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Re: Australodocus a titanosauriform and other new papers



By Tim Williams:

 So for the sake of tradition and convenience, African _Giraffatitan_
 gets put back into North American _Brachiosaurus_ - but a second
 presumptive brachiosaur from Tendaguru (_Australodocus_) remains as
 a standalone genus...despite the stated opinion that it is
 "uncertain" whether the two Tendaguru titanosauriforms can be
 differentiated at the genus level?! I'm not warming to this purely
 utilitarian approach one bit.

Your approach, too, is utilitarian. The difference is that it's _more_ utilitarian: it emphasizes the difference between the two biocoenoses instead of hiding it, facilitating discussion of this difference instead of impeding it, and it does not pretend that we know which "species" are sister-groups.

That's a good thing.

All else being equal, it's good to stick with tradition to avoid confusion instead of introducing meaningless discrepancies into the literature. But when tradition actively obscures things and clouds the minds of scientists instead of facilitating discussion of biology, I'm all for bloody revolution.

By Jaime Headden:

 The use of *Giraffatitan* superimposes the idea or concept of "genus"
 on the discussion of diversity

No. The ICZN superimposes the silly idea and silly concept of "genus", and the 147* concepts of "species" that are mostly inapplicable to the animals in question, on the discussion of diversity.

* As of February 2009.

By Mickey Mortimer:

 When we discussed this on your blog, we narrowed our disagreement
 down to the fact that you don't see genera as clades. But I can
 assure you that Taylor, Williams, myself and most others on here DO
 think of genera as being clades. Thus retaining brancai in
 Brachiosaurus implies it is in a clade with altithorax to the
 exclusion of Sonorasaurus, Cedarosaurus and every other named genus.
 And THAT's the reason we all have a problem with it. You may view
 genera as just Linnaean labels, but most of us see them as implying
 monophyly.

I agree. Genus names should be converted to clade names.

I also agree with Mike Taylor that clade names, all the way to the LITUs, should look like genus names, not like species names. Species are several different kinds of things, and not necessarily clades. Most species concepts, and arguably all interesting ones, require some approximation to population biology before they can be applied -- and there are very few, if any, extinct dinosaurs with which this could be attempted! Clades we can recognize, species... not. (Except under a few of those concepts under which species are clades.)

We should simply stop pretending we can discern species in the dinosaur fossil record. The problem is that the ICZN _forces_ us to pretend anyway -- and the JVP, among others, insists that all manuscripts conform to the ICZN.

The PhyloCode will allow using specimens that do not belong to a named species as specifiers for clade names. This is the way to go.