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Re: Horns and Beaks: New taxa and descriptions

Denver Fowler wrote:

As someone who routinely works with this material, I am not planning on using the name Mantellisaurus. The differences between the species have existed for some time (indeed, over 130Million years), and were recognised by Norman in his many papers on the animals, and he never saw fit to split them. In real terms, one name or the other merely serves to create more monospecific genera, which in my opinion is not a desirable thing.

As David said, the two species (_bernissartensis_ and _atherfieldensis_) may be paraphyletic. This is a separate issue from a "lumper vs splitter" thing. I remember seeing at least one analysis that found _Iguanodon_ to be paraphyletic (e.g., Norman, 2002).

IIRC Vectisaurus derives from the old ?latin? name for the isle of wight, the same derivation as Vectis Fm. The name Vectisaurus atherfieldensis appears <erroneously> to contain geographical & formational references which are potentially confusing, and also undesirable. I'm sure there's some ICZN rule that says we can;t re-use Vectisaurus (since I. atherfieldensis came first vs V. valdensis), but i don't really care, since it's a non-issue, and ICZN chatter is insufferably dull.

The ICZN doesn't exist for entertainment value (good thing too, because it would fail dismally on that score). The ICZN is there to ensure that the right taxonomic names get priority, irrespective of personal preference (or personal indifference). Rules is rules, like it or not. Sure, such a dialogue is almost guaranteed to be "insufferably dull", but the nomenclature of _Iguanodon_ needs to be resolved in order to avoid future confusion.

The nomenclature of _Vectisaurus_ is certainly not a "non-issue". There is no ICZN rule that says we can't re-use _Vectisaurus_. _V. vectensis_ was actually named before _I. atherfieldensis_ (Hulke 1879 vs Hooley 1924). The fact that the name "Vectisaurus atherfieldensis" would cause confusion given the stratigraphic origin of the hypodigm is totally irrelevent.

Now, if _Vectisaurus_ and _Heterosaurus_ are nomina dubia and/or composite taxa then it is OK to set them aside. But if either are diagnostic at the level of genus or species, then there 'in the game'.

When do we stop calling something Iguanodon, and start using a new name? Of course, where we get a good record, we encounter the same problems (eg. the Late Cretaceous of North America). It is best if we have a series of species of the same genus.

It depends. It may be that we have not so much a "series of species" but an assemblage of ornithopod taxa that are non-monophyletic. How do _I. fittoni_ and _I. dawsoni_ fit in, for example? _I. hoggii_ has already been removed from _Iguanodon_.

Also, don't forget, that named _Iguanodon_ species exist outside of Europe, like _I. mongoliensis_ and _I. lakotaensis_.



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