An Early Cretaceous Sphenophyllum or a hatchling turtle?

Correctly identifying fossil specimens from parautochtonous deposits where marine and terrestrial organisms co-occur can be challenging due to the abundance of rare and obscure specimens with unclear morphologies. In this study, we reviewed fossils from the Lower Cretaceous La Paja Formation (Ricaurte Alto, Villa de Leyva, Colombia) that were originally described as the plant “Sphenophyllum colombianum” based on an apparent resemblance to the upper Paleozoic genus. We determined that the type specimen corresponds to the carapace of a hatchling turtle. In addition, a sec-ond specimen of “S. colombianum” although less well-preserved, also exhibits similar features of a hatchling turtle. The two fossil specimens are significant as they represent the first report of hatchling marine turtles from the Aptian of northwestern South America and provide evidence of the exceptional preservation of the Marine Reptile Lager-stätte of Ricaurte Alto.