RT Journal Article SR Electronic T1 Monotreme middle ear is not primitive for Mammalia JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.05.03.442467 DO 10.1101/2021.05.03.442467 A1 Jin Meng A1 Fangyuan Mao YR 2021 UL http://biorxiv.org/content/early/2021/05/05/2021.05.03.442467.abstract AB The study on evolution of the mammalian middle ear has been fueled by continuous discoveries of Mesozoic fossils in the last two decades. Wang et al.1 recently reported a specimen of Vilevolodon diplomylos (IMMNH-PV01699)2 that adds to the increasing knowledge about the auditory apparatus of ‘haramiyidans’, an extinct Mesozoic group of mammaliaforms. The authors hypothesized that a middle ear with a monotreme-like incus and malleus and incudomallear articulation was primitive for mammals, which challenges the convention that the monotreme middle ear is specialized3 or autapomorphic4 in mammals. We raise concerns about terminology and identification of the incus presented by Wang et al. and show that their analysis does not support their hypothesis; instead, it supports the one by Mao et al.5,6.Competing Interest StatementThe authors have declared no competing interest.