Middle Holocene marine and land-tetrapod biodiversity recovered from Galeao shell mound, Guanabara Bay, Brazil

Pristine environmental conditions and wide biodiversity are the best evidence of pre-colonial times, before anthropic interference in the Anthropocene. The Galeao shell mound represents the main example of an insular archaeological site located in the context of the Guanabara Bay in the Middle Holocene. The faunal remains from this shell mound were identified through comparative anatomy, to access the ichthyofauna and also amphibian, reptile and mammal paleodiversity. The diagnostic elements revealed the presence of predominantly demersal teleost fish, typical inhabitants of estuarine and marine systems, along with the usual species inhabiting rocky shores and rocky bottoms. Additionally, it revealed an exceptional diversity of sharks, including the presence of pelagic taxa, as well as stingrays. The local wildlife consists of species commonly found in swampy, mangrove, Brazilian restinga and Atlantic forest biomes. This study shows widely practiced fishery and hunting by the Amerindian using the resources of the Guanabara Bay and indicates specific targets during the Middle Holocene. Degradation of coastal environments and/or overfishing threaten the local biodiversity, with species now absent and some with statuses which go from Vulnerable to Critically Endangered.

Automated summary

The study of the Galeao shell mound in the Middle Holocene in Guanabara Bay reveals the paleodiversity of the region and the fishing and hunting practices of the Amerindians. It shows a diverse range of local wildlife species and specific targets during the Middle Holocene, while also highlighting the threats of coastal degradation and overfishing to the biodiversity in the area.