Talk:Lophotrochozoa

From Palaeos

[edit] Appropriate usage of names

As I've indicated in the main page, I've found Lophotrochozoa to be very poorly defined in terms of content (in fact, I've dropped the name entirely from my own phylogenies because of this inconsistency). If we agree to use Lophotrochozoa in its broad sense as it already is on the Palaeos page, can I suggest that we adopt the name "Trochozoa" to refer to Lophotrochozoa in the narrower sense? I would also strongly discourage using "Lophophorata" to refer to Brachiozoa (Brachiopoda + Phoronida) alone, as it has a long-established history of referring to Brachiozoa + Bryozoa, and I think trying to restrict it just to retain the name is just plain confusing (note that Aguinaldo et al., when they coined the name Lophotrochozoa, probably assumed as many people did at the time that Lophophorata was monophyletic). -- Christopher Taylor, 15 Oct 2006, 14:10 (Brisbane).

Hi Christopher

The Lophotrochozoa seems to be well defined in this paper

Halanych, K.M., 2004, The New Animal Phylogeny. Annual Review of Ecology, Evolution, and Systematics, Vol. 35: 229-256 http://www.lirmm.fr/mab/IMG/pdf/-annurev.ecolsys.35.112202.130124.pdf -

Is this essay unreliable? (I don't know! He does have some nice phylogenetic trees there)

Also for example here: http://chuma.cas.usf.edu/~garey/ (which has a similar cladogram but differeing in some details)

But sure, if it's a controversial clade, by all means we should point that out! In fact there should be alteranative phylogenies on Palaeos org, so that the different theories each get a hearing.

re the Lophophorata - sure, I see your point. Brachiozoa sounds good; it seems pretty clear that Phoronids abd Brachiopods form a monophyletic taxon, with various early brachiopod clades developing a mineralised shell indepeendently from shell-less, phoronid-like anceetors) M alan kazlev 22:16, 14 October 2006 (PDT)

The paper glosses over the fact that only Brachiozoa were included in the original analysis, and Bryozoa were merely assumed (though the fact that it's by the same author as the original analysis suggests that he knows what he intended). Under the Giribet, Distel et al. (2000) topology, for instance, making Bryozoa a defining member of Lophotrochozoa would require Ecdysozoa to become part of Lophotrochozoa, and that would definitely violate the original intentions. Not that Bryozoa's position in that analysis was particularly strong, but that's exactly my point. I would say that Bryozoa and Chaetognatha are the two animal phyla which have the most unstable positions in current phylogenies Christopher Taylor 10:10, 16 October 2006 (Brisbane)