Auca Mahuevo is a

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

lagerstätte A Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These for ...

in the eroded

badland Badlands are a type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded."Badlands" in ''Chambers's Encyclopædia''. London: George Newnes, 1961, Vol. 2, p. 47. They are characterized by steep slopes, mi ...

s of the

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...

n province of Neuquén, Argentina. The sedimentary layers of the

Anacleto Formation The Anacleto Formation is a geologic formation with outcrops in the Argentine Patagonian provinces of Mendoza, Río Negro, and Neuquén. It is the youngest formation within the Neuquén Group and belongs to the Río Colorado Subgroup. Formerl ...

at Auca Mahuevo were deposited between 83.5 and 79.5 million years before present and offer a view of a fossilized

titanosaur Titanosaurs (or titanosaurians; members of the group Titanosauria) were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still th ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...

hatchery.Chiappe & Coria, 2004, p.591

Description

At Auca Mahuevo dinosaur eggs containing identifiable embryonic remains have been the most spectacular discoveries. The eggs retain casts of the ''membrana testacea'', the internal membrane that adheres to the shell, familiar to anyone who has peeled a hard-boiled egg. The context revealed a vast

rookery A rookery is a colony of breeding animals, generally gregarious birds. Coming from the nesting habits of rooks, the term is used for corvids and the breeding grounds of colony-forming seabirds, marine mammals (true seals and sea lions), and ev ...

of excavated nest structures that can be compared to living egg-layers such as turtles, crocodilians and birds. Even their spacing within the nesting locality (two to three meters apart) can be assessed. Reconstruction of nesting strategies suggest that shallow pits with rims were excavated and plant material incorporated in the surface. The Auca Mahuevo lagerstätte was discovered during two expeditions, in 1997 and 1999, by

Luis Chiappe Luis María Chiappe (born 18 June 1962) is an Argentine paleontologist born in Buenos Aires who is best known for his discovery of the first sauropod nesting sites in the badlands of Patagonia in 1997 and for his work on the origin and early evo ...

, Lowell Dingus, and Rodolfo Coria, who were looking for fossilized birds.Coria, R.A. and Chiappe, L.M. - 2007 - Embryonic Skin From Late Cretaceous Sauropods (Dinosauria) of Auca Mahuevo, Patagonia, Argentina
''Journal of Paleontology'' v81(6):1528-1532 The site is now officially protected.

References

Bibliography

External links

BBC h2g2 site
Auca Maheuevo Dinosaur trace fossils Cretaceous Argentina Geology of Neuquén Province Lagerstätten Cretaceous paleontological sites of South America Paleontological sites of Argentina {{trace-fossil-stub

Description

See also

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