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"Long before it's in the papers"
July 07, 2015

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24 dinos may have perished with “babysitter”

July 7, 2015
Courtesy of the U.S. National Science Foundation
and World Science staff

A slab of fos­sils found in Chi­na may rep­re­sent twen­ty-four very young di­no­saurs that per­ished along with a larg­er “babysit­ter” in a vol­can­ic erup­tion, sci­en­tists be­lieve.

Re­search­ers say the un­hap­py beasts seem to have been caught in a la­har—a mix­ture of mud, wa­ter, rock and junk set aflow by a vol­can­ic out­burst. The old­er di­no­saur may have been a broth­er or a sis­ter of the young­er ones, as it does­n’t seem old enough to have been a par­ent, the re­search­ers add.

A rock slab with fossils attributed to youngsters of the dinosaur species Psit­ta­cosaurus lu­jiatunen­sis. (Courtesy Nat'l Science Foundation)


The fos­sils, all at­trib­ut­ed to a plant-eating spe­cies known as Psit­ta­cosaurus lu­jiatunen­sis, turned up over a dec­ade ago in the Lu­jiatun beds of the Yix­ian Forma­t­ion in north­east­ern Chi­na’s Liao­ning Prov­ince. 

A pa­per pub­lished in 2004 briefly de­scribed the rock slab, es­ti­mat­ed as 120 mil­lion years old. More re­cent­ly, pa­le­on­tol­ogist Pe­ter Dod­son and doc­tor­al stu­dent Bran­don P. Hedrick of the Uni­vers­ity of Penn­syl­va­nia stud­ied the ob­ject fur­ther. 

They say they could­n’t find proof that it rep­re­sents a nest, as oth­ers have pro­posed. “It cer­tainly seems like it might be,” Hedrick said, though no eggshells were found.

Anal­y­sis of the rock ma­te­ri­al through a pro­ce­dure called X-ray dif­frac­tion, and mag­nif­ica­t­ion of sliv­ers of rock, sug­gested to the re­search­ers that the slab hold­ing the fos­sils con­sisted of vol­can­ic ma­te­ri­al. The ori­enta­t­ion of the fos­sils seemed to sup­port this as well, they said.

The larg­er an­i­mal’s skull was em­bed­ded in the same rock as the smaller an­i­mals and two of the young­er ones were ac­tu­ally in­ter­twined with the skull, said Hedrick and Dod­son. They be­lieve this proxim­ity sug­gests co­op­er­a­tive be­hav­ior si­m­i­lar to that shown by some modern-day birds. 

Based on the size of the larg­er di­no­saur’s skul­l—a­bout 4.5 inches long—sci­en­tists have es­ti­mat­ed its age as be­tween 4 and 5 years, about half of the age at which mem­bers of the spe­cies nor­mally be­gan to re­pro­duce.


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A slab of fossils found in China may represent twenty-four very young dinosaurs that perished along with a larger “babysitter” in a volcanic eruption, scientists believe. Researchers suggest the unhappy beasts may have been caught in a lahar—a mixture of mud, water, rock and junk set aflow by a volcanic outburst. The older dinosaur may have been a brother or a sister of the younger ones, as it doesn’t seem old enough to have been a parent, the researchers add. The fossils, all attributed to a plant-eating species known as Psittacosaurus lujiatunensis, turned up over a decade ago in the Lujiatun beds of the Yixian Formation in northeastern China’s Liaoning Province. A paper published in 2004 briefly described the rock slab, estimated as 120 million years old. More recently, paleontologist Peter Dodson and doctoral student Brandon P. Hedrick of the University of Pennsylvania studied the object further. They say they couldn’t find proof that it represents a nest, as others have proposed. “It certainly seems like it might be,” Hedrick said, though no eggshells were found. Analysis of the rock material through a procedure called X-ray diffraction, and magnification of slivers of rock, suggested to the researchers that the slab holding the fossils consisted of volcanic material. The orientation of the fossils seemed to support this as well, they said. The larger animal’s skull was embedded in the same rock as the smaller animals and two of the younger ones were actually intertwined with the skull, said Hedrick and Dodson. They believe this proximity suggests cooperative behavior similar to that shown by some modern-day birds. Based on the size of the larger dinosaur’s skull—about 4.5 inches long—scientists have estimated its age as between 4 and 5 years, about half of the age at which members of the species normally began to reproduce.