Anomalocaris - the FIRST super-predator!

Posted by Nima On Friday, September 4, 2009 8 comments

A lot of times I notice most people are at a loss to explain what exactly was on Earth before the dinosaurs... ask them and they just freeze up and draw a blank. Draw a few therapsids and pelycosaurs and you get odd stares and questions like "wait, so that's NOT a dinosaur"? Phytosaurs and rauisuchians: "heh cool, a big gator".

Draw early amphibians of the Coal Age and you get "oh, a big newt. Wait we still have them today, what's so special about that?..." And go back to the Devonian and I swear somebody will mistake a Dunkleosteus for an overgrown Sheepshead or Mahi Mahi. Tell them it ate sharks for breakfast, and watch the eyes roll...

But now take a look at some TRULY ancient creatures. Some of the oldest animal fossils known are from a formation called the Burgess Shale, dating back to the Cambrian period over 500 million years ago. The Burgess Shale provides a valuable window into the ecosystem of some of the first animals. Back then, all life was in the seas. The atmosphere was still far too devoid of oxygen to allow much more than bacteria to survive. Few of the creatures preserved in Burgess bear any resemblance to animals living today, but the Cambrian does have one BIG distinguishing feature - it was the time of the world's first super-predator.

Anomalocaris, the "strange shrimp" of the Cambrian, was an early arthropod distantly related to true shrimps and scorpions. Arthropods would later diversify into insects, arachnids, centipedes and so on, but their first "legend" was this creature. Nearly a meter long (not counting the long tail filaments of some species) it was many times larger than any other Cambrian life form.



Anomalocaris by John Sibbick.
It is rumored that this painting is actually based on Laggania,
a smaller relative of Anomalocaris. At top left you can see Pikaia,
the translucent ancestor of vertebrates. That's right, look at our humble beginnings ;)

And this was possibly the ONLY time that a predator dwarfed all other species by such a huge margin. Anomalocaris had no legs, only rows of undulating fins on its sides. Two huge spiny "jaws" raked food into its disk-shaped mouth. It was insatiable, eating anything its monstrous jaws could capture and kill.

Ironically, the first specimens of Anomalocaris were only small parts of it, and were actually described as several different animals! Decades after its initial discovery, the errors were resolved and it turned out Anomalocaris was truly the Godzilla of the ancient seas, dwarfing everything else in sight - it was fifty times larger than the next largest creature of that time (its relative Laggania). Indeed, with the possible exception of the Devonian fish Dunkleosteus, it's probably the only REAL "Godzilla" predator that ever existed in terms of relative scale.

So here for your enjoyment is a somewhat hasty, minimalist scene from the Cambrian, a few hundred miles south of the Burgess Shale.




Deadly Stalkers of a Crystal Sea

Two Anomalocaris, hunting for food, seem to soar in an iridescent shallow sea over smaller arthropods like the flat-bodied Helmetia and the compact trilobite Brachyaspidia, as well as a few smaller forms. Also seen are early sponges, the spiky worm Hallucigenia, the strange, urchin-like Wiwaxia and the ten-jawed ambush predator Sanctacaris. There were even odder creatures not pictured here such as Opabinia, a finned "worm" with five eyes and tiny toothed jaws at the end of a long "trunk", and Aysheaia, a soft caterpillar-like creature related to Velvet Worms, that likely ate sponges. (I'm too impatient to post links to these critters. Google them if you're curious!)

Yeah. It was a VERY weird world. Where only the seas had life, the air was toxic, multi-celled plants didn't exist, and a "shrimp" was the undisputed King of Beasts. How's THAT for a romantic time-travel getaway spot!

8 comments:

Zach Armstrong said...

Wonderful post, and an even more wonderful illustration!

I agree that people seem to have an inability to identify anything you draw that is prehistoric as anything else than a dinosaur (even paleo-mammals! argh!), which is very frustrating to me. You try to explain it, and it's like a deer stairing into the headlights of a vehicle: they just don't get it.

One small correction, you said, "multi-celled plants didn't exist" at the time of Anomalocaris. Apparently, there is various lines of evidence that indicate land plants were in existence at least as early as the mid-Cambrian (520 mya+). For instance, the bryophyte-like nonvascular plant Parafunaria sinensis is known from the early-to-mid Cambrian Kaili Formation in Guizhou Province, China, which dates to about 520 mya. Also, isotopic delta-Carbon-13 values from the Neoproterozoic Beck Spring Dolomite and Mesoroterozoic Mescal Limestone paleokarst indicate that land plants may have lived around as early as 1.2 bya, and molecular clock estimates predict the earliest land plants to have existed by 700 mya. I would give you the link, but this comment-posting thing won't let me cut and paste!

At any rate, it does appear that there were land plants around the time of the Burgess Shale which is appr. 505 myo, as the bryophyte-like plant Parafunaria was appr. 520 myo.

Nima said...

That sure comes as a shock! So I'm assuming these things were like primitive lichens or club moss.... I'm not sure if they would be "plants" by a modern botanist's definition, but it's amazing to think that anything capable of photosynthesis had reached a multi-cellular scale THAT early!

With all the carbon dioxide in the atmosphere that would make sense. Plants could easily take advantage of the CO2 surplus (you wish comments allowed cut and paste, and I wish for subscripts!!!! Arrrgh!!!). Animals didn't venture onto land until oxygen levels increased enough to support them (probably due to the plants!)

Thank you Zach, I stand corrected. As Paleo King, I should make you the Paleo World's foreign minister... or at least minister of intelligence, seeing as you have it in abundance! :D

Zach Armstrong said...

It came as a shock to me, too, when I first read about it...as for what constitutes a "plant": if Parafunaria is what its describers think it is, namely a bryophyte, then under current plant classification, it is a nonvascular embryophyte--basically, a land plant.

You are right though, it would resemble a club moss or lichen. It was more basal than the more familiar Cooksonia, evidently. You're right that land plants probably took advantage of all that CO2 early on.

I wasn't really trying to correct you, just notify you. I don't think many know about this paper (there is nothing about it on Wikipedia's sections on fossil plants, bryophytes, early life on land, etc.). After all, it was published in Acta Botanica Sinica, which isn't exactly a high-profile journal. I just stumbled upon it by accident. I can't really find much else about it. It is easy to overlook plants. I'm sure you've read that Greg Paul has often complained about the lack of good paleo-botanic information/illustrations. I think it is fairly common for most paleo-aficionados to overlook the Plantae (including me, I don't really do many paleo-scenes because I have a hard time "faking" ancient plants; easily accessible information on stratigraphy and location of fossil plants is nearly non-existent).

You're welcome on the information....I hope it helps or is of interest.

As for "foreign minister" or "minster of intelligence", I'll have to decline as i don't really have the time...that offer did make me chuckle though :D

Anonymous said...

i am so inerested with the paleozoic era i know animals from alaneocaris to petrolacosoris to hinepitan, and guss what... im only 13!

Anonymous said...

I'll never ear Dole pineapple out of the can the same.

Anonymous said...

That is "eat". By the way my name is Paul De Vinny not anonymous and I can be reached for comment at paul.devinny@gmail.com

Anonymous said...

cool but i'd like to say i loved the pictures...but you could describe the animals around him

Anonymous said...

This is so cool! I used to have book on all of this stuff, so it's good to get a memory refresher. Whenever I try to tell people about before the dinosaurs, its like I send them into an ungodly realm, filled with giant millipedes and twenty foot long fish. and when I'm done they either give me a blank stare or say "THAT'S SCARY!!"

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