overly-inflated Family Staphylinidae

Margaret K. Thayer mthayer at FIELDMUSEUM.ORG
Thu Feb 10 14:26:34 CST 2005


Ken,

You seem to have missed the fact that Pselaphinae (=former Pselaphidae) is
merely a PART of the Omaliine group, not the whole thing by a long
shot.  This is quite clearly shown on the Staphylinidae TOL page
http://tolweb.org/tree?group=Staphylinidae.  If our analysis (Newton &
Thayer 1995) shown there is correct, Pselaphinae is nested at least several
nodes up within the Omaliine group, so Pselaphinae is not by any means a
potential sister group to the ...hmmm... more traditional
Staphylinidae.  ("More traditional" is a slightly problematic description,
since some other groups have also been added to Staphylinidae in recent
decades, but I won't try to address that here.)  And although the tree on
the TOL page shows the Omaliine group (Pselaphinae + 9 other subfamilies)
as the sister taxon of the remainder of the family, there is currently no
strong support for the three other groups of subfamilies forming a
monophyletic unit.  In other words, the basal nodes within Staphylinidae
are currently not well resolved.  I hope that will change in the next
several years through some planned work...

I agree with Derek that it seems likely that Silphidae will end up within a
broad Staphylinidae (and NOT basally), and perhaps also
Scydmaenidae.  These three current families taken together are
well-supported as monophyletic, but "Staphylinidae" without the other two
is not.  I discuss this at some length in my upcoming chapter on
Staphylinidae in the Handbook of Zoology (Thayer, M. K.  11.
Staphylinoidea. 11.7. Staphylinidae Latreille, 1802. 40+ pp. In:
Coleoptera, Vol. I. Morphology and Systematics (Archostemata, Adephaga,
Myxophaga, Polyphaga partim). Handbook of Zoology Vol. IV, Arthropoda:
Insecta (ed. by Kristensen, N.P. & Beutel, R.G., vol. ed. by Beutel, R.G. &
Leschen, R.A.B.). De Gruyter, Berlin, New York.)  This is in press and due
out sometime this year, I think.

If the Omaliine group (or something like it) eventually gets a formal
taxonomic name, it would have to be coordinate with Pselaphidae, which
dates to 1802, rather than Omaliinae (1825).  When Lawrence and Newton
(1982, Ann. Rev. Ecol. Syst.) first recognized and named the four informal
groups of staphylinid subfamilies, they suggested that Pselaphinae might
belong in the Omaliine group but included it there somewhat
tentatively.  After Pselaphinae, Omaliinae is by far the largest and most
widely distributed and known subfamily in the group, which I believe was
their reason for using it.  (Micropeplinae Leach, 1815 is also an older
name than Omaliinae, but like Pselaphi*ae was only tentatively included by
L&N 1982.)

The fundamental problem as far as both grouping and ranking (as always) is
that we do not yet have a solid phylogenetic foundation for the
Staphylinidae (however defined!) and its relatives.

Margaret Thayer

At 11:41 AM 10-02-05 -0600, Ken Kinman wrote:
>Dear Derek,
>      I disagree that taking the Pselaphidae (= Omaliinae group) back out
> would *definitely* make Staphylinidae paraphyletic.  On the contrary, the
> Omaliinae grouping splits off at the base, before all the other
> staphylinids.  Therefore, this makes for a perfectly natural cladistic
> split of this huge group into two separate sister families.
>      This seems preferable to letting Staphylinidae keep sucking in more
> and more families until it becomes equivalent to Staphylinoidea (which
> itself could be paraphyletic to all the Scarabaeiform groups; wouldn't
> that be a fine taxonomic mess).  In other words, this growing family
> could well become a taxonomic black-hole, which someone will end up
> having to split back up into Pselaphidae, Staphylinidae, and any other
> taxa that got sucked in trying to avoid paraphyly (you yourself indicated
> such a future possibility).  I just don't see the point in going down
> that slippery slope (of more and more taxonomic lumping) when it can be
> easily avoided now.  I think this alternative (more conservative)
> approach would promote stability in the long term and also create a more
> balanced classification now (rather than later).  It also seems less
> confusing calling it Family Pselaphidae, rather than the "Omaliinae
> group".   Anyway, something to think about.
>         -----Cheers,
>                   Ken
>P.S.  If you read other quotes by Darwin, it is clear that when he speaks
>of genealogical classifications, he also favored the use of paraphyletic
>taxa when an exgroup was clearly different from its parent taxon due to an
>accelerated evolutionary spurt.  I forget the quote, but he said it using
>very elegant 19th Century phraseology.



Margaret K. Thayer, Ph.D.               mthayer at fieldmuseum.org
Assistant Curator, Zoology -- Insects    Personal Web
page:   http://tinyurl.com/4g4zz
Field Museum of Natural History       http://www.fieldmuseum.org
1400 South Lake Shore Drive
Chicago IL 60605-2496, USA
PHONE: +1-312-665-7741 (direct-dial)
FAX: +1-312-665-7754
Austral Staphylinidae project, including Staphyliniformia databases:
         http://www.fieldmuseum.org/peet_staph/




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