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Dinosauria: Original Definition VS Clade Conversion (WAS: Re: tiny-armed theropods)



Though using vicious reverse-thinking of article 11.7 of the Phylocode, the dinocephalian *Dinosaurus* Fischer, 1847 (= *Brithopus*) and the sauropodomorph *Dinosaurus* Rütimeyer, 1856 (= *Gresslyosaurus* = *Plateosaurus*) could be interesting specifiers. And by interesting, I mean funny. :-)

Joke apart, Owen having used *Megalosaurus*, *Iguanodon*, and *Hylaeosaurus* to define his Dinosauria, it would have been interesting to preserve the use of the original specifiers - the underlying issue being the validity of these taxa. *Megalosaurus* was indeed considered by some (Molnar et al., 1990; Allain & Chure, 2002) as a dubious taxon until its recent resurrection by Benson et al. (2008) - though I know that some paleontologists were not pleased with it. And, of course, *Iguanodon* was assigned a new type species (*I. bernissartensis*) to stabilize ornithopod taxonomy.

Though these three genera cannot be considered as "types", they were specifically included in this group by Owen. Types are a special kind of specifiers of which the use is strictly regulated by the ICZN. Other specifiers are used according to the recommendations of the Phylocode. This might lead to some looseness in phylogenetic taxonomy - but this was precisely the intention of the redactors of this code (if I am not mistaken) as it gives also a greater flexibility to this taxonomy, limiting therefore stability threats.

I read numerous papers dealing with the phylogenetic taxonomy of dinosaurs. As far as I know, no one has ever proposed to use Owen's specifiers... Did you ever hear of a such attempt ?

Cheers,
Jocelyn

'As a Professor of Science, I assure you we did in fact evolve from filthy monkey men.'

Le 22/10/2011 06:08, David Marjanovic a écrit :
Being above the family group of ranks, Dinosauria does not have a type specimen, not even indirectly. (In animal nomenclature, species have type specimens, genera have type species, and so on; superfamilies have type families; taxa at higher ranks lack types, which is often a distinct disadvantage.)

Oct. 17th 02:21, Anthony Docimo wrote:
 that reminds me - what is the type specimen of _Dinosauria_? surely
 after over a century of new discoveries, it is even less secure than
 _Troodon_'s type fossil in Troodontidae(sp).