December 15th

Box #15 in our count down is Asteracanthus…

Days 1-5 of the count down.
Days 6-10 in the count down
Days 11-15 of the count down
Days 16-20 of the count down
Days 21-25 of the count down
Asteracanthus, a shark with unusual teeth just trying to make a living

Asteracanthus: the “Star Spine”

Asteracanthus is one of those critters that range a large time span and many places across the globe from United States to Europe, from Iran to Morocco…But the most complete specimen is known from the Solnhofen formation of Late Jurassic Germany. It looks like a shark, but is about as close a relative as an animal can be without actually being a shark. The biggest clue to what it actually is are its teeth and the spines in front of each dorsal (top) fin. Most sharks have teeth that are all similar in shape, but this critter is a Hybodontiform.

The Greek hybos means humped, and the Greek dontus means tooth, so you can probably guess what makes them so unusual. Since most of their skeletons are made of cartilage- the stuff that gives our nose and ears their structure- most of these creatures are only known by differences in their teeth and fin spines. But the Solnhofen Asteracanthus preserved the entire body in the soft sea bottom.

Asteracanthus is among the largest of its kind, and grew to about 9ft (3m) long. Paleontologists propose that it preferred the deeper water of the open ocean rather than shallower seas, mostly staying close to the sea bed. Since most of the group are considered slow swimmers compared to most sharks, perhaps it was an ambush predator. The modern zebra shark (or leopard shark) uses a similar hunting strategy and grows to about the same size.

For most of the day they rest on the sea floor, always aware of larger predators, and at night they hunt for clams, crabs, fish, and shrimp. Perhaps Asteracanthus could also prey upon ammonites and weird critters like Clausocaris, which basically look just like the brainbots in the movie Megamind. Bulbous carapace body about the size of your hand, large compound eyes that take up most of that body, and long, dangling shrimp legs.

Learning more about creatures like Asteracanthus can lead us to surprising places, like finding out about the very alien-looking Clausocaris! It all works together to bring these animals to life in our imaginations, and provides a stage for the dinosaurs and other prehistoric creatures that lived alongside them.

5 thoughts on “December 15th

  1. I didn’t know about this until today. I must say, I’m happy that I was introduced to this fish, it’s cool to learn about relatives of the critters in the Paleo Petshop.
    For me, Gigantophis will be my topic of today(as in December 15). Before Titanoboa was known to the world, Gigantophis was regarded as the largest known snake to live. It was discovered in Northern Africa within layers dating to the Eocene epoch of the Paleogene. The original estimate of this snake’s length was up to 35 ft, but later estimates reduced that number to just under 23 ft. It was a constrictor and would have squeezed its prey, much like today’s anacondas and pythons. Remains attributed to Gigantophis were found in Pakistan and, in addition to likely having a larger distribution, this also suggests an earlier radiation of the genus, perhaps beginning earlier in the Eocene and maybe even as far back as the Paleocene. It is part of the family of snakes that also includes forms such as Madtsoia of South America and Madagascar and Wonambi of Australia.

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    1. Thank you! Asteracanthus may not be the biggest critter in the sea, but it’s still pretty cool.

      Giant prehistoric snakes are pretty cool. I think it’s funny that some are said to be 25 or 30 feet as if that was something unique, when there are a few extant snakes that are every bit as big. 🙂

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