Evaluation of Iranipeda abeli (Avian track) from the Zagros Mountains, SW Iran: re-examination of the original material and overview of primary sources

A slab with three tetradactyl avian footprints was excavated from the Agha Jari Formation (Mio-Pliocene) in the Zagros Mountains, southwest Iran, in the early last century and named as Urmiornis abeli. The name Urmiornis had been used for the didactyl bird fossil and ichnogenus name was later revised to Iranipeda. Validity of Iranipeda abeli has been discussed by authors in recent decades, and revision of the original material is necessary. Based on re-examination the holotype I. abeli reveals that this name is valid and it differs by long hallux, separate digit imprints and size of lateral digit II and IV traces with other large wading bird footprints. Iranipeda include three ichnospecies: I. abeli and I. millumi and I. intermedia by emended diagnosis of Iranipeda. Ciconiidae is the nearest track-maker candidate for Iranipeda. I. abeli type specimen has been collected from the lower part of the Agha Jari Formation and based on lithostratigraphic position and radiometric data, it is of Late Miocene age.