Hesperornis - Marine Dinosaur

[Mike Everhart <mjever@southwind.net>]

All,
I'm looking for a general answer to a question concerning the lineage of
Hesperoronis (fossil record and such). T. Mike Kelsey has already done
the cladogram, so it is unnecessary to repeat those:
   < http://dinosaur.umbc.edu/taxa/hesperornithiformes.html >

Hesperornis has been referred to as the "only marine dinosaur" and is
certainly the only one for which we have a fossil record. It apparently
returned to the oceans (late Cretaceous), about the same time as the
demise of the Ichthyosaurs and was competing successfully with
plesiosaurs, mosasaurs and large fish in the more northern (cooler?)
oceans. It arrived in Kansas in the early Campanian (Smoky Hill Chalk /
Pierre Shale) but is never as common there as late Cretaceous deposits
further north.

           < http://www.oceansofkansas.com/hesper.html >

It was very much a bird, with feathers,  but still had teeth, and solid
(not hollow) bones. It's upper limbs were atrophied to the point of
being almost useless, and it's lower limbs were so specialized for
swimming that Hersperornis probably could not walk very well on land, if
at all.  They apparently fed on fish and other small prey and in turn
were eaten by mosasaurs:
           < http://www.oceansofkansas.com/sdsmt.html >
           < http://www.oceansofkansas.com/Varner/varner10.jpg > 

Also, described in this quote from:
        < http://www.ummz.lsa.umich.edu/birds/ornclass/lecpa.html >
"Mid-Cretaceous fossils Hesperornis and Ichthyornis were marine,
toothed, large birds. Hesperornis includes 13 species of diving seabird
ranging in size from a chicken to a large penguin, foot-propelled,
superficially resembled modern loons, flightless. No keel on sternum,
large cnemial crest on tarsometatarsus for swimming muscles like loon &
grebe but different origin, vertebrae were heterocoelous like modern
birds. Ichthyornis was a flying, tern-like bird, keel on sternum, same
time as plesiosaurs in oceans. Apparently off the main lineage of bird
evolution, vertebrae amphicoelous like primitive reptile, they left
no living descendants. Both are closely related to modern birds, in
Ornithurae." 

Is there any fossil evidence that they evolved from a bird that was
capable of flight?  Other comments??

Mike Everhart                       < http://www.oceansofkansas.com >
Adjunct Curator of Paleontology
Sternberg Museum of Natural History
Fort Hays State University, Hays, KS