Re: [dinosaur] Miragaia new specimen and taxonomy of dacentrurine stegosaurs (free pdf)

[Tim Williams <tijawi@gmail.com>]

ThomasHoltz <tholtz@umd.edu> wrote:

> The abstract's final sentence understates their point: they sink Alcovasaurus 
> into Miragaia.


Yes, _Alcovasaurus longispinus_ (originally _Stegosaurus longispinus_)
becomes the new combination _Miragaia longispinus_.  So _Miragaia_ now
has two species: _Miragaia longicollum_ and _Miragaia longispinus_.

Note that Costa and Mateus refer to _Natronasaurus longispinus_ as a
nomen dubium, as does Galton & Carpenter (2016) (DOI:
10.1127/njgpa/2016/0551).  However, _Natronasaurus_ should be regarded
as a nomen nudum, rather than a nomen dubium.  As Galton & Carpenter
make clear: "his [Ulansky's] names are not valid
for purposes of zoological nomenclature".  This is the very definition
of a nomen nudum.  Galton & Carpenter's rationale was correct for
rejecting _Natronasaurus_ as a valid name, but they chose to call it a
nomen dubium.

The distinction between nomen nudum and nomen dubium is important.  As
a nomen nudum, it's an empty name that is not attached to anything -
and so, from a scientific nomenclature standpoint, is not a name at
all.  A nomen dubium is a nomenclaturally valid name that is attached
to a dubious specimen.  Treating _Natronasaurus_ as a nomen nudum
means that it can henceforth be ignored in the scientific literature.
The same goes for all of Ulansky's "names".