Wednesday, April 22, 2020

A Fossil of a Miniature Bird Encased in Amber

Environmental & Science Education
Earth Science
Biological Evolution
Edward Hessler

Reporting in Nature, Giuliana Viglione, reports on the discovery of a fossil bird, about the size of the bee hummingbird (Mellisuga helenae). It's skull--less than 2 cm long (ca 0.8 inch) is preserved in Burmese amber and has been dated to 99 million years years old. Viglione writes,

“'It reveals to us a whole new lineage of birds,'” says Jingmai O’Connor, a palaeontologist at the Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, who co-led the study. O’Connor and her team assigned the animal a new genus and species, Oculudentavis khaungraae (Oculudentavis means "eye tooth bird") ; the genus name means ‘eye-teeth bird’. The dinosaur weighed perhaps two grams (`0.07 oz, a little less than a penny) and lived during the Mesozoic era, which lasted from about 250 million to 65 million years ago.'"

Paleontologist Roger B. J. Benson (University of Oxford) calls attention to two features of the skull in an accompanying essay. It "is dominated by two enormous eye sockets containing scleral ossicles--rings of bone that form the eye skeletons of birds. The opening at the narrow, restricting access for light into the eye. "This provides strong evidence that Oculudentavis was active in well-lit, daytime environments."

The second feature is the presence of many teeth. This is not an uncommon feature in early fossil birds. But Oculudentavis "has more teeth than other bireds of the period, and these extend unusually far back in the jaws.  These and other observations suggest that "Oculudentavis was a predator that mainly ate invertebrates."

A photograph in the research paper show the two features discussed above.

Benson discusses the difficulties of determining evolutionary relationships to other dinosaurs and birds. What is desperately needed is "knowing more about its skeleton."
Further details may be found in Viglione's essay here which includes a short video (2 m 19 s). 

Access to the original paper is restricted to subscribers but you can read the abstract and find the names of the authors here.

UPDATE 1. Jerry Coyne, at WEIT, has an update about this fossil. I quote a statement from it but urge you to read Coyne's essay. He IS an evolutionary biologist who knows much more about this than me. In it, Coyne reports important information from vertebrate paleontologist Darren Naish.

"There are two issues raised by Darren. The first is whether this really is a feathered, avian-like theropod. The second is the ethicality of using specimens from Burmese amber."  The fossil may be a lizard. The purchase of the original amber was likely illegal and it is possible that purchasing funds may have been used by the Burmese military in their fight with ethnic minorities. (Rohinga, Kashkin). Coyne has much more information about both concerns and also includes a link to a video on amber specimens.

UPDATE 2.Emeritus professor Jerry Coyne, an evolutionary biologist at the University of Chicago, has posted another review of the paper which disputes the original claims and interpretations. Neither bird nor theropod says paleontologist Andrea Cau. Professor Coyne's comments may be read here. More is likely to follow!

UPDATE 3. Hearing nothing more I think this is ready to send. 

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