A species identified in 2016 as an ancient form of chameleon was misidentified at that time, say researchers, many of whom were part of the original 2016 report. According to the new look at similar amber-bound fossils uncovered not long after, the species were albanerpetontids - a long-extinct lineage of tiny, enigmatic amphibians quite unlike amphibians living today. "What strange lissamphibians these albanerpetontids are: They have claws, scales, and armored skulls - and at least one had a tongue like a modern chameleon," writes David Wake in a related Perspective. Today, amphibians are represented by three distinct lineages - frogs, salamanders and the limbless caecilians. However, until the early Pleistocene, there was a fourth: the albanerpetontids. This obscure group is generally only known through a limited collection of fragmented and poorly preserved fossil remains, and a great deal about them remains a mystery. Juan Daza and colleagues report on new, ethically collected, fossil discoveries from Myanmar's fossil-rich amber deposits and present a new genus and species of albanerpetontid - Yaksha perettii. Similar fossils, which were previously described in the 2016 Science Advances study, initially led researchers including authors on this new study to identify Yaksha as an ancient form of chameleon, based largely on the presence of an entoglossal - the bespoke bone that gives the species its tongue-firing ability. "No other taxon was thought to have such an extreme entoglossal. Hence, the initial identification seemed to make sense," writes Wake in the Perspective. However, the new findings, which include a complete, articulated skull and, importantly, associated soft tissues like skin, tongue and jaw muscles, indicate that the species was initially misidentified. Daza et al. show that Yaksha instead belongs to the albanerpetontids. Based on these new findings, the authors suggest that these ancient amphibians were climbers - living near or in trees, rather than underground - and used their ballistic tongues to catch food - a specialized feeding mode that now appears to have been evolutionarily convergent with that in present-day chameleons.
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Journal
Science