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
Spiny eel 43 species known from two genera: Aethiomastacembelus, with 19 known species, and Afromastacembelus, with 24 known species. Spiny Eels from Sri Lanka, China, Southeast Asia and India are also from two genera: Macrognathus and Mastacembelus. The most commonly found Spiny eels in the Aquarium trade are the Macrognathus and Mastacembelus from Sri Lanka, China, Southeast Asia and India. These include such eels as the Peacock and Striped Peacock, the Tire Track and or White spotted eel, the Zig Zag, Fire, Siamese, and Zebra eels. Spiny eel The name spiny eel is used to describe members of two different families of