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Re: A Clutter of Duckbills



RaptorRKC@aol.com
<<Hypacrosaurus, Corythosaurus, and Lambeosaurus, for example.  
Without the crests, it is rather hard distinguishing one animal from 
the other.  Indeed, one juvenile AMNH specimen of a lambeosaurine 
duckbill could easily have either been a Corythosaurus or a 
Lambeosaurus (I think the final arguments placed it in 
Lambeosaurus).  Thats how undistinguishable those species are.
 What details keep this lump of animals in different genera?  
Actually, what kind of details keep one species in one genera or the 
other?  The details on these three lambeosaurine genera certainly 
indicate how closely related they are.  Hypacrosaurus and 
Corythosaurus have the same type of crest, the "helmet" crest, and 
Lambeosaurus has a similar crest except that the lambeosaurus 
crest has a thin spine sticking backwards on it.  Without these
crests, the rest of the skeleton indicate that these animals had 
probably evolved from a recent common ancestor a few million years 
before they came about.  

What keeps Lambeosaurus, Corythosaurus, and Hypacrosaurus in 
different genera?  Stanley Friesen suggested to me that all of the 
species of these three genera may actually belong to only one genus 
-- the first one coined, Hypacrosaurus.

Sounds like a decent lumping to me.  (Much more probable that 
lumping Deinonychus into Velociraptor.)>>

I like that idea.  It was argued by Horner and someone else (sorry) I 
think, that Lambeosaurus was almost certainly ancesteral to 
Corythosaurus, and that Corythosaurus was almost certainly 
ancesteral to Hypacrosaurus; so it's not too much of a stretch to put 
them all in the same genus.  I like the sound of Hypacrosaurus 
lambei better than Lambeosaurus lambei; a little to cheezy to have 
the same word in the generic and specific name (sort-of like 
Prenocephalus prenus).  In any case I like this idea.  Does anyone 
know however, if Procheneosaurus (the juvinile) was named before or 
after Hypacrosaurus; since it almost certainly belongs in that genus 
(in the big lumped sense, that is), it should have priority over 
Hypacrosaurus IF it was named first.

<<Another group of hadrosaurs that confuse me are Gryposaurus, 
Hadrosaurus, Kritosaurus, and Brachylophosaurus.  I know little 
about these genera in particular, except for the fact that they are so 
closely related and similar.  Any thoughts about which genus and 
species should go where?  Which one was coined first?  
Hadrosaurus was the first good hadrosaur skeleton to be
discovered in N. America.  Just how good was it?  Was it good 
enough to show that Gryposaurus, Kritosaurus, and 
Brachylophosaurus were actually different species of 
Hadrosaurus?>>

George Olshevsky has shown that Hadrosaurus is (no joke) a 
nomum dubium!  Since there was no skull associated with the 
original, no one can really decide which later, and better, described 
genus really belongs in Hadrosaurus, if any at all.  Horner has some 
strange ideas about Brachylophosaurus being a sister taxa to 
Maiasaura (an idea I don't buy for a second).  He also puts 
Kritosaurus in with Anasazisaurus and Naashoibitosaurus in the 
Saurolophines (I think).  He has seperated Gryposaurus from 
Kritosaurus (something he claimed was not possible a few years 
ago) and put it into its own subfamily.  I'm not sure why; in my 
opinion Kritosaurus, Gryposaurus, Anasazisaurus, 
Brachylophosaurus, and Naashoibitosaurus should be put in a 
subfamily together; seperate from Saurolophs + Edmontosaurs.  
Anyways.... Those are just my opinions.

In case any of you are wondering (like you haven't figured it out 
already) I tend to lump genera, and split species and families.

Peter Buchholz
Stang1996@aol.com

Go Mariners!