[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Alamosaurus as biggest North American sauropod



Exactly. I would argue that the person who named the second taxon from
a sample where no justification for multiple taxa exists was the first
to act, and any subsequent sinking is a correction of their taxonomic
over-reach. Sinking _Jainosaurus_ into _Titanosaurus_, for example,
would be an act to correct the misguided act of pervious workers, who
by both philosophies should not have acted to split those taxa.

Matt

On Fri, Dec 9, 2011 at 8:09 AM, David Marjanovic
<david.marjanovic@gmx.at> wrote:
> Am 09.12.2011 01:25, schrieb Tim Williams:
>
>>  Matthew Martyniuk <martyniuk@gmail.com> wrote:
>>
>> > I don't see the issue with using parsimony. In fact I have kind of
>> > an issue when people don't use it. If the remains can't be
>> > differentiated from _A. sanjuanenis_, and there is no evidence to
>> > suggest multiple taxa were present in this environment, it should
>> > be considered _A. sanjuanenis_ until evidence to the contrary can
>> > be produced.
>>
>>  As a rule of thumb, this "rule" is unevenly applied. For example,
>>  Carpenter and Tidwell (2004) referred all sauropod material from the
>>  Arundel Formation to a single taxon. All the Arundel sauropod
>>  material was consistent with the presence of a single species, which
>>  took the name _Astrodon johnsoni_. In the process, _Pleurocoelus
>>  nanus_ and _P. altus_ were considered to be subjective junior
>>  synonyms of _Astrodon johnsoni_, a taxon that was originally
>>  established on material that is not diagnostic at the genus level
>>  (tooth + tooth fragment).
>>
>>  On the other hand, Wilson and Upchurch (2003) did *not* combine
>>  _Titanosaurus indicus_ and _Antarctosaurus septentrionalis_ into a
>>  single taxon in their revision of the titanosaur material from the
>>  'Sauropod bed' of the Lameta Formation at Bara Simla. This was
>>  despite the fact that this study found no reason to recognize more
>>  than one species at Bara Simla. The Conclusion makes this clear:
>>  [...]
>
>
> Carpenter & Tidwell seem to have thought "if there's no evidence for
> multiple taxa, don't split". Wilson & Upchurch seem to have thought "if
> there's no evidence for lumping, don't sink established names, even when
> there's no evidence that would support splitting either". Both agree "if
> there's no evidence, don't act" -- they just disagree on what counts as
> acting...