Ymboirana, Santos & Wilkinson & Ribeiro & Carvalho & Zaher, 2024

Santos, Rodolfo Otávio, Wilkinson, Mark, Ribeiro, do Couto Graziela, Carvalho, Alberto B. & Zaher, Hussam, 2024, The first fossil record of an aquatic caecilian (Gymnophiona: Typhlonectidae), Zoological Journal of the Linnean Society 202 (2), pp. 1-23 : 3

Ymboirana gen. nov.

ZooBank registration: urn:lsid:zoobank.org:act:1B16342C - 6788-4962-BF69-E970F3F93A56

Diagnosis: The new taxon is recognized as a caecilian because it has a pseudangular with a distinctive retroarticular process, an elongate vertebral column comprised of amphicoelous vertebrae bearing well -developed anterior basapophyseal processes, and lacks limbs and girdles. Ymboirana differs from rhinatrematids in lacking sagittal crests on the parietals; from caeciliids in having all teeth roughly similar in size; from siphonopids and scolecomorphids in having an inner mandibular tooth row; from the herpelid Herpele by having a smooth dorsal surface of the parietal (i.e. without ornamentations in the form of foramina for neurovascular canals) and from chikilids, dermophiids, grandisoniids, ichthyophiids, and the herpelid Boulengerula by having only monocuspid teeth. Ymboirana shares with all typhlonectids, except Chthonerpeton , the presence of elongate trunk vertebrae and well -developed ventral ridges on the basapophyseal processes. Unique characteristics include the following: pseudangular dorsally recurved and posteriorly pro - jected, bearing a poorly developed processus condyloides and a fossa leading to the canalis primordialis located far from (i.e. not immediately adjacent to) the articular surface.

Content: Ymboirana acrux , sp. nov., by monotypy and designation.

Etymology: From the Tupi Y (water), mboî (snake), and rana (similar to). Caecilians are often misidentified as snakes due to their overall similarity, and typhlonectids are distin - guished from other caecilians by their aquatic or semi -aquatic lifestyles.