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| Chelus colombiana MUSM-920 specimen from the Middle Miocene of Fitzcarrald Arch, Peru. (A) Shell in anterior (cranial) view. (B) Shell in left lateral view. (C) Shell in posterior (caudal) view, showing both pelvic girdles articulated and sutured to the carapace and plastron. in Cadena, Salas-Gismondi, Zamora-Vega, ... et Pérez-García. 2026. Artistic reconstruction by Juan Giraldo |
Abstract
We describe two fossil turtle shells of Chelus colombiana from Middle Miocene vertebrate localities in the Fitzcarrald Arch and Iquitos regions of Peru. One specimen represents one of the most complete fossil shells of the genus, also one of the largest known, measuring 84.6 cm in carapace length and estimated to have weighed approximately 65 kg. Morphological comparisons confirm synchronous consistency with other C. colombiana specimens from Colombia and Brazil, with only minor variation in the gular and extragular scutes. These new records extend the known geographic distribution of C. colombiana to the southwestern margins of the Pebas wetland system and support a broader pattern of body size gigantism among Miocene South American turtles, likely driven by ecological connectivity rather than climatic factors. However, the absence of associated cranial material remains a major obstacle to fully resolving the taxonomy of fossil Chelus, a problem further explored in this study.
Keywords: South America; Neogene; Pebas Formation; Testudines; Pleurodira; paleobiogeography
Systematic paleontology
Order Testudines Batsch, 1788 sensu Joyce et al., 2020a
Suborder Pleurodira Cope, 1865 sensu Joyce et al., 2020b
Family Chelidae Gray, 1825 sensu Joyce et al., 2021
Genus Chelus Duméril, 1806
Chelus colombiana Wood, 1976
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| Shell of Chelus colombiana MUSM-920 specimen from the Middle Miocene of Fitzcarrald Arch, Peru. (A) Shell in anterior (cranial) view. (B) Shell in left lateral view. (C) Shell in posterior (caudal) view, showing both pelvic girdles articulated and sutured to the carapace and plastron. (D) Artistic reconstruction of Chelus colombiana by Juan Giraldo. |
Edwin-Alberto Cadena, Rodolfo Salas-Gismondi, Camila Zamora-Vega, John Flynn, Pierre-Olivier Antoine, Patrice Baby and Adán Pérez-García. 2026. New Fossil Material of Chelus (Testudines: Chelidae) from the Middle Miocene of Peru. Palaeoworld. 35(5); 201135. DOI: doi.org/10.1016/j.palwor.2026.201135 [25 May 2026]
