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
Jaliscan spiny pocket mouse species to the interior. Jaliscan spiny pocket mouse The Jaliscan spiny pocket mouse ("Heteromys spectabilis") is a species of heteromyid rodent endemic to Mexico. The specific name "spectabilis" means "striking", and refers to the animal's relatively bright coloration. It was formerly placed in the genus "Liomys", which is now recognized to be paraphyletic and has been subsumed into "Heteromys". The Jaliscan spiny pocket mouse is a relatively large member of its genus, measuring in head-body length, with a tail about the same length again. Adult males weigh about on average, while females are significantly smaller, weighing on average. The fur