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Unformatted text preview: ive t: the Ecdysozoa i cludes all mol .g. nematodes and arthropods), and is n to Spiralia (Lophotrochozoa). Since Radiation enerally lack spiral cleavage which is alians, we prefer to use the term SpirLophotUsed to all be inalarge 1994 rochozoa (see Mal khov, phylum 1995 for descriptions of cleavage in he Ecdysozoa/Spiralia (LophotrochoAschelminthes of protostomes appears consistent with characters. For example, the developFigure 6. Proposed position of Rotifera within the Bilateria based of growNematodes are the most diverse morphological and molecular data. The annelid-mollusc lineage th by molting under the control on refers to the bulk of the non-ecdysozoan protostomes, but not neceshormone ecdysone has been conﬁrmed poda, pNematoda, this grouprada (see 86 sarily all of them. Only a few key characters are given. 1: Blastopore hylum in and Tardig becomes the anus. 2: Ventral lateral nerve chord (Ahlrichs, 1995). avies & Fisher, 1994). 3: Molting by ecdysis (Aguinaldo et al., 1997). 4: Spiral cleavage. Most numerous
nd future directions pseudocoelomates in r and morphological evidence is overfavor umber se relspecies between nof a clo and ationship canthocephala. Analyses of nuclear 18S tochondrial 16S rRNA genes strongly Tolerate harsh conditions relationship between Bdelloidea and la, one of three possible relationships H studies, but the morphol rphological ave highly varied life oor the sister relationship of Bdelloidea phalahistory weak and is very controappears strategies regard, the time is ripe for a series of tructural comparisons of the epidermis rotatory organ...
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- Spring '08