Oculudentavis khaungraae Not a Stem Bird

The preliminary manuscript has been made available on-line.  It seems that the remarkable fossil skull found preserved in amber from northern Myanmar does not represent a stem bird but it is the remains of a bizarre lizard.  Everything Dinosaur team members were aware of something big brewing within the scientific community earlier this year and on March 11th (2020), we were able to post up an article on this amazing fossil discovery coinciding with the scientific paper being published in the journal “Nature”.

The Polished Amber Nodule Containing the Fossil Skull

Oculudentavis khaungraae skull in amber.

Tiny fossil skull preserved in amber (Oculudentavis khaungraae).  Once thought to be a tiny avian, scientists how think that the skull is from a bizarre lizard.

Picture Credit: Lida Xing et al (Nature)

Doubts Over the Scientific Paper

Almost immediately academics cast doubt over the conclusion that the specimen represented an archosaur, specifically a bird.  However, a media feeding frenzy followed with many outlets reporting that the smallest dinosaur known to science had been found.  In our first blog post we highlighted some of the inconsistencies that had been raised by other scientists and included a synopsis of some of the criticisms in a section entitled “Post Publication Doubts”.

Oculudentavis khaungraae Computer Generated Image of the Skull

Oculudentavis khaungraae computer generated image of the skull.

Oculudentavis khaungraae computer generated image of the skull (left lateral view).

Picture Credit: Xing et al (Nature)

Everything Dinosaur followed this up with a second article published on March 15th entitled “Casting Doubt over Oculudentavis”.  Late last month, in a highly unusual development, the scientific paper was retracted: Scientific Paper on Hummingbird-sized Dinosaur Retracted.  Academic papers are often amended and reprised as new evidence/research comes to light, it is very unusual to have a paper retracted, clearly something was amiss.

Rumours had been circulating that a second specimen would confirm that the holotype (HPG-15-3), currently stored in the Hupoge Amber Museum in China, did not represent a bird or a tiny dinosaur.  Scientists from the University of Calgary (Canada), Sam Houston State University, Florida Museum of Natural History, Villanova University, (USA), Bristol University, University College London, Fundación Miguel Lillo, CONICET (Argentina) and Institut Català de Paleontologia, Universitat Autònoma de Barcelona (Spain), have used an analysis of the second specimen to propose that Oculudentavis is actually a bizarre lizard of uncertain taxonomic position.

The narrow rostrum, the huge orbits and the shape of the braincase led to erection of “eye tooth bird”, as the smallest member of the Dinosauria known from the Mesozoic.  However, Oculudentavis showed several traits that were inconsistent with the original assessment.  This amazing specimen might look like a bird, but it the new interpretation and phylogenetic placement highlights a rare case of convergent evolution rarely seen among the Reptilia. This new manuscript does reinforce the view that amber from Myanmar is affording science an unprecedented insight into the biota that existed in a coastal forest Cretaceous environment, but it also indicates that Oculudentavis khaungraae is a member of the Squamata and not the Archosauria.

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