An article published in the journal “Royal Society Open Science” reports the identification of a new species of radiodont that was named Titanokorys gainesi dating back to about half a billion years ago thanks to fossils discovered in the famous Burgess Shale. A team of researchers examined what is the largest radiodont of the Hurdiidae family discovered so far and in particular the large carapace that covered its head, which is very long compared to its body. Such an animal must have been of considerable importance in its ecosystem, like other predatory radiodonts of the Cambrian period. Its discovery helps to understand the diversification of these arthropods and in particular of the ones of the Hurdiidae family, which had a great variability in the characteristics and in particular of the carapace.
The animals of the radiodont (Radiodonta) group include some of the earliest known predators such as Anomalocaris canadensis. Their study is important to try to reconstruct the phases that led to the diversification of the first animals in the phylums existing today. They are considered to be primitive arthropods but their relationships with insects and other members of that phylum are still a matter of debate.
A length of half a meter may seem scarce but in the Cambrian an animal like the Titanokorys gainesi was a giant. That period was characterized by an incredible level of species diversification but started with primitive animals that were very small. Anomalocaris briggsi, which was perhaps the first top predator in the history of life on Earth, could perhaps reach one meter in length. Aegirocassis benmoulai, a radiodont that lived in the following period, the Ordovician, could perhaps exceed two meters in length and in its time may have been the largest animal in the world.
The fossils of Titanokorys gainesi were discovered in the Burgess Shale, one of the most famous paleontological sites in the world thanks to its richness. In fact, it continues to offer new discoveries over a century after the first excavations.
The carapace was a characteristic of radiodonts in general and in the case of those belonging to the Hurdiidae family, the head, in particular, is equipped with a particularly large carapace that was perhaps useful in swimming. Titanokorys gainesi, with a very long head compared to the body, is an exceptional case even in its family. For this reason, it was likened to a swimming head thinking that its characteristics indicate it was a good swimmer.
Probably, Titanokorys gainesi swam close to the seabed and used its forelimbs full of spines that must have been excellent for capturing small prey and bringing them to its mouth. The dorsal carapace could perhaps have been used as a plough. The bottom image (Courtesy Caron & Moysiuk. All rights reserved) shows a reconstruction of Titanokorys gainesi in various views: dorsal (a), ventral (b), lateral (c), and frontal (d).
The discovery of Titanokorys gainesi confirms the remarkable success that radiodonts had during the Cambrian period. The findings of recent years continue to confirm that there was considerable diversification within this group. Animals so large by the standards of the time had a significant influence on their ecosystems and were probably a key group in the Cambrian explosion, the most important diversification period in the history of life on Earth.