This fossil trapped in amber was thought to be a dinosaur, but it is likely to be a lizard.Credit: Lida Xing
A high-profile document withdrawing what was thought to be the remains of the smallest known bird-like dinosaur was removed. New evidence suggests that the specimen, trapped in amber in what is now Myanmar nearly 100 million years ago, could be a lizard, part of a different group of reptiles.
The authors of the work.one, published in Nature On March 11, let’s say his original description of the fossil, a bird-like skull less than 2 centimeters long, its mouth full of dozens of teeth, is still accurate. But they recognize that its classification as a dinosaur is incorrect.
Skepticism about the categorization of the animal surrounded by amber arose almost immediately after the article was published in March. In a prepresstwo Posted on the bioRxiv server, some paleontologists claimed that the fossil was a lizard, rather than a dinosaur (the work has not yet been peer-reviewed). The authors of the original article published a response.3, which has also not been peer reviewed, refuting those arguments. But another research team showed the authors unpublished data that described a similar fossil that the team had classified as a lizard. Those data have cast doubt on the original taxonomic classification, according to the retraction notice published in Nature July 22. (NatureThe news team is editorially independent from its magazine team.)
The new data “definitely says we were wrong,” says Jingmai O’Connor, a paleontologist at the Institute of Paleontology and Vertebrate Paleoanthropology at the Chinese Academy of Sciences in Beijing, who co-led the now-withdrawn study. But, she contends, the specimen cannot be reclassified until the other fossil data is released.
Andrea Cau, a vertebrate paleontologist in Parma, Italy, was one of the skeptical scientists of the original classification. The fossil has several characteristics typical of lizards that have never been seen before in a bird-shaped fossil from that time, says Cau. And because many of the specimen’s characteristics are lizard-like, about ten, in his estimation, “the idea that it was a lizard instead could not be excluded.” Cau is not surprised by the retraction, noting that reclassifications, especially of incomplete fossil specimens from unknown groups, are not uncommon in the field.
Although the fossil is no longer believed to be the smallest known dinosaur, O’Connor and Cau say it is still compelling due to its unusual combination of features. “The specimen is still very interesting to science,” says O’Connor.
