Partial characterization of a new adenovirus lineage discovered in testudinoid turtles

•Novel adenoviruses (with balanced G+C) were detected in different turtles.•These viruses form a lineage different from every earlier adenovirus genus.•The novel virus lineage is hypothesized to have coevolved with testudinoid turtles.•Establishment of a new genus (with a putative name Testadenovirus) is proposed.