A new testudinoid turtle from the middle to late Eocene of Vietnam.

Background: Testudinoidea is a major clade of turtles that has colonized different ecological environments across the globe throughout the Tertiary. Aquatic testudinoids have a particularly rich fossil record in the Tertiary of the northern hemisphere, but little is known about the evolutionary history of the group, as the phylogenetic relationships of most fossils have not been established with confidence, in part due to high levels of homoplasy and polymorphism.

Methods: We here focus on describing a sample of 30 testudinoid shells, belonging to a single population that was collected from lake sediments from the middle to late Eocene (35-39 Ma) Na Duong Formation in Vietnam.

Morphological variation in the Brazilian Radiated Swamp Turtle Acanthochelys radiolata (Mikan, 1820) (Testudines: Chelidae).

The freshwater turtle Acanthochelys radiolata (Mikan, 1820) is endemic to the Atlantic Forest domain in Brazil and few studies have been done on the morphology, geographic variation and taxonomy of this species. In this paper we record the morphological variation, as well as sexual dimorphism and ontogenetic changes in A. radiolata throughout its distribution range.