[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Brontosauria? Vote for Apatosauria!
David Marjanovic wrote-
Was Megalosauroidea ever formally named as an ICZN taxon, complete with
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
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.).
Very debatable, isn't it? Spinosauroidea was supposedly used to indicate
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,
I agree here. Sinraptoridae was clearly proposed for Sinraptor +
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 +
''Metriacanthosauridae'' for the less stable Sinraptoridae +
Metriacanthosaurus - of course, this
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
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.