Re: Ceratopsian Systematics [was: Avaceratops and Ceratops (was Re: THE NEW I...

[Dinogeorge@aol.com]

In a message dated 1/26/00 1:11:59 PM EST, znc14@TTACS.TTU.EDU writes:

<< >There are questions about the validity of the name Centrosaurus 
 >(it's preoccupied, or may require a petition to retain as a valid name), so
         My understanding was that it is not pre-occupied, but that there is
 a potential homonym: _Kentrosaurus_. Is this what you are referring to? >>

No, the name Centrosaurus appeared in print in 1843 in Fitzinger's monograph 
on reptilian (or was it vertebrate?) classification (a notorious source of 
preoccupying names, by the way). That right there would do it for 
Centrosaurus, except that Fitzinger used it as a synonym of Phrynosoma (the 
horned toad genus), not as a standalone genus. In the Code, a name that is 
first used as a synonym and is not subsequently used as >anything else< does 
not preoccupy a standalone genus. The problem is to find a paper or two in 
which the name Centrosaurus itself is used standalone, and so far the 
earliest paper I know of that so uses Centrosaurus Fitzinger 1843 is Kuhn's 
1964 Fossilium Catalogus of Ornithischia, in which he points out that Lambe's 
Centrosaurus is preoccupied by Fitzinger's usage. But the 1985 ICZN mandated 
that a standalone usage has to occur >before 1961< in order for a name 
initially proposed as a synonym to preoccupy a standalone generic name, so by 
three years Centrosaurus Lambe has not yet been shown to be preoccupied by 
Centrosaurus Fitzinger. However, Romer's 1956 Osteology of the Reptiles has 
Centrosaurus Fitzinger used as a synonym, but of Heloderma rather than 
Phrynosoma. Something happened with Centrosaurus Fitzinger during the 1950s 
that may be considered to be a standalone usage, but so far I haven't heard 
of it. It would take time to search the reptilian scientific literature for 
this kind of obscurity, but until this is done, there will be a cloud over 
the name Centrosaurus Lambe.

The alternative is to petition the ICZN to place Centrosaurus Lambe on the 
Official List of Conserved Names (or whatever it's called) and to set aside 
all prior usages in favor of its well-known and most familiar use as the name 
of the ceratopian. And Centrosaurus Fitzinger would be placed on the Official 
List of Rejected Names. I'm certain that such a petition would be granted; 
all that's necessary is for someone to open the case before the Commission.

The Kentrosaurus business has to do with Lambe's Centrosaurus potentially 
preoccupying Hennig's Kentrosaurus, because they differ by only one letter 
and have essentially the same derivation. At the turn of the century (1900's, 
that is), one genus could preoccupy another even if their spellings differed, 
if they were sufficiently close in spelling, pronunciation, and derivation. 
So Hennig changed the name to Kentrurosaurus to avoid this problem. This is 
no longer the case now; spelling is all that matters. So Kentrosaurus is 
available for the stegosaur even though the similar Centrosaurus had 
previously been used for the ceratopian.