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Re: VERY Stupid question, but I dont know the answer...

In a message dated 2/20/02 12:53:35 PM Pacific Standard Time, 
tmk@dinosauricon.com writes:

<< That is very often the case, but there are instances where the oldest
 genus in a family is not the eponymous genus. Tyrannosauridae, for
 example, includes _Deinodon_, a dubious genus which was named almost 50
 years before _Tyrannosaurus_. Actually, since _Deinodon_ was placed in a
 new family, Deinodontidae, that's probably the correct name by ICZN rules,
 but I never see anyone use it. A less complicated example would be
 Allosauridae, which includes _Antrodemus_, a dubious genus published 7
 years before _Allosaurus_. (There is no Antrodemidae -- not sure where
 _Antrodemus_ was originally place....) >>

The person who first defines a family is the one who decides which genus 
becomes the nominotypical genus of the family. Tyrannosauridae was named by 
Osborn in 1906, and he chose Tyrannosaurus Osborn, 1905 to be the 
nominotypical genus (that is, the genus after which the family is named). The 
choice is purely at the discretion of the original author and is independent 
of whether the nominotypical genus is the historically oldest genus in the 
family or even the best-known genus in the family. Usually, however, it is 
the best-known or one of the best-known genera in the family.

With regard to Deinodontidae, the nominotypical genus Deinodon is universally 
regarded as a nomen dubium, so the historically next oldest family-level 
name, Tyrannosauridae, is used for the family that contains Deinodon. 
According to ICZN philosophy, the name Deinodontidae would be just as 
doubtful for this family as Deinodon is a doubtful genus.