A multidisciplinary team carried out, for the first time, the biomineral analysis of two complete fossil Shearwater eggs (family Procellariidae) recovered from one of the Roman sites on the Ilhéu de Lobos (Las Palmas), with a chronology dating back to the mid-20th century. 1st century BC to mid-1st century AD The results of this research were published in diversity magazine.
Fossil remains of birds are common in Quaternary sites, especially bones. In the case of eggs, it is not so common, although sometimes small fragments or, very rarely, complete eggs can be preserved and recovered.
The work was led by Carmen Núñez-Lahuerta, a postdoctoral researcher at the Catalan Institute of Human Paleoecology and Social Evolution (IPHES-CERCA) and in which researchers from the University of La Laguna (ULL), the Archaeological Museum of Tenerife and the University of Zaragoza (UNIZAR).
Bone fossils from Quaternary sites are common, but complete eggs are very rare to find.
In the Canary Islands, the remains of fossil eggs are relatively common and have been the subject of research since the 1970s. Despite this research tradition, studies focused on their biomineral structure are very scarce, a fact that reinforces the relevance of the study that ends to be accomplished. Published. “Although a priori all bird eggs are very similar, they have a highly variable complex structure,” says Núñez-Lahuerta.
Excavation at Lobos-3 on Lobos Islet. / Carmina del Arco Aguilar
“The eggshell is formed by three layers, but their relative thickness can be different, as well as the presence and distribution of other structures, such as cuticles or vesicles.” Therefore, this set of variations “are typical of each species, so their study allows the identification of the laying bird”, he adds.
Although a priori all bird eggs are very similar, they have a highly variable complex structure.
Carmen Núñez-Lahuerta, first author of the work
The work team that produced this publication described the methodology that is used for the first time on this type of Canarian fossils: various microscopy techniques were used, requiring the preparation of thinly sliced samples to be observed in a petrographic and microscopy microscope. samples in test tubes, for observation in electronic microscope.
Images of Lesbos-3 eggshells under scanning electron microscope (SEM) and petrographic microscope. / Carmen Núñez-Lahuerta/Carmina del Arco
The study found two extinct species of shearwater endemic to the Canary Islands
These analyzes made it possible to observe the structure of the three typical layers of bird eggs. The proportions between the thickness of these layers, as well as the distribution of structures called vesicles along the layers, allowed us to attribute the eggs to shearwaters, seabirds with long wings typical of temperate and cold waters. Thanks to the fact that the eggs were recovered practically complete, it was also possible to measure their size and sphericity. These analyzes allowed assigning the eggs to taxa cf. Calonectris/Puffinus and cf. puffins.
The study of fossils from the Canary Islands allowed us to describe two species of shearwater that are endemic to the islands, and which are currently extinct: Puffinus holeae and Puffinus olsoni. For this reason, the next line of work of this multidisciplinary team is the characterization of the biomineral structure of extinct Shearwater’s eggs, with the aim of increasing knowledge about their fossil record, and learning more about their behavior and extinction.
The only Roman site in the Canary Islands
The Lobos-3 deposit is located on a small island of about 500 hectares, of volcanic origin, located in the Strait of La Bocaina, between the islands of Fuerteventura and Lanzarote. It is the only Roman site in the Canary Islands that is over 2,000 years old.
According to ULL Archeology Professor Carmina del Arco, who led the excavations from the start, “Lobos is a privilege” and, at the same time, an “exotic” location for Canarian cultures. “It is only Roman, with no material related to Canary indigenous cultures” and “underlines the economic interests that existed in the exploitation of the resources of the Canary Islands since ancient times”.
The site of Lobos is exclusively Roman and is over 2,000 years old
Archaeological excavation work has identified the village as a purple workshop that operated from the mid-1st century BC to the mid-20th century. I AD The set of evidence located in Lobos (heaps of Purpura haemastoma shells, amphorae for salting, wine and oil, common pottery, fishing implements, etc.) reflects the frequentation of the Canary Islands by Roman populations. Its origin may be in Gades (current city of Cádiz), who traveled with the aim of exploiting the natural resources of the island, in this case, the purple dye.
The Lobos deposit highlights the economic interests that existed since antiquity in the exploitation of the Canary Islands’ resources.
Carmina del Arco
Purple dyed fabrics were popular throughout the ancient world, from the Greeks and Phoenicians to the Romans, and led to the development of profitable purple dye industries in ancient times. They were considered luxury objects and a sign of social distinction, to the point that the State itself controlled their monopoly and organized commercial and military expeditions in search of the products necessary for their production.
According to the researcher from IPHES-CERCA, Carmen Núñez, “the identification and distribution of the remains of eggs in the different levels that make up the Lobos-3 site allowed us to corroborate that the use of the workshop occurred seasonally, since the shearwater spawning occurs in the summer months, and the exploitation of the molluscs used to obtain the purple dye occurs in the autumn and winter”.
Reference:
Núñez-Lahuerta, C. et al. Shearwater eggs in Lobos 3, Holocene Site of Fuerteventura (Canary Islands). Diversity (2023).