Animals in the Phylum Arthropoda are considered Arthropods. This name origonates from the Greek, arthron, “joint” and podos “foot”. The jointed-feet as it were, includes insects, arachnids, and crustaceans to name a few. They are characterized by their jointed limbs that are made from α-chitin.
The body plan of arthropods is composed of repeated segments. Each segment has a pair of appendages.
Partly due to their body plan, arthropods are a very versitile group. They comprise more than 80% of all described species. In fact there are over 1 million described so far, with new ones being discovered all the time.
Most insects can be divided into the following major orders:
Arachnida – spiders, scorpions, etc.
Merostomata – horseshoe crabs,eurypterids
Pycnogonida – sea spiders
Chilopoda – centipedes
Diplopoda – millipedes
Pauropoda – sister group to millipedes
Symphyla – resemble centipedes
Branchiopoda – brine shrimp etc.
Remipedia – blind crustaceans
Cephalocarida – horseshoe shrimp
Maxillopoda – barnacles, copepods, fish lice, etc.
Ostracoda – seed shrimp
Malacostraca – lobsters, crabs, shrimp, etc.
Entognatha – springtails, etc.
If you’re curious about entomology, we compiled a list of entomologists you should follow here.