Three excavation campaigns have been undertaken on the site of Filigosa, in 1965, 1981 and 1993. The necropolis consists of at least four domus, opening on the side of a tufaceous and trachytic hill, on whose summit stands the single-towered nuraghe Ruggiu. Close by stands an unusual monumental head formed from a trachyte rock and known locally as “the sentinel”. Its probable function was that of protecting the inviolability of the funerary area.

The 1993 excavations examined tomb IV. The installation of large shaped stones showed that the corridor had been reused and contained a large amount of nuragic material belonging to the phase with pottery decorated with bands of dots, Tamuli- S. Cosimo type.

At least four phases of use were documented, the first dating to the Lower Neolithic with materials similar to Santu Pedru- Alghero, with sharply carinated vases and grafitto decoration. The second phase was the Full Eneolithic with long-necked vases, impressed-cup decoration and small spiral rings or plait holders made of silver. The third phase was attested by elbow handles and small jars with double bugna on the body, characteristic of Sardinian and Sicilian Early Bronze Age contexts. The fourth phase presented well-refined impasto pottery with shiny surfaces and bands of dotted decoration typical of the Middle Bronze Age, probably to be associated with the builders and inhabitants of the Raggiu nuraghe. Various Macomer artefacts were found including several mended vases, a wooden bowl, small stone picks and the head of a large clay pin and are displayed in the “ G. A. Sanna” Museum in Sassari. In 2007 conservation of the second lot of the abundant archaeological material which will be displayed in the Archaeological Museum of the Marghine at Macomer.