T. rex endangered species

Tyrannosaurus rex: An endangered species

Thomas D. Carr

Article number: 28.1.a16
https://doi.org/10.26879/1337
Copyright Society of Vertebrate Paleontology, April 2025

Author biography
Plain-language and multi-lingual abstracts
PDF version

Submission: 9 September 2023. Acceptance: 26 March 2025.

ABSTRACT

Most fossils of Tyrannosaurus rex are commercially or privately owned. The market has depleted the scientific record of T. rex because vertebrate fossils that are not in public trusts are unavailable for scientific study. This ethical principle protects the integrity of vertebrate paleontology as a science by ensuring replicability and testability of observations. Unfortunately, scientists regularly publish on privately owned T. rex fossils. The goal of this study is to quantify the market’s impact upon the sample size of T. rex. The data are from the primary literature, museum records, mainstream media, personal observation, and anecdote; specimens range from individual bones and teeth to nearly complete skeletons. There are 61 T. rex fossils in public trusts, whereas 71 are privately held. The rate of discovery of T. rex fossils made by commercial companies is twice as high as that of museums, and exploitation is heaviest in Montana and South Dakota. Of particular concern is the private ownership of juvenile and subadult specimens, the part of growth that is least understood, which make up 20% of privately held T. rex. The purchase of show-stopping fossils is problematic because T. rex skeletons command top dollar, from $1.55 million to $38.68 million USD, preventing most museums from acquiring the fossils. Only 11% of commercially collected T. rex fossils are in public trusts. The sample size of T. rex would be more than doubled (from 61 to 141) if it weren’t for profit-driven commercial interests on private lands in the American West.

Thomas D. Carr. Department of Biology, Carthage College, 2001 Alford Park Drive, Kenosha, Wisconsin, 53140. tcarr@carthage.edu.

Keywords: Tyrannosaurus; commercial; private; public; ownership; ethics

Final citation: Carr, Thomas D. 2025. Tyrannosaurus rex: An endangered species. Palaeontologia Electronica, 28(1):a16.
https://doi.org/10.26879/1337
palaeo-electronica.org/content/2025/5499-t-rex-endangered-species

Copyright: April 2025 Society of Vertebrate Paleontology.
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
creativecommons.org/licenses/by/4.0

INTRODUCTION

The Problem

Vertebrate paleontology is at a point in history where it is faced with a society that considers it acceptable to sell rare nonrenewable fossil resources as luxury items, including skulls and skeletons of Tyrannosaurus rex (Keaten, 2023a). A high cultural status (=esteem sensu Chippindale and Gill, 2000) combined with the legal sale of fossils collected from private lands in the American West has made T. rex a lucrative target for commercial interests and a desirable object d’art for private collectors. The problem of the commercialization of fossils has increased since Shimada et al. (2014) identified the market as one of the three greatest challenges to paleontology in the twenty-first century. Since fossils are the data, they belong in public trusts where all paleontologists have access (Shimada et al. 2014). The authors identified public misinformation about the problem of the commercial market and the lack of recognition of the problem among paleontologists as additional reasons for alarm (Shimada et al. 2014). Among fossils, dinosaurs are relatively rare and so the effect of sales to private individuals can decimate the sample size for a given species. As for living species, a substantial sample size of a fossil species is required to recover a statistically significant biological signal; for example, it is estimated that a sample size of 70 to 100 specimens of adult nonavian dinosaurs are required to statistically detect sexual dimorphism in a species with a high degree of dimorphism (Kościński and Pietraszewski, 2004; Hone and Mallon, 2017). However, most dinosaurs are known from a mere handful of specimens or only one fossil (Weishampel et al. 2004) and so maximizing sample size is a scientific priority.

The sale of T. rex fossils, in particular, results in data lost regarding the range of variation at all growth stages, stratigraphic position, taphonomy, and geological context. In recent years, new techniques and technologies have been used to rigorously investigate these areas of study (Currie, 2023); the loss of fossils and their locality information to the market deprives the science of advances that could be brought to bear on, and from, new fossils. The loss of dinosaur fossils has cascading effects up the chain of functional and ecological inferences that are drawn above the specimen level (Witmer, 1995). For a secure scientific footing, vertebrate paleontologists should be working with sample sizes that approximate the variation seen in a natural population. The fossil market works against this because it reduces the sample size that scientists ought to work with. The commodification of dinosaur fossils is an example of the collision between the social values of science, education, heritage, and history on the one hand, and commercial values on the other (Santucci et al. 2016). Often the non-commercial values are appropriated to enhance the market value of fossils (Roddy, 2022); in the end, the scientific enterprise experiences a substantial and measurable data loss to multimillion-dollar auctions.

At the heart of the issue are the principles that safeguard replication of scientific observations of vertebrate fossils, the most important of which is repository status. It is generally understood that a public repository is the institutional requirement for the storage and safekeeping of fossils far into the future. It has been argued that privately owned fossils should be studied and published on and if this bothers anyone, then the “simple, non-bureaucratic solution for dealing with scientific conclusions that cannot be reproduced or data that cannot be accessed - one can simply place less confidence in those conclusions” (Saitta, 2020, p. 7). This argument proposes the worst of all possible outcomes by opening the door to a future where we can have no confidence in results if the data (the fossils) are inaccessible for further study. The repository status of fossils is central to the legitimacy of vertebrate paleontology, and the goal here is to use T. rex to assess the threat to science that the commercial trade poses.

Dinosaur Fossils Have Become an Art Auction Staple

The loss of T. rex fossils is only one example of the larger problem of the surging luxury fossil market (Shimada et al. 2014; Demeulemeester and Stein, 2022; Roddy, 2022). In recent years, several high-profile international auctions have sold dinosaur skeletons as decorative art (Schultz, 2020; Robaglia, 2022; Keaten, 2023b). In addition to T. rex, the auction houses have sold skeletons of Triceratops, Diplodocus, Allosaurus, Albertosaurus libratus, Stegosaurus, and the extremely rare and bird-like Deinonychus (Goldstein, 2022; Robaglia, 2022). The high monetary value of dinosaur fossils is reinforced by previous auctions, and this should be expected to continue (Fourcade, 2011 cited in Jones, 2020; Cascone, 2024). The commodification of dinosaur fossils is enhanced by the art world that promotes them as exclusive decorative art (Christie’s, 2020), and the noncritical interest in the fossil trade - and fossil collectors - that is taken by journalists and commentators (Hippensteel and Condliffe, 2013; Conniff, 2019; Gross, 2020). These messages drown out the scientific perspective, unless journalists are aware of the problems that the fossil trade presents for science, and reach out to paleontologists for comment (Barras, 2019; Geggel, 2022). The reaction on the scientific side is also represented by the press releases issued by the Society of Vertebrate Paleontology (SVP) that in some cases has called on auction houses to limit their sales to public trusts, to no avail (SVP, 2020). Although the issue of the commercial trade in vertebrate fossils is not limited to the United States (e.g., Cisneros et al. 2022), the T. rex example is representative of how the market efficiently chisels away at the sample size of important fossil species.

The claims made by Shimada et al. (2014) about the negative effect of the commercial trade upon vertebrate paleontology, and the counterclaims made by commercial collectors (Larson N.L., 2008; Larson N.L. et al. 2014; Larson, P.L. and Russell, 2014; Larson, P.L., 2023) are recounted here in order to assess them as testable hypotheses in light of a comparison between the number of T. rex fossils in public trusts and those in commercial or private hands.

The Claims Made by Shimada et al. (2014)

Shimada et al. (2014) describe three testable claims about the effect of the commercial fossil market upon paleontology:

1. Sales of fossils have increased, especially online. Sales can be quantified by counting the number of fossils collected and sold per year.

2. Fossils that are sold in high-profile auctions are not purchased by public trusts. The outcome of auctions can be quantified through news reports.

3. The sale of fossils results in a decline in collections-based research (=commercialization of fossils hurts the science of paleontology). This can be quantified by counting and comparing the number of fossils that are unavailable (privately owned) and available (in public trust) to scientists.

Testable Claims Made by Commercial Interests

In contrast to Shimada et al. (2014), commercial collectors (Larson N.L., 2008; Larson N.L. et al. 2014; Larson, P.L. and Russell, 2014; Larson, P.L., 2023) and some scientists (Haug et al. 2020) have published testable claims that science benefits from the commercialization of fossils:

1. More fossils are discovered in a shorter time frame (Larson N.L., 2008; Larson, P.L. and Russell, 2014). This can be tested by comparing the rate of collection between public trusts and commercial enterprises. Implicit in this claim is that commercially collected fossils are rescued from erosion (Larson, P.L. and Russell, 2014), which is made explicit in Larson N.L. et al. (2014, p. 7), “There are untold numbers of fossils lost to the elements...every year.” However, the logical fallacy of this claim is that this abundance of fossils will not necessarily be reposited in a public trust.

2. Some commercially obtained fossils are intensely scientifically studied (Larson, P.L. and Russell, 2014). This claim falls under the purview of scientific best practices; as set out by the SVP, privately owned fossils should not enter the scientific literature. However, several privately owned T. rex fossils have been published in peer-reviewed journals, and that issue is quantified and discussed below. However, since this practice contravenes best practices, it is not a valid argument for fossil commodification.

3. The most significant fossil discoveries have ended up in museums (Larson, P.L. and Russell, 2014). This can be tested by simply comparing the number of commercially collected fossils that are reposited in public trusts with those that are not. This claim is a primary focus of this work.

A similar argument is that “...fossil collections...are often eventually donated to their local museum” (Larson, P.L. and Russell, 2014, p. 5; Stein, 2019) or private collections are often sold museums (Larson N.L. et al. 2014), which is testable through counts of specimens, where they were reposited historically, and where they are currently reposited (i.e., their provenance; see definitions below).

4. “Many [private collectors] readily donate specimens...to research programs” (Larson, P.L. and Russell, 2014, p. 5). Haug et al. (2020) make a similar claim about amateur collectors, and they describe a positive culture of co-operation between amateur and professional paleontologists in Europe that is prevented in the USA by the market in dinosaur fossils. However, this claim is relevant only if “donate” means that the ownership of a specimen is transferred in perpetuity from a private collector to a public trust. This is a testable hypothesis that is investigated here.

5. There should be “regulated amateur and commercial collecting be allowed on public lands” (Larson, P.L. and Russell, 2014, p. 5). This claim can be assessed by the standard of where the fossils are reposited, which must be consistent with the repository conditions of the Code of Federal Regulations (Section 49; eCFAR, 2025). Haug et al. (2020) make a similar claim about the scientific benefits of legally unimpeded access to fossil-bearing deposits to amateur collectors. It is difficult to envision such benefits in the American West where the financial incentives for commercial exploitation are so high. This line of argument is assessed here based on the repository criterion.

6. Commercial collecting dates back to the 1700s, which justifies current practice (Larson N.L. et al. 2014; Winters, 2014). Historically this may be true, but times have changed, where multimillion-dollar and high-profile auctions have priced public trusts out of obtaining scientifically significant specimens. This claim implies that the practices and market of the eighteenth century are unchanged to the present day, and, by inference, modern commercial practice is benign. Larson N.L. et al. (2014) make a series of similar claims that are based on the assumption of historical continuity: museums and universities are in the habit of buying fossils, from the 1600s to the present; purchased fossils are central to many of those collections; commercially supplied fossils have become type specimens; and commercial collectors have found most T. rex specimens. This continuity claim is testable, and it is pursued here.

7. “...concerns about fossil commerce are predominantly a North American attitude” and “free enterprise...does not conflict with the science of paleontology (Larson N.L. et al. 2014, p. 3). “Indeed, fossil commerce enhances paleontological research [by working with an] institutional paleontologist” (Larson N.L. et al. 2014, p. 7). These claims avoid the main concern dealt with here, specifically the actual impact of commercial activities on the sample size of rare fossil species. Whether or not attitudes are regional is irrelevant to the material effect of commercialization upon the science. Regardless, this claim can be quantified by comparing the number of commercially collected T. rex in public trusts with the number that aren’t.

8. Paleontology is an outlier among the sciences for having an issue with commercial collectors (Larson N.L. et al. 2014). Whether or not that claim is true, the goal of this work is to assess whether there is rational ground for the conflict by comparing the repository status principle with the actual number of fossils lost to commercialization. Likewise, the related claims of “Our work does not undermine collections-based research...our efforts enhance and supplement academic endeavors” (Larson N.L. et al, 2014, p. 5) are tested by the same approach.

9. Commercial collectors abide by the principles of the Association of Applied Paleontological Sciences (AAPS, 2025a; Larson N.L. et al. 2014, p. 5). Of note are these two principles: “5. Report to the proper local authorities any significant discoveries of scientific or public interest.” and “6. Strive to place specimens of unique scientific interest into responsible hands for study, research and preservation”. It is the intent of this work to test whether these happen in practice.

10. “There is an unfortunate misperception...that commercial collectors are only out for money and have little interest in science” and “...high price fossils are the exception, not the rule” (Larson N.L. et al, 2014, p. 6). The recent high-profile and multimillion dollar auctions are relevant to the issue of commercialization and its interaction with the fine art world are examined here.

Goals

The goal of this article is to present a case study of the impact of the fossil market on the sample size of one species of dinosaur, namely T. rex. Aside from headline-grabbing auctions, the actual number of fossils lost to the market is something not usually documented in literature or in books on the topic (Shimada et al. 2014; Demeulemeester and Stein, 2022). In agreement with Roddy (2022) the unregulated collection and sale of dinosaur fossils from private land harms science because money is valued more than science, and the market is too expensive for museums to compete. Therefore, it is important to quantify the material harm (i.e., effect upon sample size) done to science by commercial interests.

The main goal of this work is to estimate the effect of the commercial trade of T. rex fossils upon science by counting and comparing the number of specimens collected by commercial outfits with those of public trusts. There are two secondary goals: (1) test the claim that the commercial trade facilitates the scientific study of T. rex (Larson N.L., 2008) and (2) quantify the frequency of privately-owned T. rex specimens that have been published in scientific literature. This case study does not discuss the illicit fossil trade (e.g., Raja and Dunne, 2023) as far as the published and unpublished record shows, the T. rex fossils documented here were collected within the limits of United States law, although legal disputes over ownership or compensation between landowners and commercial companies do arise with some regularity (Vondracek, 2018; Mazurek, 2020). It is hoped that this contribution can serve as motivation and a model for other paleontologists to quantify the effect of the market on the taxa they study. Only then can it be assessed how broadly this issue applies across dinosaurs and other relatively rare vertebrate taxa. In short, this article seeks to answer the question raised by Roddy (2022, p. 480): “[Is the] collection of fossils for commercial gain...a blow to science[?]”

MATERIAL AND METHODS 

A list of 61 scientifically informative specimens that are reposited in public trusts was compiled (Table 1). Carr (2020) was the primary source of specimens in public trusts, supplemented by fossils that were not included in that study. The book chapter written by Larson N.L. (2008) and the article published by Stein (2019) were the primary sources of specimens in commercial or private hands, supplemented by mentions of fossils in news reports, auction catalogs, and fossil dealer websites; first-hand observation; and word of mouth (Table 2). The number of commercially and privately owned fossils presented here is almost certainly an underestimate; given the secretive nature of the market, and the addition of new specimens found from year to year, it is less probable that this number is an overestimation. Specifically, it is nearly impossible to track privately held specimens. The data presented in Table 2 are likely missing some numbers of specimens, contain duplicates owing to specimen name changes, or have ghost specimens that do not exist that result from rumors. In short, the data presented here are an estimate of the impact commercialization has had on the sample size of T. rex.

The approach taken here is different from that of Stein (2019), which includes total counts of all specimens, including isolated bones and teeth held in collections of public trusts, commercial stockrooms, and private individuals. The criteria of this article is narrower, in that the many hundreds (or, possibly, thousands) of isolated bones and teeth are not counted. Instead, fossils that are judged scientifically informative in terms of ontogeny (sensu Carr, 2020) are counted here. This is of necessity, because of the many isolated teeth in collections only a small subset (incisiform teeth) contain ontogenetically informative variation (Carr, 2020). For this reason, my approach is different from that of Larson N.L. (2008), who defined a specimen as represented by 10 bones or more.

This report differs from Chippindale and Gill’s (2000) approach to classical antiquities, in that the provenance and history (see definitions below) of the fossils are not quantified here. In recent years, the provenance of dinosaur fossils from the Hell Creek Formation means the specific depth it was found below the K/Pg boundary layer, which places a given fossil in the precise context of the overall succession of the geological unit (Scannella et al. 2014). The provenance and history of fossils are important, and the issue of provenance is a main criticism that paleontologists have of commercial fossil collectors (Santucci et al. 2016). Instead of a review of provenance, the goal here is to capture a snapshot of the number of fossils that are currently outside of the reach of science.

Ethical Framework

The ethical guidelines of the Society of Vertebrate Paleontology are followed here (https://vertpaleo.org), as well as the general scientific principle of reproducibility of observations.

Justification for Including Student-Written Articles

Several articles cited here were written by law school students (Mazurek, 2020; Paxton-Turner, 2020; Roddy, 2022). Since the authors are not academics, lawyers, or justices, these articles are not part of the canon of legal scholarship. Instead, there are essays that were written by undergraduate students, which were reviewed by their student colleagues, and published in online law school journals. Although these articles are not peer-reviewed literature, they are thoughtful engagements with the issue of the commercial fossil trade from a viewpoint outside of vertebrate paleontology. Of specific interest here is that they propose ideas to ameliorate the commercialization problem that science faces. Since these articles are publicly accessible, they are a part of the cultural zeitgeist, and so their insights and ideas are discussed here alongside other secondary sources.

Incomplete and Imprecise Nature of the Data Set

The world of the fossil trade is murky and it can only be observed indirectly. The specific challenge in writing this work was that not all fossils appear in the public record and those that do surface might undergo one or several name changes. Where unknown fossils will result in an underestimate of privately owned fossils, those that have had their name changed will result in an overestimate of the number, if the name changes unnoticed.

Another confound is the practice of listing several specimens under the same identification number. This is an issue with specimens that were listed on the now-defunct Theropoda Expeditions website, where three specimens were listed under the number TE-36 and two under TE-76. These specimens are treated separately here based on the information in the website, where it was stated that the specimens were collected from different localities. Indeed, one specimen of TE-36 was from Wyoming, whereas the others were from Montana. The single number for several specimens was presumably used to identify the composite skeleton cobbled together from different specimens, and that interpretation is followed here. Therefore, the TE specimen counts are not regarded here as overestimates.

Another issue is a set of specimens - KRex, JKRex, Ryker/Tyson, Barbara - that might be one and the same, but have had their nicknames changed. Although KRex, Ryker, and Tyson are regarded here as the same specimen, based on information from a confidential source, there is insufficient information to decide if Barbara is the same as JKRex and so they are treated separately here (Table 2); differences between the Tyson and Barbara mounts seen in photographs indicates they are not the same specimen, and so Barbara presumably does not include KRex material (see sources in Table 2).

Over the course of the writing of this manuscript, the data on privately held specimens has been revised several times as new information became available. Another limitation of the data is that the year and location of many commercially collected specimens is unknown, so the results regarding time and place are incomplete. Given the amount of commercial activity in the American West, the number of T. rex specimens is expected to increase from field season to field season, at a higher rate than public trusts. Considering these issues, the data presented here are an estimate of privately held specimens, as in any quantitative scientific study. Even if the data presented here are an order-of-magnitude underestimate of the true number of privately held fossils, readers can assess for themselves the extent of the impact of commercial trade on the sample size of T. rex.

List of Primary Literature that Included Privately Owned T. rex specimens

The presence of privately owned T. rex specimens in scientific literature is a long-standing issue. The goal here was to provide an exhaustive list of publications drawn from English-language journals. The intent was not to call out specific scientists - indeed, the name of the author of this article appears in several of the articles as a primary author or co-author - but to provide an estimate of the breadth of the issue in terms of the types of studies (e.g., descriptive, functional morphology, etc.) that are, in whole or in part, based on privately owned fossils.

Terminology

Commercial company/outfit. A company that collects fossils from the field and sells them for profit.

Fossil dealer, commercial fossil dealer. An individual who sells fossils for profit.

Paleontologist. A scientist who publishes descriptive and analytical studies of fossil materials, and who is not a fossil dealer nor a member of a commercial company/outfit, nor a private collector of rare vertebrate fossils. A paleontologist adheres to the ethics of the scientific society of which they have membership, and the laws in the country where they do science.

Private collector. An individual or corporation that purchases fossils for their personal or corporate collection.

Privately owned. A fossil that is the personal property of an individual or corporation, is in the stockroom of a commercial company or fossil dealer, is in the collection of a museum that is not accredited by the American Alliance of Museums (AAM; US only), is in the collection of a museum that is not a repository the Bureau of Land Management or a state repository (US only), or is in a private museum that is not a recognized public trust.

Provenance. The original source of a specimen and its history of ownership (modified from Coggins, 1998 in Chippindale and Gill, 2000).

Public trust. A museum or university collection that, in the United States, is AAM accredited or is a state or federal repository, or some combination thereof.

Scientifically informative specimen. This can range from a single bone or tooth to a complete skull and skeleton; a specimen with sufficient information content to be included in an extensive osteological analysis such as published in Carr (2020).

Surface. The term used for the occasion that a privately held specimen first enters the public record (cf. Chippindale and Gill, 2000).

Institutional Abbreviations

AMNH, American Museum of Natural History (New York, NY, USA); BHI, Black Hills Institute of Geological Research, Inc. (Hill City, SD, USA); BMRP, Burpee Museum of Natural History (Rockford, IL, USA); CM, Carnegie Museum (Pittsburgh, PA, USA); CMNH, Cleveland Museum of Natural History (Cleveland, OH, USA); DDM, Dinosaur Discovery Museum (Kenosha, WI, USA); FMNH, Field Museum (Chicago, IL, USA); HRS, Hanson Research Station (Newcastle, WY, USA); KUVP, Kansas University, Vertebrate Paleontology (Lawrence, KU, USA); LACM, Los Angeles County Museum of Natural History (Los Angeles, CA, USA); LDP, University of New Orleans (LA); MOR, Museum of the Rockies (Bozeman, MT USA); NHMUK, Natural History Museum (London, UK); NMMNH, New Mexico Museum of natural History and Science (Albuquerque, NM, USA); RSM, Royal Saskatchewan Museum (Eastend, SK, CAN); SDSM, South Dakota School of Mines and Technology (Rapid City, SD, USA); TA, Timescale Adventures Research and Interpretive Center (Bynum, MT, USA); TATE, Tate Museum (Caspar, WY, USA); TMM, Texas Memorial Museum (Austin, TX, USA); TMP, Royal Tyrrell Museum of Palaeontology (Drumheller, AB, CAN); UCMP, University of California Museum of Paleontology (Berkeley, CA, USA); UCRC, University of Chicago (Chicago, IL, USA); UMNH, Utah Museum of Natural History (Salt Lake City, UT, USA); UWBM, University of Washington Burke Museum (Seattle, WA, USA).

RESULTS

Effect of the Commercial Trade on the Sample Size of Tyrannosaurus rex

1. Commercial and academic collection compared. Over half of the sample size of T. rex (80 of 141 specimens, or 57%) has been collected by commercial outfits (Figure 1; Table 2, Table 3). Of commercially collected specimens, only nine (11%) are in public trusts (Figure 2; Table 3). The remaining 89% are in stockrooms, private collections, or nonaccredited museums in the USA or overseas. The commercial exploitation of T. rex started in 1992 shortly after the discovery of Sue (FMNH PR2081) (Figure 3). Since then, commercial collection of T. rex fossils (n = 80) has overtaken public trusts (n = 34), such that they have found 2.4 times more T. rex specimens than public trusts. Commercial exploitation of T. rex happens in the Northern Rocky Mountain region of the United States, which is most active in Montana (n = 25) and South Dakota (n = 22) (Figure 4).

The high cultural profile of T. rex results in million-dollar prices for skeletons, a decisive obstacle to acquisition by most public trusts (Figure 5). Public trusts must rely on consortia of donors to purchase a multimillion-dollar specimen (Field Museum, 2018). Taken together, the mean price tag on a T. rex is USD $10.8M (Table 4). Over half of the sample size (n = 14) of T. rex juveniles are commercially or privately held, the growth stage that is least understood scientifically (Carr, 2020) (Figure 6). Of those, nine are represented by associated bones whereas the rest are isolated bones (Table 2).

2. T. rex overseas. Eighteen commercially obtained T. rex specimens have gone overseas (Table 5), presumably for good. Several of these fossils are exhibited in bona fide museums (Museum fur Naturkunde; NZ Herald, 2022), whereas others are exhibited in shopping malls (Tie, 2018). The exhibit of privately owned T. rex in public museums is accompanied by media fanfare (Murray, 2021; NZ Herald, 2022) that does not discuss the ethics of privately owned dinosaur fossils. Although these privately owned fossils are on loan to museums and, in rare cases, the museum will assign a catalog number to the fossil, the specimens are owned by private individuals and so they are not available for scientific research.

3. Data loss. The scientific value of a fossil can be measured by its information content, which includes quantitative data such as measurements and ratios, and qualitative data such as the physical appearance of a structure. To quantify the information content of a T. rex skeleton here, the number of characters and character states from Carr (2020) were counted for each osteological part, and the ratio of character states to characters was calculated for each part and across the entire data (Table 6).

The growth series in Carr (2020) was based on the analysis of 1,850 characters that were scored for 44 specimens, ranging from single teeth and bones to nearly complete skulls and skeletons, and the skeleton was divided into 118 parts (Carr, 2020). Each character has at least two states, which results in a minimum state to character ratio of 2.0; the ratio is greater than this in multistate characters, indicating higher information content. The ratio enables the comparison of relative amount of information content for each region of the skeleton; for example, the body has two characters and six states, giving a ratio of 3 whereas the subnarial foramen is represented by one character that has three states, also giving a ratio of 3. Therefore, the relative information content between the body and the foramen is the same. This comparison finds that for every part of the skeleton, the information content is greater than 2.0 (1 character, 2 states), which is the lowest possible score.

A total of 4,005 character states was counted (Table 6), which is 2.2 times greater than the number of characters. The mean number of characters per part is 20.5, the mean number of states per part is 32.9, and the mean ratio of character states per character is 2.2. Therefore, each part of the skeleton, from teeth to bones to histological data, has information content; it cannot be said that any part is uninformative. In terms of numbers of characters, the most informative bone in each major skeletal region (skull, axial column, pectoral girdle and limb, pelvic girdle, and limb) is the maxilla (123), axis (71), scapula (25), and fibula (42), respectively.

Privately Owned Tyrannosaurus rex in the Scientific Literature

Despite the ethics guidelines of the SVP, paleontologists have published on privately owned T. rex fossils, most frequently from the Black Hills Institute of Geological Research, Inc. (Table 7). This practice dates to at least 1995 and has continued through to the present day nearly every year since. Haug et al. (2020) argued that fossils in private collections are a service to science, but that assumes that they are on equal footing with public trusts. The auction of Stan the T. rex is a clear example that private collections, in part or in whole, are not immune to dissolution (Greshko, 2022; Raja and Dunne, 2023).

DISCUSSION

Summary of Results

The effect of the commercial trade of T. rex fossils upon science is decisive and negative: the sample size of scientifically available specimens is reduced by more than half. From this fact, the claim that commercial trade facilitates the scientific study of T. rex (Larson N.L., 2008) cannot be true. Since the market in dinosaur fossils has no end in sight, vertebrate paleontologists are faced with persistent issues that result from the trade, the American context, and arguments made in defense of the fossil trade and publication of privately owned fossils; the next section explicates those problems based on the claims made by Shimada et al. (2014) and the commercial sources cited above.

Testing the Claims of Shimada et al. (2014)

1. Sales of fossils have increased, especially online. Although online sales of large-ticket T. rex fossils have not happened, the frequency of T. rex appearing on the market has increased, especially since 2019, when each year one or more specimens are made available to buyers (Table 4).

2. Fossils that are sold in high-profile auctions are not purchased by public trusts. This claim is supported by the data; of the five T. rex sold at auction, only one lot (Sue + associated subadult tibia + associated juvenile lacrimal) was obtained by a public trust.

3. The sale of fossils results in a decline in collections-based research. The data collated here show that there are more T. rex fossils in commercial or private hands than in public trusts. Consequently, the sample sizes required for rigorous quantitative research is compromised. A decline of collections research per se does not happen, but the low sample size does compromise the scientific value of the research that is done on T. rex.

Testing the Claims of Commercial Collectors

The results show that in the case of T. rex, vertebrate paleontology is on its back foot because it is unequivocally losing scientifically significant fossils to the commercial market. The 10 arguments posed by commercial interests that were described above are tested here based on the results of this survey.

1. More fossils are discovered in a shorter time frame. The results here find that; indeed, commercial interests have found more T. rex specimens since 1992 than public trusts have collected since 1892. However, the issue examined here is whether or not the commercially collected fossils are reposited in public trusts. The evidence shows that most T. rex fossils either stay in commercial stockrooms or they are in the collections of private individuals and so the high rate of commercial collection works against scientific interests, not for them. Therefore, the benefits of this claim are not supported by the evidence.

2. Some commercially obtained fossils are intensely scientifically studied. The results here find that this claim is true, but this practice contravenes scientific best practices as set out by the ethics guidelines of the SVP.

3. The most significant fossil discoveries made by commercial entities have ended up in museums. As pointed out above, and setting aside the subjectivity in establishing what makes a fossil “the most significant,” the majority of commercially collected T. rex - only nine of 80 fossils - do not wind up in public trusts. Therefore, this claim is not supported by the evidence.

4. Many private collectors donate specimens to research programs. This claim is not supported by the evidence - commercially collected specimens are obtained by museums through purchases (e.g., Sue, Dueler, Trix), not donations.

5. There should be regulated amateur and commercial collecting on public lands. The data here show that most commercially collected T. rex fossils (89%) do not wind up in public trusts; there is no reason to think that sales of dinosaur fossils to private individuals would not stop wherever fossils are collected, so this suggestion would not benefit science.

6. Commercial collecting and the sale of fossils dates to the 1700s, so the practice should continue unimpeded. The evidence collated here shows that most commercially collected T. rex fossils do not wind up in public trusts. There is a closer relationship between commercial collectors with auction houses and well-heeled individuals who purchase fossils than there is with public trusts. As such, this suggestion works against scientific interests.

7. Concerns about fossil commerce are predominantly a North American attitude and free enterprise does not conflict with the science of paleontology. Most commercially collected T. rex fossils are either in stockrooms or in private collections, so this set of claims is not supported by the data.

8. Paleontology is an outlier among the sciences for having an issue with commercial collectors. As with most of the claims assessed here, there is reason for academics to be wary of commercial collectors given that most commercially collected T. rex specimens are not reposited in public trusts.

9. Commercial collectors abide by the principles of the AAPS. The data shows that the specific principles regarding the reportage and deposition of specimens are not followed, since commercially collected specimens do not find their way into public trusts.

10. There is an unfortunate misperception that commercial collectors are only out for money and have little interest in science and high price fossils are the exception, not the rule. Commercially collected T. rex fossils are offered for sale, auctioned, or sold in the millions of dollars (Figure 5; Table 4) and most of the fossils do not make it into a public trust. Therefore, the evidence does not support these related claims.

SUMMARY

The evidence shows that commercial exploitation of T. rex fossils does not aid science because more than half the sample size has either been sold to private individuals or fossils sit in commercial stockrooms. Sample size, in addition to replication of observations, is a cornerstone of rigorous science; in the case of T. rex, the market has reduced the sample size to below the number required to quantitatively test hypotheses such as sexual dimorphism. In science, the value of dinosaur fossils is their information content and any new specimen is an opportunity to test previous hypotheses.

Although the quantification of information content presented here focuses on osteology, there are many other aspects of scientific study of T. rex skeletons to consider. The specimens lost to the market deprives science of better understanding T. rex in terms of histology and the inferences of growth and physiology that could be made from those data. Without the real specimens, science loses the isotopic data that are important for making secure inferences about diet, physiology, and paleoenvironment. This means that the real fossils cannot be replaced by casts or high-resolution CT-scans, or digital surface scans because scientifically informative data are present throughout a fossil.

In addition to the specimens, data loss includes the geological context of a fossil; in recent years, attention has become focused on the precise stratigraphic distribution of fossils in the Hell Creek Formation (Scannella et al. 2014). Without reliable locality data, commercially collected T. rex fossils cannot be put into the larger chronostratigraphic context with the rest of the faunal community (Santucci et al. 2016). Therefore, the commercial and private ownership of T. rex fossils has resulted in a tremendous amount of data loss since the entirety of the data - from the bones to the enclosing rock - are scientifically informative.

This scientific value of information content collides with the financial interests of commercial collectors, dealers, insurers, and auction houses, and it collides with the desires of a private collector to possess a rare fossil. Although the phenomenon of the commodification of T. rex fossils only started in 1997 with the auction of Sue, the evidence shows that the private possession of them is not momentary. So far, none of the privately owned T. rex fossils have been donated to, or offered for purchase to a public trust, by a private estate. However, not enough time has elapsed to assess if transfer of T. rex fossils from a private collection to a public trust will be a trend or ever happen.

Finally, it is unclear whether the commercial trade effectively capitalizes on the scientific publications of privately owned fossils to enhance the value of their fossil wares. Either way, it is advisable for authors and editors to be more circumspect and rigorous regarding that questionable scientific practice, which is probably not limited to T. rex.

CONCLUSIONS

The evidence shows that the sample size of Tyrannosaurus rex has been damaged by commercial exploitation. In three brisk decades commercial interests have collected more scientifically significant fossils than the 132 years of collection made by public trusts. It is reasonable to assume that the number of T. rex reported here that were collected by commercial interests is an underestimation; other dinosaur species surface with regularity on the market, but their total numbers are unknown. The commercial exploitation of dinosaur fossils results in the concomitant loss of scientifically informative data. The evidence also shows that there is a lax scientific culture regarding the publication of data from privately owned T. rex fossils.

ACKNOWLEDGMENTS

I thank the editors of PE for facilitating the publication of this article. I also thank two anonymous reviewers for their constructive feedback that greatly improved the earlier drafts of the manuscript.

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