Threatened arthropods United States, and IUCN Red List for international purposes. Only a tiny fraction of the planet's endangered arthropods are formally recognized as such, as no one has ever evaluated the conservation status of the vast majority of arthropod species. It is difficult to estimate the total number of endangered arthropod species, since many of the taxa themselves have not been recorded. For example, in North America the estimated number of insect species exceeds 163,000, of which only about two thirds are taxonomically known. An even greater discovery awaiting, over 72 percent of North American arachnids are yet to be named
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