Hairy Museum of Natural History

Study of the head of Tanystropheus

The Triassic protorosaur Tanystropheus has long been one of the more popular attractions in evolution’s endless freakshow—no doubt because it looked something like a large carnivorous lizard that managed to get a fishing pole stuck in its throat. That is to say that its neck was unusually long (making up about half of its total 6-meter length), and unusually inflexible (it possessed only a dozen elongated neck vertebrae, bound together by bundles of cervical ribs). Exactly how Tanystropheus carried its remarkable neck has been the subject of differing interpretations over the past 70 years or so.

Most restorations of Tanystropheus portray it sitting along the shoreline, stretching its long neck out over the water and plucking up any fish that might come into reach. But some researchers have argued that extending such a disproportionately long neck would have put Tanystropheus‘ center of gravity out in front of its arms—literally causing it to fall flat on its face anytime it stuck its neck out. According to this view, Tanystropheus would either have to spend its life underwater where its neck would be supported, or else raise its neck up like a question mark over its shoulders in order to keep itself centered on land.

But a recently described specimen from southern Switzerland is helping revive the view of Tanystropheus as a shoreline fish-plucker. Or perhaps it would be more accurate to say that the new fossil puts a little more weight behind that interpretation.

The fossil, described by Dr. Silvio Renesto (previously mentioned here for his work on drepanosaurs), preserves a partial skeleton of Tanystropheus that includes the first reported example of the animal’s soft tissue. A few traces of skin show that Tanystropheus had subrectangular, non-overlapping scales on at least part of its body. But even more intriguing are the “wide patches of black material” preserved around the base of its tail.

The “black material” shows no signs of skin or scale impressions, but does contain a large number of calcium carbonate spherules. Dr. Renesto suggests that these spherules precipitated in an acidic microenvironment that was created when a large mass of muscle began to decay. The fact that the spherules only formed at the base of the tail implies that Tanystropheus sported an impressive amount of flesh behind its hips.

The biomechanical implications of all that junk in the trunk are obvious. In addition to housing powerful hindlimb muscles, a big backside would have shifted the animal’s weight further to its rear. This would have helped stabilize the animal as it swung its 2–3 meter neck around, allowing it to snap up its prey without losing its balance.

Further Reading:

Renesto, S. (2005) A new specimen of Tanystropheus (Reptilia Protorosauria) from the Middle Triassic of Switzerland and the ecology of the genus. Rivista Italiana di Paleontologia e Stratigrafia vol. 111, no. 3, 377–394.

Silvio’s Tanystropheus pages.

—Matt Celeskey.

File under: Recent Discoveries, Reptiles, Triassic.