Letters to Nature

Nature 396, 258-261 (19 November 1998) | doi:10.1038/24370; Received 19 June 1998; Accepted 24 August 1998

Sauropod dinosaur embryos from the Late Cretaceous of Patagonia

Luis M. Chiappe1, Rodolfo A. Coria2, Lowell Dingus3, Frankie Jackson4, Anusuya Chinsamy5,6 & Marilyn Fox7

  1. Department of Ornithology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA
  2. Museo Municipal 'Carmen Funes', 8318 Plaza Huincul, Neuquén, Argentina
  3. Department of Vertebrate Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA
  4. Department of Paleontology, Museum of the Rockies, Montana State University, Bozeman, Montana 59717, USA
  5. Zoology Department, University of Cape Town, Private Bag, Rondebosch 7700, South Africa
  6. South African Museum, PO Box 81, Cape Town 8000, South Africa
  7. Department of Vertebrate Paleontology, Peabody Museum of Natural History, Yale University, New Haven, Connecticut 06520, USA

Correspondence to: Luis M. Chiappe1 Correspondence and requests for materials should be addressed to L.M.C. (e-mail: Email: chiappe@amnh.org).

Definitive non-avian dinosaur embryos, those contained inside fossil eggs, are rare1,2. Here we describe the first known unequivocal embryonic remains of sauropod dinosaurs—the only known non-avian dinosaur embryos from Gondwana—from a nesting ground in the Upper Cretaceous stage of Patagonia, Argentina. At this new site, Auca Mahuevo (Fig. 1), thousands of eggs are distributed over an area greater than 1 km2. The proportion of eggs containing embryonic remains is high: over a dozen in situ eggs and nearly 40 egg fragments encasing embryonic material were recovered. In addition to bone, these specimens contain large patches of fossil skin casts, the first definitive portions of integument ever reported for a non-avian dinosaur embryo. As morphology of the eggs enclosing these osseous and integumentary remains is identical, we propose that these specimens belong to the same sauropod species. This discovery allows the confident association of the megaloolithid type of dinosaur eggshell3 with sauropod dinosaurs.