Archaeologists have discovered new details about Habelia optata, a small, extinct aquatic predator first found by scientists over 100 years ago. The 508-million-year-old creature measured just 2 centimeters long. It had a segmented body with an external skeleton, jointed limbs, and a long tail. The odd animal was a chelicerate, which means it was an arthropod like spiders, insects, and crustaceans.
Though researchers have known about the ancient animals for some time, they still have many unanswered questions about the species. To help shed light on such mysteries, researchers from the University of Toronto analyzed 41 different H. optata specimens.
That study revealed the creature’s armor-covered body was divided into three distinct sections — a head, mid-section, and lower section — and all three regions were covered in spines and appendages. The midsection had five walking legs, while the back was connected to appendages that were likely used for respiration.
“Scorpions and the now-extinct sea scorpions are also chelicerates with bodies divided into three distinct regions,” said Cédric Aria, a researcher at the University of Toronto, according to International Business Times. “We think that these regions broadly correspond to those of Habelia. But a major difference is that scorpions and sea scorpions, like all chelicerates, literally ‘walk on their heads,’ while Habelia still had walking appendages in its thorax.”
That unique anatomy is important because researchers believe the difference between H. optata and modern chelicerates led to the evolution of an especially complex head. H. optata had five strange appendages, including a large plate for chewing, a leg-like branch with grasping spines grasping, and a slender branch that allowed the animal to feel. That combination made it an exceptionally fierce predator for its size.
Not only is the animal interesting from a biological standpoint, but it also existed during the Cambrian explosion. The team hopes further study of the species could reveal more about the ancient time period.
The research was published in BMC Evolutionary Biology.