Re: Forthcoming theropod paper of note on the manus

["Aspidel" <aspidel@wanadoo.be>]

From: "Stephan Pickering"
(...)
> But, unless I am
> misreading the literature, it is presumed theropod
> hands consist of I, II, III. The recent embryological
> research may revise this, as avian embryos show five
> digits, with I and V lost. Could it be that theropod
> hands are not I-III, but II-IV?
(...)

How can one explain this?
Really not obvious for me:

MANUS:
                                  Number of    Number of    Number of
Taxon       Number of   phalanges     phalanges      phalanges
                 digits            of digit I       of digit II      of
digit III

Eoraptor             5            2                  3                   4
(IV & V reduced)

Coelophysis        4            2                  3                   4
(IV reduced)

Archaeopt.         3            2                   3                   4

Confuciusorn.     3            2                   3                   4

Source: DA p. 172-173

Cheers - Aspidel.