Maximus Rex

Maximus Rex

View full screen - View 1 of Lot 1. Tyrannosaurus Rex Skull.

Tyrannosaurus Rex Skull

Auction Closed

December 9, 03:10 PM GMT


15,000,000 - 20,000,000 USD

Lot Details


Tyrannosaurus Rex

Hell Creek Formation, Maastrichtian, Late Cretaceous (approx. 67 million years ago)

Harding County, South Dakota, USA

Articulated skull length 53.5 inches, weighing approximately 160.25 lbs. 30 bones (of an approximate total of 39), with additional cast elements, as well as 29 teeth represented in various states of completeness. Judging from the overall size and degree of the bone development, it can be determined that the skull belonged to a large, adult individual.

Professionally prepared, and accurately articulated anatomically, the skull elements are mounted on a custom armature and stand with jaws opened, rising to 79.75 inches in height on stand (weight with stand 609 lbs.) Offered together with the skull are the scant remains of the post-cranial skeleton; a weathered scapula (30.4 inches in length), and approximately 160 additional bone fragments. 

The skull is offered with full rights, and the offering includes full documentation certifying condition, authenticity, and legality of ownership.

Excavated over field seasons in 2020 and 2021 on private land, Hell Creek Formation, Harding County, South Dakota




At approximately 75% complete, Maximus ranks amongst the top known specimens in the world, all of which are housed in institutions, making it the only such specimen available for purchase; these include Sue, housed at the Field Museum of Natural History in Chicago (at an estimated overall completeness of 85%); Trix, housed at the Naturalis Biodiversity Center in the Netherlands (at an estimated overall completeness of 80%); Scotty, housed at the Royal Saskatchewan Museum in Canada (at an estimated overall completeness of 70-75%); Thomas at the Natural History Museum in Los Angeles (at an estimated overall completeness of 70%); and the recently sold Stan, slated to be displayed at the Natural History Museum Abu Dhabi (at an estimated overall completeness of 65%).


The skull is not only the most recognizable and emblematic part of the dinosaur, but also the most important from a scientific perspective. This is particularly the case for Tyrannosaurus rex, as the skull is what allows palaeontologists to distinguish the phylogenetically related species (Tyrannosauridae: Daspletosaurus, Albertosaurus, Tarbosaurus, Gorgosaurus, etc.) Post-cranial skeletons of large tyrannosaurids are very similar, such that the bones of an immature T. rex individual are indistinguishable in comparison to the adults of other species.


The bones of the fossilized skull were found disarticulated, and these elements are well preserved, resulting in an informative specimen with a high degree of integrity. The separately preserved skull elements allow for individual examination and comparison. Importantly there is no composite material, with the elements all belonging to one individual.

Overall, the bones are preserved in exquisite detail, exhibiting little distortion, and retaining much of their original shape and surface characteristics. The fossilization is superb, with even small, delicate bones being preserved in fine detail. In addition to the normal foramina and nutrient grooves, numerous small cracks and splits cover much of the surface of the bones, due to their having been close to the ground surface.

All the tooth bearing jaw elements are preserved, as are most of the external bones on both right and left sides of the skull, including but not limited to these major elements - premaxillae, maxillae, nasal, jugal, lacrimal, postorbital, quadratojugal, squamosal, ectopterygoid, pterygoid, vomer, palatine, quadrate, dentaries, surangular, splenial, angular, prearticular, coronoids, and numerous upper and lower teeth.

Adding much character and individuality to the skull are several interesting pathologies. The most noticeable of these include circular perforations/punctures, some possibly being bite marks, others possibly the result of a form of the protozoan parasite Trichomonosis similar to Trichomonas gallinae, as seen in modern birds of prey (holes found in the surangular area in the lower jaws of other Tyrannosaurus specimens have been attributed to this form of Trichomonosis). Also present are signs of possible bone infections (osteomyelitis), as well as numerous insect borings, which suggest that the carcass was exposed for a period of time before burial.


The best fossils of large carnivorous dinosaurs such as Tyrannosaurus rex are mainly found in four countries; China, Mongolia, Canada, and the United States. China, Canada, and Mongolia do not grant export permits for these types of fossils, meaning that the only place where such dinosaurs can be legally bought and sold internationally is in the United States, provided that the specimen originates from private land. Such is the case of course, for Maximus, who was discovered on private property in Harding County, South Dakota, in what is known as the Hell Creek Formation.

A division of rocks about 575 feet thick, dating to the end of the Cretaceous period (approx. 65 million years ago), the Hell Creek Formation occurs in Eastern Montana, as well as portions of both North and South Dakota and Wyoming. It has preserved more T. rex material than anywhere else, and has produced both Sue (sold in 1997 in these rooms for $8.3 million), as well as Stan (sold in 2020 for $31.8 million). The formation is world renowned for Cretaceous Period dinosaur fossils, and fossils of Triceratops, Edmontosaurus, Pachycephalosaurus and many other dinosaur species have been found there together with T. rex.


The dig site where Maximus was unearthed had been severely weathered and most of the post-cranial skeleton destroyed by erosion — save for a very weathered scapula, and numerous small fragments, offered together with the skull. In a stroke of great luck, this remarkable skull survived, and was collected and preserved by experienced field palaeontologists, underlining the crucial role commercial palaeontology plays in saving and preserving important specimens on private lands.


Tyrannosaurus rex is the most widely recognized dinosaur in the world, dominating the popular perception of the Age of Dinosaurs ever since the genus was first named by Henry Fairfield Osborn, founding chairman of the Department of Vertebrate Paleontology at the American Museum of Natural History, in 1905. The type specimen that Osborn described as the "tyrant lizard king" was recovered in Garfield Country, Montana, by the indefatigable dinosaur hunter Barnum Brown. Returning to central Montana in 1907, Brown found a second and more complete Tyrannosaurus skeleton, which included one of the finest skulls yet discovered. Between these two finds, Osborn reconsidered his designation of some fragmentary theropod bones unearthed by Brown in northwestern Wyoming in 1900. Osborn had originally christened this previously unknown carnivore Dynamosaurus imperiosus, but he subsequently decided that it too was a Tyrannosaurus rex.

For six decades these three specimens at the American Museum of Natural History were the only known examples of Tyrannosaurus. (In 1941, the type specimen was sold to the Carnegie Museum; the first discovered, but misnamed T. rex fossils are currently at the London Museum of Natural History ; Brown's greatest find, the second Montana skeleton, is still at the American Museum). Despite this paucity of fossil evidence, Tyrannosaurus quickly captured the imagination of the general public and the attention of the paleontological community. When announced to the press, Brown's discoveries and Osborn's researches inspired headlines and articles describing Tyrannosaurus rex as "The Prize Fighter of Antiquity" and a "swift two-footed tyrant" that "munched giant amphibians and elephant à la naturel." So universally accepted was Osborn's coronation of Tyrannosaurus as the "king" of the tyrant lizards that T. rex became—and remains—the only dinosaur commonly called by both its genus and species names. (Virtually everyone familiar with Tyrannosaurus rex also knows Stegosaurus, but apart from the taxonomic literature, the species names of that genus are seldom encountered: Stegosaurus armatus, Stegosaurus stenops, and Stegosaurus longispinus.)

In 1915, the American Museum of Natural History unveiled the first public exhibition of a free standing, fully restored skeleton of Tyrannosaurus, modeled of elements from Brown's two Montana specimens. Posed standing nearly upright with its huge jaws agape, the tip of its inaccurately long tail trailing on the floor some forty-eight feet behind its snout, the enormous carnivore silently stalked the Museum's dinosaur halls for nearly eighty years. Although the AMNH had the only authentic T. rex on display anywhere in the world, the allure of the massive meat eater—possibly predator, possibly scavenger—was irresistible, and its terrifying image rapidly proliferated throughout both the public and scientific domains. The natural history artist Charles R. Knight prominently featured a Tyrannosaurus facing off against a Triceratops in his monumental 1920s mural cycle at the Field Museum of Natural History in Chicago, even though that collection had no T. rex among its holdings at the time (the Field Museum is of course now the home of Sue the T. rex, sold in these rooms in 1997). In 1933 RKO's special effects department brought a stop-motion Tyrannosaurus to life, only to have it killed at the hands of David O. Selznik's King Kong. Casts of the AMNH specimens went on exhibition at natural history museums and universities around the world, and variously accurate full-scale models were displayed at world's fairs, amusement parks, miniature golf courses, roadside attractions (the most famous being the steel and concrete Cabazon's Dinosaurs near Palm Springs, California, consisting of a 150-foot long Brontosaurus and a 65-foot tall T. rex, both made famous in the 1985 Tim Burton film Pee-Wee's Big Adventure) and virtually any other spot an enthusiastic crowd could be gathered. Michael Crichton's 1990 novel Jurassic Park proved the public's fascination with dinosaurs, and its 1993 film adaptation by Steven Spielberg remains one of the highest-grossing films of all time, spawning several sequels, including one released just a few months ago. Despite the ubiquitous presence of Tyrannosaurus in the modern world, we still understand very little about these animals apart from their enduring ability to fascinate us. As Molnar, Kurzanov, and Dong state at the outset of their survey of large theropods, meat-eating "dinosaurs were the largest carnivorous animals to inhabit the land. Some of these, such as Tyrannosaurus rex, are known to almost every schoolchild. Unfortunately, our knowledge of many of these forms does not compare to their popularity." ("The King of the Tyrant Lizard" section excerpted, with minor additions, from the original 1997 catalogue for Sue the T. rex, by Selby Kiffer, Sotheby's SVP, International Senior Specialist, in consultation with Henry Galiano, Sotheby's consultant for the sale of Sue, and Sotheby's current consultant for Natural History).