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Re: Theropod "migrations"
In a message dated 4/25/99 1:25:49 PM EST, firstname.lastname@example.org writes:
<< I thought Ceratop[s]idae was node-based, with Ceratop[s]inae
(=Chasmosaurinae) and Centrosaurinae (=Pachyrhinosaurinae) as stem-based
clades within, meaning that if it's not a ceratop[s]ine or a
centrosaurine, it's not a ceratop[s]id. I have it as a non-ceratopsid
ceratopsomorph, just above _Montanoceratops_. >>
Umm--who cares? I mean about node-based, stem-based, whatnot. Tomorrow the
definitions will change yet again; I might change some of them myself--a hoot
until someone else changes them to something else. There's no Code for
taxonomic definitions, just for taxonomic names. Redefining taxa has a long
tradition in dinosaur paleontology.
If Ceratopidae, Ceratopinae, and Centrosaurinae form a node-stem triplet (a
la Sereno), as you have it, then I'd make Turanoceratops a basal ceratopine.
Supraorbital horns are apomorphic for Ceratopinae and T. has them. So does
Zuniceratops, by the way, so it's a basal ceratopine, too (don't know which
is higher up the tree [they're pretty close]; not enough material).
Montanoceratops has no supraorbital horns, so it's a good candidate for the
stem below Ceratopidae (which is also where its other characters place it).
But if Ceratopidae and Protoceratopidae form a node-stem triplet with[in]
Neoceratopia, then the stem from Neoceratopia to the node Ceratopidae is also
part of Ceratopidae (but outside the two subfamilies), and then
Montanoceratops is a basal ceratopid rather than a protoceratopid.