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
Tuft-tailed spiny tree-rat (), meaning "hair". "Lonchothrix" is a member of the Echimyini clade of arboreal Echimyidae rodents. The closest relative of "Lonchothrix" is "Mesomys", reflecting the fact that these taxa have once been classified in the same subfamily (Eumysopinae). These two genera share phylogenetic affinities with several taxa and clades: (i) "Echimys", "Phyllomys", "Makalata", "Pattonomys", and "Toromys" ; (ii) the bamboo rats "Dactylomys", "Olallamys", "Kannabateomys" together with "Diplomys" and "Santamartamys" ; and (iii) "Isothrix". Tuft-tailed spiny tree-rat The tuft-tailed spiny tree rat ("Lonchothrix emiliae") is a spiny rat species from South America. It is known from Brazil south of the Amazon River,