TAXA OF LIFE	ANIMAL KINGDOM
TAXONOMY OF THE LOPHOTROCHOZOA

INTRODUCTION TO THE LOPHOTROCHOZOA

The Lophotrochozoa is a large monophyletic group within the Protostomata, which was first recognized by Halanych et al. (1995).  It helped to resolve a long-standing debate about the placement of the lophophorates.  Were they deuterostomes (Nielsen, 2001 and Margulis & Schwartz 1998) or protostomes?  Furthermore, Nielsen (2001) considers the lophophorate condition to be ancestral in the clade of the Bilateria which would make it a plesiomorphic character within the Bilateria.  This view has been borne out by several independent studies summarized by Halanych (2004) and Peterson and Eernisse (2001).  Valentine (2004) summarizes molecular, fossil, structural, and developmental work that unites them.  However, he still cannot come up with structural/developmental synapomorphies that define them.  So, he describes the Lophophorata and Eutrochozoa as clades within the Lophotrochozoa.  Follow the links below to their respective phyla.  Please consult The Major Clades of the Animal Kingdom for some views on the relationships of the protostome phyla with each other and with the other phyla of protostomes.  

LOPHOPHORATA

EUTROCHOZOA

LITERATURE CITED

Halanych, K. M. 1996. Testing hypotheses of chaetognath origins: long branches revealed by 18S ribosomal DNA. Systematic Biology 45:223-246.

Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3^rd Edition. W. H. Freeman and Company.  New York.

Nielsen, C. 2001. Animal Evolution: Interrelationships of the Living Phyla. 2nd Edition. Oxford University Press. Oxford. 

Peterson, K. J. and D. J. Eernisse. 2001. Animal phylogeny and the ancestry of bilaterians: inferences from morphology and 18S rDNA gene sequences. Evolution & Development. 3:170-205.

Valentine, J. W. 2004. The Origin of Phyla. University of Chicago Press. Chicago.  614 pp.