Between about 67 and 66 million years ago, during a period that geologists call the Maastrichtian, there was a thriving ecosystem of dinosaurs in what is now the Hell Creek formation which spans parts of Montana, Wyoming, and North and South Dakota. We know this because their remains are frequently found in this fossil-rich formation known as the Hell Creek Formation.
The great thing about this formation is the way, as the layers built up, nearby volcanoes periodically spread a layer of ash (or tufa) over it forming neat bands that can be accurately dated using one of the most accurate radiometric dating methods - Uranium-Lead (U-Pb) in zircons. This gives a maximum and minimum age of the fossils found between these layers of tufa.
I wrote about U-Pb dating in a recent blogpost, but for the sake of creationists who are about to squawk "Radiometric dating is false!", I'll expand on what I said here:
U-Pb dating of volcanic tufaThe fossils in question were discovered by Kyle Atkins-Weltman, a PhD student in the School of Biomedical Sciences, Oklahoma State University Center for Health Sciences, who was studying a small collection of foot and leg bone fossils of what was believed to be a juvenile Anzu wyliei, which was described as a “chicken from hell” when it was discovered in 2014. But histology tests of the bones conducted at OSU-CHS determined that it wasn’t a juvenile, but a different species in the dinosaur family caenagnathid. The Oklahoma State University news release continues:
A small amount of radioactive uranium (238U and 235U gets included in zircon crystals (zirconium silicate (ZrSiO4)) which form in volcanic lava and ash. 238U has a half-life of about 4.5 billion years and 235U has a half-life of 700 million years. These both decay into stable isotopes of lead (206Pb and 207Pb, respectively), locked within the crystal lattice, which could not have been incorporated into zircon crystals any other way, and there is no mechanism by which it could leach out, so by measuring the amount of lead and the amount of uranium in the zircon crystals, the age of the zircon crystals and the volcanic rock they formed in, can be calculated.
The only way this dating method could be wrong to the extent that it makes 10,000 years look like tens of million years would be if the decay rates of 238U and 235U were so massively different that it would now take tens of million years for the same number of atoms of 238U and 235U to decay to lead as decayed in the previous 10,000 years, which would mean the weak and strong nuclear forces (the forces that bind the particles in an atomic nucleus together and so govern the half-life of radioactive isotopes) were so much weaker 10,000 years ago that atoms could not have existed when creationists believe the universe was magicked out of nothing, so stars, planets, minerals, rocks and life itself would not have been possible. The universe would consist of elementary particles and electromagnetic radiation and nothing else. Since that is manifestly not the case, we know that the half-lives of radioactive isotopes have not changed over time.
The age (\(t\)) of the sample can be calculated using the formula: \[ t = \frac{1}{\lambda} \ln\left(\frac{{\text{Pb}}_{\text{measured}}}{{\text{Pb}}_{\text{initial}} + 1}\right) \] In this formula, λ represents the decay constant of the (uranium) isotope and is calculated using the formula: \[ \lambda = \frac{\ln(2)}{T_{1/2}} \] where T1/2 is the half-life of the isotope.
For a young sample, the initial value of Pb is assumed to be 0, since there is no mechanism for incorporating lead into zircon crystals.
Atkins-Weltman named the new dinosaur Eoneophron infernalis, which translates to Pharaoh’s dawn chicken from hell. The name honors the description of the Anzu as well as his late beloved pet, a Nile monitor lizard named Pharaoh. Based on rough estimates, Eoneophron weighed around 150 to 160 pounds and stood about 3 feet tall at the hip, about the size of a human.More technical information is provided in the team's research paper in PLOS ONE:Atkins-Weltman’s paper on the new Eoneophron species was just published in the peer-reviewed journal PLOS ONE, released by the Public Library of Science. “Kyle is the first student researcher at OSU-CHS to reveal, describe and name a new dinosaur,” said associate professor of anatomy Eric Snively, Ph.D., and Atkins-Weltman’s faculty advisor. Atkins-Weltman said he never intended to find a new species, he was analyzing these foot and leg bone fossils to study the weight-bearing metatarsal, or toe, bones of the Anzu dinosaur. The fossils were found in the Hell Creek Formation that spans parts of Montana, Wyoming, and North and South Dakota and date back to the end of the Cretaceous period before dinosaurs went extinct. “They were about 25% smaller than other Anzu fossils. We figured it was a juvenile Anzu,” he said. “I assumed it was an Anzu until the evidence showed it wasn’t.” When it looked like the fossils may not belong to an Anzu, Atkins-Weltman turned to caenagnathid researchers Greg Funston, Ph.D., a paleontologist with the Royal Ontario Museum in Ontario, Canada, and paleontology Ph.D. candidate Jade Simons with the University of Toronto for their help and expertise. He also called on the help of OSU-CHS associate professor of anatomy Holly Woodward Ballard, Ph.D., whose own research utilizes paleohistology — the study of fossil bone microstructures. Through paleohistology techniques, they were able to determine that the foot and leg bones were not structurally those of a juvenile, but of a more mature specimen, meaning a new dinosaur species in the caenagnathid family. “It was really thrilling. Based on the work and research I do, I never thought I would be someone to discover a new dinosaur species,” he said.It was a very bird-like dinosaur. It had a toothless beak and relatively short tail. It’s hard to tell its diet because of the toothless beak. It definitely had feathers. It was covered in feathers and had wings.
Kyle L. Atkins-Weltman, lead author
School of Biomedical Sciences
Oklahoma State University, Tahlequah, OK, USA.
AbstractThe traditional way creationists cope with news of these finds from the long period of Earth's history that occurred before creationists believe it was created, is to squawk 'Dating methods are wrong!' like a trained parrot squawking to trigger words, but none of them are ever prepared to explain what exactly these flaws in the technique are, how they know better than the geochronologists and what fundamental forces could change to the extent that they can make tens or hundreds of millions of years look like 10,000 years or less, while still making the formation of atoms, and so of living organisms, possible.
Caenagnathidae is a clade of derived, Late Cretaceous oviraptorosaurian theropods from Asia and North America. Because their remains are rare and often fragmentary, caenagnathid diversity is poorly understood. Anzu wyliei is the only caenagnathid species currently described from the late Maastrichtian Hell Creek Formation of the USA and is also among the largest and most completely preserved North American caenagnathids. Smaller, less complete caenagnathid material has long been known from the Hell Creek Formation, but it is unclear whether these are juvenile representatives of Anzu or if they represent distinct, unnamed taxa. Here, we describe a relatively small caenagnathid hindlimb from the Hell Creek Formation, and conduct osteohistological analysis to assess its maturity. Histological data and morphological differences from Anzu wyliei and other caenagnathids allow us to conclude that this specimen represents a new species of caenagnathid from the Hell Creek Formation, with a smaller adult body size than Anzu. This new taxon is also distinct from other small caenagnathid material previously described from the area, potentially indicating the coexistence of three distinct caenagnathid species in the Hell Creek Formation. These results show that caenagnathid diversity in the Hell Creek ecosystem has been underestimated.
Introduction
Oviraptorosauria was a clade of maniraptoran theropods characterized by a foreshortened rostrum, often bearing an edentulous beak, and highly pneumatic skeletons, a combination that easily distinguishes them from other theropod groups [1]. Oviraptorosaurs are known from well-preserved fossils, primarily from Asia, that have yielded insight into the biology, morphology, diversity, and evolutionary history of this peculiar group of theropods [1–19]. The earliest certain oviraptorosaurs are known from the Barremian stage of the Early Cretaceous, between 125–129 million years ago [20,21], although links have recently been drawn with the unusual scansoriopterygids [13] and Ornitholestes [13], potentially reconciling a gap that extends into the Jurassic between their presumed divergence from other coelurosaurs and their earliest appearances. The Late Cretaceous record of oviraptorosaurs is excellent, and it is clear that they persisted until the K-Pg extinction event in Laurasia [12].
[…]
Here we describe the morphology and osteohistology of a new, partial caenagnathid hindlimb intermediate in size between known specimens from the Hell Creek Formation. Building on recent work [46,51,52], we anticipated that this specimen might provide an opportunity to assess growth across ontogeny in Anzu wyliei. Surprisingly, our morphological and histological results indicate that the specimen does not represent a juvenile Anzu wyliei, but a morphologically-distinct adult individual approaching asymptotic body size, representing a new taxon. This prompted a reevaluation of the diversity of caenagnathids in the Hell Creek Formation, which has ramifications for the diversity of oviraptorosaurs prior to the end-Cretaceous extinction.
Fig 1. Left femur of CM 96523.
A) Anterior view, showing connections between the three fragments as presently preserved. The distal two fragments were initially united before palaeohistological sampling. B) interpretive illustration of femur; C) lateral view, D) posterior view, E) medial view, F) proximal view, and G) distal view. Abbreviations: af, adductor fossa; at, anterior trochanter; atr, accessory trochanteric ridge; ctf, crista tibiofibularis; ect, ectocondylar tuber; fc, fovea capitis, gt, greater trochanter; mc, medial condyle; pf, popliteal fossa; tc, tibial condyle. Scale bar = 2 cm.
Fig 2. Right tibia and astragalocalcaneum of Eoneophron infernalis.
In A) Anterior, B) Posterior, C) Lateral, D) Medial, E) Proximal, and F) Distal views. Abbreviations: ap, ascending process; cal, calcaneum; cc, cnemial crest; fc, fibular crest; tu?, tubercle? Scale bar = 10cm.
Fig 3. Coossification of hindlimb elements in Eoneophron infernalis.
A) Tibiotarsus in medial view, showing coossification of the astragalocalcaneum and tibia (arrow). B) Interpretive illustration of (A). C) Distal tarsal IV and proximal end of Metatarsal IV in anterior view, showing fusion of the distal tarsal to the proximal metatarsal (arrow). D) interpretive illustration of (C). E) Distal tarsal IV and Metatarsal IV in proximal view, showing fusion of the elements (arrow). F) Interpretive illustration of (E). Abbreviations: ast, astragalus; dt IV, distal tarsal IV; mt IV, Metatarsal IV; tib, tibia.
Fig 4. Right Metatarsal III of CM 96523.
In A) Anterior, B) Posterior, C) Posterior (cruciate ridges highlighted), D) Lateral, E) Medial, F) Proximal, and G) Distal views. Cruciate ridges highlighted in white where visible. Abbreviations: clp, collateral ligament pit; cps, concave posterior surface; cr, cruciate ridges; mtII, articular surface for Metatarsal II; mt IV, articular surface for Metatarsal IV. Scale bar = 5cm.
Fig 5. Right Metatarsal IV of Eoneophron infernalis.
In A) Anterior, B) Posterior, C) Lateral, D) Medial, E) Proximal, and F) Distal views. Abbreviations: clp, collateral ligament pit; dtIV, distal tarsal IV; gls, M. gastrocnemius pars lateralis insertion scar; lr, longitudinal ridge; mtIII, articular surface for Metatarsal III; pmdp, broken base of proximodistal process; su, suture between distal tarsal IV and mt IV; tas, M tibialis anterior insertion scar. Scale bar = 5cm.Fig 6. Osteological thin-section of the femur of Eoneophron infernalis in plain polarized light.
A) Reconstructed cross section of femur with lines of arrested growth [LAGs] traced in light blue; B) Close up of cross section with black arrows denoting lines of arrested growth [LAGs]. Note the change in vascularity from the inner to outer cortex. Scale bar = 1000μm.Fig 7. Osteological thin section of right tibia of Eoneophron infernalis in plain polarized light.
A) Reconstructed cross section of tibia with lines of arrested growth [LAGs] traced in light blue; B) Close up of cross section with black arrows denoting lines of arrested growth [LAGs]. Note the change in vascularity from the inner to outer cortex. Scale bar = 1000μm.Fig 8. Osteological thin section of right Metatarsal IV of Eoneophron infernalis in plain polarized light.
A) Cross section of Metatarsal IV with lines of arrested growth [LAGs] traced in light blue, with area missing due to modeling or medullary cavity expansion in red, and putative neonatal line in purple B) Close up of posterior side where CCCB, a possible neonatal line (purple arrows), and six LAGs are observed (blue arrows). Imaged in plane polarized light on the left, circularly polarized light on the right. Note the change in vascularity from the inner to outer cortex. Scale bar = 1000μm.
Atkins-Weltman KL, Simon DJ, Woodward HN, Funston GF, Snively E (2024)
A new oviraptorosaur (Dinosauria: Theropoda) from the end-Maastrichtian Hell Creek Formation of North America.
PLoS ONE 19(1): e0294901. https://doi.org/10.1371/journal.pone.0294901
Copyright: © 2024 The authors.
Published by PLoS. Open access
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
I doubt very much that the discovery of a 67 million-year-old fossil of a parrot-like dinosaur will produce anything better by way of refutation of the science.
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