In case some haven't seen the paper yet here is the abstract.
Rouse GW; Fauchald K
The Articulation of Annelids
Zoologica Scripta, 1995, 24(4) (OCT): 269-301
Abstract: The aim of this paper is to assess the monophyly of the
Annelida. Also, recent cladistic analyses of metazoan taxa, using a
variety of data, have shown incongruities with regards to annelids and
associated taxa that should be resolved. The Platyhelminthes is selected
as the taxon to root our minimal length trees and polarise our characters
in a parsimony analysis; ingroup taxa being Mollusca, Nemertea, Sipuncula,
Echiura, Pogonophora, Vestimentifera, Euarthropoda, Onychophora, and the
groups most commonly regarded as true 'annelids', the Clitellata and
Polychaeta. We use 13 characters and a total of 33 states. This results in
18 minimal length trees of 23 steps. The consensus tree has the topology
(Platyhelminthes (Nemertea (Sipuncula Mollusca (Echiura (Polychaeta
(Vestimentifera Pogonophora) Clitellata (Euarthropoda Onychophora)))))).
The name Articulata is applied to the Clitellata, Euarthropoda,
Onychophora, Pogonophora, Polychaeta, and Vestimentifera. The
Vestimentifera is the sister group to, or more likely a clade within, the
frenulate pogonophores, and the name Pogonophora is retained for this
group. In half of the 18 minimal length trees, the traditionally
formulated Annelida, i.e. Polychaeta and Clitellata, is paraphyletic if
the Pogonophora are excluded. In the remaining minimal length trees, a
monophyletic Annelida cannot be formulated. The name Annelida should not
be used unless relationships within the Articulata are resolved to show it
is a monophyletic taxon.
The taxon name Articulata, originally formulated to include the Annelida
and Arthropoda by Cuvier, is defined as the clade stemming from the first
ancestor to show repetition of homologous body structures derived by
teloblastic growth with a pygidial growth zone (segmentation) and
longitudinal muscles broken into bands. The Articulata is considered, on
current evidence, to consist of four monophyletic groups; the Arthropoda,
Clitellata, Polychaeta, and Pogonophora, though the latter group may be a
clade of polychaetes. If this is shown, the Pogonophora should revert to
the original family name Lamellisabellidae Uschakov, 1933. An indented
classification reflective of the cladistic pattern is provided. Other
recent hypotheses about metazoan systematics are analysed.
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