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Re: Sauropodz r kewl WAS silly ramble



But as i said before, there are so many even older (albeit more common) fossil 
vertebrate genera with multiple species, often more than 10.


From: "Mike Taylor" <mike@indexdata.com> 
To: keenir@hotmail.com 
Cc: "david marjanovic" <david.marjanovic@gmx.at>, dinosaur@usc.edu 
Sent: Tuesday, April 17, 2012 4:36:34 AM 
Subject: Re: Sauropodz r kewl WAS silly ramble 

On 17 April 2012 09:13, Anthony Docimo <keenir@hotmail.com> wrote: 
>> Date: Tue, 17 Apr 2012 08:15:15 +0100 
>> From: mike@indexdata.com 
>> To: keenir@hotmail.com 
>> CC: david.marjanovic@gmx.at; dinosaur@usc.edu 
>> Subject: Re: Sauropodz r kewl WAS silly ramble 
> 
> 
>> >> > (Well, that or dinosaur paleontologists could stop putting every new 
>> >> > species in its own genus, already!) 
>> >> 
>> >> I think they should (at least for the most part) stop pretending to 
>> >> recognize species at all. 
>> > 
>> > but then wouldn't the Genus be the new LITUs? 
>> 
>> Yes. But with the crucial advantage that the name itself no longer 
>> depends on a phylogenetic hypothesis. When I name a new dinosaur as 
>> (say)_a species of Brachiosaurus, if it then turns out that 
>> Cedarosaurus weiskopfae clades closer to Brachiosaurus altithorax 
>> proper than to my new animal, then either I have to move mine to a new 
>> genus, or move the species weiskopfae into Brachiosaurus. 
> 
> Ah, okay; see, here is where my confusion may have arisen in this case:  when 
> I hear "let's get rid of the 'Species' rank"...what my mind interprets that 
> as is "let there be nothing below Genus". 

Yes, exactly.  Among dinosaurs, there really IS nothing below genus. 
(There are a few exceptions: a few dinosaur genera that contain 
multiple species.  In pretty much every case, there are arguments 
about those referrals.) 

> ...which leads to, in your example, the question of "how do you move 
> weiskopfae into Brachiosaurus, when there is nothing below Brachiosaurus?" 

Correct.  For all *practical* purposes, Brachiosaurus is a terminal 
taxon.  The moment you try to refer another species into that genus 
(e.g. "Brachiosaurus" brancai (Janensch 1914)) you are gambling your 
name on a phylogenetic hypothesis, and begging to have it removed to a 
different genus (Paul 1988, Taylor 2009). 

>> Either way, 
>> an actual NAME changes, which is never good for any meaningful 
>> stability. Much better just to give each species its own genus name 
>> and let them shuffle around the tree as they will. 
> 
> Sounds like a paradise for splitters.  (or a paradise of what lumpers fear 
> from splitters) 

So? 

Really.  What *specifically* would be bad about this? 

Linnaeus invented the binomial convention while thinking about extant 
diversity.  That differs hugely from Mesozoic diversity in two ways. 
First, there is appallingly more of it, so that coming up with a 
unique uninomial for each species is just impractical, whereas for all 
the rapid growth in named dinosaur genera, we're still only around the 
1000 mark.  Second, you can get multiple complete specimens of extant 
species, so you can make much firmer conclusions about phylogeny 
(which isn't to say that that neontologists don't make mistakes).  But 
when you're dealing with 150-million-year-old species that are based 
on very partial, badly crushed and broken specimens (usually only 
one), then EVERY phylogenetic hypothesis is really a wild guess, and 
almost certain to be contradicted somewhere down the line.  In that 
situation, it's crazy to tie terminal-taxon nomenclature to phylogeny. 

Put it this way: if Linnaean taxonomy didn't exist and we were 
inventing a nomenclatural system from scratch for Mesozoic dinosaurs, 
we would NEVER come up with the idea of binomials. 

> Though, if there are no species ranks, wouldn't that create even more 
> arguments about if the new find is a Brachiosaurus? (before the elimination 
> of Species, we might have said "the new find is a variant of Brachiosaurus 
> altithorax")...I'm particularly fearing what the ceratopsian debates will 
> become with no subdivisions below Torosaurus, Triceratops, etc. 

Why?  What exactly do you fear?  The arguments would be arguments 
about *science* rather than about taxonomy.  That's a better use of 
all our time. 

-- Mike.