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On prototype pterosaurs, Dave Peters wrote...
Was wondering if anyone has done anything similar with
the "shrewy-looking placental" to bat transition?
A series of hypothetical proto-bats were illustrated by Smith
(1977) - they are also depicted in Hill & Smith (1984).
Smith thought that patagial membranes evolved in pretty
much the same manner as they have in other gliding
mammals and the proto-bats illustrated look like miniature
colugos. Digital elongation was one of the last things to
occur and it was not suggested that patagial evolution
started at the hand. So, no special function suggested for
long fingers other than that they evolved to support the
3. Has any one yet figured out what the closest sister taxon
to bats might be? And if so, are any clues regarding flight
origins forthcoming from this relationship?
As you might have gathered from discussion on this list,
placental phylogenetics are rather controversial at present.
A morphological perspective on bat affinities (note 'A'
morphological perspective) might be that they are
archontans and the sister-group to colugos (Dermoptera),
both being united in the Volitantia. If so, the very first bats
were presumably already gliders with patagia. A molecular
perspective might be that bats are laurasiatheres (the group
proposed to include Eulipotyphla [moles, shrews etc],
assorted ungulates and carnivorans etc etc) in which case
the groups closest to them in the phylogeny are all terrestrial
quadrupeds without even a hint of gliding ability.
Hill, J. E. & Smith, J. D. 1984. _Bats - A Natural History_.
British Museum (Natural History), pp. 243.
Smith, J. D. 1977. Comments on flight and the evolution of
bats. In Hecht, M. K., Goody, P. C. & Hecht, D. M. (eds)
_Major Patterns of Vertebrate Evolution_. Plenum Press,
New York, pp. 427-437.
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