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
Hexapoda ago. Hexapoda The subphylum Hexapoda (from the Greek for "six legs") constitutes the largest number of species of arthropods and includes the insects as well as three much smaller groups of wingless arthropods: Collembola, Protura, and Diplura (all of these were once considered insects). The Collembola (or springtails) are very abundant in terrestrial environments. "Hexapods" are named for their most distinctive feature: a consolidated thorax with three pairs of legs (six legs). Most other arthropods have more than three pairs of legs. Hexapods have bodies ranging in length from 0.5 mm to over 300 mm which are divided into an