Hello comrades! Today's post will be about ammonites.
I was planning to make this post about one specific species of ammonite, but there were just so many different kinds, that I thought it would be more interesting to talk about the entire order of ammonites and their fascinating multiformity. First of all, ammonites are obviously not dinosaurs, so this goes under that whole "things" category. They are a specific order of aquatic animals belonging to the phylum mollusca, the same one that including squid and snails. They were common throughout the Mesozoic Era, the same time as the dinosaurs. The whole order went extinct at the same time as the dinosaurs as well. Their closest living relative today is the nautilus, which looks similar to how many scientists today think an ammonite would have looked in life.
Ammonites came in a surprisingly diverse variety of shapes and sizes. The most famous of these shapes being the coiled spiral or "evolute serpenticone." There are technical terms to describe pretty much every conceivable variation of this shape, so a guide is included below.
Ammonites could be enormous or incredibly small depending on the species. Serpenticone's like Promicroceras were only 1.5 cm across, whereas others like Parapuzosia were 2.6 meters across! These are always just the shells that are found as fossils. The soft bodied parts obviously could not survive the fossilization process. The shells were composed of aragonite and so are quite durable. Ammonites would've eaten small prey like minnows and isopods, which are small swimming crustaceans. Depending on the thickness of their shells they could have swam to all sorts of different depths.
That's that for ammonites. The next post will be on some kind of dinosaur.
Monks, Neale, and Philip Palmer. Ammonites. Washington, D.C.: Smithsonian Institution, 2002. Print.