Rosa Rubicondior: Refuting Creationism - Reassessing The 'Bite Marks' on 66-Million-Year-Old Dinosaur Fossils

Tooth traces on ulna HRS10076.

A) Ulna with black boxes indicating areas with tooth traces. B-C) Magnification of corresponding boxes from Fig 7A. White arrows indicate pits and red arrows indicate parallel scores.

C. T. Siviero B, et al (2026)

Study finds marks in fossilized dinosaur bones may not always be bite marks | News

Last month produced the usual crop of research papers which, quite incidentally, refuted creationism simply by revealing evidence utterly incompatible with its basic dogmas. It also produced another answer to a favourite creationist conspiracy theory: that scientists are not permitted to publish anything that challenges the supposedly ‘materialist orthodoxy’ of the scientific establishment.

This allegation confuses philosophical materialism with methodological naturalism. Science confines itself to explanations that can be tested against evidence. That is a working method, not a compulsory metaphysical belief. Findings that challenge established interpretations are not prohibited; provided they are supported by evidence and survive critical scrutiny, they are an essential part of the way science advances.

Literalist creationism works in the opposite direction. It begins with the non-negotiable conclusion that scripture must be inerrant, so any contrary evidence must be denied, explained away or forced into conformity with that predetermined belief. Changing one’s mind in response to evidence is therefore treated not as intellectual honesty but as a failure of faith.

Creationists consequently try to have it both ways. When scientists agree, this is presented as evidence of a conspiracy suppressing dissent; when scientists challenge or refine an earlier interpretation, it supposedly proves that scientists are always changing their minds and that science is therefore unreliable. It is a convenient rhetorical trick in which both consistency and self-correction are declared to be evidence against science.

A modest but revealing example is a study published recently in PLOS ONE by researchers from Loma Linda University, Western University of Health Sciences, The Master’s University, Southern Adventist University and Southwestern Adventist University. Four of those five institutions are explicitly Christian: Loma Linda, Southern Adventist and Southwestern Adventist are Seventh-day Adventist universities, while The Master’s University declares a commitment to Christ and ‘biblical fidelity’. So much for the supposed exclusion of religious scientists from mainstream scientific publication.

The paper itself is not creationist research: it employs standard palaeontological methods and places the fossils within the conventional Maastrichtian stage of the Late Cretaceous. What it does show is that evidence-based research can be published and scrutinised irrespective of the religious affiliations of the institutions involved.

The researchers examined 3,013 dinosaur bones, most belonging to Edmontosaurus annectens, excavated between 1997 and 2017 from the Hanson Ranch Station bonebed in the Lance Formation of eastern Wyoming. Thirteen bones initially displayed perforations or other features that resembled tooth traces. Closer examination—including microscopy, comparison with other fossils and, in an ambiguous case, CT scanning—showed that one specimen contained normal openings in the bone, or foramina, rather than bite marks. The remaining 12 bones, just under 0.4 per cent of the total examined, preserved genuine tooth traces.

Four of those bones carried particularly diagnostic traces known as Knethichnus parallelum and Linichnus serratus. By comparing the spacing of the preserved striations and serrations with the denticles on carnivorous dinosaur teeth recovered from the same bonebed, the researchers identified Tyrannosaurus rex as the most likely culprit. Other, less diagnostic marks may have been produced by crocodilians living in the same ecosystem.

Most of the tooth traces showed no associated bone remodelling, suggesting that they were inflicted at or after the time of death. The evidence therefore points more strongly towards scavenging than successful predation, although the two cannot always be distinguished. Weathering, bioerosion and characteristic fractures in fresh bone also indicate that the carcasses remained exposed for some time before burial and were probably exploited by theropods, crocodilians or both.

The wider importance of the study lies in showing how easily natural foramina, disease-related lesions, infection channels, bone necrosis, bioerosion and other alterations can resemble tooth marks when they are considered without sufficient anatomical and taphonomic context. The researchers consequently refined the criteria used to identify fossil tooth traces and produced a guide that can be applied to other fossil assemblages. This should lead to more reliable reconstructions of feeding behaviour, scavenging and predator–prey relationships in extinct ecosystems.

No major palaeontological conclusion has been overturned here: T. rex really did bite some of these animals. Instead, an interpretation has been tested, qualified and made more precise. That is not evidence that science is unreliable; it is evidence that science possesses a mechanism for detecting possible errors and improving its explanations.

Creationists will doubtless ignore the fossils’ Late Cretaceous origin, tens of millions of years before their mythical ‘Creation Week’, and concentrate instead on the fact that scientists have refined their criteria. The Bible’s supposed ‘inerrant truth’, by contrast, remains eternally unchanged only because no contrary evidence is ever permitted to count against it. That is not reliability. It is immunity from testing.

The Hanson Ranch Station Bonebed. The Hanson Ranch, or Hanson Ranch Station, Bonebed lies in the Lance Formation of northeastern Wyoming, on the eastern side of the Powder River Basin. The Lance Formation dates from the latest Cretaceous, during the late Maastrichtian, approximately 69–66 million years ago. It records river, floodplain and deltaic environments that existed near the western margin of the retreating Western Interior Seaway.

The bonebed is overwhelmingly dominated by the large herbivorous hadrosaur Edmontosaurus annectens, one of the last non-avian dinosaurs to inhabit North America. It is described as monodominant rather than monospecific because, although Edmontosaurus accounts for about 94 per cent of identifiable material from the principal quarries, fossils of many other animals are also present.

These include ceratopsians, pachycephalosaurs, armoured dinosaurs and small ornithischians, together with tyrannosaurids, dromaeosaurids and troodontids. Crocodilians, turtles, gars and other fish, molluscs, lizards, mammals and possible birds are also represented. Many of the carnivorous dinosaurs are known principally from teeth shed while feeding or scavenging.

Excavation began in the mid-1990s and intensified from 2000 onwards. By the end of the 2016 field season, five principal quarries and three exploratory quarries had exposed about 508 square metres of the deposit and produced more than 13,600 catalogued elements. These included approximately 8,460 identifiable Edmontosaurus bones, as well as teeth, ossified tendons and unidentifiable fragments.

The figure of more than 13,000 elements does not mean that 13,000 dinosaurs are represented. Counting the most abundant left-sided skeletal element gave a conservative minimum of 61 individual Edmontosaurus. The animals were predominantly subadults and adults, with very young individuals conspicuously scarce. This may indicate that Edmontosaurus lived in age-segregated herds.

The fossils occur in a grey claystone-to-siltstone layer approximately one to two metres thick. It is a normally graded deposit: large bones tend to occur near the bottom, while progressively smaller elements are found higher in the bed. Almost all the skeletons had become disarticulated before burial, with fewer than 0.1 per cent of the bones retaining any anatomical connection.

Despite their disarticulation, about 97 per cent of the examined bones showed little or no abrasion and 98.5 per cent showed no significant weathering. This combination suggests that the carcasses remained exposed for long enough—probably weeks or months—for decay and scavenging to separate the skeletons, but not for the bones to undergo prolonged weathering. Their excellent preservation also suggests that they were transported within a thick, sediment-rich flow that protected them from repeated impacts.

The researchers therefore proposed that a large group of Edmontosaurus died during a local mass-mortality event, possibly involving drowning. The carcasses accumulated and decomposed in or near water, where scavengers fed on them. A later flood, sediment collapse or seismic disturbance then remobilised the disarticulated bones in a cohesive, probably subaqueous debris flow and deposited them in their present graded layer. The precise cause of the animals’ deaths remains uncertain, and the proposed seismic trigger for the debris flow is an interpretation rather than an established fact.

The 2026 tooth-trace study examined 3,013 bones from the North and South quarries, rather than the entire Hanson Ranch collection. Only 12 contained convincing tooth traces—just under 0.4 per cent of the sample. Four preserved diagnostic marks attributable to Tyrannosaurus rex, while some of the less distinctive traces may have been produced by crocodilians.

The site is scientifically valuable because its enormous sample permits researchers to investigate herd composition, decomposition, scavenging, hydraulic sorting and the biases that determine which parts of a skeleton enter the fossil record. It also illustrates that a “catastrophic” fossil deposit need signify only a rapid, local event. The Hanson Ranch fossils record death and exposure followed by decay, disarticulation, remobilisation and eventual burial within an ordered succession of Late Cretaceous sediments—not a single, recent global flood.

The paper in PLOS ONE was accompanied by a news item from Loma Linda University Health:

Study finds marks in fossilized dinosaur bones may not always be bite marks
Marks in fossilized dinosaur bones may have several causes ranging from pre-mortem natural causes to postmortem alterations, including bite marks, according to a new study.

Excavation of dinosaur fossil bones from a bonebed of the Upper Cretaceous Lance Formation near Lance Creek, Wyoming.
Photo by Bethania C. T. Siveiero.

Researchers said the study of marks on fossil bones is important because it provides valuable insights into animal living conditions, diseases, behavior and interactions between species.
Distinguishing between these different types of bone modifications is essential, as they can provide valuable information about an animal’s condition before death as well as the processes that affected its remains after death. Figuring out what caused holes and other marks on fossil bones is not always easy. Context is important. Many are labeled as bite marks, even though they may have other causes, leading to mistaken conclusions about the behavior of extinct animals.

Assistant Professor Dr. Bethania C. T. Siviero, PhD, lead author.
Department of Pathology and Human Anatomy
Loma Linda University
Loma Linda, California, USA.

Researchers published their findings last week in a manuscript titled Identification of Tooth Traces from a Cretaceous (Maastrichtian) Edmontosaurus annectens Bonebed in the Lance Formation, Wyoming, U.S.A. The study, by C. T. Siviero and colleagues, appeared in PLOS One Journal.

The team studied more than 3,000 dinosaur bones, with only less than 0.4% showing clear evidence of bite marks. The size, shape, and spacing of some of these marks closely match the teeth of Tyrannosaurus rex, making it the most likely animal to have left them, although some of the other bones analyzed may have been marked by other animals living at the same time, such as crocodiles, Siviero said.

Most of the bitten bones show no signs of healing, indicating that the bites were made either around the time the animals died or after they were already dead. Other evidence, including surface alterations by weathering, and damage caused by other organisms, suggests that the carcasses remained exposed on the landscape for some time before they were buried, Siviero said.

As a result of this study, the authors’ revised and refined the criteria for the identification of bite marks on fossil bones considering also other types of holes that could potentially be mistaken by bite marks.

The team examined bones that had been excavated from a bone bed in Wyoming from 1997 to 2017. The bones are now stored at Southwestern Adventist University in Keene, Texas.

Publication:
C. T. Siviero B, Rega E, McLain MA, Brand LR, Nelsen D, Chadwick AV (2026)
Identification of tooth traces from a Cretaceous (Maastrichtian) Edmontosaurus annectens bonebed in the Lance Formation, Wyoming, U.S.A.
PLoS One 21(7): e0351939. https://doi.org/10.1371/journal.pone.0351939

Abstract
Identifying the origin of perforating lesions on fossil bone is often difficult, and many are considered tooth traces, in spite of more likely and more parsimonious etiologies. Much of this confusion stems from tooth trace criteria that are ambiguous when the context for the lesions is not considered. Mistaken identification of tooth traces has led to misleading interpretations of animal behavior. This study of tooth traces on fossil bones critically reviews previous criteria and applies them to assessing bones from an Edmontosaurus annectens bonebed within the Lance Formation, Wyoming, USA. Of the 3013 bones examined, thirteen bones had features indicative of tooth traces based on gross appearance. Of these, one bone had perforations determined to have a different etiology. Twelve bones had traces attributed to tooth marks, including four bones with Knethichnus parallelum and Linichnus serratus ichnotaxa. Tyrannosaurus rex was identified as the likely inflictor of traces attributable to both ichnotaxa, by comparison of denticle density of carnivore teeth within the bonebed with striation/serration density of the traces. The importance of context in the analysis of perforating lesions on fossil bones is shown through the mistaken identification of features such as neurovasculature foramina and lesions associated with pathology as tooth traces. This study contributes to the literature on biting behavior and refines the criteria used to identify perforations caused by bite marks. The application of these refined criteria also proved useful in accurately identifying tooth traces on bone. This, in turn, enhances the guidelines for recognizing perforations as tooth traces and encourages further research on this topic.

Fig 1. Bone perforation on surangular HRS05499.

A) Lateral view of surangular. B) Medial view of surangular. Red arrows indicate different bone perforations and blue arrow indicates a different type of perforation. C) Comparison of bone perforations alignment and spacing of surangular with the tooth alignment and spacing of a modern crocodile maxilla.

Fig 2. CT scanning of surangular HRS05499.

A-H) Sequential images in coronal view (due to crossing angle of perforations). Numbers indicating the perforations correspond to Fig 1A and 1B. Red arrows indicate perforations continuing deep into the bone. I) Rostral view of bone. Blue arrow corresponding to blue arrow on Fig 1B, indicates different types of perforation on which several of the smaller ones (red arrows) connect.

Fig 3. Tooth trace types on rib specimens.

A) Prominent furrow tooth trace on rib fragment HRS09477. B) Two puncture traces on rib fragment HRS09477 indicated by arrows on the opposing side of a furrow on Fig 3A. C) Magnified image of the puncture on HRS09477 indicated by arrow 2 on Fig 3B, indicating the pull and drag from the bite. D) Rib fragment HRS03161 with puncture and associated drag from the bite. E) Rib fragment HRS09551 with parallel scores. F) Rib HRS03387 with prominent scores and associated tooth trace ichnotaxon Knethichnus parallelum. G) Magnification of area indicated by the white box on Fig 3F featuring prominent and detailed parallel Knethichnus parallelum traces. H) Rib HRS09954 with a long score trace indicated by the arrow.

Fig 4. Tooth trace types on neural spine fragments.

A) Punctures on opposing surfaces in neural spine HRS01295. The image only depicts one of the punctures indicated by the white box. An arrow indicates the location of the other puncture not visible in the image. B) A magnified view of the puncture within the white box area on Fig 4A. C) A view of the puncture opposing the puncture on Fig 4B and indicated by arrow on Fig 4A. D) Neural spine fragment HRS03650 with a score indicated by an arrow. E) A view of the opposing surface from HRS03650 (Fig 4D) shows a deep and curved score with associated tooth trace ichnotaxon Linichnus serratus.

Fig 5. Tooth trace types on caudal vertebrae.

A) Distal caudal vertebra HRS00428 (from middle-distal region of tail) with the distal end of the neural spine missing. Note bone proliferation on the distal neural spine. B) HRS00428 with curved scores on the neural spine associated with the tooth trace ichnotaxon Linichnus serratus. C) Magnification of the scores from the white box on Fig 5B depicting details of the prominent Linichnus serratus traces. D) Neural spine HRS09830 from a caudal vertebra (middle-distal region of tail) with scores within the white box area. E) Magnification of the scores associated with the white box from Fig 5D. F) Distal caudal vertebra HRS00473 with arrows indicating tooth traces on the centrum. G) Score on HRS00473 associated with arrow “G” on Fig 5F. Note another score closer to the junction of the centrum with the neural spine. H) Puncture on the centrum HRS00473 associated with arrow “H” on Fig 5F.

Fig 6. Tooth traces on radius HRS13582.

A) Radius with several scores indicated by white boxes and corresponding letters. B) Magnification of white box B depicting score with also associated ichnotaxon for Knethichnus parallelum. C) Magnification of white box C depicting parallel scores. D-F) Magnification of associated white boxes from Fig 6A with deep scores for tooth traces and associated ichnotaxon Linichnus serratus with serrations especially clear with associated score in Fig 6D.

Fig 7. Tooth traces on ulna HRS10076.

A) Ulna with black boxes indicating areas with tooth traces. B-C) Magnification of corresponding boxes from Fig 7A. White arrows indicate pits and red arrows indicate parallel scores.

Fig 8. Striation density associated with scores of ichnotaxon Knethichnus parallelum.

A) Scores on rib HRS03387 with striation density of three per 2 mm. B) Score on radius HRS13582 with striation density of three per 2 mm.

C. T. Siviero B, Rega E, McLain MA, Brand LR, Nelsen D, Chadwick AV (2026)
Identification of tooth traces from a Cretaceous (Maastrichtian) Edmontosaurus annectens bonebed in the Lance Formation, Wyoming, U.S.A.
PLoS One 21(7): e0351939. https://doi.org/10.1371/journal.pone.0351939

Copyright: © 2026 The authors.
Published by PLoS. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

In the end, this study neither banishes Tyrannosaurus rex from the Hanson Ranch story nor overturns the evidence that it fed upon Edmontosaurus. On the contrary, it confirms genuine tooth traces on 12 bones and identifies T. rex as the probable maker of the most diagnostic examples. What it removes is unwarranted certainty: not every hole, groove or depression in a fossil bone was necessarily made by a predator.

That is how science improves. Researchers test earlier interpretations, identify possible sources of error and develop better criteria with which to distinguish competing explanations. The result is not weaker knowledge but greater precision—fewer questionable bite marks, stronger evidence for the genuine ones and a more reliable reconstruction of what happened to these animals before burial.

Meanwhile, the Hanson Ranch Bonebed itself remains another substantial problem for creationism. It records a population of dinosaurs living during the Late Cretaceous, some 66–69 million years ago. Their carcasses lay exposed for long enough to decay, become almost completely disarticulated and attract scavengers before their bones were transported and buried in a later, local sediment flow. This is a sequence of biological and geological events preserved within an ordered stratigraphic succession, not an indiscriminate jumble produced by a recent global flood.

Nor does the paper sit comfortably with claims that a militantly atheistic scientific establishment excludes religious researchers. Four of the five participating institutions are explicitly Christian, yet their work was published in a mainstream peer-reviewed journal because it employed testable methods and presented evidence that other researchers could examine. Religious affiliation was no barrier; replacing evidence with supernatural assertion would have been.

Creationists may nevertheless present this refinement as another occasion on which scientists have “changed their minds”. Yet the ability to correct an interpretation is one of science’s greatest strengths. Creationism offers the appearance of certainty only because its central conclusion is protected from every possible test: conflicting evidence must always be rejected, reinterpreted or blamed upon a conspiracy.

Science changes its mind when the evidence requires it; creationism merely changes the subject. An explanation that survives repeated testing and correction earns confidence. A belief that survives only because nothing is permitted to count against it has earned nothing at all.

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