OTHER DEUTEROSTOMES (Other deuterostome study images;
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1) The lophophorates include 3 phyla with traits of both deuterostomes [tri-coelomate body (protocoel, mesocoel, metacoel), radial cleavage, blastopore yields anus (e.g., brachiopods), coeloms via enterocoely (some)] and protostomes [larval protonephridia (some), mouth from blastopore (e.g., bryozoans)]
c) Ph. BRYOZOA (moss animals) approx. 5,000 marine and freshwater spp; encrusting colonial animals with polyp-like zooids that extend out of a gelatinous, leathery or calcareous exoskeleton; particles are captured by lateral cilia or tentacular flicking; many colony forms
d) Ph. BRACHIOPODA (lamp shells) approx. 440 marine spp; solitary animals enclosed by 2 shells (dorsal & ventral!) attached to a stalk (=pedicle); coiled lophophore pumps slowly to maximize efficiency vs rate; most extinct by 225 MYA; some have a blind gut (no anus!)
2) Ph. HEMICHORDATA (acorn worms) ~120 marine spp; the phylum is pivotal to our understanding of deuterostome origins
b) the Cl. Enteropneusta (acorn worms) ~90 marine spp;
3) Echinoderms and hemichordates share several traits:
4) Ph. XENOTURBELLIDA (1 marine genus, Xenoturbella; 2 spp.) odd 3-4 cm ciliated flatworm-like animal described in 1949 (no brain, no anus, no excretory system, no gonads, diffuse nervous system)
Copyright (c) 2017 by A. Richard Palmer. All rights reserved.
(revised Dec. 19, 2016)