Re: Brontosauria? Vote for Apatosauria!

[Michael Mortimer <mickey_mortimer111@msn.com>]

David Marjanovic wrote-

> Was Megalosauroidea ever formally named as an ICZN taxon, complete with 
> "superfam. nov."?

It doesn't need to be.  It was implicitly created when Megalosauridae was.  
Megalosauroidea was first used by Nopcsa in 1928, but I've never seen that 
paper.

> If *Metriacanthosaurus* really turns out to be a sinraptorid, however... 
> Metriacanthosauridae might qualify as a nomen nudum (I don't have PDW here, 
> nor do I know if that particular work introduced the name), but if not, it 
> certainly has priority.

Can a family name even be a nomen nudum?  I can't picture the rules applying 
(illustration necessary, holotype listed, etc.).

Jay wrote-

> Very debatable, isn't it? Spinosauroidea was supposedly used to indicate 
> the phylogenetic
> realtionship between Spinosaurids and Torvosaurus, with Spinosauroidea 
> having priority over
> Torvosauroidea. Megalosaurus may not unambigously belong to this group. 
> Some exclude it citing
> nomina dubia, others include it. If Megalosaurus's position is uncertain in 
> this group, why would
> one want the name Megalosauroidea for the group of Torvosaurus + 
> Spinosauridae then to have
> Megalosaurus subsequently removed from this group.

It doesn't matter if Megalosaurus is a nomen dubium or not.  See Ceratops or 
Hadrosaurus as examples.  As for whether Megalosaurus belongs to the clade, 
I have yet to see anyone dispute it.  Holtz et al. (2004) found it to be a 
member in their analysis, and Allain (2002) believes so as well.  The 
confusing thing is that Holtz uses and defines Megalosauridae, but then uses 
and defines Spinosauroidea to contain it.  Of course, the issue of multiple 
Stonesfield Slate large theropods complicates things (Day and Barrett, 
2004).

> I agree here.  Sinraptoridae was clearly proposed for Sinraptor + 
> Yangchuanosaurus.
> Metriacanthosaurus isn't as well known wasn't even a purported founding 
> member of this group. The
> relationship between Sinraptor + Yangchuanosaurus is quite stable/strong 
> and so warrants a name.
> It can't be helped that Metriacanthosaurus's relationship was subsequently 
> revealed. It may not
> even be an sinraptorid. Is it an Allosauroid?
> But as some believe, if it's related to Sinraptor + Yangchuanosaurus, then 
> perhaps both names
> could be preseved. Sinraptoridae for the very stable and strong Sinraptor + 
> Yangchuanosaurus, and
> ''Metriacanthosauridae'' for the less stable Sinraptoridae + 
> Metriacanthosaurus - of course, this
> ignores rank.

Well, Sinraptoridae is already defined as a stem, so if Metriacanthosaurus 
is closer to Sinraptor than to Allosaurus or Carcharodontosaurus, it's a 
member.  True, it wasn't an original member, but the ICZN doesn't care how 
long it takes to assign a genus to a family.  If that genus has its own 
older family-level name, the latter gets priority.
Is it an allosauroid?  Allain (2002) found it to be one in his analysis, and 
Rauhut (2003) found it to code identically to Sinraptoridae.  It comes out 
sister to included sinraptorid genera in the latter analysis.  Much as with 
Megalosaurus, though few people have included it in their studies, the ones 
that have get similar results.  Of course, it would be nice if it were 
restudied in depth.  Allain just did so for Erectopus, perhaps he'll get to 
Metriacanthosaurus next.
Once we start including family names inside other family names, we're 
spiting the ICZN enough that I don't think we'd care about its family-level 
priority rule either.

Mickey Mortimer