Meet the Giant Crab That Ruled Ancient New Zealand
It was an ordinary day in 2008 when amateur fossil hunter Karl Raubenheimer stumbled upon an extraordinary sight during a walk near his home in Taranaki, New Zealand. Protruding from a rock was a massive claw, so large and perfectly preserved that it seemed impossible. This wasn't just a fragment of a long-dead creature; it was a gateway to an 8.8-million-year-old world 1 .
Raubenheimer, a musician with a passion for paleontology, carefully extracted the fossil. What emerged was a complete, enormous crab, unlike anything he had seen before. A decade later, his persistence led to another remarkable find—a second, similarly intact specimen. Recognizing their significance, he donated both to the Museum of New Zealand Te Papa Tongarewa, setting in motion a scientific investigation 1 7 .
Occupation: Musician & Amateur Fossil Hunter
Location: Taranaki, New Zealand
First Discovery: 2008
Second Discovery: 2018
The results, published by researchers Barry W. M. van Bakel and Àlex Ossó, confirmed Raubenheimer's discovery was a new, extinct species. In a fitting tribute, they named it Pseudocarcinus karlraubenheimeri in his honor. This crab is not just new to science; it holds the title of the largest fossil crab ever discovered, a testament to a lost ecosystem that thrived in the deep waters off New Zealand's ancient coast 1 9 .
Pseudocarcinus karlraubenheimeri lived during the Miocene Epoch, approximately 8.8 million years ago. The larger of the two fossils found by Raubenheimer provides a clear picture of its impressive stature. Its body, or carapace, measured eight inches across, and it possessed a formidable claw of the same length, a weapon capable of cracking open the toughest shells of its prey 1 9 .
This crab was a dominant predator in its deep-water habitat, several hundred meters below the surface. Its powerful claws were perfect for feasting on crustaceans, clams, and snails. Yet, it was also part of the food web, serving as a meal for the ancient seals, whales, and dolphins that shared its marine environment 1 .
The remarkable preservation of these crabs is directly linked to the region's violent geological past. Researchers believe the crabs died and were buried by an eruption of the nearby Mohakatino Volcanic Center. Underwater volcanic activity spewed sediment, mud, and volcanic ash, rapidly encasing the creatures and protecting their bodies from decay over millions of years 1 7 .
This period in Taranaki was one of incredible marine biodiversity. The study's co-author, Nic Rawlence, describes it as a "lost ecosystem," where underwater volcanic vents added nutrients to the water, creating rich feeding grounds. The discovery of P. karlraubenheimeri helps paleontologists piece together the structure of this ancient deep-sea community 1 .
Responsible for the exceptional preservation of the fossils
P. karlraubenheimeri lives in the deep waters off New Zealand's coast, thriving in a nutrient-rich ecosystem.
Volcanic activity from the Mohakatino Volcanic Center buries the crabs in sediment, leading to their exceptional fossilization.
Karl Raubenheimer discovers the first complete fossil specimen near his home in Taranaki.
Raubenheimer finds a second specimen, providing researchers with more material for study.
Scientists confirm it as a new species and the largest fossil crab ever discovered.
While P. karlraubenheimeri is the largest fossil crab known, its modern descendant is even more colossal. The crab belongs to the same genus as the modern southern giant crab or Tasmanian giant crab (Pseudocarcinus gigas) 1 .
These living giants are spectacular creatures. Their claws can grow up to 20 inches long, and the largest individuals can weigh as much as a human toddler—around 37 pounds 1 . They are a commercially important species today, fished off the coast of Tasmania in Australia. However, they do not have an established population in New Zealand waters, making the fossil discovery the first evidence that this lineage ever lived there 1 9 .
P. karlraubenheimeri
8.8 MYA
Common Ancestor
P. gigas
Present Day
The discovery of P. karlraubenheimeri is a breakthrough for scientists trying to understand the evolution of giant crabs. Javier Luque, a crustacean evolution researcher at the University of Cambridge, notes that "crabs are a spectacular example of the complexities of evolution," with an "astonishing diversity of form and function" 1 .
This new fossil provides a critical missing link. As Luque explains, "in order to make sense of that current diversity, we need to take a glimpse into the past. So it is really exciting to see more fossils of this group coming to light" 9 . It helps fill in the blanks about how and when the southern giant crabs evolved to their immense size, suggesting that the driver for large claws—whether for defense, competition, or feeding—has deep evolutionary roots 1 .
Unlocking the secrets of a fossil requires a blend of traditional techniques and cutting-edge technology.
Analyzes the chemical composition of the rock surrounding the fossil (e.g., carbon and oxygen isotopes) to determine its age and confirm the environment of preservation 2 .
Studies the rock layers (strata) where the fossil was found to understand its geological context and the paleoenvironment it lived in 1 .
The story of Pseudocarcinus karlraubenheimeri is more than a tale of an ancient giant. It highlights the vital role of amateur naturalists and fossil hunters like Karl Raubenheimer. Their keen eyes and dedication to donating finds to science are invaluable for expanding our knowledge of the prehistoric world 9 .
As Luque aptly puts it, "A fossil that is not accessible to science is a fossil that does not exist" 9 . This discovery beautifully bridges the past and present, connecting an 8.8-million-year-old crab to its modern relatives and revealing the dynamic, volcanic history of New Zealand's lost marine world. It's a powerful reminder that there are still ancient giants waiting to be unearthed, their stories hidden in plain sight, just waiting for someone to look.
Miocene Epoch (8.8 million years ago)
Carapace: 8 inches, Claw: 8 inches
Taranaki, New Zealand
Deep-water continental slope
Largest fossil crab ever discovered
Pseudocarcinus gigas
Southern Giant Crab / Tasmanian Giant Crab
First complete specimen discovered by Karl Raubenheimer
Second specimen found by Raubenheimer
Species formally described and named