[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

No Gastric Mill in Sauropod Dinosaurs

I wonder if the authors address the gastroliths in

Guy Leahy
Proc Biol Sci. 2007 Mar 7;274(1610):635-40.   
No gastric mill in sauropod dinosaurs: new evidence
from analysis of gastrolith mass and function in
Wings O, Sander PM. 
Institut fur Palaontologie, Universitat Bonn,
Nussallee 8, 53115 Bonn, Germany.

Polished pebbles occasionally found within skeletons
of giant herbivorous sauropod dinosaurs are very
likely to be gastroliths (stomach stones). Here, we
show that based on feeding experiments with ostriches
and comparative data for relative gastrolith mass in
birds, sauropod gastroliths do not represent the
remains of an avian-style gastric mill. Feeding
experiments with farm ostriches showed that bird
gastroliths experience fast abrasion in the gizzard
and do not develop a polish. Relative gastrolith mass
in sauropods (gastrolith mass much less than 0.1% of
body mass) is at least an order of magnitude less than
that in ostriches and other herbivorous birds
(gastrolith mass approximates 1% of body mass), also
arguing against the presence of a gastric mill in
sauropods. Sauropod dinosaurs possibly compensated for
their limited oral processing and gastric trituration
capabilities by greatly increasing food retention time
in the digestive system. Gastrolith clusters of some
derived theropod dinosaurs (oviraptorosaurs and
ornithomimosaurs) compare well with those of birds,
suggesting that the gastric mill evolved in the avian
stem lineage.