Radiodonts (the order including Anomalocaris)
My little meme post about Anomalocaris seemed to be enjoyed by a small, very cool group of people so I thought I'd make a more informative post about the Radiodont order.
The name "radiodont" essentially means circular mouth (more specifically referring to the circular arrangement of teeth in the animal's oral cone)
While most radiodonts probably had this circular mouth, it wasn't exactly the same for all of them. For example Anomalocaris' mouth had triradial symmetry whereas most other radiodonts' mouths had tetraradial symmetry (here's an article specifically about the differentiation between Anomalocaris and Peytoia)
Radiodonts' oral cones and specifically Peytoia's oral cone
Radiodonts all had the same basic body plan which included a head carapace and a many-segmented body, with two front appendages on either side of a mouth on the ventral side of the body, one or two rows of "fins" or flaps along the sides of the body, and possibly a set of tail flaps.
Radiodonts were very diverse, Anomalocaris is obv known for being an apex predator, but other radiodonts were sediment sifters (such as Peytoia and Hurdia) or filter feeders (such as Aegirocassis and Cambroraster). They also ranged widely in size across different species, from just a few centimeters long to over two meters long. Aegirocassis was the largest radiodont by a long shot.
Some radiodonts had only one row of side flaps, whereas others had two. It's been theorized that the two rows are homologous to insects' legs and wings (source).
Here is a picture of some Radiodonts: Left to right, top to bottom: Amplectobelua symbrachiata, Anomalocaris canadensis, Aegirocassis benmoulai, Peytoia nathorsti, Lyrarapax unguispinus, Cambroraster falcatus, and Hurdia victoria
Finally, here's the Wikimedia Commons page for Radiodonts, for your viewing pleasure. I hope you enjoyed this short presentation about my favorite Cambrian guys!
