Opabinia

One of the things studying earth’s ancient fossils has revealed is that the planet had some pretty odd creatures millions of years ago. Opabinia is one of such strange-looking creatures that swam the earth’s oceans 500 million years ago. Unearthed from Canada’s Burgess Shale, this ancient arthropod had an odd appearance; it looked like something you would see in an alien sci-fi movie. Despite being such an interesting-looking creature, many things about the Opabinia have remained a mystery because of the limited fossils available. 

Description & Size

Opabinia was a bizarre-looking arthropod that lived during the Cambrian about 505 million years ago. The species was named after Opabin Pass. A mountain pass between Mt. Hungabee and Mt. Biddle, located in British Columbia. The creature was a slender, soft-bodied arthropod with a total length of about 2.8 inches (7 cm). Generally, its body is divided into a head, a segmented trunk, and a fan-like tail. The lack of mineralized armor meant scientists produced different interpretations of how the animal might have looked. 

One of the most bizarre features of Opabinia is its eyes. It had five eyes, and all were stalked and pointed upwards. Two eyes were longer and located towards the back of the head, with a shorter one between them. The remaining two were sited around the middle of the head. 

The creature’s mouth occupied a weird position under its head and faced backward. A hollow proboscis was also attached right in the front of the mouth. The length of this structure is a third of the total body’s length. This appendage was long and flexible enough to reach the mouth of the organism comfortably. It was striated and had a lateral claw-like form at the tip with five spines with inwards projection. 

Opabinia had bilateral symmetry, and its main body parts were segmented. There were 15 segments, each with pairs of lobes facing outwards and downwards. They were overlapped in such a manner that the rear end of each covered the preceding pairs. The tail was conical in shape and had three “fan” blades that overlapped each other, creating a V-shaped impression. The organism’s respiration was via paired dorsal extensions that served as gills connected to the base of the flaps. 

Diet — What Did Opabinia Eat?

Most interpretations of this creature’s habits suggest that Opabinia was a carnivore. However, the absence of jaw-like structures and teeth in the fossils means it probably fed on small and soft-bodied animals. Opabinia’s diet most likely included smaller invertebrates that lived in the same habitat. The creature captured its prey with its claw-like proboscis and passed them to its mouth for digestion. It had a paired gut diverticula, which would have increased the efficiency of food digestion. 

Habitat — When and Where It Lived

Opabinia lived during the Cambrian Period. The group survived on the seafloor for a few million years before going extinct. Scientists in support of the “no legs” theory proposed that they crawled on their lobes on the prehistoric seafloor. Some experts believed that Opabinia could swim slowly by flapping its lobes. 

Threats and Predators

We know very little about Opabinia’s lifestyle and habits. Although most experts agree that this creature was most likely a predator, we don’t know enough about its place in the food chain or whether it faced significant threats from other animals. However, Opabinia lived during a period when the earth underwent rapid, severe changes that might have threatened its existence. For instance, the burial of the Burgess Shale organisms suggests that a mudslide or a sediment-laden current buried them quickly. Incidents like this might have been very uncommon in the dangerous Cambrian sea. 

Discoveries and Fossils — Where It Was Found

Paleontologists found Opabinia in Cambrian fossil deposits that date back to approximately 505 million years ago. Charles Doolittle Walcott discovered 11 Opabinia fossils in 1911. It was first seen in the Burgess Shale deposits of British Columbia, Canada. The site of Opabinia’s discovery is famous for its abundant deposits of strange Cambrian animals. Harry B. Whittington discovered more well-preserved Opabinia fossils in 1966.

Opabinia showed how difficult it is to derive facts from soft-bodied animals preserved in fossil records. Since they mainly trace fossils, it leaves a lot of assumptions and arguments to be debated. This species had no armor or noticeable exoskeletons. Hence their bodies had been flattened at their burial and fossilization. The internal features only appear as markings inside the bigger outline of the fossils. More fossils have been found over the years, but these proved difficult to study due to their poor state of preservation. 

Extinction – When Did It Die Out?

This bizarre creature most likely became extinct during the Permian-Triassic mass extinction. The extinction occurred more than 250 million years ago. The event regarded as earth’s biggest extinction wiped out more than 90% of life on the planet. 

Similar Animals to Opabinia

Similar creatures to Opabinia Include:

• Anomalocaris — A group of sea arthropods with similar gill blades, stalked eyes, and stalked appendages. They were bigger than Opabinia (1.25 ft long), with well-developed claws for catching prey.
• Wiwaxia — A group of Cambrian marine animals characterized by spiky, shorter, slender bodies of about 2 inches. It was oval and had rows of spines running along its back.
• Utaurora — A species very similar to Opabinia in morphology but had more extensive blades covering the posterior of each flap. Like Opabinia, this creature also had a tail fan composed of 7 pairs of blades. 

Related Animals 

• Anomalocaris
• Hallucigenia
• Eurypterus