Panderichthys had tetrapod ears (today's Nature)

[Tim Williams <twilliams_alpha@hotmail.com>]

Nice stuff...

Martin D. Brazeau and Per E. Ahlberg.  (2006) Tetrapod-like middle ear 
architecture in a Devonian fish.  Nature 439: 318-321.

Abstract: "Few fossils show the incipient stages of complex morphological 
transformations.  For example, the earliest stages in the remodelling of the 
spiracular tract and suspensorium (jaw suspension) of osteolepiform fishes 
into the middle ear of tetrapods have remained elusive.  The most primitive 
known tetrapods show a middle ear architecture that is very different from 
osteolepiforms such as _Eusthenopteron_, with little indication of how this 
transformation took place.  Here we present an analysis of tetrapod middle 
ear origins that is based on a detailed study of _Panderichthys_, the 
immediate sister taxon of tetrapods.  We show that the spiracular region is 
radically transformed from osteolepiforms and represents the earliest stages 
in the origin of the tetrapod middle ear architecture.  The posterior 
palatoquadrate of _Panderichthys_ is completely tetrapod-like and defines a 
similarly tetrapod-like spiracular tract.  The hyomandibula has lost its 
distal portion, representing a previously unrecognized advance towards a 
stapes-like morphology.  This spiracular specialization suggests that the 
middle ear of early tetrapods evolved initially as part of a spiracular 
breathing apparatus."