The World's First Carnivores

This week at Discovery News, you can read about a 500-million-year-old carnivore that once lived at what is now British Columbia. 

(The Cambrian carnivore: Nectocaris pteryx. © 2009 Marianne Collins.)

The newly described species, a primitive cephalopod, comes pretty close in time to the world's oldest known meat eaters. 

Paleobiologist Martin Smith, who worked on the Nectocaris research, told me, "The earliest evidence for predation in the fossil record comes in the form of microscopic bore-holes in the calcified tube of the Ediacaran worm Cloudina, some fifty million years before Nectocaris."

"No known fossil animals can be implicated in this predation, probably because they lacked any easily-fossilized hard parts," added Smith, who works at the Royal Ontario Museum's Department of Natural History."

Cloudina (Wikipedia image)

"The origin of carnivory has been put forwards as a possible contributor to the Cambrian 'explosion' of animal life, but since much of the early Cambrian ecosystem lacked readily-fossilized hard parts, our understanding of this important time in life history is restricted to rare windows of exceptional soft-part preservation known as lagerstätten," Smith continued.

"Our study identifies members of some of the earliest Cambrian lagerstätten, the Chinese Chengjiang and Australian Emu Bay shale, as close relatives of Nectocaris, where they would have lived alongside predatory worms, arrow-worms, arthropods -- and other carnivores that defy precise classification. These animals, including Nectocaris, are the first predators that we can unambiguously reconstruct, but with much of the early Cambrian devoid of lagerstätten, we are as yet unable to constrain the expansion of the carnivorous lifestyle."

Smith believes that Nectocaris most likely evolved from "a creeping, slug-like organism." 

While the precise, very first meat eater that ever lived is therefore a mystery, we can now make some educated guesses about it. The species was probably...

• a marine dweller
• small
• consumed tiny, waterborne prey
• had a soft body
• didn't have a shell

It could have even been one of the slug-like early relatives of Nectocaris, or maybe one of the predatory worms.

A lot of people mistakenly think that dinosaurs were the world's first meat eaters. Dinosaurs actually didn't emerge until 300 million years AFTER Nectocaris lived. That shows you how old this primitive cephalopod species is. It existed before any animals, or even plants, made it to land. 

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