitochondrial and nuclear DNA signatures confirmed this oven feature contained fragments of at least 31 moa eggs, representing three moa genera: Emeus; Euryapteryx; Dinornis. We demonstrate through the genetic identification of 127 moa eggshell fragments that thickness is an unreliable character for species assignment. We also present a protocol for assessing the preservation likelihood of DNA in burnt eggshell. This is useful because eggshell fragments found in archaeological contexts have often been thermally modified, and heat significantly increases DNA fragmentation. Eggshell is widely used in radiocarbon dating and stable isotope research, this study showcases how aDNA can also add to our knowledge of eggshell in both archaeological and palaeoecological contexts.

► First time eggshell aDNA has been used to investigate zooarchaeological assemblages.
► Eggshell thickness is an unreliable characteristic for moa species identification.
► Extreme heating of eggshell is detrimental to DNA preservation.
► DNA analyses of 56 eggshell fragments reveal at least 31 individual moa eggs.
► Study provides insights into hunting practices at the significant Wairau Bar site.