In America, a “longneck” usually refers to a bottle of beer, so called because of its long top. But, this creature, which lived about 250 million years ago, was a real longneck: it had a stiff, 9-foot (2.7 m) neck on a body that, with the neck, was only 20 feet (6.1 m) long. Moreover, the neck was lengthened not by evolving more vertebrate, but by evolving elongation of each of the 13 extant vertebrae, so each was about 8½ inches (0.21 m) long. Here’s an artist’s rendition of this aquatic reptile, taken from a new “Trilobite” column in the New York Times, which calls it “one of the most baffling animals that ever lived.”
The new paper below, from Current Biology (read it by clicking on screenshot, get pdf here, and see full reference at the bottom), unravels some mysteries about this very bizarre reptile, like what it ate and why there was a much smaller version living in the same area at the same time.
The main analysis was on a single crushed skull of the creature (Tanystropheus hydroides), which has been known for some time. What was good about the crushing was that although the three-dimensional anatomy of the whole skull was obscured, many of the bones became disarticulated and did retain their three-dimensional structure. Also, the bones at the rear of the skull were revealed, which were not well known previously.
Researchers also knew of a smaller version of this reptile in the same strata and area, but it was unclear whether they were juveniles of T. hydroides or individuals from a smaller but similar species. Here’s a diagram from the paper showing a photo of the fossil, the bones and a reconstruction of the 3D skull from CT scans. The color-coding of the bones can be unraveled by going to Table S1 in the paper:
The paper is very technical, but the main results are clear.
First, the creature was certainly fully aquatic: the nostrils are atop the head (making it easy to breathe when it surfaced), and it had long unserrated fangs, visible in figure “G” above. These are characteristic of an aquatic diet, jibing with stomach contents that had been previously identified (cephalopods and fish). Thus it almost certainly wasn’t a land animal that entered the water to feed. That is also ruled out by that long, stiff neck, which would have been a serious impediment on land.
The articulation of the jaw and the teeth suggest that it was a “ram-feeding”, “ambush” predator that probably sat or crawled on the bottom in shallow water (the shape and delicacy of the ear canal suggests that it wasn’t able to dive deep, and its appendages suggest that it wasn’t a particularly fast swimmer). The authors suggest that it fed by striking at prey with that long neck in a sideways notion, biting them with its sharp fangs.
The other issue was the smaller version of this species, now named Tanystropheus longobardicus. That alone tells you that these aren’t juveniles, but members of a similar, related, but different species. How do they know? They looked at the bones, which once a year form a “line of arrested growth” (LAG) as the metabolism slows down annually, probably during cold weather. As the growth of an individual slows, when it’s reaching full size at maturity, the lines become closer and closer together until growth stops and no LAGs are formed.
And so, in the smaller species, about one-fourth the size of the larger T. hydroides, the LAGs get closer together as the individual grew, indicating that the tiny individuals were not juveniles of the big ones, but adults of a different species. Here’s a diagram showing the slowing down of the LAGs in the smaller individual, now T. longobardicus. The arrowheads get closer together as one approaches the edge of the bone.
Here’s a reconstruction of the two species shown in the paper with a human shown for scale:
Finally, since fossils of the two species are found in the same strata and were close to each other, they almost certainly shared a habitat in the sea. The authors suggest that the coexistence was partly due to “niche partitioning”, with the two species taking different kinds of prey, insuring that they did not compete for food. The larger species ate fish and squid, the smaller probably marine invertebrates like shrimp.
As to why the neck was stiff rather than flexible, well, you tell me. I would have thought that a flexible neck would be better at catching prey.
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Spiekman, S. N. F., J. M. Neenan, N. C. Fraser, V. Fernandez, O. Rieppel, S. Nosotti, and T. M. Scheyer. 2020. Aquatic habits and niche partitioning in the extraordinarily long-necked Triassic reptile Tanystropheus. Current Biology. https://doi.org/10.1016/j.cub.2020.07.025
Weird.
Maybe it ate stuff that stayed hidden in thick kelp or seaweed, and the stiff neck let it spear through the flexible obstructions.
My guess is that the long neck (like the modern giraffe) was an adaptation to reach food that was unavailable to other animals.
Or possibly female Tanystropheus hydroides really liked that long-necked look (or fitness signal) so we have another case of runaway sexual selection…
Yeah, I thought of giraffes too. Same evolutionary pattern – get a big long neck by enlarging the same number of vertebrae, rather than adding more vertebrae.
Which is why I’m surprised the authors say they know the neck was stiff. Giraffe necks aren’t like rods – they can twist, bend, and move them. Here is a good example picture. So I’m unsure why the scientists studying this fossil would conclude ‘stiff neck’ from elongation of existent vertebrae – because we know of a real, live, example where that evolutionary adaptative pathway does not lead to a stiff neck.
Its hard to see in the reconstruction drawing, but I think there are super long spine-like bones along the underside of the neck vertebrae. These appear in some other long-necked aquatic reptiles. They must be important for something. Support certainly. I don’t know if these help in neck flexion, or would interfere with it.
I think it will matter that the neck is vertically oriented in a giraffe. Gravity matters. A horizontal neck will not necessarily develop or have to account for gravity or other things – such as predators reaching for it – the same way.
The effect of gravity on land and in the water is not the same. They could have been effectively weightless in the water. Comparisons to giraffes go only so far.
The gravitational force opposes the buoyant force.
How did you calculate that the animal was weightless in water? what length of neck was used? What density of bone – which contains mostly the alkaline earth metal calcium with atomic mass 40 g/mol? Was the mass even along the length? Where were the lungs in this model, and of what volume? How long could it hold its breath?
Further, how much torque developed on the neck with the head – of what mass? – at the end? Did the animal swim head down with its body cavity floating on the surface? Was it difficult for it to swim horizontally, or indeed to rapidly shift position? Did it use ballast as those crocodiles we discussed way back?
Huh? One does not need to make calculations in order to know that the effects are different on land than they are in the water. One needs do no more than learn to scuba dive. Even that is unnecessary. One can go swimming and discover the difference. It is why aquatic exercises are better for people with joint problems than exercising in the gym.
Water supports things better than air. It is why there are no land animals the size of blue whales.
“ … the effects are different on land than they are in the water.“
The gravitational force opposes the buoyant force. Full stop,
I don’t know what you are talking about with how these two opposing forces work differently on land compared to water. I also don’t understand how we are supposed to know without any experiment or model calculations that the animal “could have been effectively weightless in water”.
For some reason Tanystropheus has become popular as an identity for the Loch Ness Monster. I can’t think why as none of the claimed sightings are anything like it.
I have read that the the much better known plesiosaurs are supposed to be the basis of Nessie.
Nessie does not like to present as the tongue-twister Tanystropheus because she adjusts her appearance to fit in with popular culture. In medieval times she was supposedly a dragon, and for now she is a plesiosaur until Hollywood can provide her with a new makeover.
Fascinating!
“As to why the neck was stiff rather than flexible, well, you tell me. I would have thought that a flexible neck would be better at catching prey.”
Ideas 100% speculation but I write some of these with language that sounds like fact – but it’s just hypothetical:
• the animal is extinct so perhaps it wasn’t good at surviving with a stiff neck
• prey wasn’t as we expect it to be back then
• flexible neck of that length and positioning – i.e. horizontal and nit like the giraffe neck – would be prone to choking. Are there many extant horizontal long necks?
• high pressure under water might facilitate feeding with such a neck
• stiff neck at that length is difficult to protect, so perhaps a big bite sent it’s way was hard to avoid, so it is extinct now.
You cannot use its extinction as anargument for unfitness of a long stiff neck. The mere sumultaneous presence of two different species with the same weird morphology but different sizes suggests they share a common ancestor showing the same characteristics and had therefore a rather long and successful evolutionary history. As for the long stiff neck, it remembers me of the pipefishes (genus Nerophis) where it is not the neck, but the the whole body which is long and stiff. The are perfectly camouflaged in algae, looking like vegetal twigs. Perhaps Tanystropheus did live in kelp forests, looking like inocuous sticks…
I did not know that!… but if some life forms become extinct, doesn’t that mean… they….
It just means that conditions changed.
also I sort of think I know what anargument means but … what does “anargument” mean, because I haven’t found it yet…
oops
“an argument”.
It sounded so cool though “anargument”. Pfff.
Sorry for my typing…too bad!
I have not looked at the paper, but perhaps it used a bit of suction to pull in prey. Maybe by sudden elevation of delicate bones in the hyoid area. Lots of fish rely on using suction, and I thought there was some of this in other extinct marine reptiles.
Triassic began abt. 250 my ago immediately following the great Permian extinction. The middle Triassic was about 235 my ago at latest. These critters represent a lot of evolution in just 10-15 million years.
I think it will matter that the neck is vertically oriented in a giraffe. Gravity matters. A horizontal neck will not necessarily develop or have to account for gravity or other things – such as predators reaching for it – the same way.
For some reason the non-existant Lake Champlain monster was named Champ tanystrpheus by Dennis Hall, a cryptozoologist with, of course, zero education in biology.
What an odd critter. I’d have to say it looks unexpected and unpredictable. There must be a huge number of potential morphologies in the evolutionary landscape. Many forms you’d expect to be unreachable, probably aren’t. If we ever discover another planet with large fauna, I suspect there will be similarly bizarre animals, but different. Very, very, different.
Nature is more imaginative than any SciFi-film maker when it comes to fantastic animals.
Prehistoric history rules!
Absolutely! And the amount of information about diet etc. that we’re able to find out about something that lived so long ago never ceases to amaze me.
Nature likes to tinker with a lot of ideas.
The strangeness of nature is a delight, and much of it very mysterious, like this long neck. I like many of the suggestions above, and they all seem plausible to some extent.
Or perhaps it hasn’t got a long neck so much as a shortened body?
Interesting point.
The size of a Kiwi’s egg, in proportion to its body-weight is very large. It is suggested that egg size evolved less rapidly than did reducing body-size for extant species.
This really is a weird critter!
I thought that neck made hunting in kelp easier, too.
The stiffness might be an adaptation to fast swimming. With a long neck you’d need strong muscles and a lot of energy to prevent injury as a fast swimmer. With a less flexible long neck you’d need less.
Kelp is a cooler water species is it not?
Shallow warm water seems appropriate for the Tanystropheus… But we’re they viviparous?
Tanystropheus has long been one of my favourite strange creatures. The biology of long extinct extreme critters is a difficult mystery to solve. I include dinosaurs in this – there is nothing alive today that even comes close (birds no doubt provide a hint).
rz
Fascinating creature. Thank you for pointing it out to me — I hadn’t previously heard of it. For both it and the giraffe, a sore throat would be (have been) torture!
Fascinating, not just because it is an unusual animal, but because of how scientists from a few clues in the fossils can infer so much information about it.
Non-scientists can infer much, much more. It was probably left-flippered.
Wow. I so want one for my aquarium!
I love the scientific specificity of these papers (which is way over my head). I’ve seen human autopsy/pathology reports with lesser detail.
Excellent piece. Excellent….creature.
D.A., J.D., NYC
It was found close to the place I from. I will look if I find one for your aquarium, the next time I go visit my parents. 🙂
Read: I come from.