CT scans of toothed bird fossil leads to jaw-dropping discovery - The Guardian

Fossil experts person cooked the goose of a cardinal tenet successful avian improvement aft uncovering a premodern vertebrate from much than 65m years agone that could determination its beak similar modern fowl.

The toothy carnal was discovered successful the 1990s by an amateur fossil collector astatine a quarry successful Belgium and dates to astir 66.7m years agone – soon earlier the asteroid strike that wiped retired non-avian dinosaurs.

While the fossil was archetypal described successful a survey astir 20 years ago, researchers re-examining the specimen accidental they person made an unexpected discovery: the carnal had a mobile palate.

“If you ideate however we unfastened our mouths, the lone happening we’re capable to bash is [move] our little jaw. Our precocious jaw is wholly fused to our skull – it’s wholly immobile,” said Dr Daniel Field, elder writer of the probe from the University of Cambridge.

Non-avian dinosaurs, including tyrannosaurs, besides had a fused palate, arsenic bash a tiny fig of modern birds specified arsenic ostriches and and cassowaries. By contrast, the immense bulk of modern birds including chickens, ducks and parrots are capable to determination some their little and precocious jaw independently from the remainder of the skull and each other.

That, says Field, makes the beak much flexible and dextrous, helping with preening, nest gathering and uncovering food. “That is simply a truly important innovation successful the evolutionary past of birds. But it was ever thought to beryllium a comparatively caller innovation,” helium said.

“The presumption has ever been … that the ancestral information for each modern birds was this fused-up information typified by ostriches and their relatives conscionable due to the fact that it seems simpler and much reminiscent of non-bird reptiles,” Field added.

Birds with a mobile palate are called neognaths, oregon “new jaws”, portion those with a fused palate are palaeognaths, oregon “old jaws”.

The study, which was published successful the diary Nature, is expected to ruffle feathers, not lone for suggesting the mobile palate predates the root of modern birds but that the contiguous ancestors of ostriches and their relatives went connected to germinate a fused palate.

“Why the ancestors of ostriches and their relatives would person mislaid that beneficial conformation of the palette is, astatine this point, inactive a enigma to me,” said Field.

The find was made erstwhile Field and colleagues examined the fossils utilizing CT scanning techniques. The researchers discovered that a bony antecedently thought to beryllium from the animal’s enarthrosis was really from its palate.

Palate of Janavis finalidens compared with that of a pheasant and an ostrich. Photograph: Dr Juan Benito and Daniel Field, University of Cambridge

The squad person labelled the recently discovered carnal Janavis finalidens successful notation to the Roman deity that looked some backwards and forwards, and a motion to the animal’s spot connected the vertebrate household tree. The portmanteau of the Latin words for “final” and “teeth” reflects the beingness of Janavis soon earlier toothed birds were wiped retired successful the consequent wide extinction.

The tract of its find means it lived astir the aforesaid clip and spot arsenic the toothless “wonderchicken”, the oldest known modern bird, though astatine 1.5kg (3.3lb), Janavis would person have weighed astir 4 times arsenic much.

While the palate bones of wonderchicken person not been preserved, Field said helium was assured they would person been akin to those of Janavis. However, helium added that the size quality of the creatures could explicate wherefore relatives of wonderchicken survived the catastrophe 66m years ago, but those of Janavis did not.

“We deliberation that this wide extinction lawsuit was highly size selective,” helium said. “Large bodied animals successful terrestrial environments did terribly crossed this wide extinction event.”

Prof Mike Benton, a palaeontologist astatine the University of Bristol who was not portion of the research, said the survey raised questions of the presumption connected the vertebrate household histrion of 3 unusual, extinct groups that lived aft the wide extinction including Dromornithidae, known arsenic demon ducks, and Gastornithidae, thought to beryllium a benignant of elephantine flightless fowl.

“If this palate diagnostic is primitive, I spot that [these groups] could person had earlier origins and possibly survived from Cretaceous onwards,” helium said.