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Abstract

The advent of numerical methods for analysing phylogenetic relationships, along with the study of morphology and molecular data, has driven our understanding of animal relationships for the past three decades. Within the protostome branch of the animal tree of life, these data have sufficed to establish its two main side branches, the moulting Ecdysozoa and the non-moulting Lophotrochozoa. In this review, I explore our current knowledge of protostome relationships and discuss progress and future perspectives and strategies to increase resolution within the main lophotrochozoan clades. Novel approaches to coding morphological characters are needed by scoring real observations on species selected as terminals. Still, methodological issues, for example, how to deal with inapplicable characters or the coding of absences, may require novel algorithmic developments. Taxon sampling is another key issue, as phyla should include enough species so as to represent their span of anatomical disparity. On the molecular side, phylogenomics is playing an increasingly important role in elucidating animal relationships, but genomic sampling is still fairly limited within the lophotrochozoan protostomes, for which only three phyla are represented in currently available phylogenies. Future work should therefore concentrate on generating novel morphological observations and on producing genomic data for the lophotrochozoan side of the animal tree of life.

References

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This Issue

Philosophical Transactions of the Royal Society B: Biological Sciences cover image

27 April 2008

Volume 363Issue 1496

Discussion Meeting Issue ‘Evolution of the animals: a Linnean tercentenary celebration’ organized by Maximilian J. Telford and D. Timothy J. Littlewood

Article Information

DOI:https://doi.org/10.1098/rstb.2007.2241
PubMed:18192183
Published by:Royal Society
Print ISSN:0962-8436
Online ISSN:1471-2970

History:

Published online11/01/2008
Published in print27/04/2008

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Citations and impact

Keywords

Section

Assembling the lophotrochozoan (=spiralian) tree of life

Abstract

References

This Issue