The paper that identified the skull of an animal preserved in amber as a new species of avian dinosaur has been retracted. Trapped in amber 99 million years ago, the skull definitely looks like a bird’s with dozens of small teeth, but newly released data points to it being a 99-million-year old lizard instead of the smallest dinosaur.
The new data “do definitively say that we were wrong”, says Jingmai O’Connor, a palaeontologist at the Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, who co-led the now-retracted study. But, she contends, the specimen cannot be reclassified until the other fossil data are published.
Andrea Cau, a vertebrate palaeontologist in Parma, Italy, was among the scientists who were sceptical of the original classification. The fossil has several characteristics typical of lizards that have never before been seen in a bird-like fossil from that era, Cau says. And because so many of the specimen’s features are lizard-like — about ten, by his estimate — “the idea that it was instead a lizard could not be excluded”. Cau is not surprised by the retraction, and notes that reclassifications, especially of incomplete fossil specimens from unknown groups, are not uncommon in the field.
Although the fossil is no longer thought to be the smallest-known dinosaur, O’Connor and Cau both say that it is still compelling because of its unusual combination of features. “The specimen is still very interesting to science,” O’Connor says.