List of animal phyla
Arthropoda: by far the largest phylum. A recent estimate of the number of arthropods on Earth today is 3.7 million species. It includes animals with jointed limbs and an exoskeleton made of chitin. There are many opinions about its classification. An arrangement found in several texts is: Superphylum Arthropoda: Phyla Chelicerata, Crustacea, Uniramia (Insects + Myriapoda).p61 If Arthropoda is ranked as a phylum, its subdivisions rank as Subphyla: