It’s no secret that I love checklists, especially pretty ones.

There’s something about having that little chart that makes me want to come back and look at it. Coming back to look at the pretty checklist keeps me focused so that I can get stuff done. Getting stuff done means I can check things off one by one and have physical PROOF that I’m actually getting stuff done.

If they’re pretty enough to paste on my wall, or print out as stickers that I can stick on all my journals? Well then that adds a little extra cute into my day, and there’s nothing like having a bad day and opening my journal or sketchbook to find a cute paleo critter waving up at me. 😀

So here we have all of the critters available for adoption at Pete’s Paleo Petshop, in adorable chibi form. The critters with a spot of blue behind them have already been prepped and are ready for professional printing. They are also available on various items for sale on Redbubble. Once they’re all prepped then I’ll take all the files to be printed and they’ll be ready for exhibits.

If you are interested in stickers, then let me know and I’ll figure out some way to make them available.

In short, my lessons learned this month are…

• Find small ways to bring joy to your day, everyday
• A chart or written set of goals is even more inspiring if it brings you joy. Finding a way to easily and quickly make it beautiful or fun will make one more likely to go back and reasses those goals.

And the Critter of the Month is…

Way back in 1822, Sir Henry Thomas de la Beche discovered some very interesting fossils never before seen on the southern coast of England, in the Lias formation. Among the fossils of Ichthyosaurs and Plesiosaurs (which were new and exciting discoveries at this time), he found spines that he described as similar to those of the triggerfish.

Triggerfish have two dorsal fins on their backs, and the first of these is reduced to three strong spines. These spines usually lay flat against the fish’s back in a shallow groove, but can be quickly raised when startled. Sometimes the fish will flee from danger into a crevice, and lock itself in place with the spines on its back and belly.

Sir De la Beche also found teeth and curious platelike fossils alongside the spines. He determined that it was some kind of shark, but did not assign a name to the creature. The remains were the first known fossils of Hybodus reticulatus, confirmed as that species by John G. Maisey in “Cranial Anatomy of the Lower Jurassic Shark Hybodus reticulatus.”

Exactly when Hybodus was officially described and named I do not know, because all the early papers describing it were either in German or French, but I did manage to find a catalog of fossil fish species published in 1837. Hybodus has 12 different species listed, but Mr. Maisey says that at one time there were as many as 20 species. This leads us to a common problem in early paleontology. Wastebasket taxon.

A wastebasket taxon is when paleontologists lump many different fossils under one genus, like when all the pterosaur fossils were lumped under the name Pterodactylus. This tended to happen simply because there were very few fossils, and many of them were incomplete or in pieces. Fossils that looked similar would logically be grouped together under the same name, until more complete fossils were found. Of course many of these fossils would have enough differences anyway that they still need to be separated, so the fossils are assigned to different species. Once there are fossils complete enough to see that they are not only different from the original genus (Pterodactylus in our example), but also have enough fossils to be able to identify them as a completely different animal, then a new paper can be written and a new genus is named, like Dimorphodon.

This is exactly what has happened to Hybodus. Of course with a prehistoric shark-ish critter the teeth and spines were usually the only identifiable bits. Many were different enough that Paleontologists grouped them into different species, but it wasn’t enough to be able to determine if they were entirely different genus until more recently.

Fast forward to the time I created Chum. I went to Wikipedia, followed the trail of crumbs to all the papers I could find at the time, and it seemed that the general consensus was maybe about four contested species of Hybodus. Murky water? Yes. A case of “we need more fossils?” Yes. Subject to change as soon as something new was discovered? Absolutely guaranteed.

So I did the best I could with the information I had and picked a species with a really nice descriptive paper. At the time the one I could understand best happened to be Hybodus fraasi. Mr. Maisey had a few beautiful papers on both Hybodus fraasi and H. hauffianus, but I had a hard time figuring out which formation H. hauffianus was found. Now I am better at reading papers, and I know that H. hauffianus comes from Holzmaden, Early Jurassic Germany. H. fraasi comes from the Solnhofen of Late Jurassic Germany, so at the time of Chum’s creation I chose the species from the Solnhofen.

Now Hybodus is down to two species that still need further evaluation and research…

H. reticulatus and H. hauffianus

But wait, H. fraasi is not on that list.

You’re right, it’s not, so what is it? What kind of critter is Chum then?

Two Hybodus species, including H. fraasi, were given a new genus name of Egertonodus.

So is Chum a Hybodus hauffianus or a Egertonodus fraasi?

Unfortunately I don’t have an easy answer for that one. My primary sources of reference were the fossil of H. fraasi, accompanied by the generic hybodus body plan as illustrated in the paper written by Mr. Maisey. I honestly don’t think Chum fits the soft body tissue preserved for H. hauffianus closely enough to say he fits that species precisely, especially since I was primarily thinking of H. fraasi at the time, but I may be biased according to my own intentions at the time. I need to take another look to be sure.

What do you think? Is my brand new book already outdated? Is Chum good enough for H. hauffianus or should I change his genus to Egertonodus? Let me know in the comments!

And to all my American neighbors, I hope you have a safe and fun Fourth of July! 😀

See you August 1st for the next Critter of the Month!

This little critter loves a ride on your shoulder.

Share your guess in the comments! She’ll be one of the critters over on the critter page. 🙂

References

de La Beche, H.T. (1822)
Remarks on the Geology of the South Coast of England, from Bridport Harbour, Dorset, to Babbacombe Bay, Devon. Transactions of the Geological Society, ser.2, 1: 40–47, 6 plts.

Egerton, P. (1837)
A systematic and stratigraphical cataloge of the fossil fish in the cabinets of Lord Cole and Sir Philip Grey Egerton: together with an alphabetical and stratigraphical catalogue of the same species with references to their published figures and descriptions. London, 1837
DOI: 10.5962/bhl.title.23781

Maisey, J.G. (1982)
The Anatomy and Interrelationships of Mesozoic Hybodont Sharks. American Museum Novitates, 2724, 1–48

Maisey, J.G. (1986)
Anatomical Revision of the Fossil Shark Hybodus fraasi (Chondrichthyes: Elasmobranchii). American Museum Novitates, 2857, 1–16

Maisey, J.G. (1987)
Cranial anatomy of the lower Jurassic shark Hybodus reticulatus (Chondrichthyes: Elasmobranchii), with comments on hybodontid systematics. American Museum Novitates, 2878, 1–39