[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Horns and Beaks: New taxa and descriptions



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.

On Mickey's point: Vectisaurus atherfieldensis is a very confused sounding 
name... most I. atherfieldensis material doesn't come from Atherfield (the 
place: mainly defined as Atherfield point, which is a ledge of marine 
calcareous sandstone), where the Vectis Fm (lagoonal) is overlain by the 
Atherfield Clay (shallow marine). In ye olde days (where this naming problem 
arises), material was labelled as having come from whichever bay it was 
collected (eg. 'atherfield' 'brixton' etc). If we found and named this new 
material today, we might call the specimen Iggy vectisensis or something... 
later this locality naming  habit changed to recalling whichever gorge (called 
'chines': in the local lingo) the collector happened to walk down to get to the 
beach. Consequently, locality data for much historical IOW material is a bit 
dodgy.. Thankfully, if you collect enough you get a good feel for slight 
variations in preservation (mainly bone colour and the nature of the siderite), 
and you can
 relocate which horizon bones actually came from. Iggy material from the Vectis 
Fm (=Wealden Shales of old usage) is very rare.. hell, most terrestrial 
vertebrates are rare there (mostly pterosaurs, croc, sharks.. it's actually 
possibly considerable as a lagerstatten.. but that's something for another 
study). Anyway, most Iggy atherfieldensis comes from the Wessex, and within the 
Wessex, from the fire-flood mass-death-assemblage plant debris beds.

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.

I have not got a copy of the book yet (I'll order one when I am in the states), 
so i do not know how Greg Paul addresses the issue of all the other potential 
'gracile' Iguanodon species. No doubt some of the older mainland deposits have 
ancestors of I. atherfieldensis in their ranks. 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.

I will admit that, for convenience's sake, saying Mantellisaurus may be more 
desirable than our current usage (where we have 'berni' and 'atherfieldensis'). 
However, an additonal problem is that all the 'Iguanodon sp.' material 
currently in collections should be relabelled as 'iguanodontidae indet.' , and 
that's going to cause even more confusion, especially if a future uninformed 
researcher suddenly thinks that mantellisaurus collections are hopelessly 
sparse. Maybe in the paper Greg Paul has good reason for erecting the new 
taxon, but those of us that work with it (on a daily basis for some of us) 
don't see any real issue.

D.

----- Original Message ----
From: Michael Mortimer <mickey_mortimer111@msn.com>
To: dinosaur@usc.edu
Sent: Monday, 6 November, 2006 8:23:22 AM
Subject: RE: Horns and Beaks: New taxa and descriptions

Andrew A. Farke wrote-

>Paul, G. S. 2006. Turning the old into the new: a separate genus for the
>gracile iguanodont from the Wealden of England; pp. 69-77 in K. Carpenter
>(ed.), Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Indiana
>University Press, Bloomington.
>
>Iguanodon atherfieldensis is renamed Mantellisaurus atherfieldensis.

Why isn't 
ere synonyms of 
Iguanodon atherfieldensis.

Mickey Mortimer






Send instant messages to your online friends http://uk.messenger.yahoo.com