For each radiograph, the intensities of both the gastrolith and the cuticle that surrounds it were determined.
FTIR spectroscopic analysis of the cuticle and gastrolith were performed on a Bruker (Fourier transform spectrometer) equipped with a DTGS detector.
Mineralized cuticle and gastrolith samples were prepared for SEM inspection by rinsing in water and drying in air.
The rest is transported out of the apical membrane to form gastroliths. This explains the greater content of calcium in R cells during premolt compared to intermolt.
(1) The amount of calcium that flows into R cells is higher during postmolt, since the calcium coming from reingestion of exuviae is added to the calcium released from gastroliths and intracellular stores (Zanotto and Wheatly, 2003).
Cloning and expression of a cDNA encoding an insoluble matrix protein in the gastroliths
of a crayfish, Procambarus clarkii.
Paleontologists often treat report of gastroliths skeptically because rivers can produce very similar stones.
He says it therefore appears that as the dinosaur swallowed, its diet of plant material would pass from the crop - where gastroliths ground it - to a gastrolith-free stomach where digestive enzymes attacked the food, then into the gizzard for more grinding, and finally into the intestines.
However, the Seismosaurus fossil found with the most gastroliths held only 15 kg of stones, the largest no bigger than a grapefruit.
Or, he notes, dinosaurs may have habitually swallowed rocks for their mineral content, and the gastroliths that survived to be fossilized were those that were resistant to erosion and stomach acid.
Those clues include gastroliths
, or stomach stones, that would have ground ingested vegetation to a pulp.
, or stomach stones, that have been found in some ornithomimids provide another clue that the creatures didn't consume large animals, says Makovicky.