Palaeontologists solve mystery of 500 million-year-old squid-like carnivore

May 26, 2010
This is a reconstruction of Nectocaris pteryx. Credit: Copyright (c) 2009 Marianne Collins.

A study by researchers at the University of Toronto and the Royal Ontario Museum sheds new light on a previously unclassifiable 500 million-year-old squid-like carnivore known as Nectocaris pteryx.

"We think that this extremely rare creature is an early ancestor of squids, octopuses, and other cephalopods", says Martin Smith of U of T's Department of Ecology and (EEB) and the Department of Natural History at the ROM. "This is significant because it means that primitive cephalopods were around much earlier than we thought, and offers a reinterpretation of the long-held origins of this important group of ."

The new interpretation became possible with the discovery of 91 new fossils that were collected by the ROM from the famous Burgess Shale site (Yoho National Park) in the UNESCO World Heritage Canadian Rocky Mountain Parks, British Columbia over the past three decades, and examined by PhD student Martin Smith along with U of T EEB and Geology assistant professor and ROM palaeontologist Jean-Bernard Caron.

"Previously, all knowledge of Nectocaris came from a lone specimen described in 1976. Due to the ambiguous characteristics evident on that specimen, Nectocaris has remained unclassified until now," says Smith, lead author of the study published this week in Nature. "Our study reveals that Nectocaris is similar to known members of the modern cephalopod group, which includes squid, , cuttlefish and the nautilus, as well as common fossils such as ammonites and belemnites, which are now extinct."

"We know very little about the relationships between the major groups of molluscs, and the early history of the group," says Smith. "Fossils like Nectocaris help us to map out how the groups alive today might be related, and how they evolved. This tells us something about how biodiversity originated in the past, and helps us to understand the rich tapestry of life today."

The new specimens, between two and five centimetres long, show that Nectocaris was kite-shaped and flattened from top to bottom, with large, stalked eyes and a long pair of grasping tentacles, which the researchers believe helped it to hunt for and consume prey. Smith and Caron further suggest that the creature swum using its large lateral fins, and, like modern cephalopods, probably used its nozzle-like funnel to accelerate by jet propulsion. "Some of the specimens' large gills were choked with mud, suggesting that the animals were fossilized after being caught in an underwater mud-flow," says Smith.

This is a Nectocaris pteryx from the Middle Cambrian Burgess Shale. Credit: Jean-Bernard Caron

"Our findings mean that cephalopods originated 30 million years earlier than we thought, and much closer to the first appearance of complex animals in the 'Cambrian explosion'" says Smith. Nectocaris does not have a mineralized shell, a fact that surprised the scientists. "It's long been thought that cephalopods evolved in the Late Cambrian period, when gradual modifications to the shells of creeping, snail-like animals made them able to float. Nectocaris shows us that the first cephalopods actually started swimming without the aid of gas-filled shells. Shells evolved much later, probably in response to increased levels of competition and predation in the Late Cambrian."

"Modern cephalopods are very complex, with intricate organs and startling intelligence. We go from very simple pre-Cambrian life-forms to something as complex as a cephalopod in the geological blink of an eye, which illustrates just how quickly evolution can produce complexity."

Smith says Nectocaris proves that there are still surprises in the fossil record. "Fossils can only ever tell us a part of the story," he says. "Exceptional soft-bodied fossils such as Nectocaris, combined with advances in developmental and molecular biology, still have a lot to bring to the table, and I'm sure that they will continue to help to refine and replace our current hypotheses."

Explore further: T. rex gets new home in Smithsonian dinosaur hall

More information: The findings are presented in a paper titled "Primitive soft-bodied cephalopods from the Cambrian", to be published May 27, 2010 in Nature.

Related Stories

Fossil find fills in picture of ancient marine life

May 13, 2010

Paleontologists have discovered a rich array of exceptionally preserved fossils of marine animals that lived between 480 million and 472 million years ago, during the early part of a period known as the Ordovician. ...

Geologist analyzes earliest shell-covered fossil animals

Oct 22, 2009

The fossil remains of some of the first animals with shells, ocean-dwelling creatures that measure a few centimeters in length and date to about 520 million years ago, provide a window on evolution at this ...

A new fossil species found in Spain

Mar 25, 2010

In the '80s, Spanish researchers found the first fossils of Cloudina in Spain, a small fossil of tubular appearance and one of the first animals that developed an external skeleton between 550 and 543 millio ...

Fossils show earliest animal trails

Feb 04, 2010

(PhysOrg.com) -- Trails found in rocks dating back 565 million years are thought to be the earliest evidence of animal locomotion ever found, Oxford University scientists report.

Recommended for you

Clippers and coiners in 16th-century England

Apr 14, 2014

In 2017 a new £1 coin will appear in our pockets with a design extremely difficult to forge. In the mid-16th century, Elizabeth I's government came up with a series of measures to deter "divers evil persons" ...

Serbia experts use heavy machinery to move mammoth

Apr 11, 2014

Serbian archaeologists on Friday used heavy machinery to move a female mammoth skeleton—believed to be one million years old—from an open mine pit where it was unearthed nearly five years ago.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Ronan
not rated yet May 27, 2010
...Am I just being horribly misled, or isn't there something marvelously...anomalocariid about Nectocaris' general appearance? Or rather, sort of half-squid and half-anomalocariid? Probably just convergent evolution--probably. Probably.

...And yet, I can't help being hopeful. The idea of Anomalocaris having had living descendants is just so wonderful...Bah. Mustn't get hopes up. Besides, interpretations of fossils DO change over time, and it seems unlikely that this particular interpretation'll go completely unchallenged. Wait and see, I suppose, and keep the name Nectocaris in mind.

More news stories

Can science eliminate extreme poverty?

Science has often come to the rescue when it comes to the world's big problems, be it the Green Revolution that helped avoid mass starvation or the small pox vaccine that eradicated the disease. There is ...

Investment helps keep transport up to speed

Greater investment in education and training for employees will be required to meet the future needs of the transport and logistics industry, according to recent reports by Monash University researchers.

Floating nuclear plants could ride out tsunamis

When an earthquake and tsunami struck the Fukushima Daiichi nuclear plant complex in 2011, neither the quake nor the inundation caused the ensuing contamination. Rather, it was the aftereffects—specifically, ...

Unlocking secrets of new solar material

(Phys.org) —A new solar material that has the same crystal structure as a mineral first found in the Ural Mountains in 1839 is shooting up the efficiency charts faster than almost anything researchers have ...