New research suggests that the T. rex was much larger than previously thought

Research suggests that the largest T. rex may have weighed up to 15 tons and measured 15 meters tall, significantly larger than any previously known specimen. This suggests that further paleontological research may reveal even greater discoveries.

New research results published in the journal Ecology and Evolution estimates the maximum possible size of dinosaurs based on Tyrannosaurus rex as an example. Using computer models, Dr. Jordan Mallon of the Canadian Museum of Nature and Dr. David Hone of Queen Mary University of London estimated that T. Rex could have been 70% heavier than fossil finds suggest.

Investigating dinosaur size estimation

The enormous sizes that many dinosaurs reached make them a source of endless fascination and raise the question of how these animals could grow so large. There are always claims and counter-claims about which dinosaur species was the largest of its group or even the largest of all time.

For most dinosaur species, only one or a few specimens are known, so it is extremely unlikely that their size range includes the largest specimens that ever existed. The question remains: how big were the largest specimens and are we likely to find them?

Insights into computer modelling

To answer this question, Mallon and Hone used computer models to create a population of T. rexThey took into account variables such as population size, growth rate, lifespan, the incompleteness of the fossil record, and more.

T. rex was chosen for the model because it is a well-known dinosaur for which many of these details are already well appreciated. The body size variation in adulthood, which T. rexwas modeled with and without sex differences and is based on examples of living alligators selected for their size and close relationship to dinosaurs.

The discovery of gigantic dinosaurs

The paleontologists found that the largest known T. rex Fossils are thought to fall in the 99th percentile, representing the top 1% of body size. However, to find an animal in the top 99.99% (an individual under 10,000), scientists would have to dig up fossils for another 1,000 years at the current rate.

The computer models suggest that the largest individual that could have ever existed (one of 2.5 billion animals) could have been 70% heavier than the currently largest known T. rex specimens (estimated 15 tons versus 8.8 tons) and 25% longer (15 meters versus 12 meters).

The values ​​are estimates based on the model, but the pattern of discovering giant modern species tells us that there must have been larger dinosaurs that have not been found so far. “Some isolated bones and pieces certainly suggest even larger individuals than we currently have skeletons of,” says Hone.

Impact of new fossil discoveries

This study contributes to the debate about the largest fossil animals. Many of the largest dinosaurs in different groups are known from only one good specimen, so it is impossible to know whether that one animal was a large or small specimen of the species. A seemingly large species could be based on a single giant individual, and a small species could be based on a particularly tiny individual – neither of which reflects the average size of the species in question.

Mallon said: “Our study suggests that for large fossil animals such as T. rexWe have no idea from the fossil finds what absolute sizes they could have reached. It is funny to imagine that a 15 ton T. rexbut the implications are also interesting from a biomechanical or ecological point of view.”

Hone adds: “It is important to stress that this is not really about T. rexwhich is the basis of our study, but this question would apply to all dinosaurs and many other fossil species. Arguing about ‘which is the biggest?’ based on a handful of skeletons really doesn’t make much sense.”

The likelihood of paleontologists finding the largest specimens of a particular species ever found is incredibly low. Despite the enormous skeletons on display in museums around the world, the very largest specimens of these species were probably even larger than those on display.

Reference: “Estimation of maximum body size in fossil species: A case study using Tyrannosaurus rex” by Jordan C. Mallon and David WE Hone, July 24, 2024, Ecology and Evolution.
DOI: 10.1002/ece3.11658