Tweet
Paleontologists have gotten a better understanding of how birds evolved from terrestrial dinosaurs after examining the material from four skulls which came from Ichthyornis dispar, which lived in North America during the later Cretaceous between 100 and 66 mya and, resembling a modern seagull as well as living like one, was close to the ancestry of modern birds, the Aves, but represents an independent lineage.
The first remains were discovered in 1870 by Benjamin Franklin Mudge, Kansas' state geologist, and named as well as first officially described by Othniel Charles Marsh. Unfortunately the skull material was fragmentary and no substantial new cranial material from the creature has been described beyond these incomplete remains recovered nearly a century and a half ago.
Now, a team led by Daniel J. Field of the Milner Centre for Evolution at the University of Bath, has examined four Ichthyornis skulls (including an unusually complete skull found in Kansas in 2014 as well as two previously overlooked cranial elements from the original holotype[1]), and with these specimens created a nearly complete 3-D digital reconstruction of the Ichthyornis skull using high-resolution CT-scan technology in order to gain substantial new insights into how modern birds' skulls eventually formed.
Paleontologist Stephen L. Brusatte, a Chancellor's Fellow in Vertebrate Palaentology at the School of GeoSciences in the University of Edinburgh, and member of the Editorial Board for Current Biology who specializes in the anatomy and evolution of dinosaurs and was not involved in this discovery described this discovery's significance as being a "game changer."
"The famous bird Archaeopteryx and a lot of the fossils in the early history of bird evolution, they had wings, but their skulls basically looked like little baby dinosaur skulls," said paper co-author Bhart-Anjan Bhullar, a paleontologist and assistant curator at the Department of Geology & Geophysics and Peabody Museum of Natural History at Yale University. "Ichthyornis, it turns out, is just at this transitional moment," he explained, adding that the results "show the order of appearance of modern bird features."
IOW, again according to Bhullar, "Right under our noses this whole time was an amazing, transitional bird" and "It’s a real mosaic of features, a transitional form."
The researchers discovered that Ichthyornis had a beak and a brain much like those found in modern birds, but unlike modern birds possessed jaws filled with sharp, curved teeth that, as Fields describes, "is very large, and comparable to what you see in a dinosaur like Velociraptor."
Also it had a skull with space for large, powerful jaw muscles comparable to those found in closely related dinosaurs like Velociraptor. Ichthyornis even retains primitive openings in the top of their skulls, exactly like those found in T. rex fossils, to allow for large muscles to attach to the jaw.
Further, a particular type of bone that largely makes up the beaks in modern birds was restricted to the very tips of the Ichthyornis' jaws -- the same as found in many dinosaurs, and even in animals today. However, like modern birds, this tiny beak was covered in keratin (the same material that our finger nails consist of) and was toothless and hooked, but apparently unlike extant birds lacked a palatal shelf.
As Bhullar points out Ichthyornis reveals what a bird's beak looked like as it first appeared in nature: "The first beak was a horn-covered pincer tip at the end of the jaw. The remainder of the jaw was filled with teeth. At its origin, the beak was a precision grasping mechanism that served as a surrogate hand as the hands transformed into wings."
"It was flying around eating probably fish, shellfish and other things, plucking them out of the water with its abbreviated little pincer-tip beak and then tossing them back into its mouth and crunching down on them with its powerful dinosaur-like jaws,” said Bhullar.
It also likely used its beak for preening, grabbing and pecking -- functions helped by the fact it was able to raise its upper jaw in the same manner that modern birds can.
Along with its transitional beak, Ichthyornis also had a brain very much like what we see in birds today, except with a temporal region of the skull that is remarkably similar to that of those found in dinosaurs. This strongly suggests that as birds evolved from their terrestrial dinosaur ancestors, the brain transformed first while the rest of the skull remained more primitive and dinosaur-like.
As Jingmai O’Connor, an expert on early birds and professor at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, and not involved in this discovery has pointed out, "these scientists are showing us just how bizarre the skull of Ichthyornis really was, with an odd combination of derived and primitive features, but many more primitive features than we'd expect."
Or, more simply put, as Field explained, "This extraordinary new specimen reveals the surprisingly late retention of dinosaur-like features in the skull of Ichthyornis -- one of the closest-known relatives of modern birds from the Age of Reptiles."
It also provides strong evidence against the widely held notion that a large brain evolved at the expense of space for jaw muscles. Bhullar speculates that a larger brain was necessary "to deal with the demands of flight."
All of this means that the face of Ichthyornis likely looked like it was half bird, half Velociraptor meaning that for much of the Cretaceous there would have existed flying creatures that looked half-dinosaur, half-bird.
Bhullar also observed how "the skull of Ichthyornis even substantiates our molecular finding that the beak and palate are patterned by the same genes. The story of the evolution of birds, the most species-rich group of vertebrates on land, is one of the most important in all of history. It is, after all, still the age of dinosaurs."
Scientists find the first bird beak, right under their noses 1.5 min.
Ichthyornis 1.jpg
Ichthyornis2.jpgIchthyornis3.jpg
Further Reading:
1. primarily important bones surrounding the eye socket and nostrils that had not previously been recognized
2. also available here: https://pmdvod.nationalgeographic.co...udio_eng_3.mp4
The first remains were discovered in 1870 by Benjamin Franklin Mudge, Kansas' state geologist, and named as well as first officially described by Othniel Charles Marsh. Unfortunately the skull material was fragmentary and no substantial new cranial material from the creature has been described beyond these incomplete remains recovered nearly a century and a half ago.
Now, a team led by Daniel J. Field of the Milner Centre for Evolution at the University of Bath, has examined four Ichthyornis skulls (including an unusually complete skull found in Kansas in 2014 as well as two previously overlooked cranial elements from the original holotype[1]), and with these specimens created a nearly complete 3-D digital reconstruction of the Ichthyornis skull using high-resolution CT-scan technology in order to gain substantial new insights into how modern birds' skulls eventually formed.
Paleontologist Stephen L. Brusatte, a Chancellor's Fellow in Vertebrate Palaentology at the School of GeoSciences in the University of Edinburgh, and member of the Editorial Board for Current Biology who specializes in the anatomy and evolution of dinosaurs and was not involved in this discovery described this discovery's significance as being a "game changer."
"The famous bird Archaeopteryx and a lot of the fossils in the early history of bird evolution, they had wings, but their skulls basically looked like little baby dinosaur skulls," said paper co-author Bhart-Anjan Bhullar, a paleontologist and assistant curator at the Department of Geology & Geophysics and Peabody Museum of Natural History at Yale University. "Ichthyornis, it turns out, is just at this transitional moment," he explained, adding that the results "show the order of appearance of modern bird features."
IOW, again according to Bhullar, "Right under our noses this whole time was an amazing, transitional bird" and "It’s a real mosaic of features, a transitional form."
The researchers discovered that Ichthyornis had a beak and a brain much like those found in modern birds, but unlike modern birds possessed jaws filled with sharp, curved teeth that, as Fields describes, "is very large, and comparable to what you see in a dinosaur like Velociraptor."
Also it had a skull with space for large, powerful jaw muscles comparable to those found in closely related dinosaurs like Velociraptor. Ichthyornis even retains primitive openings in the top of their skulls, exactly like those found in T. rex fossils, to allow for large muscles to attach to the jaw.
Further, a particular type of bone that largely makes up the beaks in modern birds was restricted to the very tips of the Ichthyornis' jaws -- the same as found in many dinosaurs, and even in animals today. However, like modern birds, this tiny beak was covered in keratin (the same material that our finger nails consist of) and was toothless and hooked, but apparently unlike extant birds lacked a palatal shelf.
As Bhullar points out Ichthyornis reveals what a bird's beak looked like as it first appeared in nature: "The first beak was a horn-covered pincer tip at the end of the jaw. The remainder of the jaw was filled with teeth. At its origin, the beak was a precision grasping mechanism that served as a surrogate hand as the hands transformed into wings."
"It was flying around eating probably fish, shellfish and other things, plucking them out of the water with its abbreviated little pincer-tip beak and then tossing them back into its mouth and crunching down on them with its powerful dinosaur-like jaws,” said Bhullar.
It also likely used its beak for preening, grabbing and pecking -- functions helped by the fact it was able to raise its upper jaw in the same manner that modern birds can.
Along with its transitional beak, Ichthyornis also had a brain very much like what we see in birds today, except with a temporal region of the skull that is remarkably similar to that of those found in dinosaurs. This strongly suggests that as birds evolved from their terrestrial dinosaur ancestors, the brain transformed first while the rest of the skull remained more primitive and dinosaur-like.
As Jingmai O’Connor, an expert on early birds and professor at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, and not involved in this discovery has pointed out, "these scientists are showing us just how bizarre the skull of Ichthyornis really was, with an odd combination of derived and primitive features, but many more primitive features than we'd expect."
Or, more simply put, as Field explained, "This extraordinary new specimen reveals the surprisingly late retention of dinosaur-like features in the skull of Ichthyornis -- one of the closest-known relatives of modern birds from the Age of Reptiles."
It also provides strong evidence against the widely held notion that a large brain evolved at the expense of space for jaw muscles. Bhullar speculates that a larger brain was necessary "to deal with the demands of flight."
All of this means that the face of Ichthyornis likely looked like it was half bird, half Velociraptor meaning that for much of the Cretaceous there would have existed flying creatures that looked half-dinosaur, half-bird.
Bhullar also observed how "the skull of Ichthyornis even substantiates our molecular finding that the beak and palate are patterned by the same genes. The story of the evolution of birds, the most species-rich group of vertebrates on land, is one of the most important in all of history. It is, after all, still the age of dinosaurs."
Scientists find the first bird beak, right under their noses 1.5 min.
Ichthyornis 1.jpg
Ichthyornis2.jpgIchthyornis3.jpg
Further Reading:
Complete Ichthyornis skull illuminates mosaic assembly of the avian head Abstract
Dinosaur-Era Bird Found With Shockingly Intact Skull includes revolving 3-D image of skull[2]
Scientists find the first bird beak, right under their noses
Unprecedented Fossil Provides New Understanding of Bird Evolution
Fossil sheds light on evolutionary journey from dinosaur to bird
Creationists Quickly Dismiss New Fossil Evidence of Modern Bird Evolution
Ancient bird with beak and teeth blended dinosaur, avian traits
Scientists Identify the Bird That Bridges the Gap Between Bird and Dinosaur
Dinosaur-Era Bird Found With Shockingly Intact Skull includes revolving 3-D image of skull[2]
Scientists find the first bird beak, right under their noses
Unprecedented Fossil Provides New Understanding of Bird Evolution
Fossil sheds light on evolutionary journey from dinosaur to bird
Creationists Quickly Dismiss New Fossil Evidence of Modern Bird Evolution
Ancient bird with beak and teeth blended dinosaur, avian traits
Scientists Identify the Bird That Bridges the Gap Between Bird and Dinosaur
1. primarily important bones surrounding the eye socket and nostrils that had not previously been recognized
2. also available here: https://pmdvod.nationalgeographic.co...udio_eng_3.mp4
Comment