Trinomys mirapitanga, a new species of spiny rat (Rodentia: Echimyidae) from the Brazilian Atlantic Forest

A new species of spiny rat (genus Trinomys) from Porto Seguro, state of Bahia in the Atlantic Forest of Brazil is described based on skin, skull, and bacular characters and mitochondrial cytochrome b gene sequences. The new species is the sister to T. dimidiatus and T. iheringi which forms a monophyletic group together with T. gratiosus. It is diagnosed by having a tail less than head and body length that is covered by short hairs, without a brush of elongated hairs on the tail tip, a round post-orbital process of the zygomatic arch that is formed by both the squamosal and jugal, an oval incisive foramen with a well developed maxillary portion of the septum, and a baculum with well developed basal expansion, a median trough on the dorsal surface and ventral flexion.