The “Ostrich Dinosaur Body Plan” has Evolved … Twice!


Seems like convergent evolution has been a hot topic recently. (See, for example, this recent PT post.)

On January 25th, the National Geographic reported that

After languishing for decades in the bowels of a New York museum, a dinosaur- era crocodile relative is seeing the light—and shedding secrets. New studies of the forgotten fossil reveal that the species walked on two feet and looked much like a so-called ostrich dinosaur, though the two are barely related, paleontologists report.

The specimen, Effigia okeeffeae, languished at the American Museum of Natural History for almost 60 years since its discovery at the Ghost Ranch quarry in New Mexico, near the digs of artist Georgia O’Keeffe, after whom the creature is named.

The National Geographic article also mentions that

Recently, though, Norell and study coauthor Sterling Nesbitt, a graduate student, reexamined the long-warehoused fossils. The pair soon spotted the distinctive “crocodile” ankle that first alerted them to the fossil’s potential importance.Ankle aside, Effigia had large eyes, a long tail, and a toothless beak—not unlike the ostrich dinosaurs. Effigia also walked on two feet, unlike modern crocs. These physical similarities suggest that Effigia and the ornithomimid dinosaurs evolved similarly during two different eras, the scientists say. The fossil record shows that many different features have been reinvented time and again in different species … Both Effigia and the ostrich dinosaurs would have evolved from a common ancestor that lived long before, the study says. Modern crocodiles are but one remnant of what was once a far more diverse croc family. “Today we think of crocodiles as looking basically the same,” said Nesbitt, of the American Museum of Natural History and Columbia University’s Lamont-Doherty Earth Observatory. “But in their history they took on a wide variety of different body plans.”

Please feel free to comment on this story. I won’t be around to moderate, however - I’ll be presenting at the Amaz!ng Meeting 4 in Las Vegas this weekend.

So, rather than send off-topic posts to the Bathroom Wall, I will come back next week and tally up who was Naughty (off-topic) and who was Nice. Then I’ll post your grades for all to see.

Have a great weekend! - Dave

PS - check out P.Z. Myers’ take on some other interesting crocodilian fossils.


Where is the link to the main story?

Moses - see how the word “reported” in the sentence “On January 25th, the National Geographic reported that …” is blue and different-looking? That’s the hyperlink to the NG article.

Also, hyperlinks betray themselves by turning arrow cursors into hand-with-index-finger pointer icons.



Thanks Dave.

So, maybe the whole idea about birds is wrong and have they evolved much earlier than people want to believe. I know some people who work on that and the arguments they have are convincing. The peoblem is the hardheadedness of the paleotologist who want to keep their dogma.….

Some time ago, there was a similar article (I don’t recall where) pointing out the similarities in body plan between the certitopsian dinosaurs (e.g. the familiar triceratops) and the modern rhinoceros.

As with the ostrich comparison, this is not meant to imply that there is any genetic relationship between the rhino or the ostrich and their respective dinosaur counterparts. The point is that creatures who occupy a similar ecological niche, even though separated by millions of years, can in some cases arrive (through evolution) at similar solutions to similar problems.

One should say that the “ostrich body plan” has not evolved in this animal at all, since it lacks the long, slender, cursorial-built legs and very slender neck that go with such a body plan. This “croc”, unlike the ostrich-dinos of the Cretaceous, seems to be more typically croc in the form of its legs and ankle, and the femur is longer than the tibia with a deep, “sculling” tail and flexible dorsum.

What’s even more amazing that in Seattle just under the foundation of the new wing of the Discovery Institute (the wing to hold the headlines of all their winning court cases) was found a new Ostrich dinosaur. Large and costly with its long neck curved forward to bury its head in the bedrock it probably was crucial to the demise of dinosaurs in general by its denial of meteors. It has been christened “Truthiomimus”.

The “Ostrich Dinosaur Body Plan” has Evolved … Twice!

Umm, shouldn’t that be three times? This guy, Struthiomimus, and, of course, the ostrich.

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This page contains a single entry by Dave Thomas published on January 27, 2006 8:18 PM.

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