reanalysis based on a shift in a philosophical concept???

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Posted by troy h on January 20, 2003 at 19:40:08:

In Reply to: Re: collins list question posted by TTaggart on January 20, 2003 at 13:16:39:

:However, your question, with respect to Elaphe emoryi, is not applicable. Elaphe emoryi was diagnosed at the specific level [Scotophis emoryi] in its original description (= first usage). (Baird & Girard (1853) Cat. North Am. Rept. Mus. Smiths. Inst. 1. Serpents. p. 157).

true, however, a series of workers since that time have considered emoryi to be a ssp of guttata, based on data. Collin's paper presented no new evidence to refute the previous hypothesis of relationships.

:Your assertion that 'no biological data' existed for Collins to make the proposals he did in the 1991 paper, simply ignores the fact that each of those taxa in his list, were properly diagnosed species or subspecies already. Those data already existed. His proposals amount to a revision, which included an additional hypothesis of allopatry, and a new framework in which to operate (= the ESC).

again no new data.

:You may disagree with his hypothesis of allopatry in this case, but his methodology is certainly consistent with a reanalysis based on a shift in a philosophical concept. Characters were reexamined, not by counting or measuring, but with respect to an operation of the ESC.

i do disagree with the idea that emoryi is allopatric from forms variously recognized at "slowinskii" (Burbink) or "brown phase cornsnakes" (Vaughan, et. al.). in fact, solid, hard data does exist for the notion that these two forms are not in fact allopatric, but rather that they intergrade across a wide area in East Texas - see Dixon 2000 or Wehler & Dixon 2000, if you disagree. In fact, the Vaughan, et al, paper does not show any allopatry, and in discussions with these researchers, they assert that there is no allopatry (as will be born out in a forthcoming paper by the same authors).

furthermore, how does "reanalysis based on a shift in a philosophical concept" qualify as any sort of analysis? All Collins did was look at a published range map that showed populations to be allopatric, and use his new understanding of the ESC and suggest that a bunch of taxa that qualified as "allopatric" by poor field guide-style range maps were in fact distinct species.

:Finally, the 'Collins list' makes no changes autonomously. Rather, like the SSAR/ASIH/HL list of Crother et al., it relies on specialists groups of publishing herpetological systematists to determine the taxonomic layout of the list.

on a related note, though . . . why did SSAR, etc, replace Collins with Crother . . . and then why did Collins start up his own competing list (CNAH)? makes you wonder . . .

troy

Follow Ups:

Re: reanalysis based on a shift in a philosophical concept??? TW Taggart 01/21/03 (1)
- on emoryi/"slowinskii" in east Texas troy h 01/21/03 (0)