Re: [dinosaur] Tanystropheus (Archosauromorpha) revised; Sclerostropheus, new genus (free pdf)

["David Marjanovic" <david.marjanovic@gmx.at>]

> Type species *T. conspicuus* is made a nomen dubium but genus name 
> *Tanystropheus* is considered valid... Hmmm....Â
>
>Â"Nevertheless it remains the type species as the first named species of the 
>genus, and it is diagnostic on the genus level based on the characteristic 
>cervical vertebrae of the type material that are unique to the genus 
>*Tanystropheus*."

Further quotes:

"The size and shape of the vertebral centra, neural spines, and zygapophyses 
that can be observed for the large morphotype of *T. longobardicus* are 
indistinguishable from *T. conspicuus* and *T. haasi*. Additionally, other 
isolated material assigned to *T. conspicuus*, comprising dorsal, sacral, and 
caudal vertebrae, as well as a humerus and femora, also cannot be distinguished 
from this taxon (Wild, 1973; personal observation SNFS). However, because only 
a very limited comparison is possible, and skull material, which is likely more 
diagnostic, is completely lacking for both taxa, an unambiguous taxonomic 
identification of *T. conspicuus* and *T. haasi* is not possible. Therefore we 
propose to consider both taxa as nomina dubia."

"*Tanystropheus conspicuus* is considered to be represented by insufficient 
material to distinguish it convincingly from other *Tanystropheus* taxa, and we 
therefore consider it a nomen dubium. Nevertheless" (continued above)

So, the normal thing to do would be to sink *T. longobardicus* and *T. haasi* 
into *T. conspicuus*, because all three are indistinguishable from another. But 
because the material of *T. conspicuus* and *T. haasi* is so limited that 
hardly anything can be compared, the authors prefer to withhold judgment, and 
they implement that by calling *T. conspicuus* and *T. haasi* nomina dubia and 
maintaining the name *T. longobardicus*.

None of this turns the genus name into a nomen dubium. It is completely clear 
that the material called *T. conspicuus* and *T. haasi* forms an exclusive 
clade with the material called *T. longobardicus* and *T. antiquus*, and the 
available name for this clade is *Tanystropheus*.