Two of my favorite things in the natural world are rock art (which readers of RockArtBlog will have recognized by now), and fossilized dinosaur tracks. Any report of finding them in conjunction in the same site is positively exciting, and now we have a report of just such an occurrence in Brazil.
Leonardo Troiano wrote in the 2024 paper describing this discovery: “The Serrote do Letreiro Site, found on the northwest periphery of the Sousa Basin, Brazil, presents a remarkable convergence of paleontological and archaeological elements. It is constituted of subhorizontal "lajeiros", or rock outcrops, intermingled with endemic Caatinga vegetation. The three prominent outcrops feature fossilized footprints of theropod, sauropod, and iguanodontian dinosaurs from the Early Cretaceous Period. Adjacent to these dinosaur tracks, indigenous petroglyphs adorn the surface. The petroglyphs, mainly characterized by circular motifs, maintain a striking resemblance to other petroglyphs found in the states of Paraíba and Rio Grande do Norte.” (Troiano et al. 2024) Caatinga is a type of semi-arid tropical vegetation, and an ecoregion characterized by this vegetation in interior northeastern Brazil (Wikipedia). Rock outcroppings in this forest have been found to contain not only three different types of dinosaur footprints, but petroglyphs as well, and it is herein postulated that the dinosaur tracks themselves were one reason for the subsequent placement of petroglyphs on those rock faces.
"The lithological support on which petroglyphs and dinosaur tracks are located are sub-horizontal sandstone and comglomerate sandstone strata situated on a small hill, known as 'Serrote'. There is evident displacement of sizable surface portions due to rainwater runoff on the inclined support. The makers' preference for such type of sandstone is commonly observed in the Northeast region of Brazil, where many of these rock formations were used as support for petroglyphs. Additionally, the site in question is positioned near a water source, specifically a small lake and a temporary stream, which is likewise a recurring factor is similar sites in the region. The process of creating the petroglyphs involved the use of mixed techniques. The petroglyphs were first carved by scraping with light contact between an abrasive instrument and the rock surface. Irregularities are observed on the inner endes of the rock grooves, a result of fast movement, causing friction between the instrument and the surface. Many of the petroglyphs underwest subsequent pecking so that the ingraving line was refined by a series of continuous impacts using a sharp instrument. This complementary process resulted in small and repeated concavities of greater depth than those observed in petroglyphs made only through scraping. The preference in some instances for the scraping technique often produces shallow petroglyphs, with renders them more vulnerable to erosion, resulting in the current low visibility and legibility of many petroglyphs." (Troiano et al. 2024) Note, they report that some of the petroglyphs had been renewed or repecked. When I carefully read the authors' description of how these petroglyphs were produced I found myself in disagreement. Carving stone with "scraping with light contact" and then "fast movement, causing friction" is not a practical way to remove stone. One either grinds or pecks the surface with a harder stone. The comment about "subsequent pecking", however appears to be right on. No real blame though, kunless a person has actually worked stone they can be forgiven for not totally understanding the process.
“Concerning the morphology of the identified petroglyphs, the presence of tetrapartite or pentapartite circumferences stands out. Nevertheless, there are notable exceptions to this trend, including engravings comprised of rectangular grid structures and others resembling stars. Despite the profusion of identified petroglyphs, no overlap was observed between these inscriptions and the fossilized footprints. In none of the cases was it found that the creation of a petroglyph resulted in damage to the existing footprints, suggesting thoughtfulness by the makers. In some cases, there is an extreme proximity between petroglyphs and footprints, with some occurring immediately adjacent to the fossilized tracks. This only highlights and establishes a more profound relationship between the archaeological and paleontological records. Concerning the graphic identity, or the "set of characteristics that allow attributing a set of graphisms to a particular social authorship, it was determined that the Serrote do Letreiro site belongs to a broad set of archaeological rock art sites in the Brazilian Northeast region that present an identical repertoire of motifs, either pure or abstract, and of similar or identical execution techniques. In the first rock outcrop, located further north, it is possible to identify a higher concentration of dinosaur tracks. Reports from previous visitors to the site from the past twenty years, as well as statements from residents, indicate that until not long ago, there were a minimum of thirty such petroglyphs that were discernible on outcrop 1. The legible petroglyphs found on this outcrop consist predominantly of circles internally divided by lines and are positioned close to the footprints, in some cases as close as a distance of 10 cm.” (Troiano et al. 2024) It would appear to be important that “no overlap was observed between these inscriptions and the fossilized footprints.” This implies to me that the makers of these images carefully avoided overlapping any of the dinosaur footprints, suggesting that they were recognized as being of import.
No culture leaves basic questions unanswered. I have written elsewhere that one thing that the indigenous inhabitants of the Americas knew well was animal tracks. So many of the tribes depended upon hunting for sustenance would have made reading tracks a priority. Finding these tracks in stone would have presented a conundrum to them – animal tracks in stone that they did not recognize. Something made those tracks, and they did not fit any of the contemporary animals that they knew. I have speculated that this would be one of the factors that led to beliefs in supernatural creatures that could have made the tracks, and once the idea of supernatural is involved such a site probably acquires ritual and spiritual importance. In the past I have referred to this as Native American Paleontology. They had their answers, just not the same ones that we had come up with. This spiritual importance led to the production of the petroglyphs, carefully avoiding the tracks.
Here, the authors refer to the eloquent writings of Adrienne Mayor. “Overall, the systematic examination of interactions between humans and the fossil record, such as fossil discoveries in the pre-Columbian era, is a relatively recent scholarly endeavor. Adrienne Mayor played an important role in highlighting the evolution of this research in two significant publications: "The First Fossil Hunters: Paleontology in Greek and Roman Times" (2000) and "Fossil Legends of the First Americans" (2013). As early as 1935, there was recognition that the discipline of paleontology is indebted to Native Americans, considering their relevant discoveries, as described by Edward M. Kindle in his notes in the Journal of Paleontology. Despite this, some prominent paleontologists, such as G. Gaylord Simpson, held the opposite view, exemplifying the paradigm that prevailed for most of that time. According to him, pre-Columbian fossil findings were occasional events and are not to be considered in the history of paleontology. Furthermore, he claimed that Native American reports were untrustworthy, being of little ethnological and no paleontological value. This hegemonic conception disregarded native contributions, arguing that fossil discoveries made by indigenous people were the mere result of chance finds, devoid of any scientific continuity (see page 26 in Mayor). Nonetheless, today, it is indisputable that Native American thought represents a distinct and valuable form of scientific reflection and inquiry. This knowledge, developed over generations, is often referred to as “Native Science”. It is important to highlight that, despite the differences between the Western Scientific Method and Native Science or Traditional Knowledge, both represent equally valid efforts to grasp, describe, and understand the reality that surrounds humans. The integration of Native science knowledge provides a valuable opportunity for academic exchange while at the same time contributing to the empowerment and inclusion of Native American voices in this sphere.” (Troiano et al. 2024)
These last few lines once again provide a well presented view of what I have called Native American Paleontology. Our science might not have agreed with their conclusions, but their conclusions were valid for their world view and belief systems, and worked for them.
NOTE: Previous RockArtBlog columns on the concurrence of rock art and dinosaur tracks can be accessed through “dinosaur tracks” in the cloud index at the bottom of this column. For much more thorough descriptions of the three sites read the original paper by Troiano et al. (2024).
PRIMARY REFERENCE:
Troiano, Leonardo P., Heloísa B. dos Santos, Tito Aureliano, Aline M. Ghilardi, 2024, A remarkable assemblage of petroglyphs and Dinosaur footprints in Northeast Brazil, Nature/Scientific Reports 14:6528, https://doi.org/10.1038/s41598-024-56479-3. Accessed 22 March 2024.
SECONDARY REFERENCES:
Mayor, Adrienne, 2000, The First Fossil Hunters: Paleontology in Greek and Roman Times, Princeton University Press.
Mayor, Adrienne, 2013, Fossil Legends of
the First Americans. Princeton
University Press.
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