Threatened arthropods and described. The total number of living arthropod species is probably in the tens of millions. One conservative estimate puts the number of arthropod species in tropical forests alone at six to nine million species. As a consequence of all of the above, most published estimates of the total number of endangered insects and arachnids are probably low by at least an order of magnitude. Conservatively at least eighty percent of all living animal species are arthropods. Since arthropods constitute the majority of the faunal biomass on Earth, their role is vital to the survival of large numbers of insectivores
Arthropods in culture and glioma. Possible medical uses for other spider venoms have been investigated for the treatment of cardiac arrhythmia, Alzheimer's disease, strokes, and erectile dysfunction. Arthropods appear in folklore, in mythology, and in religion. Since Insects in mythology and in religion are covered elsewhere, this section focuses on other arthropods. Both the constellation Cancer and the astrological sign Cancer are named after the crab, and depicted as a crab. William Parsons, 3rd Earl of Rosse drew the Crab Nebula in 1848 and noticed its similarity to the animal; the Crab pulsar lies at the centre of the nebula. The Moche people