A new cryptodire from the Eocene of the Na Duong Basin (northern Vietnam) sheds new light on <i>Pan-Trionychidae</i> from Southeast Asia

<i>Striatochelys baba</i> gen. et sp. nov. is a new pan-trionychid from the middle–upper Eocene (late Bartonian–Priabonian, 39–35 Ma) of the Na Duong Basin in northern Vietnam. It represents one of the best documented and most completely known Palaeogene pan-trionychid species from Asia. <i>Striatochelys baba</i> can be diagnosed by: (1) its relatively small size; (2) the absence of a preneural; (3) the presence of well-developed straight ridges on the costals and neurals in adults; (4) ridges more strongly developed posteriorly than anteriorly; and (5) entoplastron callosity in the shape of a bulge. A phylogenetic analysis recovers <i>S. baba</i> within <i>Pan-Trionychinae</i> in an unresolved polytomy with species of the genus <i>Nilssonia</i>. In addition, comparisons of the new taxon with plastomenids, pan-trionychids from the Palaeogene and extant trionychids from Asia demonstrate a particularly close resemblance to <i>Nilssonia</i> spp. Based on the close resemblance between <i>S. baba</i> and ‘<i>Trionyx</i>’ <i>impressus</i> (a pan-trionychid from the Maoming Basin of southern China), we here assign the latter species to the new genus <i>Striatochelys</i>. The close relationship between <i>S. baba</i> gen. et sp. nov. from the Na Duong Basin and <i>S. impressa</i> comb. nov. from the Maoming Basin further supports the hypothesis that a close connection between both localities existed, as already exemplified by other faunal elements such as pan-geoemydids and crocodylians. http://zoobank.org/urn:lsid:zoobank.org:pub:E8E5C4DE-E52A-43FB-B9C1-CE3ED2ED66C1