DECAPODA: Where are those ten legs!
Crabs, Lobsters, Shrimp? I'm counting the legs!
If you search on-line to try to find more information on Decapoda, you may become more confused than you were when you started out. If your schooling in the Classics has stayed with you, you will know that Decapoda is derived directly from Latin for 'ten legs' (decem is 'ten' and pous is 'leg' or 'foot' in Greek), but when you do a little research you find that there are chelipeds, uropods, biramous pleopods and all sorts of images and drawings which appear to have anything from just a few legs to seemingly endless numbers of leggy appendages.
From a decapoda wiki entry, for example:
"As their name implies, all decapods have ten legs; these are five pairs of thoracic appendages on the last five thoracic segments. The front three pairs function as mouthparts and are generally referred to as maxillipeds, the remainder being pereiopods. In many decapods, however, one pair of legs has enlarged pincers; the claws are called chelae, so those legs may be called chelipeds. Further appendages are found on the abdomen, with each segment capable of carrying a pair of biramous pleopods, the last of which form part of the tail fan (together with the telson) and are called uropods."
While we all like the idea of the wiki, you may perhaps ask having read this explanation what a 'biramous pleopod' is exactly. Or, why the last pair of biramous pleopods together with the telson might be called uropods in the first place?