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
Diania Diania Diania is an extinct genus of animal found in the Lower Cambrian Maotianshan shale of China, represented by a single species D. cactiformis. Known during its investigation by the nickname "walking cactus", this organism belongs to a group known as the armoured lobopodians and has a simple worm-like body with robust, spiny, and apparently jointed legs. Its significance is that jointed legs are the defining character of the arthropods and "Diania" may thus be very close to the origins of the most diverse group of animals on the planet. Fossils of these animals were discovered independently by Jianni Liu