TY - JOUR
T1 - A Second Specimen of Citipati Osmolskae Associated with a Nest of Eggs from Ukhaa Tolgod, Omnogov Aimag, Mongolia
AU - Norell, Mark A.
AU - Balanoff, Amy M.
AU - Barta, Daniel E.
AU - Erickson, Gregory M.
N1 - Publisher Copyright:
© 2018 American Museum of Natural History.
PY - 2018/4/26
Y1 - 2018/4/26
N2 - Adult dinosaurs preserved attending their nests in brooding positions are among the rarest vertebrate fossils. By far the most common occurrences are members of the dinosaur group Oviraptorosauria. The first finds of these were specimens recovered from the Djadokhta Formation at the Mongolian locality of Ukhaa Tolgod and the Chinese locality of Bayan Mandahu. Since the initial discovery of these specimens, a few more occurrences of nesting oviraptors have been found at other Asian localities. Here we report on a second nesting oviraptorid specimen (IGM 100/1004) sitting in a brooding position atop a nest of eggs from Ukhaa Tolgod, Omnogov, Mongolia. This is a large specimen of the ubiquitous Ukhaa Tolgod taxon Citipati osmolskae. It is approximately 11% larger based on humeral length than the original Ukhaa Tolgod nesting Citipati osmolskae specimen (IGM 100/979), yet eggshell structure and egg arrangement are identical. No evidence for colonial breeding of these animals has been recovered. Reexamination of another "nesting" oviraptorosaur, the holotype of Oviraptor philoceratops (AMNH FARB 6517) indicates that in addition to the numerous partial eggs associated with the original skeleton that originally led to its referral as a protoceratopsian predator, there are the remains of a tiny theropod. This hind limb can be provisionally assigned to Oviraptoridae. It is thus at least possible that some of the eggs associated with the holotype had hatched and the perinates had not left the nest.
AB - Adult dinosaurs preserved attending their nests in brooding positions are among the rarest vertebrate fossils. By far the most common occurrences are members of the dinosaur group Oviraptorosauria. The first finds of these were specimens recovered from the Djadokhta Formation at the Mongolian locality of Ukhaa Tolgod and the Chinese locality of Bayan Mandahu. Since the initial discovery of these specimens, a few more occurrences of nesting oviraptors have been found at other Asian localities. Here we report on a second nesting oviraptorid specimen (IGM 100/1004) sitting in a brooding position atop a nest of eggs from Ukhaa Tolgod, Omnogov, Mongolia. This is a large specimen of the ubiquitous Ukhaa Tolgod taxon Citipati osmolskae. It is approximately 11% larger based on humeral length than the original Ukhaa Tolgod nesting Citipati osmolskae specimen (IGM 100/979), yet eggshell structure and egg arrangement are identical. No evidence for colonial breeding of these animals has been recovered. Reexamination of another "nesting" oviraptorosaur, the holotype of Oviraptor philoceratops (AMNH FARB 6517) indicates that in addition to the numerous partial eggs associated with the original skeleton that originally led to its referral as a protoceratopsian predator, there are the remains of a tiny theropod. This hind limb can be provisionally assigned to Oviraptoridae. It is thus at least possible that some of the eggs associated with the holotype had hatched and the perinates had not left the nest.
UR - http://www.scopus.com/inward/record.url?scp=85046074415&partnerID=8YFLogxK
U2 - 10.1206/3899.1
DO - 10.1206/3899.1
M3 - Article
AN - SCOPUS:85046074415
SN - 0003-0082
VL - 2018-April
SP - 1
EP - 44
JO - American Museum Novitates
JF - American Museum Novitates
IS - 3899
ER -