With similar rami

Geoff Read g.read at niwa.cri.nz
Thu Feb 19 23:39:26 EST 1998


I am looking at the characters in Rouse and Fauchald (1997) "Cladistics &
polychaetes," one of two important papers that Kristian, Greg (and the
Smithsonian) have most generously provided free copies of around the world
& at vast expense.

There is a lot to digest, but at present I need help on one small aspect. I
do not understand the parapodial distinctions -  'with similar rami,'
'spioniform' (aha - we might know a priori who have those!), 'with
projecting neuropodia.'

In particular I am unclear how for example a nereid (grouped as 
'projecting neuropodia') could not have 'similar rami.' Although Fauchald
and Rouse claim (p105) that nereid notopodia are shorter 'in most taxa,'
this is not my experience.  So it is subjective (thus agreeing with F&R on
p81), and in any case not something that is so clear-cut as to be of
fundamental significance.   And one might also say that a spioniform has
similar rami or that a spionid may, in other places, be without postsetal
lobes and thus have  tori (another parapodial classification) - unless one
defines a torus as only having uncini - but that is dealt with under setae
and would eliminate the example arenicolids (getting messy here).

Given that they are short-hand for (I hope) much more complex 
decision-making than those simple titles imply, I am not sure that we are
finally told enough to be convinced those groups are well-defined and
mutually exclusive (they are permitted to overlap in the analysis, but have
not been overlapped, I think, in the coding).

Perhaps it does not matter in the overall context - &  I look forward to
the enlightenment from the list that will dispel my current faint
discontent with the R&F parapodial classification.

PS: I assume Capitellidae singled out as having _uncini_ (p88) is not true
since this character is not listed in its family review  or in the matrix? 

  Geoff Read <g.read at niwa.cri.nz>

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