Animal mesoderm forms by enterocoelic pouching, through invagination of the endoderm. The main deuterostome phyla are the Echinodermata and the Chordata. Echinoderms are exclusively marine and include starfish, sea urchins, and sea cucumbers. The chordates are dominated by the vertebrates (animals with backbones), which consist of fishes, amphibians, reptiles, birds, and mammals. The deuterostomes also include the Hemichordata (acorn worms). The Ecdysozoa are protostomes, named after their shared trait of ecdysis, growth by moulting. They include the largest animal phylum, the Arthropoda, which contains insects, spiders, crabs, and their kin. All of these have a body divided into repeating segments, typically
Fiery spiny mouse Fiery spiny mouse The fiery spiny mouse ("Acomys ignitus") is a species of rodent in the family Muridae found in Kenya and Tanzania. Its natural habitats are dry savanna and rocky areas. It may be found as a commensal in human habitations. While most spiny mice are small in size, the fiery spiny mouse ("A. ignitus") is slightly larger, measuring at approximately 10 cm in length. The species gets its name from the hair on their coats that are connected in groups. These groups of hair are stiff guard hairs, resembling tiny quills and they are able to separate from