Blood vessels preserved in a broken rib of the largest known T. rex show healing in progress

Overview

Updated Sep 24

Scotty, the largest Tyrannosaurus rex skeleton on record, died 66 million years ago with a broken rib that was still healing. The rib holds a dense network of mineralized blood vessels that formed as the dinosaur's body worked to repair the fracture.

The find is the first high-resolution 3D look at dinosaur healing blood vessels. It also points paleontologists toward a new hunting ground for soft tissue that survives deep time: broken bones.

Why it matters

Broken bones trigger a surge of blood vessels during healing, and those vessels may fossilize where normal ones don't. Paleontologists gain a new soft-tissue target.

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Key Indicators

66M

Years since Scotty died

The rib preserves a healing Late Cretaceous fracture, roughly 66 million years old.

8.87

Estimated body mass of Scotty

The 2019 study that crowned Scotty the largest T. rex on record.

Mineral layers in vessel casts

Pyrite partially oxidized to goethite or hematite, laid down in two distinct layers.

Months

Between rib fracture and death

Scotty died before the fracture finished healing, which let the vessels fossilize.

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Mauricio Barbi

Physics professor and study co-author

Leading the team analyzing Scotty's rib

Jerit Mitchell

Physics doctoral student and lead author

First flagged the preserved tissue in 2020

Organizations Involved

University of Regina

Public university

Led the study of Scotty's rib

The Saskatchewan university whose physics department ran the synchrotron and neutron imaging of Scotty's rib.

Oak Ridge National Laboratory

National Laboratory

Provided neutron imaging capability

The DOE lab whose MARS and VENUS neutron instruments let the team confirm the synchrotron findings without damaging the fossil.

Royal Saskatchewan Museum

Provincial museum

Holds the Scotty specimen (RSKM P2523.8)

The museum that holds Scotty's skeleton and authorized the imaging study of the rib.

Timeline

August 1991 September 2026

7 events Latest: September 5th, 2026 · 2 months ago

Tap a bar to jump to that date

September 2026
NY Post covers Scotty's healing wound
Latest Media

Wider coverage framed the rib as evidence of how the apex predator died in a Canadian salt marsh.
September 5th, 2026
April 2026
Blood vessel finding reported to the public
Media

ScienceDaily and other outlets detailed the discovery of iron-rich vessels in the healed rib.
April 26th, 2026
Neutron imaging at Oak Ridge National Laboratory
Research

The team used the MARS and VENUS instruments to verify the synchrotron findings nondestructively.
April 2026
2025
Paper describes mineralized vessel casts
Publication

Scientific Reports published the team's synchrotron analysis showing the vessels are casts of pyrite oxidized to goethite and hematite.
2025
2020
Mitchell flags preserved tissue in Scotty's rib
Discovery

University of Regina student Jerit Mitchell spotted vessel-like structures in the rib using micro-CT scans.
2020
March 2019
Scotty confirmed as largest T. rex on record
Research

A study in The Anatomical Record estimated Scotty's mass at roughly 8.87 tonnes, above all other known T. rex specimens.
March 2019
August 1991
Scotty's skeleton discovered in Saskatchewan
Discovery

Amateur paleontologist Robert Gebhardt found the T. rex skeleton in the Frenchman Formation near Eastend. Excavation took years.
August 1991

Scenarios

Follow-up tests find organic material in Scotty's vessels

Possible Resolves by End of 2028

Discussed by: The University of Regina team, which said future studies will examine "organic or pliable-type vessels" in the casts

The team's Scientific Reports paper says it will test whether any original organic or pliable material survives inside the mineralized casts. The April 2026 neutron runs at ORNL were partly aimed at detecting light elements that synchrotron X-rays struggle to see. Data supporting organic remnants would move the vessels beyond mineral casts to preserved tissue.

Fractured bones become a standard fossil soft-tissue target

Possible Resolves by End of 2030

Discussed by: The research team's postulate in Scientific Reports, which argues pathologies "may provide a target for future soft tissue preservation searches in bone"

If trauma-driven healing reliably produces dense, iron-rich blood vessels that fossilize well, paleontologists could target healed fractures in large fossils. The team says it will expand studies to more specimens and compare healing patterns across species. A second independent confirmation would turn the postulate into a widely used strategy.

Critics argue the vessels formed from microbes, not blood

Possible Resolves by End of 2028

Discussed by: Skeptics of dinosaur soft tissue claims, following the pattern of the biofilm debate over Mary Schweitzer's 2005 B-rex finds

The paper itself recovered no original soft tissue and describes the vessels as permineralized casts of pyrite and iron oxides. A critic could argue the shapes formed from microbial activity in the salty marsh where Scotty died, not from angiogenic blood vessels. The team's chemical mapping, which ties the vessel morphology to the fracture callus, is its main counter.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

March 2005

Mary Schweitzer's B-rex soft tissue (2005)

Paleontologist Mary Schweitzer reported flexible, translucent vessels and cell-like structures inside a 68-million-year-old Tyrannosaurus rex femur known as MOR 1125. The find challenged the assumption that soft tissue cannot survive tens of millions of years.

Then

The claim drew intense skepticism and replication attempts, with some labs unable to reproduce the results.

Now

It opened a research field hunting for molecular and cellular remnants in dinosaur bone, and it remains contested today.

Why this matters now

Scotty's rib vessels are the same kind of claim, extended to healing structures. The current team's careful chemical work responds directly to the criticisms Schweitzer faced.

July 2008

The biofilm interpretation challenge (2008)

Thomas Kaye and colleagues argued in PLoS ONE that the "soft tissue" in Schweitzer's dinosaur bones was bacterial biofilm, not original vessels or cells. They presented scanning electron microscope images of slime-like structures on both modern and fossil bone.

Then

The debate split the field, with supporters on both sides publishing follow-up evidence.

Now

The episode set a standard: soft tissue claims now require chemical and structural evidence, not just visual similarity.

Why this matters now

Scotty's team preempted this critique by chemically mapping the vessel casts' pyrite and iron oxide composition and tying their shape to the fracture callus.