Rouse G.W. & Fauchald K. 1997. Cladistics and polychaetes.
Zoologica Scripta 26: 139-204
ABSTRACT
A series of cladistic analyses assess the status and membership
of the taxon Polychaeta. The available literature, and a review by
Fauchald & Rouse (1997), on the 80 accepted families of the
Polychaeta is used to develop characters and data matrices. As well
as the polychaete families, non-polychaete taxa such as the Echiura,
Euarthropoda, Onychophora, Pogonophora (as Frenulata and
Vestimentifera), Clitellata, Aeolosomatidae and Potamodrilidae are
included in the analyses. All trees are rooted using the Sipuncula as
outgroup. Characters are based on features (where present) such as
the prostomium, peristomium, antennae, palps, nuchal organs,
parapodia, stomodaeum, segmental organ structure and distribution,
circulation and chaetae. A number of analyses are performed involving
different ways of coding and weighting the characters, as well as the
number of taxa included. Transformation series are provided for
several of these analyses. One of the analyses is chosen to provide a
new classification. The Annelida is found to be monophyletic, though
weakly supported, and comprises the Clitellata and Polychaeta. The
Polychaeta is monophyletic only if taxa such as the Pogonophora,
Aeolosomatidae and Potamodrilidae are included and is also weakly
supported. The Pogonophora is reduced to the rank of family within
the Polychaeta and reverts to the name Siboglinidae Caullery, 1914.
The new classification does not use Linnaean categories and the
Polychaeta comprises two clades, the Scolecida and Palpata. The
Palpata has the clades Aciculata and Canalipalpata. The Aciculata
contains the Phyllodocida and Eunicida. The Canalipalpata has three
clades; the Sabellida (including the Siboglinidae) Spionida and
Terebellida. The position of a number of families requires further
investigation.
'Cladistics and polychaetes' contains two data matrices. One of
these is coded according to the method known as A/P coding (Pleijel
F. 1995. On character coding for phylogeny reconstruction. Cladistics
11: 309-315). The other is a more traditional multistate character
matrix. The A/P matrix was analysed using all characters weighed
equally (as 1) and also with an a priori differential
weighting scheme. The A/P matrix is provided in two versions, one
with equal weights (A/Pe) and one with differential weights (A/Pw).
The matrices for A/P coding are downloadable in Nexus format
(MacClade, PAUP readable) files and as Hennig 86 files. The
multistate matrix is only available in Nexus format, since Hennig 86
will not accomodate more than 9 character states. The multistate
characters are all unordered. The analyses in 'Cladistics and
polychaetes' were also run using complete and restricted taxa sets.
All taxa are included in each matrix and the 29 not included in the
'restricted analyses' can be excluded if required. For further
details on characters, homology arguments and scoring justifications
see:
Fauchald K, Rouse GW. 1997. Polychaete systematics: Past and
present. Zoologica Scripta 26: 71-138.
Rouse GW, Fauchald K. 1997. Cladistics and polychaetes. Zoologica
Scripta 26: 139-204.
