April 15, 2005 | David F. Coppedge

Dinosaur Fossilized in the Act of Laying Eggs

Two eggs, with shell material still attached, were found inside the oviducts of a theropod dinosaur, a Chinese team reported in Science.1  This first-time discovery of intact eggs in the body of the female “suggests that theropod dinosaurs had two functional oviducts (like crocodiles) but that each oviduct produced only one egg at a time and that an entire egg clutch was laid through multiple ovipositions (like birds).”  The suggestion that the fossil provides an intermediate egg-laying structure between reptiles and birds was made on the basis of the position of the eggs.  It is improbable two eggs would be found in the ovary when the animal was fossilized, they explained:

Unless sequential egg formation and shelling was very rapid and/or there was an extremely prolonged period of egg laying, the preservation of only two tightly juxtaposed eggs in the specimen strongly indicates that each of the paired oviducts simultaneously produced a single egg.   (Emphasis added in all quotes.)

The fossilization process appears to have retained the shape and texture of the eggshells.  See also the popular writeups on this story in National Geographic, BBC News and MSNBC News.


1Sato et al., “A Pair of Shelled Eggs Inside A Female Dinosaur,” Science, Vol 308, Issue 5720, 375 , 15 April 2005, [DOI: 10.1126/science.1110578].

The science reporters all seem to be jumping on the spin that this might represent a transitional form, and ignoring the remarkable fact that this animal was buried and fossilized within minutes or seconds of laying eggs.  The missing-link angle depends on interpretation of positions of the eggs relative to the pelvis and oviducts.  Notice how the paper said unless sequential egg formation and shelling was very rapid – a reference to how quickly this mother dinosaur was buried.  Could the rapid fossilization of this dinosaur been contemporaneous with a worldwide event that entombed a T. rex in Montana (see 03/24/2005 entry), leaving blood vessels intact?  If so, both these specimens were living much more recently than tens of millions of years ago.
    There are many, many things different between dinosaurs and birds.  Finding structural similarities in oviducts begs the question of how egg-laying and all its prerequisite equipment evolved in the first place.  The ability to encase an embryo in a calcified incubator of the right size and shape, keep it at the right temperature for the right time, and provide instructions to the hatchling on how and when to break out, is what we want explained in the Darwinist storybook.  Even that story would beg the question of everything else that would have to be pre-existent for egg laying to work: the structure of the mother’s skeleton, the egg laying machinery, the developmental process, the mineralization and nutrient requirements, and the incredibly complex story of embryonic development.  Saying it evolved doesn’t make it so.
    MSNBC News uttered another one of those ridiculous evolutionary lines that is self-contradicting, because it implies purpose on the part of the blind mechanism of natural selection, the very thing King Charles ordered expunged from biological explanations.  Any questions on why the final sentence below deserves Stupid Evolution Quote of the Week?  This is cartoon material:

“The evolution of one egg at a time happened very early, before birds could fly, and then the evolution of only one oviduct happened later,” he said [Matt Carrano, curator of dinosaurs at the National Museum of Natural History in Washington].
    “That might be related to the origin of flight,” he said, explaining that maybe birds wanted to lighten their body and so developed one oviduct.

(Visited 19 times, 1 visits today)
Categories: Birds, Dinosaurs, Fossils

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.