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Nov. 5 (UPI) -- An unusual group of extinct amphibians known as albanerpetontids used a rapid-fire tongue to catch prey, according to a new study published Thursday in the journal Science. For years, albanerpetontids, called "albies" for short, have puzzled scientists. Despite claws, scales and tails that recall those of lizards, albies are officially amphibians.
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Their lineage diverged from today's frogs, salamanders and caecilians more than 165 million years ago, but the group only disappeared from the fossil record 2 million years ago.
"We are always interested in enigmatic extinct groups," study co-author Susan Evans told UPI in an email.
"Albies are interesting and mysterious -- in their specialized anatomy, in the fact that they became extinct only a couple of million years ago, in their distribution and lifestyle," said Evans, professor of vertebrate morphology and paleontology at University College London and an albie expert.
Albies are noted for their robust skulls, leading many scientists to suggest the amphibians were burrowers, catching mostly soil-bound prey. But new analysis of collection of 99-million-year-old amber fossils from Myanmar suggests albies were capable of zapping flies from midair.
Evans had never seen an albie trapped in Myanmar amber until a group of scientists led by Juan Diego Daza, assistant professor of biological sciences at Sam Houston State University, described a group of lizard fossils in a 2016 paper.
The identification of one particular specimen from the cadre of fossils proved especially vexing for Daza and his colleagues. The creature boasted an array of befuddling characteristics. After much debate, researchers classified the specimen as an early chameleon.
When Evans read the paper, she realized the authors had made a mistake. The specimen wasn't a lizard. It was an albanerpetontid. Evans reached out to Daza to inform him of his error.
Daza's paper also caught the attention of another researcher, Adolf Peretti, a gemologist who had acquired another collection of similar amber fossils.
After performing a series of CT scans, Daza realized one of the fossils contained the complete skull of an albanerpetontid. He made sure the 3D images of the albie fossils made their way to Evans.
Evans said she had never seen such a well-preserved albie skull. The fossil featured bits of soft tissue, as well as jaw muscles and eyelids. But most importantly, the fossilized skull boasted a tongue pad -- the kinds of pad that supports a sling-shot tongue.
"I had already speculated that this might be part of a ballistic tongue apparatus in previous work, but the main Myanmar specimen shows it beautifully," Evans said. "Importantly, it preserves part of the soft tissue of the tongue itself showing that the long 'tongue bone' is really part of a tongue mechanism."
Daza, Evans and their research partners compared the tongue bone with those found in modern chameleons and a group of modern salamanders called bolitoglossa -- the only living animals known to use a slingshot tongue. The structures proved nearly identical.
Researchers confirmed that the only living species with a slingshot tongue are also the only living species with a specialized elongated hyoid apparatus.
"Thus, in having this exceptionally long hyoid element -- tongue-bone -- in the floor of the mouth, we can conclude that they shared a ballistic mechanism," Evans said. "Moreover, this also fits with other strange adaptations we know albies have -- large eyes, a complex anterior jaw joint and a mobile neck."
Researchers determined that the ballistic-tongued albies specimen represented a new genus and species, Yaksha perettii, but Evans estimates the slingshot tongue was common among the early amphibians.
If the earliest albies -- which date back 165 million years -- had rapid-fire tongues, too, it would mean amphibians evolved an elongated hyoid apparatus and ballistic tongue before chameleons.
Previously, albies fossils were mostly found in North America, Europe and East Asia -- and less often in Morocco.
Now, the evidence suggests they were living in the part of Gondwana that became Southeast Asia. New, yet discovered albies fossils could provide clues as to what exactly the earliest amphibians looked like.
"[Albies remain] of interest because they possess a mix of primitive amphibian characters and very derived ones," Evans said.
"There is a big debate at the moment about the origins of modern amphibians and, as an early branch from the modern amphibian stem, albanerpetontids have the potential to tell us something about amphibian relationships generally and the origins of modern forms," she said.
