326:
in a high-impact environment, show less polishing on higher surfaces, often with many small pits or cracks on these higher surfaces. Finally, highly polished gastroliths often show long microscopic rilles, presumably caused by contact with stomach acid. Since most gastroliths were scattered when the animal died and many entered a stream or beach environment, some gastroliths show a mixture of these wear features. Others were undoubtedly swallowed by other dinosaurs and highly polished gastroliths may have been swallowed repeatedly.
106:
531:
that the gastroliths may have broken down ingested plant material by grinding or crushing it. The sandstone clasts tended to be fragile and some broke in the process of collection. The sandstone gastroliths may have been rendered fragile after deposition by loss of cement caused by the external chemical environment. If the clasts had been that fragile while the animal was alive, they probably rolled and tumbled in the digestive tract. If they were more robust, they could have served as part of a ball-mill system.
340:
507:
being toward the smaller end of that range. The clasts tended to be close to spherical in shape, although the largest specimens were also the most irregular. The largest gastroliths contributed the most to the total surface area of the set. Some gastroliths were so large and irregularly shaped that they may have been difficult to swallow. The gastroliths were mostly composed of
278:
20:
300:. Second, the stone must be unlike the rock found in its geological vicinity, i.e., its geologic context. Many gastroliths have been found in fine grained lake, mud, and swamp deposits. These environs are calm water deposits and could not carry pebbles and cobbles (unlike a river or beach). Oliver Wings also argues that the stone must be found with the
543:
gastrolithic rocks back to their original source area where the dinosaur first swallowed the rock. This may provide important information on how dinosaurs migrated. Because the number of suspected gastroliths is substantial, they might provide significant new information and insights into the lives and behaviour of dinosaurs.
450:, and other rounded quartzose clasts, which may partly represent gastroliths. The cherts may themselves contain fossils of ancient animals, such as corals. These stones do not appear to be associated with stream deposits and are rarely more than fist-sized, which is consistent with the idea that they are gastroliths.
530:
may have found irregular clasts to be attractive potential gastroliths or was not selective about shape. The clasts were generally of dull coloration, suggesting that color was not a major factor for the sauropod's decision making. The high surface area to volume ratio of the largest clasts suggests
325:
Gastroliths can be distinguished from stream- or beach-rounded rocks by several criteria: gastroliths are highly polished on the higher surfaces, with little or no polish in depressions or crevices, often strongly resembling the surface of worn animal teeth. Stream- or beach-worn rocks, particularly
506:
The total mass of the gastroliths themselves was 7 kilograms (15 lb). Most were less than 10 millilitres (0.35 imp fl oz; 0.34 US fl oz) in volume. The least massive clast was 0.1 grams (0.0035 oz) and the most was 715 grams (25.2 oz), with most of them
335:
gastroliths had the "soapy" texture popularly used to distinguish gastroliths from other types of clast. The researchers dismissed using a soapy texture to identify gastroliths as "unreliable". Gastroliths tended to be universally dull, although the colors represented were varied including black,
336:
dark brown, purplish red and grey-blue. Reflectance values greater than 50% are very diagnostic for identifying gastroliths. Clasts from beaches and streams tended to have reflectance values of less than 35%. Less than ten percent of beach clasts have reflectance values lying between 50 and 80%.
542:
and geologists are researching new methods of identifying gastroliths that have been found disassociated from animal remains, because of the important information they can provide, if indeed they are trace fossils. If the validity of such gastroliths can be verified, it may be possible to trace
494:
specimen. The stones were identified as gastroliths on the basis of their tight spatial distribution, partial matrix support, and an edge-on orientation indicative of their being deposited while the carcass still had soft tissue. Their high surface
247:
and interpreted it as gastroliths. Brown was among the first paleontologists to recognize that dinosaurs used gastroliths in their digestive systems to aid in the grinding of food. Other paleontologists over the years were unconvinced. In 1932,
317:
gastroliths would be deposited outside the skeleton if the carcass was deposited in an aquatic environment for as little as a few days following death. He concludes that this is likely to hold true for all birds (with the possible exception of
304:
of the dinosaur which ingested it. It is this last criterion that causes trouble in identification, as smooth stones found without context can (possibly erroneously in some cases) be dismissed as having been polished by water or wind.
296:. First, it should be rounded on all edges (and some are polished) because inside a dinosaur's gizzard any genuine gastrolith would have been acted upon by other stones and fibrous materials in a process similar to the action of a
205:
Certain crayfish store gastroliths in their stomachs. Crayfish living in freshwater store these gastroliths as the presence of calcium is limited in freshwater. These gastroliths serve as a calcium source for molting.
177:
from northeastern China, which was discovered with a series of small stones, interpreted as gastroliths, in the area of its skeleton that would have corresponded with its abdominal region. Aquatic animals, such as
261:
and interpreted them as gastroliths. In 1934, the Howe Quarry, a fossil location in northwestern
Wyoming also yielded dinosaur bones with their associated gastroliths. In 1942,
1055:
Schmeisser, R.L. and
Gilette, D.D. (2009). Unusual occurrence of gastroliths in a polycotylid plesiosaur from the Upper Cretaceous Tropic Shale, southern Utah. "PALAIOS",
152:
can exceed a length of 10 centimetres (3.9 in). Apparent microgastroliths have also been found in frog tadpoles. Ingestion of silt and gravel by tadpoles of various
919:
Whittle, C. (1989). On the
Origins of Gastroliths: Determining the Weathering Environment of Rounded and Polished Stones by Scanning Electron Microscope Analysis.
322:) due to their air-filled bones which would cause a carcass deposited in water to float for the time it needs to rot sufficiently to allow gastroliths to escape.
753:
Huene, F. von. 1932. Die fossile Reptil-Ordnung
Saurischia, ihre Entwicklung und Geschichte. Monographien für Geologie und Paläontologie (1) 4: 1–361.
954:
718:
655:
Luquet, Gilles; Dauphin, Yannicke; Percot, Aline; Salomé, Murielle; Ziegler, Andreas; Fernández, Maria S.; Arias, José L. (February 2016).
946:
Wings, Oliver (2004): Identification, distribution, and function of gastroliths in dinosaurs and extant birds with emphasis on ostriches (
933:
Wings, Oliver (2003): Observations on the
Release of Gastroliths from Ostrich Chick Carcasses in Terrestrial and Aquatic Environments.
350:
1046:
824:
607:
979:
466:
animals. The largest known gastroliths found in association with sauropod skeletons are approximately ten centimeters in length.
959:
Wings, Oliver (2007): A review of gastrolith function with implications for fossil vertebrates and a revised classification.
920:
967:
310:
526:
Since some of the most irregular gastroliths are also the largest, it is unlikely that they were ingested by accident.
198:
gastroliths are rounded and polished, many stones in living birds are not polished at all. Gastroliths associated with
355:
819:
Martin, A.J. (2006). Introduction to the Study of
Dinosaurs. Second Edition. Oxford, Blackwell Publishing. 560 pp.
477:
916:
Darby, D.G. and
Ojakangas, J. (1980). Gastroliths from an Upper Cretaceous Plesiosaur. Journal of Paleontology 54:3
941:
1090:
292:
usually require several pieces of evidence before they will accept that a rock was used by a dinosaur to aid its
61:. In other species the rocks are ingested and pass through the digestive system and are frequently replaced. The
975:"No gastric mill in sauropod dinosaurs: new evidence from analysis of gastrolith mass and function in ostriches"
170:
appear to have used stones to grind tough plant matter. A rare example of this is the Early
Cretaceous theropod
439:
191:
187:
105:
65:
depends upon the size of the animal and the gastrolith's role in digestion. Other species use gastroliths as
927:
1080:
306:
220:
50:
265:
recognized the presence of gastroliths in the remains of sauropod dinosaurs recovered from Late
Jurassic
657:"Calcium Deposits in the Crayfish, Cherax quadricarinatus: Microstructure Versus Elemental Distribution"
668:
360:
557:
249:
996:
700:
400:
396:
262:
1030:
481:
339:
1042:
1014:
820:
692:
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182:, may have used them as ballast, to help balance themselves or to decrease their buoyancy, as
594:
1085:
1004:
988:
676:
436:
367:
86:
74:
951:
1025:
Stokes, W. L. 1987. Dinosaur gastroliths revisited. Journal of
Paleontology 61: 1242–1246.
637:
503:
gastroliths were found within a .06 m volume of space in the gut region of the skeleton.
223:
reported the presence of worn and polished quartz pebbles associated with the remains of
672:
1039:
Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie
1009:
974:
719:"Why freshwater crayfish don't need milk for healthy bones | Western Australian Museum"
539:
416:
252:
found stones in Late Triassic sediments, in association with the fossil remains of the
46:
608:
Ontogenetic changes in diet and intestinal morphology in semi-terrestrial tadpoles of
1074:
572:
704:
277:
490:
331:
297:
235:
133:
27:
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fossil with gastroliths in its stomach region, American Museum of Natural History
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values are consistent with other known dinosaur gastroliths. Nearly all of the
496:
257:
253:
224:
179:
172:
810:"Occurrence of Gastroliths in Mesozoic Taxa," Sanders et al. (2001). Page 168.
680:
567:
364:
282:
243:
114:
62:
23:
1060:
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found gravel in close association with the fossil remains of the duck-billed
656:
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183:
149:
126:
122:
118:
1018:
992:
696:
735:
Wieland, G. R., 1906, Dinosaurian gastroliths: Science, v. 23, p. 819-821.
463:
459:
424:
420:
412:
408:
371:
228:
199:
167:
164:
137:
19:
1000:
314:
160:
66:
54:
488:
published a study on 115 gastroliths discovered in association with a
415:
formation roughly 150 million years old. Some gastroliths are made of
950:). Ph.D. Thesis, The University of Bonn, Bonn, Germany, 187 pp. URN:
552:
404:
301:
266:
195:
153:
508:
447:
338:
313:
analysis of wear patterns on gastroliths. Wings (2003) found that
276:
104:
58:
18:
595:
Larval Anurans Adjust Buoyancy in Response to Substrate Ingestion
443:
141:
129:
70:
926:
Whittle, C. (1988). On the Origins of Gastroliths. Journal of
375:
353:
Photograph # 311488 demonstrates an articulated skeleton of a
319:
156:(frog) species has been observed to improve buoyancy control.
285:
ingesting gastroliths entangled in vegetation it is consuming
57:
and used to grind food in animals lacking suitable grinding
186:
do. Research indicates that the presence of gastroliths in
53:. Gastroliths in some species are retained in the muscular
374:, showing a collection of about 40 gastroliths inside the
109:
Gastroliths from Jurassic strata near Starr Springs, Utah
980:
Proceedings of the Royal Society B: Biological Sciences
875:
873:
871:
839:
837:
835:
833:
806:
804:
589:
587:
234:
and interpreted these stones as gastroliths. In 1907,
597:
Copeia: February 2005, Vol. 2005, No. 1, pp. 188-195.
973:
Wings, Oliver & Sander, P. Martin (April 2007).
329:
None of the gastroliths examined in a 2001 study of
891:
889:
887:
885:
794:
792:
790:
788:
782:"Description," Sanders et al. (2001). Pp. 176-177.
769:
767:
765:
763:
761:
759:
744:Brown, B. 1907. Gastroliths. Science 25(636): 392.
1031:"Gastroliths from the Lower Cretaceous sauropod
1029:Sanders, F.; Manley, K.; Carpenter, K. (2001).
895:"Description," Sanders et al. (2001). Page 174.
879:"Description," Sanders et al. (2001). Page 172.
798:"Description," Sanders et al. (2001). Page 177.
773:"Description," Sanders et al. (2001). Page 176.
1041:. Indiana University Press. pp. 166–180.
904:"Conclusion," Sanders et al. (2001). Page 177.
865:"Table 12.2," Sanders et al. (2001). Page 171.
8:
843:"Abstract," Sanders et al. (2001). Page 166.
378:, about midway between shoulder and pelvis.
1037:. In Tanke, Darren; Carpenter, Ken (eds.).
1008:
446:is full of highly polished red and black
583:
391:Gastroliths have sometimes been called
351:The American Museum of Natural History
202:fossils can weigh several kilograms.
16:Rock held inside the intestinal tract
7:
419:. Most known instances of preserved
395:because they are often found in the
856:," Sanders et al. (2001). Page 169.
458:Most known instances of preserved
14:
618:Copeia, Vol2007, Iss 4 (Dec 2007)
93:), meaning "stomach", and λίθος (
69:. Particles ranging in size from
117:, gastroliths are common among
1:
961:Acta Palaeontologica Polonica
921:Geological Society of America
661:Microscopy and Microanalysis
311:scanning electron microscope
627:Darby and Ojakangas (1980).
356:Psittacosaurus mongoliensis
1109:
85:Gastrolith comes from the
681:10.1017/S1431927615015767
606:Wickramasinghe, DD et al
399:(named after the town of
190:differs from that of the
440:Cedar Mountain Formation
192:short-necked plesiosaurs
188:elasmosaurid plesiosaurs
1033:Cedarosaurus weiskopfae
952:urn:nbn:de:hbz:5N-04626
928:Vertebrate Paleontology
471:Cedarosaurus weiskopfae
148:. Stones swallowed by
993:10.1098/rspb.2006.3763
638:"Crayfish Gastroliths"
610:Nannophrys ceylonensis
523:clasts also included.
347:
307:Christopher H. Whittle
286:
110:
77:have been documented.
51:gastrointestinal tract
30:
930:, Supplement to 3:28.
462:gastroliths are from
423:gastroliths are from
382:Geologic distribution
342:
280:
108:
22:
935:Journal of Taphonomy
361:Ondai Sair Formation
221:George Reber Weiland
215:History of discovery
97:), meaning "stone".
673:2016MiMic..22...22L
558:Calculus (medicine)
309:(1988,9) pioneered
250:Friedrich von Huene
397:Morrison Formation
348:
287:
263:William Lee Stokes
144:require access to
111:
31:
987:(1610): 635–640.
486:Kenneth Carpenter
26:gastroliths from
1098:
1091:Digestive system
1052:
1022:
1012:
948:Struthio camelus
905:
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642:to know the land
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628:
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604:
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437:Early Cretaceous
163:animals such as
37:, also called a
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852:"Occurrence in
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540:Paleontologists
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393:Morrison stones
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417:petrified wood
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344:Psittacosaurus
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273:Identification
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194:. While some
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49:held inside a
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1081:Trace fossils
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1059:(7):453-459.
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113:Among living
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43:gizzard stone
40:
39:stomach stone
36:
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25:
21:
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1038:
1032:
984:
978:
968:PDF fulltext
963:
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955:PDF fulltext
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942:PDF fulltext
937:
934:
900:
861:
854:Cedarosaurus
853:
848:
815:
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749:
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722:
713:
667:(1): 22–38.
664:
660:
650:
641:
632:
623:
613:
609:
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538:
528:Cedarosaurus
527:
525:
511:, with some
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501:Cedarosaurus
500:
491:Cedarosaurus
489:
475:
470:
457:
434:
392:
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343:
332:Cedarosaurus
330:
328:
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298:rock tumbler
288:
256:
242:
236:Barnum Brown
218:
210:Paleontology
204:
171:
158:
145:
112:
94:
90:
84:
42:
38:
34:
32:
28:Tropic Shale
966:(1): 1-16.
497:reflectance
442:of Central
359:, from the
258:Sellosaurus
254:prosauropod
225:plesiosaurs
180:plesiosaurs
173:Caudipteryx
140:. Domestic
127:herbivorous
115:vertebrates
1075:Categories
911:References
568:Enterolith
482:Kim Manley
431:Cretaceous
411:), a late
403:, west of
365:Cretaceous
290:Geologists
283:diplodocid
244:Claosaurus
184:crocodiles
123:alligators
119:crocodiles
101:Occurrence
63:grain size
35:gastrolith
24:Plesiosaur
689:1435-8115
579:Footnotes
563:Coprolite
535:Migration
521:quartzite
517:siltstone
513:sandstone
454:Sauropods
427:animals.
294:digestion
240:hadrosaur
232:dinosaurs
219:In 1906,
168:dinosaurs
150:ostriches
138:sea lions
81:Etymology
1019:17254987
705:26280256
697:26818557
547:See also
476:In 2001
464:Jurassic
460:sauropod
425:Jurassic
421:sauropod
413:Jurassic
409:Colorado
401:Morrison
387:Jurassic
376:rib cage
372:Mongolia
363:, Lower
229:sauropod
200:dinosaur
165:sauropod
89:γαστήρ (
1086:Stomach
1010:2197205
1001:5223826
669:Bibcode
315:ostrich
302:fossils
161:extinct
67:ballast
55:gizzard
45:, is a
1045:
1017:
1007:
999:
823:
703:
695:
687:
553:Bezoar
519:, and
484:, and
448:cherts
405:Denver
368:Period
267:strata
196:fossil
154:anuran
95:lithos
91:gastēr
75:cobble
997:JSTOR
701:S2CID
509:chert
159:Some
134:seals
130:birds
87:Greek
59:teeth
1043:ISBN
1015:PMID
821:ISBN
693:PMID
685:ISSN
444:Utah
435:The
227:and
175:zoui
146:grit
142:fowl
136:and
71:sand
47:rock
1005:PMC
989:doi
985:274
677:doi
370:of
320:moa
73:to
41:or
1077::
1057:24
1013:.
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