Tanystropheus, a bipedal predator?

Note: I’m not quite ready for my Nesbitt – Dinosaurs blog, which was scheduled to run today. Instead, some news with pictures.

What the bizarre neck and stomach contents of Tanystropheus tell us
The nature and use of the extremely long neck of Tanystropheus langobardicus has stymied researchers for the last hundred years. Stefania Nosotti (2000) was the last to report on this odd reptile, focusing on the much smaller species. She, like so many other workers, saw Tanystropheus as a plesiosaur-like aquatic predator with a horizontal orientation and a very stiff neck. Unfortunately, there is not much  about Tanystropheus that indicates any aquatic adaptations. No flippers. No tall tail.

An aquatic cousin, Dinocephalosaurus (Fig. 1), has several traits one might expect of an aquatic sit-and-wait predator. 

 Dinocephalosaurus in resting, feeding and breathing modes.

Figure 1. Dinocephalosaurus in resting, feeding and breathing modes. In breathing mode the throat sac would capture air that would not be inhaled until the neck was horizontal at the bottom of the shallow sea. Orbits on top of the skull support this hypothesis.

On the other hand, there is not very much about giant Tanystropheus that makes it look very comfortable on land! However, smaller closest relatives include Macrocnemus, Tanytrachelos and Langibardisaurus. All were previously considered terrestrial bipeds (perhaps not always correctly). So with these comparatively tiny sisters in mind, I imagined Tanystropheus among tall trees plucking small reptiles out of high boughs (Fig. 2).

Tanystropheus ascending two trees.

Figure 2. Tanystropheus ascending two trees. In the middle, a modern analog, the extended pole tree trimmer. Unfortunately, this scenario does not mesh with the stomach contents, fish scales and squid hooks.

There’s  that stomach full of squid hooks
There’s a big problem with the terrestrial feeding hypothesis. Tanystropheus fossils are found in marine strata (but that frequently happen to terrestrial specimens washed into the sea). Most importantly the stomach contents included squid hooks and fish scales (Fig. 3).

Stomach contents of Exemplare C, Tanystropheus.

Figure 3. Stomach contents of Exemplare C, Tanystropheus. Pink indicates two femurs. Arrow indicates anterior. Ma J. = stomach contents.

Wild 1973
Wild (1973) produced the last large treatise on the large Tanystropheus fossils. He described stomach contents in several large specimens. The treatise in German was translated via Google and includes some minor editing: “Stomach contents were found (Fig. 2, Exemplare C), consisting of a light brown-colored pastel, phosphate-rich area and embedded within the mass were black checkmark-shaped squid arm hooks. In form they resemble…Phragmoteuthis. Also in the stomach contents of Exemplare M were sporadic octopus hooks. … ganoid fish scales also appear there. These scales, however, could be recognized as such only by their luster and their rhombic shape. In the stomach contents of Exemplare K shed Ganoid scales are not rare. Unfortunately, even these can not be determined with certainty. The adult specimens of Tanystropheus hunted in the sea for squid.

These squid hooks are in the range of 1-2mm in size or smaller and match those associated with a 20 cm Triassic squid, Phragmoteuthis (Fig. 4).

Phragmoteuthis, a Late Triassic squid.

Figure 4. Phragmoteuthis, a Late Triassic squid. Length, approximately 20 cm. Note the hooks that define the short arms.

So combining all this…
We have to put large specimens of Tanystropheus under water. But horizontal does not seem to offer much advantage, since nothing about it indicates it was a good swimmer.

Like many animal oddities, perhaps Tanystropheus as a mimic
Tanystropheus is, by any definition, an animal oddity. Other animal oddities include the frogfish, the stick insect, the flounder and the pipefish, all of which mimic their environment. So I wondered, what sort of environment would camouflage Tanystropheus underwater during the Triassic?

Tanystropheus underwater among tall crinoids and small squids.

Figure 5. Tanystropheus underwater among tall crinoids and small squids.

Among the stalked crinoids
Triassic stalked crinoids were widespread in the Triassic and spectacular specimens have been found in Germany (Fig. 7). Combining Tanystropheus with tall stalked crinoids seems to be the most parsimonious solution to the vexing problem of this strange reptile. It doesn’t have to swim. It doesn’t have to support its great neck. And the food comes to Tanystropheus likes bees to flowers. A quick trip vertically to the surface, replenishes air. Young can be hatched on land or underwater with mother protecting the egg in utero, like pterosaurs probably did.

Triassic sea lilies (crinoids) from Germany.

Figure 6. Triassic sea lilies (crinoids) from Germany. So imagine Tanystropheus hiding in large tracts of such crinoid forests.

Macrocnemus
Of course, this sheds light on the ancestors of TanystropheusMacrocnemus. Stalked crinoids come in a variety of heights. Perhaps the variety we find in Macrocnemus evolved to blend in with this variety in crinoids. Macrocnemus fossils are also found in marine sediments.

And Tanytrachelos
Perhaps tiny Tanytrachelos had a dual life, on land and in shallow waters. Together with Langobardisaurus, the dentition of these lizards points to some sort of odd diet, perhaps marine prey? Could use some stomach contents here.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

References
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus(Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-16.
Li C, Rieppel O and LaBarbera MC 2004. A Triassic aquatic protorosaur with an extremely long neck. Science 305:1931.
Nosotti S 2007. Tanystropheus longobardicus (Reptilia, Protorosauria: Reinterpretations of the anatomy based on new specimens from the Middle Triassic of Besano (Lombardy, Northern Italy). Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano, Vol. XXXV – Fascicolo III, pp. 1-88
Peters D, Demes B and Krause DW 2005. Suction feeding in Triassic Protorosaur? Science, 308: 1112-1113.
wiki/Dinocephalosaurus
wiki/Tanystropheus

5 thoughts on “Tanystropheus, a bipedal predator?

  1. First to comment!

    Just want to say that I don´t necessarily agree with many of your views on pterosaurs, even though I honestly lack the expertise necessary to put forward my own, solid take on them. I am merely a layman and artist who’s perpetually in awe before the wonders of evolution. But just because I do not agree with some things you say, doesn´t mean I can´t appreciate a creative idea. Your crinoid-mimicking Tany really brought a smile to my face.
    It is very true that many modern day animals would never be thought of as camouflage masters if we only had their bones to go by, and many modern day creatures use camouflage. I myself came up with an idea about hypothetical camouflage-based hunting technique by two other (and much larger) extinct predators, which I would be honored if you saw and commented about, but which I’m also not willing to share here. (Is there any e-mail address I can use to reach you? If you’re not ok with it of course, I will understand).
    But anyways, back to the Tany…I have one doubt regarding your hypothetical Tany embryo reconstruction. I have a book (by Tom Holtz, I believe) which states that Tanystropheus had a short neck when it was young, and that only later in life would it lenghten. I am rather confused about this.

    Hope you can reply

    N.

  2. Echo location is being used by an unknown animal in lake Champlain . it is believed this animal is tanystropheus. this was recorded by the fauna research institute. Then by Dennis hall and Katy Hurling. Visit champ search 2015 search results Facebook. You can see films of one of these animals stepping on a boats mooring spinning the boat. Recordings of echo location and possibly some electro location loud growling and what sounds like a submarine directly beneath them. I’m a little perplexed at why no one besides hall and heuling are trying to carefully get film footage and recordings of this animal. It recently bit a Canadian woman. She said it felt more like a warning. Your too close to my hiding spot. She captured this on gopro camera. It has one long neck as seen at the end of the film clip as it retreats back to where it was hiding..

  3. The “Triassic sea lilies” are Seirocrinus subangularis from the TOARCIAN of Germany, 20 million years latter (C´mon is literally an iconic Fossil from the Posidonienschiefer Formation, the location where you recently take and destroy Two poor Fishes, turning them into abominations)

    The “Late Triassic Squid” is an ALSO TOARCIAN Clarkeiteuthis conocauda, whose affinities with Squids (Teuthida) don´t exist, being a possible Diplobelidae Coleoidean.

    -Matzke, A. T., & Maisch, M. W. (2019). Palaeoecology and taphonomy of a Seirocrinus (Echinodermata: Crinoidea) colony from the early Jurassic Posidonienschiefer Formation (Early Toarcian) of Dotternhausen (SW Germany). Neues Jahrb. Geol. Paläontol.–Abh. Bd, 291, 89-107.

    -Fuchs, D., Donovan, D. T., & Keupp, H. (2013). Taxonomic revision of “Onychoteuthis” conocauda Quenstedt, 1849 (Cephalopoda: Coleoidea). Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 270(3), 245-255.

    • Thank you for expertise LTF. Not everyone who reads (or writes!) these posts understands the subtle differences you seem to be familiar with. You just raised the bar, which is always a good thing.

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