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
Annelid Annelids are members of the protostomes, one of the two major superphyla of bilaterian animals – the other is the deuterostomes, which includes vertebrates. Within the protostomes, annelids used to be grouped with arthropods under the super-group Articulata ("jointed animals"), as segmentation is obvious in most members of both phyla. However, the genes that drive segmentation in arthropods do not appear to do the same in annelids. Arthropods and annelids both have close relatives that are unsegmented. It is at least as easy to assume that they evolved segmented bodies independently as it is to assume that the ancestral protostome