Abstract
Here we report multiple lamniform shark teeth recovered from fluvial sediments in the (Campanian-Maastrichtian) Cerro Fortaleza Formation, Santa Cruz Province, Argentina. This small tooth assemblage is compared to various lamniform sharks possessing similar dental morphologies, including Archaeolamna, Cretalamna, Dwardius, Dallasiella, and Cretodus. Although the teeth share numerous morphological features with the genus Archaeolamna, including a developed neck that maintains a relatively consistent width along the base of the crown, the small sample size and incomplete nature of these specimens precludes definitive taxonomic assignment. Regardless, the discovery of selachian teeth unique from those previously described for the region broadens the known diversity of Late Cretaceous South American sharks. Additionally, the discovery of the teeth in fluvial sandstone may indicate a euryhaline paleobiology in the lamniform taxon or taxa represented by this tooth assemblage.
Highlights
The Cerro Fortaleza Formation (Campanian–Maastrichtian) is located in the Rıo La Leona Valley in Santa Cruz Province, Argentina
Arbe and Hechem [4] distinguished the Upper Cretaceous fluvial outcrops in the Rıo Leona Valley as a distinct formation, which we assign to the Cerro Fortaleza Formation
While we cannot entirely discount the possibility of reworking, only a few of the teeth (e.g., MPM-PV 3268) described in this study show evidence of wear or other indicators of significant transportation
Summary
The Cerro Fortaleza Formation (Campanian–Maastrichtian) is located in the Rıo La Leona Valley in Santa Cruz Province, Argentina. Stratigraphic terminology has been inconsistently applied across this region, and the Cerro Fortaleza Formation is sometimes referred to in previous publications as the Pari Aike, Chorrillo, or Mata Amarilla Formation [1,2,3,4,5,6,7,8,9,10]. Arbe and Hechem [4] distinguished the Upper Cretaceous fluvial outcrops in the Rıo Leona Valley as a distinct formation, which we assign to the Cerro Fortaleza Formation. The Cerro Fortaleza Formation is clearly terrestrial and consists predominantly of cross-bedded, friable sandstones interbedded with layers of mudstones and occasional lignitic horizons [1,2,4,5,6,7,11,12,13]. Histosols [14], carbonaceous root fossils, and silicified wood [15] suggest a low-lying, poorly drained forested terrain
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
