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RE: Platecarpus tympaniticus - how to analyze a nomen dubium
Anthony Docimo <email@example.com> wrote:
> > *Ceratops*: has anyone even looked at the material in
> > the last couple of decades?
> Wait....if nobody's looked at the material, what has this
> discussion been running on? (theory and ideals?)
Don't panic Anthony. Penkalski and Dodson (1999) provide a fairly detailed
description of the _Ceratops montanus_ type material. So does Ryan (2007).
Both studies regard the _Ceratops montanus_ material as non-diagnostic at the
genus or species level, and therefore the name _Ceratops montanus_ is a nomen
I'm not actually endorsing the view that _Ceratops montanus_ is a nomen dubium
(though I suspect it is). My argument is that given the meager remains,
_Ceratops montanus_ is a poor choice to name a family after. Both the ICZN
Code and PhyloCode agree that the family Ceratopsidae must include _Ceratops
montanus_. Thus, Ceratopsidae must be defined such that it includes _Ceratops
montanus_ as a specifier. But because _Ceratops montanus_ is unlikely to
contribute anything meaningful to a phylogenetic analysis, _Ceratops montanus_
is unlikely to be used to anchor any clade (including Ceratopsidae). Ergo,
_Ceratops_ should NOT give its name to any family-level clades (e.g.,
Ceratopsidae, Ceratopsinae, Ceratopsoidea).
> Except none of us are precognitive - we don't know
> that better species will be found. (we hope they will,
> but its not a guarantee)
Mike Taylor answered this better than I ever could, but it's worth emphasizing
the point that suprageneric taxa should not be erected for a single genus.
This used to be common practice, but it's totally unnecessary, and frequently
> okay, let's say that, twenty years from now, I discover a
> dinosaur that is as related to other Archosaurs as the
> Pangolins are to other Mammalia.
This assumes that ranks (phylum, class, order, etc) have some intrinsic
quantitative value. But they don't, and never have.
Consider this: All those many bird "orders" (Struthioniformes, Falconiforme
vialae. The Avialae is in turn a clade within the Maniraptora, which is a
clade within the Theropoda, which is a clade within the Saurischia. Yet,
Linnaean taxonomy lists Saurischia as an "order". Take-home message: Linnaean
ranks are a world of pain.