Question: are nematodes invertebrates or vertebrates?
Answer: Nematodes, as members of the phylum Nemata (or Nematoda), are one of the most abundant groups of invertebrates on earth and rival the Arthropoda in biodiversity and species abundance. While some 20,000 nematode species have been described, estimates for species diversity range from 100,000 to 10 million (Poinar, 2011).