How do the largest groups of arthropods differ?

Answer 1

Under the arthropoda phylum are subphyla Chelicerata, Myriapoda, Crustacea, and Hexapoda. There is also an extinct class Marrellomorpha and an the extinct Trilobite ("three lobes") subphylum. The chelicerata, like Spiders, scorpions, mites, etc., get their name from having appendages appear before the mouth, unlike most other arthropods they have only two body sections, and neither wings nor antennae; myriapods like centipedes and millipedes characterized by a high count of body segments and legs; crustaceans like crabs, shrimp, woodlice the only ones with biramous (two-part) limbs, and a nauplius larval form; hexapoda (with the class Insecta, the insects) named for their consolidated thorax with only three pairs of legs.