Micropachycephalosaurus (Greek for "tiny thick-headed lizard"); pronounced MY-cro-PACK-ee-SEFF-ah-low-SORE-us


Woodlands of Asia

Historical Period:

Late Cretaceous (80-70 million years ago)

Size and Weight:

About two feet long and 5-10 pounds



Distinguishing Characteristics:

Small size; bipedal posture; unusually thick skull


About Micropachycephalosaurus

The nine-syllable name Micropachycephalosaurus may sound like a mouthful, but it's not so bad if you break it down into its constituent Greek roots: micro, pachy, cephalo, and saurus. That translates into "tiny thick-headed lizard," and fittingly, Micropachycephalosaurus seems to have been the smallest of all the known pachycephalosaurs (otherwise known as bone-headed dinosaurs). For the record, one of the dinosaurs with the shortest given names--Mei--was also bite-sized; make of that what you will!

But hold the Jurassic phone: despite its imposing name, Micropachycephalosaurus may turn out not to have been a pachycephalosaur at all, but a very small (and very basal) ceratopsian, or horned, frilled dinosaur. In 2011, paleontologists closely examined the bone-headed dinosaur family tree and were unable to find a convincing place for this multisyllabic dinosaur; they also re-examined the original fossil specimen of Micropachycephalosaurus, and were unable to confirm the existence of a thickened skull (that part of the skeleton was missing from the museum collection).

What if, despite this recent classification, Micropachycephalosaurus is re-re-assigned as a true bonehead? Well, because this dinosaur has been reconstructed from a single, incomplete fossil discovered in China (by the famous paleontologist Dong Zhiming), the possibility looms that it may one day be "downgraded"--that is, paleontologists will agree that it's another type of pachycephalosaur entirely. (The skulls of pachycephalosaurs changed as these dinosaurs aged, meaning that a juvenile of a given genus is often incorrectly assigned to a new genus). If Micropachycephalosaurus winds up losing its place in the dinosaur record books, some other multisyllabic dinosaur (possibly Opisthocoelicaudia) will rise up to assume the "world's longest name" title.