Modified from Tree of Life for Kingdom Animalia (after Ruppert & Barnes 1994 p. 1052).

     ========================================== Porifera (sponges)
     |
     |      =================================== Cnidaria (jellyfish, anemones, corals, etc.)
     |      |
     |      |  ================================ Ctenophora (comb-jellies)
     |      |  |
     |      |  |       ======================== Platyhelminthes (flatworms, tapeworms,etc.)
     |      |  |       |
     |      |  |       |  =(branch uncertain)== Aschelminthes (pseudocoelomates: nematodes,rotifers,etc.)
     |      |  |       |  |
<<=M=|      |  |   =P==|  |   ================= Nemertea (ribbon worms) 
     |      |  |   |   |  |   |
     |      |  |   |   |  |   |        ======== Sipuncula (peanut worms)
     |  =E==|  |   |   ===|   |  ======|
     |  |   |  |   |      |   |  |     ======== Mollusca (snails, clams, squids, etc.)
     |  |   |  |   |      =C==|  |
     |  |   |  |   |          |  |     ======== Echiura (proboscis worms)
     |  |   |  |   |          ===|     |
     |  |   |  |   |             |  ===|  ===== Pogonophora (beard worms, vent worms)
     |  |   ===|   |             |  |  ===|
     |  |      |   |             ===|     ===== Annelida (segmented worms)
     |  |      |   |                |
     ===|      |   |                |  ======== Onychophora (velvet worms)
        |      |   |                ===|
        |      |   |                   ======== Arthropoda (insects, spiders, crabs, etc.)
        |      =B==|
        |          |   ======================== Chaetognatha (arrow worms)
        |          |   |
        |          =D==|  ===================== lophophorates (bryozoans, brachiopods, etc.)
        |              |  |
        |              ===|  ================== Echinodermata (starfish, urchins, etc.)
        |                 |  |
        |                 ===|  =============== Hemichordata (acorn worms, pterobranchs)
        |                    ===|
        |                       =============== Chordata (sea squirts, vertebrates, etc.)
        |
        =====(phyla of uncertain affinity)===== Placozoa, Monoblastozoa, Rhomobozoa, Orthonectida

Traits supporting each clade (** plesiomorphic- a primitive state, not unique to clade):

M= METAZOA: a) true multicellularity (coordinated & differentiated cell types, no real symmetry, lack endoderm, no true gut), b) monociliated cells**, c) radial, indeterminate cleavage, d) blastula stage larva**, e) diplosome**

E= EUMETAZOA: a) diploblastic organization, b) true tissues, c) gastrula stage, d) blind gut (no anus)

B= BILATERIA: a) bilateral symmetry,b) cephalization, c) triploblastic organization (extensive mesoderm), d) organ-system level of organization, e) protonephridia

P= PROTOSTOMIA: a) spiral, determinate cleavage, b) mesoderm from mesenchyme cells, c) mouth (and sometimes anus) from blastopore, d) multiciliated cells, e) trochophore-like larva

C= COELOMATE PROTOSTOMES: a) coelom via schizocoely, b) flow-through gut (anus present)

D= DEUTEROSTOMIA: a) radial, indeterminate cleavage**, b) mesoderm from epithelial cells, c) coelom via enterocoely, d) blastopore yields anus, e) tripartite coelom & body plan, f) monociliated cells**

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