Additional evidence about “A solar calendar: an interpretation of a coastal petroglyph on Santinho’s Beach, Santa Catarina Island, southern Brazil
Fabricio Souza Neves
Universidade Federal de Santa Catarina
Rua Delfino Conti, 275, Trindade, Florianópolis, Santa Catarina, Brasil – 88040-370
Phone 55-48-37214159
fabricio.souza.neves@ufsc.br
ORCID https://orcid.org/0000-0002-8725-4526
Dear Editor,
We recently published an article entitled A Solar Calendar: An Interpretation of a Coastal Petroglyph on Santinho’s Beach, Santa Catarina Island, Southern Brazil (Neves, 2025). In the article, we presented evidence of the astronomical alignment of petroglyphs that were likely created by the Sambaqui people, a Neolithic culture that inhabited southern Brazil between 8,000 and 2,000 years ago.
In this additional commentary, we present a photograph taken at sunrise on December 21, 2025 (the date of the summer solstice in the southern hemisphere), with the observer positioned at the location marked by the "eye"-shaped petroglyph (Figure 1). The alignment of the figure's main axis with the sunrise on this date is visible.
By comparing it with the sunrise observed at the winter solstice (Figure 2), which aligns with the last open accessory line on the left front side of the petroglyph, one can see the apparent displacement of the sunrise position on the horizon. This demonstrates the usefulness of the Praia do Santinho petroglyph as an instrument for measuring the passage of time throughout the solar year.
References
Neves, F. S. (2025). A solar calendar: an interpretation of a coastal petroglyph on Santinho’s Beach, Santa Catarina Island, southern Brazil. Int J South Am Archeology 21: 1-7. Cirex-ID: http://cirex.id/7435427.29818x
Figure 1. The sunrise on December 21th, 2025 (summer solstice), over the petroglyph at the Spider’s Hill cliff as seen by its west side, from the observer spot (“the eye” petroglyph).
Figure 2. The sunrise on July 21th, 2025 (near winter solstice), over the petroglyph at the Spider’s Hill cliff as seen by its west side, from the observer spot (“the eye” petroglyph).