A new fossil skeleton of an extinct bird species from northeastern China that lived with dinosaurs 120 million years ago unexpectedly retains a gnarled tongue that is almost as long as its head.
The skull is very well preserved, which shows that it had a relatively short snout and small teeth, with extremely long and curved bones to the tongue (called the hyoid apparatus).
Researchers from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences and the University of Texas at Austin have named this bird Brevirostruavis macrohyoideus, which means “bird with a short snout and large tongue.”
Their discovery was published in Journal of Anatomy on December 1, 2021.
We quickly learn as children to stick our tongues out, but most reptiles and birds do not have large muscular tongues like humans. Birds instead have a set of rod-shaped elements made of bone and cartilage, consisting of the hyoid apparatus that sits in the floor of the mouth.
In birds with larger tongues such as ducks and parrots, they use their tongue to move food around their mouths, get food into their mouths and help swallow food. Some birds today like hummingbirds and woodpeckers have a bone tongue that is as long or longer than their skulls.
This extinct bird with a short snout, big tongue is the earliest example of a bird sticking its tongue out. Of course, this feature makes one wonder why this bird would stick its tongue out. The researchers assumed that the bird could have used this feature to catch insects in the same way that live woodpeckers use their tongues to get insects out of holes in bark, wood and branches. Alternatively, the bird could have fed on pollen or nectar-like liquids from plants in the forest where it lived. No stomach contents were found with this skeleton.
This short-snout, large-tongued bird is part of an extinct group of birds called enantiornithines or “opposite” birds. They were the most successful group of birds during Chalk Period (between 66 and 145 million years ago), with fossils found around the world.
“We see a lot of variation in the size and shape of skulls in enantiornithine birds, and that probably reflects the great diversity of the foods they ate and how they caught their food. Now with this fossil, we see that it is not only their skulls, but their tongues that also vary, ”said Dr. WANG Min, co-author of the study.
Researchers have previously shown that these early birds had rather stiff skulls just like their dinosaur relatives. This feature puts some evolutionary and functional restrictions on early birds. “Perhaps the only way for them to fundamentally change through evolution how they caught their food and what food they ate was to shorten their skull in this case and to make the tongue bones much longer,” said lead author Dr. LI Zhiheng.
The long, curved hyoid apparatus of the fossil bird is made of bones called ceratobranchials. Live birds also have such bones in their hyoid, but it is the epibranchial bones that are missing in early birds that are very long in birds such as woodpeckers.
“Animals are evolutionarily experimenting with what they have at their disposal. This bird developed a long tongue using the bones it inherited from its dinosaur ancestors, and living birds developed longer tongues with the bones they have. This situation demonstrates the power of evolution. , where birds use two different evolutionary pathways to solve the same problem of getting a long tongue to stick out of their mouths, ”said co-author Dr. Thomas Stidham.
Reference: “Novel evolution of a hyper-elongated tongue in a Cretaceous enantiornithine from China and the evolution of the hyolingual apparatus and feeding in birds” by Zhiheng Li, Min Wang, Thomas A. Stidham, Zhonghe Zhou and Julia Clarke, 1 December 2021, Journal of Anatomy.
DOI: 10.1111 / joa.13588