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Tim Williams wrote-
> True. Interestingly, in a study that appeared recently in Nature, Zack et
> al. (2005) found that _Plesiorycteropus_ and _Orycteropus_ were sister
> There is hope. The Afrotheria clade, which is canonical in molecular
> phylogenies, has come under attack from morphological studies - but it
> appears to be accruing support from the fossil record. For example, Zack
> al. (2005) recently found a link between macroscelideans (elephant shrews)
> and a group of North American 'condylarths' called apheliscines
That study irritated me because the authors used Asher et al.'s (2003)
excellent data matrix (which includes the widest range of living and fossil
mammals I've seen) but proceed to delete all the non-afrotherian ingroup
taxa because "a full assessment of the position of Macroscelidea is beyond
the scope of this study". Yet they state "Phylogenetic analyses of all
three matrices ... place apheliscines on the macroscelidean stem, ..."
Well, that's not nearly as meaningful when you realize most of the other
small cursorial taxa were excluded. Especially since one of the small
cursorial taxa they left in (Anagale) comes out as the sister group to
Macroscelidea + Apheliscinae in their tree, yet is sister to Tupaia in both
the morphological and combined morph+molec trees when all taxa are examined.
The other two matrices they used were-
Meng et al.'s (2003) analysis, which was limited to Glires except for
outgroups, a couple 'condylarths', several archontans, Leptictis and a few
taxa which claded with Anagale (which is sister to Glires in this tree).
A new analysis by them with only 52 characters, all dental and tarsal,
restricted to ungulates. When your tree has a
(artiodac(macroscel(perissodac,hyracoid))) topology, how much can you trust
Apheliscines may indeed be er.... panmacroscelideans, but I'd like to see a
full range of placentals analyzed with them, and even then, morphological
data alone may be insufficient to counter homoplasy in Placentalia.
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html