PROTO-BATS

[darren.naish@port.ac.uk]

On prototype pterosaurs, Dave Peters wrote...

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Was wondering if anyone has done anything similar with 
the "shrewy-looking placental" to bat transition?
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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 
dactylopatagia.

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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?
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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.

-- 
Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL

email: darren.naish@port.ac.uk
tel: 023 92846045