Octopus Ancestors Were Among the Earliest Animals on Earth, Report Says

Fossils found in Newfoundland throw back cephalopod evolution by tens of millions of years, but does a species' longevity speak to braininess?

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Octopus tetricus.
Octopus tetricus.Credit: Sylke Rohrlach
Ruth Schuster
Ruth Schuster

Be not proud, puny human. We go back maybe half a million years, if we count our small-brained ancestors. If we go all the way back to the arboreal rat-like animal that is the oldest known ancestor of primates, OK, we reach 65 million years or so. But octopi and their cephalopod cousins are among the oldest animals on Earth, going back well over half a billion years, and new research suggests their evolution began even earlier than thought – in the early Cambrian, even before the appearance of the arthropods.

Cephalopods, a family including octopi, squids, cuttlefish and nautiluses, were believed to have arisen in the Late Cambrian. True, the Late Cambrian began 509 million years ago and the earliest cephalopod, a nautiloid, had been thought to date to about 490 million years. Ergo, we already knew cephalopods may go back half a billion years.

But the newly discovered fossils in Avalon Peninsula, Newfoundland, are believed to be cephalopods and have been dated to around 522 million years, around 30 million years earlier than thought, says a report published this week in Communications Biology

Cephalopods are actually part of the enormous phylum Mollusca, and they’re the most advanced of the lot, as far as we know. They are also the only member of that vast empire of animals to have closed circulatory systems.

The earliest known cephalopod fossils were nautiloids, and they thronged the ancient seas. Fossils of early cephalopods have been found from China to Kazakhstan to Texas. 

Octopus marginatus hiding between two shells.Credit: Nick Hobgood

All these earliest cephalopods died out except for the family of Ellesmeroceratidae, which had straight shells, as do the newly found fossils in Canada. Later, the nautiloids would develop their hallmark spiral-shelled shapes.

Assuming the identification of the fossils found in Avalon Peninsula is correct, that adds around 30 million years to the annals of the octopus.

“If they should actually be cephalopods, we would have to backdate the origin of cephalopods into the early Cambrian period,” explains Dr. Anne Hildenbrand of the University of Heidelberg, who studied the fossils together with Dr. Gregor Austermann, in cooperation with the Bavarian Natural History Collections.

The requisite conclusion is that the ancestors of today’s squid, octopi and other cephalopods were among the earliest multicellular organisms, which explosively evolved during the Cambrian.

Alien seeds

Octopi are considered so strange, so alien to other life-forms, that some – scientists at that – have even speculated they come from outer space. Not in spaceships or as pets of other aliens who did have spaceships, but as a result of “cosmic seeding.”

“Life may have been seeded here on Earth by life-bearing comets as soon as conditions on Earth allowed it to flourish,” which would have apparently been about 4.1 billion years ago, wrote a whole team in ScienceDirect in 2018.

Nor was this postulated seeding a one-off, according to the theory. “Living organisms such as space-resistant and space-hardy bacteria, viruses, more complex eukaryotic cells, fertilized ova and seeds have been continuously delivered ever since to Earth,” they wrote – a sort of external intervention that helped drive evolution.

They also postulate that cosmic seeding lay behind the Cambrian explosion, which produced the cephalopod, which produced the octopus – which many believe to be extraordinarily intelligent for what is essentially a cousin of a clam.

The "ghost octopus," dubbed "Casper," was found while searching the Pacific Ocean floor near the Hawaiian Islands.Credit: AP

Specifically regarding octopi, the outer-space team argues that they have “staggeringly” complex genomes with over 33,000 genes, which is more than we have. The tomato also has more genes than we have, but to return to our eight-legged friend, the octopus also achieved immense genetic variation from other cephalopods.  

“Its large brain and sophisticated nervous system, camera-like eyes, flexible bodies, instantaneous camouflage … are just a few of the striking features that appear suddenly on the evolutionary scene,” the panspermia paper points out, explaining that the transformative genes leading from the proto-nautilus to the cuttlefish to the squid to the octopus are “not easily found in any preexisting life-form.” They therefore suggest it plausible to suggest they arrived from outer space.

Long story short, this hypothesis of cosmic seeding in general, and contributiion to the wonder that is the octopus, has not gained wide traction.

Would-be escape artists

The truth is, we don’t know as much as we might think about the octopus. Some extol the wonders of the octo-brain, noting the antics of escapist octopi such as the famed Inky, who made Houdini look amateur; problem-solving octopi; tool-using octopi, and so on.

And what of the octo-soul? Last year’s Netflix documentary “My Octopus Teacher” detailed the relationship that developed in a South African kelp forest between a free-diving filmmaker named Craig Foster and a wild lady octopus. The world fell in love – with the octopus that is, especially when she hugged the human, spreading her arms across his chest. Assuming that’s what she was doing, not tasting him with her suckers. The naked truth is we have no idea how the octopus felt about Mr. Foster.

Anyway. In 2018 Slate ran a piece arguing against octo-smarts and our infatuation, titled “Against the octopus: The overrated cephalopod.”

“Octopus fandom is out of control and blind to the evidence,” wrote Daniel Engber, summing up his thesis: “It’s not a crafty, soulful genius. It’s dinner.” According to a source in the alleged know, Engber wrote, it isn’t that Inky had escaped the aquarium, it was that he was dead; Inky the second also passed on; and what happened that night is possibly that somebody interpreted the absence of an octopus as a sign of intelligence.

All this brings to mind the fierce fight over pre-Clovis human occupation of the Americas: where some researchers see stone tools, others see “just rocks.”

Haaretz does not have a position on octopus braininess, but sheer longevity of a species and its family tree isn’t necessarily a decisive factor. The octopus may have had more than half a billion years to evolve, but sharks aren’t far behind and nobody’s done a documentary about sharks embracing seafaring humans; in fact, we prefer they not do that.

Bacteria may go back as much as 3 to 4 billion years, but, to be fair, they are unicellular. While the climate change thriller novel “The Swarm” posits intelligent amoebae fighting filthy humanity with their hive mind, that hasn’t happened. And as mentioned, human evolution doesn’t go back that far.

Does the octopus? To get back to the postulated cephalopod found in the rocks of Newfoundland, the shells are typical of the ancestral cephalopod: a straightish cone subdivided into individual chambers – which are, tellingly, connected by the siphuncle, a rigid tube that runs through all the animal’s chambers, used to adjust buoyancy by pumping fluid in and out of vacant chambers. All chambered cephalopods have siphuncles. It means, the researchers explain, that these early cephalopods could move freely up and down the water column.

Regarding the siphuncle, octopi obviously aren’t chambered cephalopods, but their cousins the cuttlefish and nautilus are. And the bottom line of the Heidelberg study is that the fossils they found in the Avalon Peninsula resemble other known early cephalopods, but also differ so much from them that they might conceivably form a link leading to the early Cambrian.

And in any case, it sheds light on the evolution of the earliest multicellular, complex animals, culminating in We.

A giant Pacific octopus sticks to the tank glass at the Georgia Aquarium in Atlanta.Credit: Jaime Henry-White / AP

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