Archaeopterygid bird from China

[Robert Mesibov]

Responding to an off-list comment, I'll answer my own question. What
difference does "centre of origin" make? Not much, nowadays.

Taxonomists s.s. have always been interested in where things live, and have
encoded geographical information in the names they give to taxa. There's
Hespero-this and Noto-that, and an abundance of species names like
orientalis and somewhere-ensis.

Systematists s.s., on the other hand, especially in the last 30 years, have
rigorously excluded geographical information from their thinking. "Location"
is never, ever among the list of characters drawn up for a phylogenetic
analysis, and no phylogenetic software package includes algorithms for
raising a skeptical eyebrow at patterns that make no geographical or
geological sense.

The results are cladograms and classifications with character-based
relationships which hopefully reflect evolutionary history, but which have
absolutely zero geographical content. Some systematists replace the terminal
taxa in their trees with pre-defined "areas" to see what happens. Often the
results are confusing: "Whoops. That taxon's seriously out of place. Must've
been a jump dispersal."

"Centre of origin" thinking in 2005 is similarly after-the-fact. It's a
belated attempt to root character-based phylogenies in geographical reality.
The divide between systematics and biogeography these days is
disappointingly wide. I'm sure most systematists recognise that taxon
history and earth history can't be seriously discordant, and that every
taxon and every branching event has or had an address. Unfortunately, this
recognition goes out to lunch when a modern sytematist erects a phylogenetic
hypothesis, and comes back to the office to find it has no contribution to
make other than a speculation or two in the Discussion section.
---
Dr Robert Mesibov
Honorary Research Associate, Queen Victoria Museum and Art Gallery
and School of Zoology, University of Tasmania
Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
(03) 6437 1195

Tasmanian Multipedes
http://www.qvmag.tas.gov.au/zoology/multipedes/mulintro.html
Spatial data basics for Tasmania
http://www.geog.utas.edu.au/censis/locations/index.html
---