You heard it here first: Small Tanystropheus specimens were adults, too.

Updated August 13, 2020
with a new blogpost two days later that shows where a mistake was made, how it was made, then corrected. The mistake (in Fig. 4) is retained in this post for this purpose.

Spiekman et al. 2020
used bone histology and µCT scans to determine that small Tanystropheus specimens (Fig. 1) were also adults. Six years ago, the large reptile tree (LRT, 1722+ taxa) determined the same thing using phylogenetic bracketing. That’s because…

Tanystropheids are tritosaur lepidosaurs, not archosauromorphs. 
In this clade, from Huehuecuetzpalli to Zhejiangopterus, hatchlings and juveniles are identical to adults, except for size. In other words tritosaur lepidosaurs grow isometrically (Peters 2018). Thus: differences indicate distinct genera. Spiekman et al. did not discuss this aspect of tanystropheids.

Tanystropheus and kin going back to Huehuecuetzpalli.

Figure 1. Tanystropheus and kin going back to Huehuecuetzpalli.

Spiekman et al. note:
“The configuration of the temporal region of Tanystropheus differs strongly from that of other early archosauromorphs.” 

Stuck in their traditional groove,
Spiekman et al. did not realize that tanystropheids are lepidosaurs (Peters 2007, 2011, 2018). They perpetuated the myth that tanystropheids and the similar, but unrelated Dinocephalosaurus were archosauromorphs (Fig. 2). The authors cited Pritchard et al. 2015, whose study included data from Nesbitt 2011, which was shown to be so poorly scored that Nesbitt’s cladogram changed radically after corrections were made earlier in a nine-part series ending here. Nesbitt’s repaired cladogram matched the LRT.

Spiekman et al. provided a cladogram
of interrelations (Fig. 2) that suffers from massive taxon exclusion and poor scores when compared to the LRT (Fig. 3). Spiekman et al. mix archosauromorphs with lepidosauromorphs, separates Protorosaurus from Prolacerta, separates some rib gliders from other rib gliders and matches little gliding Icarosaurus with big non-gliding Trilophosaurus among other red flags.

Figure 2. Cladogram from Spiekman et al. 2020. Colors added here to show mixing of archosauromorphs and lepidosauromorphs from the LRT.

Figure 2. Cladogram from Spiekman et al. 2020. Colors added here to show mixing of archosauromorphs and lepidosauromorphs from the LRT. Gold taxa (at right) are tritosaurs in the LRT.

Trimming the LRT to match the taxon list in Spiekman et al. 2020
(Fig. 3) results in a topology that cleanly separates lepidosauromorphs and archosauromorphs… and the tritosaur lepidosaurs, including Huehuecuetzpalli, nest together.

Figure 3. LRT reduced to Spiekman et al. taxon list. Archosauromorpha - blue. Lepidosauromorpha - yellow. Tritosauria in amber.

Figure 3. LRT reduced to Spiekman et al. taxon list. Archosauromorpha – blue. Lepidosauromorpha – yellow. Tritosauria in amber.

Spiekman et al. report,
“A quadratojugal is identified confidently for the first time in Tanystropheus.” Actually that misidentified right-angle splint of bone is an ectopterygoid (Fig. 4). What Spiekman et al. identified as an ectopterygoid is instead a crushed anterior cervical (Fig. 4).

Figure 4. Identifying the quadratojugal as an ectopterygoid here.

Figure 4. Identifying the quadratojugal as an ectopterygoid, and the ectopterygoid as a short anterior cervical.

A real quadratojugal 
was confidently identified in another specimen of Tanystropheus back in 2003 (Fig. 5). As in related taxa, including pterosaurs, the tritosaur quadratojugal is a small sharp extension of the posterior process of the jugal.

Figure 2. Skull of specimen Q of Tanystropheus. Only an arrow was added to show the location of the quadratojugal first identified in 2003.

Figure 5. Skull of specimen Q of Tanystropheus. Only an arrow was added to show the location of the quadratojugal first identified in 2003.

To distinguish the large and small tanystropheids,
the team named the bigger one T. hydroides, after the hydra in Greek mythology. Its smaller cousin kept the original species name of T. longobardicus. If they were going to do this, they should have done it right and split the several large specimens apart, as done here in 2014 (Fig. 6).

Figure 2. Tanystropheus with skull reconstructions based on two specimens, exemplar i and exemplar m.

Figure 6. Tanystropheus with skull reconstructions based on two specimens, exemplar i and exemplar m.

Bone growth rings
revealed to Spiekman et al. the smaller Tanystropheus were indeed adults, making it fairly clear that what the researchers had on their hands were two separate species, confirming results from six years ago.

Breathing
“The reptile’s skull has its nostrils perched on top, much like a crocodile’s snout – just the thing for an ambush predator to keep a lung full of air while waiting for a meal to pass by.”

This is not news. We’ve known large tanystropheids had such nostrils since at least Wild 1973. The breathing regime would have taken place as described earlier for the unrelated, but overall similar Dinocephalosaurus (Peters, Demes and Krause 2005, not cited in Spiekman et al. 2020).

Configuration
“We can now almost imagine the animal’s squat, croc-like body lying against the floor of a shallow coastline some 242 million years ago, its head rising high up to the surface so its nostrils can siphon down air, its bristling mouth slightly agape in anticipation of a stray squid to stumble by.”

This is not news either. As shown earlier with Dinocephalosaurus, the air bubble in the throat would have a difficult time moving down toward the deeper lungs while submerged without assuming a horizontal configuration, whether at the surface or sea floor, for at least that portion of the respiratory cycle. Exhaling would have been no problem in a vertical configuration. Consider the possibility of an exhaled bubble net, giving the long trachea another use: for stale air storage.

Cervicals
“Part of its oddness is the shape of the neck bones. Unlike those in a snake or lizard, the cervical vertebrae in Tanystropheus fossils are stretched out like a giraffe’s.

This is not news either. Spiekman et al. noted a diet of squid, but overlooked tanystropheids lived in crinoid forests. So, tanystropheids could have been crinoid stem mimics as shown earlier in 2012 (Fig. 7). Spiekman et al. did not discuss this possibility. Nor did he discuss why two anterior chevrons on Tanystropheus were exceptionally large. Standing as a biped these chevrons would have created a tripodal set-up for Tanystropheus.

Tanystropheus underwater among tall crinoids and small squids.

Figure 7. Tanystropheus in a vertical strike elevating the neck and raising its blood pressure in order to keep circulation around its brain and another system to keep blood from pooling in its hind limb and tail.

Pterosaur homologies
“In fact, when its remains were first uncovered in 1852, the scattered bones were assumed to be the elongated wing bones of a flying pterosaur.”

Tanystropheids also have feet identical to basal fenestrasaurs and pterosaurs with a short metacarpal 5 and elongate p5.1 (Fig. 8). Only the tanystropheid cervicals were thought to be pterosaur wing bones in 1852. Not sure why no one other than Peters (2000a, b) included pterosaurs in tanystropheid studies and vice versa.

The best matches to Prorotodactylus and Rotodactylus. In this case, something between a small Tanystropheus and an even smaller Cosesaurus provides the best matches in all regards.

Figure 8. The best matches to Prorotodactylus and Rotodactylus. In this case, something between a small Tanystropheus and an even smaller Cosesaurus provides the best matches in all regards. These taxa were not even mentioned by Niedwiedcki et al. (2013) and skeletal fossils are known from geographically and chronologically similar sediments.

A valid phylogenetic context is key to understanding 
what a taxon is. Spiekman et al. lacked this understanding and context despite having seven co-authors, many with PhDs. Adding taxa and correcting scores clarifies all issues. Borrowing analyses perpetuates myths. Citing competing hypotheses might have helped this paper. Their µCT scans did not prevent them from including two mis-identifications, (noted above).


References
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D, Demes B and Krause DW 2005. Suction feeding in Triassic Protorosaur? Science, 308: 1112-1113.
Pritchard AC, Turner AH, Nesbitt SJ, Irmis RB and Smith ND 2015. Late Triassic tanystropheids (Reptilia, Archosauromorpha) from Northern New Mexico (Petrified Forest Member, Chinle Formation) and the biogeography, functional morphology, and evolution of Tanystropheidae. Journal of Vertebrrate Paleontology 35, e911186.
Spiekman SNF et al. (6 co-authors) 2020. Aquatic Habits and Niche Partitioning in the
Extraordinarily Long-Necked Triassic Reptile Tanystropheus. Current Biology 30:1–7. https://doi.org/10.1016/j.cub.2020.07.025
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus (Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-162 plus plates.

https://pterosaurheresies.wordpress.com/2019/11/28/new-tanystropheid-paper-promotes-archosauromorph-myth/

https://pterosaurheresies.wordpress.com/2019/12/19/spiekman-and-scheyer-2019-discuss-variation-in-tanystropheus/

https://pterosaurheresies.wordpress.com/2014/10/17/the-many-faces-of-tanystropheus/

https://www.sciencealert.com/half-of-this-ancient-reptile-s-body-is-made-of-neck-and-we-now-know-how-it-used-it

From October 2018:
researchgate.net/publication_A_new_lepidosaur_clade_the_Tritosauria

From September 2011:
https://pterosaurheresies.wordpress.com/2011/09/22/the-tritosauria-an-overlooked-third-clade-of-lizards/

A Tanystropheus from China

Figure 1. Click to enlarge GIF animation. The Tanystropheus specimen from China, GMPUKU-P-1527: 1)  in situ; 2) as traced by Rieppel et al. 2010; and 3) with colorized DGS tracings. Note: Rieppel et al. overlooked the interclavicle, and mistook the interclavicle + scapula for an over sized coracoid. Rieppel's clavicle is a dorsal rib. The so-called heterotopic bones are merely larger, unfused chevrons.

Figure 1. Click to enlarge GIF animation. The Tanystropheus specimen from China, GMPKU-P-1527: 1)  in situ; 2) as traced by Rieppel et al. 2010; and 3) with colorized DGS tracings. Note: Rieppel et al. overlooked the interclavicle, and mistook the interclavicle + scapula for an over sized coracoid. Rieppel’s clavicle is a dorsal rib. Clavicles here are in red. The so-called heterotopic bones are merely larger, unfused chevrons. What are those blue triangles in the dorsal area? The distal opposite rib tips apparently. Let me know if there’s a better answer.

Rieppel et al. (2010)
described a new, large (trunk length 93.5 cm), Late Triassic Tanystropheus (GMPKU-P-1527, Fig. 1), the first from China. All priors had come from the Alps of Europe. This one lacks a skull plus three cervicals and the distal tail. Based on the short rib of what used to be considered dorsal 1, the authors report it is now cervical 13. That appears to be the case across all large and small specimens. The last cervical is the size and shape of a dorsal, but the associated rib is not a dorsal-type rib. Every prior worker missed that one. Rieppel et al bucked traditions and relabeled the old first dorsal. Good job guys!

New interpretations
of the clavicle, interclavicle, scapula and one coracoid are introduced above, a little different than the original interpretations.

How similar to the European specimens?
the authors report: “The new Peking University specimen (GMPKU-P-1527) is remarkably similar to the larger specimens of Tanystropheus longobardicus housed in the paleontological collections of Zurich University. If there is any difference, then it is in the extent of chevron bones in the tail and the lack of the slight swellings and associated flexure described here for the first time along the length of the longest cervical ribs in PIMUZ T 2189 (Exemplar Q, Fig. 3.

At first glance (in situ) the Chinese specimen is indeed similar to the European specimens.

Figure 2. The Tanystropheus from China partly reconstructed using DGS methods. No foreshortening of the gastralia and limbs are present here. The preserved ilium is not a broad plate here, as in European specimens. The terminal tail vertebrae is circular suggesting the rest of the tail was preserved in another layer.

Figure 2. The Tanystropheus from China partly reconstructed using DGS methods. No foreshortening of the gastralia and limbs are present here. The preserved ilium is not a broad plate here, as in European specimens. That could be a taphonomic artifact or reality. The terminal tail vertebrae is circular suggesting the rest of the tail was preserved in another layer.

But not the same species
The China specimen is apparently more distinct from the European specimens than Rieppel et al. indicate., but then… they did not create any reconstructions. Sometimes comparisons are best seen directly with accurate reconstructions (Fig. 3). We’ve already seen that two very distinct skulls appear on the European specimens and both were distinct from the original Wild 1973 model based on a chimaera of specimens.

The China specimen
has larger girdles, larger vertebrae, more robust ribs and shorter toes (Fig. 4), among the more readily visible distinctions. The dorsal ilium appears to be much narrower, but it is obscured by an overlying femur. The interclavicle has a large, broad anterior process, making it cruciform, not T-shaped.

Figure 3. The large Tanystropheus specimens to scale. On the right the new China specimen has large girdles, larger vertebrae, more robust ribs and shorter toes, among the more visible distinctions. Click to enlarge. Above right is the new M. Witton reconstruction with erect limbs, an overly large scapula, an overly large ilium, lacking an interclavicle and other minor issues. 

Figure 3. The large Tanystropheus specimens to scale. On the right the new China specimen has large girdles, larger vertebrae, more robust ribs and shorter toes, among the more visible distinctions. Click to enlarge. Above right is the new M. Witton reconstruction with erect limbs, an overly large scapula, an overly large ilium, lacks an interclavicle and other minor issues. Otherwise it is very good looking.

Check those hands and feet!
Earlier we were able to separate Rhamphorhynchus specimens into clades using pedal traits alone. Here we’ll compare a European Tanystropheus with the Chinese one (Fig. 4). If they don’t match, they are not conspecific.

Figure 4. Above the Chinese Tanystropheus. Below a large European Tanystropheus. They are not conspecific.

Figure 4. Above the Chinese Tanystropheus. Below a large European Tanystropheus. They are not conspecific.This was overlooked by Rieppel et al. 2010. Reconstructions have value.

Mark Witton started this 
A recent blog post by Mark Witton introduced a new reconstruction of Tanystropheus (Fig. 3 top right). He wondered if the neck was too heavy to use on land while reminding readers that my work was “produced with techniques of questionable reliability”. Keep that phrase in mind.

  1. Witton labeled Tanystropheus as a protorosaur. Actually it’s a tritosaur lepidosaur as indicated by a four-year-old cladogram that now tests 602 taxa.
  2. On tradition alone, Witton includes drepanosaurs, Sharovipteryx, Tanytrachelos, Langobardisaurus and Dinocephalosaurus in the protorosaurs. All are indeed related to Tanystropheus, and are likewise tritosaur lepidosaurs.
  3. Witton reports, “I decided to try my hand at producing a new skeletal reconstruction based on the large, near complete Tanystropheus skeleton described in detail by Rieppel et al. (2010): PIMUZ T 2189.” Unfortunately the skeleton described by Rieppel et al. and traced by Witton is GMPKU-P-1527, the Chinese specimen (Figs. 1, 2). The 2189 specimen is European (Fig. 3), represented by a skull and neck only (Fig. 3). Witton’s technique was to trace a published photo. He makes no mention of visiting the specimen first hand. If you’ll remember, the technique of questionable reliability” mentioned above is my sin of tracing fossil from photographs. So Witton is doing exactly what I do. Is Witton aware of this possible hypocrisy?
  4. Witton reports, “I reconstructed missing parts using smaller Tanystropheus specimens (from Nosotti 2007) and Wild’s widely-used ‘adult’ skull reconstruction.” So he created a chimaera. That is almost never a good idea going as far back as to putting a Camarasaurus skull on a Brontosaurus body. It’s easy, but it’s wrong. “Widely used” doesn’t mean it is correct. As mentioned above, that skull is a chimaera, too.
  5. Witton’s reconstruction admits to cheating on the true sprawling pose for his geometrical analysis. That’s fine. I laid limb elements out straight,too, but not in a walking pose. That would be confusing to someone who didn’t know what the illustration was being used for.
  6. Adding to the confusion, Witton draws a medially directed femoral head which is not present in this lepidosaur.
  7. Witton’s Tanystropheus scapula is too large (see above). The pelvis is a chimaera and a shade too large. Otherwise it’s a beautiful reconstruction and part of that beauty comes from free handing certain elements. I won’t say Witton’s work as a whole is produced with techniques of questionable reliability.l like tracing, free handing and creating chimaeras… but I will say that free handing and creating chimaeras is not reliable. Tracing from photographs can be very reliable! Ad hominem blackwashing (see Witton’s comment) is never appropriate for colleagues. Everyone should realize that inappropriate habits, like creating chimaeras, never last forever. And everybody makes honest mistakes (like overlooking the interclavicle). Finally holding a grudge or never granting forgiveness for past errors is never good… Right guys? Okay. Let’s move on…
  8. Witton reports, “Our problem here is that finding a long-necked terrestrial carnivore to compare with Tanystropheus is challenging.” I realize that Witton is wondering if a large Tanystropheus could walk on land, but gut contents are marine organisms and fossils are found in marine sediments. So… what’s the point? And why were these factoids ignored? The big Tanystropheus doesn’t seem to be a terrestrial animal.
  9. Ironically, Witton compares the long neck of Tanystropheus to his favorite pterosaurs, the azhdarchids. And that’s a fair comparison. They are distantly related in the large reptile tree, but for Witton’s purposes shapes are more important.
  10. Witton’s technique for determining mass at every segment of a lateral view misses the greater mass in the wider dorsal and caudal areas visible only in dorsal view. There’s a fat rump there, but you can’t see it in lateral view.
  11. Little known pertinent fact: I once made a full scale model in wood of Tanystropheus and sold it to the AMNH. I had to add lead weights aft of the hind limbs to make it not tip over. All segments being equal, it was front heavy as a 3-D model, not just on paper.  In vivo the torso and tail would have been more dense, even with large lungs. And the air-filled cervical series and trachea would have been less dense.
  12. Check this out for a possible marine lifestyle that seems to fit the facts for Tanystropheus.

References
Rieppel O, Jiang D-Y,  Fraser NC, Hao W-C, Motani R, Sun Y-L & Sun ZY 2010. Tanystropheus cf. T. longobardicus from the early Late Triassic of Guizhou Province, southwestern China. Journal of Vertebrate Paleontology 30(4):1082-1089.
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus(Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-162 plus plates.
Witton blog post: here

The many faces of Tanystropheus

Added September 21, 2020:
Think about a bubble net, as in humpback whales, coming form the long, dead=air storage vessel that is that elongate trachea. That long neck rotating like an inverted cone to surround confused fish just above the jaws.

Tanystropheus is well known
as the sometimes giant reptile with the hyper-elongate neck (Figs. 1, 2). Several specimens are known, all by letters in the alphabet based on Wild (1973). Few specimens have skulls.

The smaller Tanystropheus specimens (Fig. 1) have multicusp posterior teeth, and some workers consider these juveniles that change their diet and teeth as they grow. Others, including yours truly, think these are two different species, if not different genera. Remember, guyz and galz, you don’t get giant species without first going through the medium and large size ranges. We learned this earlier with Pteranodon.

Wild’s (1973) reconstruction of the skull was taken as gospel for a good long time. Then Nosotti (2007) came along and rebuilt the small skull in convincing fashion. Here we’ll take a look at a skull from a small individual (Fig. 1, Exemplar a) and compare it to two skulls from the larger forms (Fig. 2, Exemplars i and q). Then you can decide if the differences are ontogenetic or phylogenetic.

Tanystropheus exemplar a.

Figure 1. Tanystropheus exemplar a.

Exemplar a has a low rostrum and large orbit. The frontals extend over the orbits like brow ridges. The nasals are not visible on any articulated skulls, and displaced samples can be placed on the skull two different ways. The ascending process of the premaxilla is also a big question mark. It could be present or absent. The pineal opening is not large in any sister taxa, so it redevelops here. The posterior skull leans down, which, by analogy with basal synapsids indicates a bit of posterior pull on the mandible, as if Exemplar a was tugging at its meals.

Figure 2. Tanystropheus with skull reconstructions based on two specimens, exemplar i and exemplar m.

Figure 2. Tanystropheus with skull reconstructions based on two specimens, exemplar i and exemplar q.

Among the giant specimens…

Exemplar i is the skull that Wild (1973) used for his ‘adult’ specimen. Like  Exemplar a, the frontals are wide, the nasals are unknown and the ascending process of the premaxilla is apparently gone. This creates quite a large confluent set of nares dorsally oriented. The posterior skull does not descend posteriorly. Only a few teeth are preserved and in dorsal view the rostrum is wide and rather flat, like a hat brim. One gets the impression that a great circle of procumbent teeth emanated from these jaws because the premaxilla appear to be quite flat in situ with no indication of any depth.

Exemplar q is lower, longer and had a reduced pterygoid and vomers. Here the nares are also very large, but divided by a slender and fragile ascending process of the premaxilla (pretty much busted up in situ). Rather than wide and flat, this rostrum is more traditionally box-like with ventrally oriented teeth. The pterygoid is greatly reduced and so are the vomers. The nasals are preserved here only as posterior rims to the large nares. The brow ridges are gone here, so Exemplar q could look up without moving its head.

The appearance of those giant nares on these tiny skulls links to that hyper-elongate neck and within, a hyper-elongate trachea that needs to be flushed of CO2 and filled with O2 every so often.

So the skulls of the big taxa are different.
It might be worthwhile to see how the post-crania also differs. There’s a PhD project waiting for someone out there, probably in Europe, where the fossils are. Or wait a few weekends and I’ll probably get around to it.

References
Bassani F 1886. Sui Fossili e sull’ età degli schisti bituminosi triasici di Besano in Lombardia. Atti della Società Italiana di Scienze Naturali 19:15–72.
Li C 2007. A juvenile Tanystropheus sp.(Protoro sauria: Tanystropheidae) from the Middle Triassic of Guizhou, China. Vertebrata PalAsiatica 45(1): 37-42.
Meyer H von 1847–55. Die saurier des Muschelkalkes mit rücksicht auf die saurier aus Buntem Sanstein und Keuper; pp. 1-167 in Zur fauna der Vorwelt, zweite Abteilung. Frankfurt.
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
Peyer B 1931. Tanystropheus longobardicus Bass sp. Die Triasfauna der Tessiner Kalkalpen. Abhandlungen Schweizerische Paläontologie Gesellschaft 50:5-110.
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus (Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-16.

wiki/Tanystropheus

Which pterosaur does this foot belong to?

Figure 1. This appears to be a classic basal pterosaur foot, but what kind? Note the presence of the ungual on digit 5. That's exciting!

Figure 1. This appears to be a classic basal pterosaur foot, but what kind? Note the presence of the ungual on digit 5. That’s exciting! So is that extra phalanx.

Here (Fig. 1) is what appears to be a classic basal pterosaur foot. Long narrow metatarsals. Metatarsals 3 and 4 are the longest, as in Preondactylus and Austriadactylus (SC332466). Pedal 5.1 extends beyond metatarsal 4, as in Austriadactylus and Dimorphodon. Digit 4 is slightly longer than digit 3. Digit 5, though, appears to have an extra phalanx or two. That astragalus is oddly shaped, but everything else seems to be very pterosaurian…

Did you guess? Or did you know?
This is Tanystropheus, a close relative to the ancestors of pterosaurs. Langobardisaurus and Cosesaurus are closer to that common ancestor and to each other.  And they both have this kind of foot.

Homoplasy, not Convergence
Those similar foot characters are homoplastic, not the result of convergence and attests to the antiquity of this foot morphology in the lineage of pterosaurs. Now, if we can only get the powers that be to start including Tanystropheus, Langobardisaurus, Cosesaurus (and the rest of the Fenestrasauria) with pterosaur and archosaur studies, it would be no surprise to find out where pterosaurs actually do nest in the scheme of things.

Archosaurs, as you already know, have only a vestige or less of a fifth pedal digit. This is where you start looking for the ancestors of pterosaurs.

And if you’re an archosaur-lover ~ take your blinders off.

Fuyuansaurus – a Baby Tanystropheid or a Mother?

A tiny new tanystropheid was recently described by Fraser et al. (2013). Complete and articulated, but unfortunately too big for its slab, despite its tiny size, the holotype fossil of  Fuyuansaurus lacks a tail and limbs, though undoubtedly limbs were present in vivo (phylogenetic bracketing).

Figure 1. Fuyuansaurus in situ and close to full scale. Unfortunately this tiny tanystropheid is too large for its tinier slab and so lacks legs and a tail.

Figure 1. Fuyuansaurus in situ and close to full scale. Unfortunately this tiny tanystropheid is too large for its even tinier slab and so legs and a tail extend off the slab. If your screen resolution is 72pdi, the upper image is full scale. The light blue structure is a possible egg and the red structure is a possible pubis more like that of sister taxa. There is a mass of soft tissue preservation from the torso covering the posterior nasals, too. The orange structure in the egg may be a displaced hemal arch (chevron).

It always helps when a reconstruction is made,
in this case to literally unwind the specimen.

Figure 2. Click to enlarge. Reconstruction of Fuyuanasaurus. Fraser et al. identified a strange circular object as the pubis, but no sister taxa have a circular pubis. Here it is tentatively ID'd as an egg because a standard pubis is found  nearby.

Figure 2. Click to enlarge. Reconstruction of Fuyuanasaurus slightly smaller than full scale. Yes=, it’s that tiny. Fraser et al. identified a strange circular object as the pubis, but no sister taxa have a circular pubis. Here it is tentatively ID’d as an egg/embryo because a standard pubis is found nearby and another soft tissue mass is also preserved anteriorly. Oddly, cervical #8 is shorter than #7 or #9. Orange in the cheek area is not the coronoid, but a portion of the pterygoid. Purple on the upper jaw margin below the cheek is not the dentary but the surangular.

Phylogenetic analysis nests Fuyuansaurus between the small Tanystropheus with multi-cusped teeth and the large one with simple stabbers. So does that make this another Tanystropheus species? Or do we need to separate the two Tanys generically? Depends if you’re a lumper or splitter. Fraser et al. did not publish their analysis if one was made.

That strange circular “pubis”.
Fraser et al. identified a round structure with ridge-like process terminating in a hollow bone end as a pubis, but noted that it was unlike the pubis of Tanystropheus or Macrocnemus. No kidding… Autapomorphies like this often have a different reality, as we learned earlier. I wonder if the flat round object was an egg because I found a regular strut-like pubis nearby on the inner mandible and the narrow structure that penetrates the soft ellipse could have been a chevron or a lumbar rib. So the possible tiny juvenile could actually be a possible tiny mother. And that ridge along the rim of the egg could be an embryo vertebral series. Hard to tell with available materials, but an interesting thought nevertheless that could pan out with higher resolution.

References
Fraser NC, Rieppel O and Chun L 2013. A long-snouted protorosaur from the Middle Triassic of southern China, Journal of Vertebrate Paleontology, 33:(5):1120-1126.

Underwater Leaping in Tanystropheus

Added September 21, 2020:
Think about a bubble net, as in humpback whales, coming form the long, dead=air storage vessel that is that elongate trachea. That long neck rotating like an inverted cone to surround confused fish just above the jaws.

Earlier we looked at an underwater bipedal configuration for Tanystropheus. Such a pose would have solved all sorts of neck and balance problems. Here (Fig. 1) is a proposal for using the epipubic bones as caudofemoralis anchors to increase vertical thrust in that environment. Thrust would be used to snare prey or reach the surface for air.

Basically the illustration (Fig. 1) says it all.
Epipubic bones on the large Tanystropheus could have anchored more powerful caudofemoralis muscles to provide more thrust during vertical strikes and trips to the surface. Of course, momentum would have taken Tanystropheus further than shown here.

What were these bones?
Odd chevrons? That’s the best guess so far. Otherwise in close kin there were no large chevrons  and the caudal transverse processes did not extend more than ten caudals back. So, when large thrusters were needed, they grew in this giant in new ways, whichever way helped the most.

Tanystropheus in a vertical strike powered by the enlarged caudofemoralis anchored by the so-called epipubic bones.

Figure 1. Tanystropheus in a vertical strike powered by the enlarged caudofemoralis (in red) anchored by the so-called epipubic bones, which may instead by enlarged and modified chevrons or neomorphs. This push could have been followed by a vertical leap/drift, whether to head to the surface or snatch unwary prey.

Just another crazy thought…

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
Bassani F 1886. Sui Fossili e sull’ età degli schisti bituminosi triasici di Besano in Lombardia. Atti della Società Italiana di Scienze Naturali 19:15–72.
Li C 2007. A juvenile Tanystropheus sp.(Protoro sauria: Tanystropheidae) from the Middle Triassic of Guizhou, China. Vertebrata PalAsiatica 45(1): 37-42.
Meyer H von 1847–55. Die saurier des Muschelkalkes mit rücksicht auf die saurier aus Buntem Sanstein und Keuper; pp. 1-167 in Zur fauna der Vorwelt, zweite Abteilung. Frankfurt.
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
Peyer B 1931. Tanystropheus longobardicus Bass sp. Die Triasfauna der Tessiner Kalkalpen. Abhandlungen Schweizerische Paläontologie Gesellschaft 50:5-110.
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus(Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-16.

wiki/Tanystropheus

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

Flipping the Nasal on Tanystropheus

Dr. Stefania Nosotti (2007) published an excellent and well-illustrated report on several smaller Tanystropheus specimens. Unfortunately the skulls of the articulated specimens were preserved in ventrolateral view obscuring the dorsal view. Several other disarticulated specimens helped fill the gaps.

Tanystropheus exemplar a

Figure 1. Tanystropheus exemplar a skulls demonstrating different interpretations of the nasal bone. The original interpretation above. A revised interpretation below.

Original Reconstruction
Nosotti (2007, Fig. 1) reconstructed the nasals in Tanystropheus with a long common median border beginning at mid naris and expanding laterally beyond the naris. Unfortunately this configuration does not match that of sister taxa (most notably the large Tanystropheus) in which a long premaxilla ascending process separates the nares, extends far beyond them and the nasals laterally border the nares and decrease in width posteriorly. By merely flipping the nasal reconstructed by Nosotti (2007) and adding a slender ascending process  (a fragile bone prone to crushing and breakage) to the premaxilla, a match is made to sister taxa.

Tanystropheus exemplar a.

Figure 2. Tanystropheus exemplar "A" overall. Click for more info.

There’s also the Premaxilla
The premaxilla doesn’t rise along the lateral rim of the naris in sister taxa like exemplar “K” (fig. 3). The rising ascending process goes back to Huehuecuetzpalli.

These exercises demonstrate the need to compare specimens to sister taxa. If autapomorphies are found, then perhaps the autapomorphies need a second look, and perhaps a revised reconstruction more in line with sister taxa – if possible and valid.

Peters (2000) made similar mistakes in Cosesaurus in which I interpreted autapomorphic elements in the pectoral and pelvic girdles that had more synapomorphic distributions.

Figure 3. The skull of the large Tanystropheus, exemplar "K". Premaxilla and nasal highlighted.

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
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 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.

Tanystropheus Feet: Keys to Speciation

The Traditional View
Wild (1978) established the concept that the small, multi-cusp toothed specimens attributed to Tanystropheus were juveniles of the larger forms without multi-cusped teeth. This would involve morphological changes during ontogenetic growth.

The question is, why wasn’t phylogenetic evolution (speciation) offered as an alternative?

The Heretical View
Earlier I blogged that the differences were too many to support an ontogenetic growth series between the smaller Tanystropheus specimens and the larger ones. Today we’ll look at the feet and you can decide whether or not such changes can be attributed to ontogeny or are better explained as a phylogenetic change attributed to evolution. Of course the split would have occurred earlier and the two species would have been adapted to distinct niches based on size and tooth morphology.

Tanystropheus feet with morphological changes noted.

Figure 1. Tanystropheus feet with morphological changes noted. Click for more info.

As in Pterosaurs
Peters (2011) was able to speciate various specimens attributed to Pterodactylus, Pteranodon, Rhamphorhynchus, Germanodactylus and other pterosaurs by looking only at  the variation in the foot morphologies. The same process is present here. If these two Tanystropheus pedes represent younger and older variations of the same species, why do the distinct changes that appear in the jaws (distinct teeth, for instance) extend to the feet?

This is especially important in a clade that otherwise demonstrates isometric growth patterns. (They don’t change much as they mature, contra traditional studies.)

Perhaps a more parsimonious solution is to place the smaller specimen in the bushy lineage of the larger specimen. Different sizes = different diets = different teeth.

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
Bassani F 1886. Sui Fossili e sull’ età degli schisti bituminosi triasici di Besano in Lombardia. Atti della Società Italiana di Scienze Naturali 19:15–72.
Li C 2007. A juvenile Tanystropheus sp.(Protoro sauria: Tanystropheidae) from the Middle Triassic of Guizhou, China. Vertebrata PalAsiatica 45(1): 37-42.
Meyer H von 1847–55. Die saurier des Muschelkalkes mit rücksicht auf die saurier aus Buntem Sanstein und Keuper; pp. 1-167 in Zur fauna der Vorwelt, zweite Abteilung. Frankfurt.
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
Peyer B 1931. Tanystropheus longobardicus Bass sp. Die Triasfauna der Tessiner Kalkalpen. Abhandlungen Schweizerische Paläontologie Gesellschaft 50:5-110.
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. online pdf
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus (Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-16.

wiki/Tanystropheus

Gwyneddichnium and Tanytrachelos

It’s rare when body fossils and ichnites are found in the same fossil beds. Gwyneddichnium (Bock 1952, the ichnite, Fig. 1) and Tanytrachelos (Olsen 1979, the body fossil) are exceptions. Found in the Appalachian valleys of Virginia, these relatively small, middle Triassic specimens both help piece together and integrate the trackmaker and the track itself.

Gwyneddichnium

Figure 1. Comparing the ichnotaxon, Gwyneddichnium to the tritosaur Tanytrachelos. Note the longer penultimate phalanges in digits 3 and 4 in YPM 7540.

We’re seeing some variation in Tanytrachelos
Note the length of the penultimate phalanges in digits 3 and 4 and the relative size of m1.1 in the two bone specimens. Note the relative length of manus digits 3 and 4 between Gwyneddichnium and the bone specimen (YPM 7491).

Tanytrachelos

Figure 2. Tanytrachelos. Click for more info.

Comparing Gwyneddichnium to Rotodactylus
Gwyneddichnium demonstrates that pedal digit 5 in Tanytrachelos was oriented alongside digits 1-4 in a plantigrade configuration. By contrast the pes of Cosesaurus was matched to the digitigrade ichnite Rotodactylus (Peters 2000), which inverts digit 5, impressing far behind digits 1-4 without making a heel impression. online story.

Foot bones attributed to Tanytrachelos

Figure 3. Foot bones attributed to Tanytrachelos. Note the great similarity between these phalangeal proportions and those of YPM 7540. Metatarsal 1 was shorter in this specimen.

Adding the Pes of Tanytrachelos to the Large Ptero Tree
A lone pes attributed to Tanytrachelos from the same formation was added to the pterosaur tree. The foot nested with Tanytrachelos.

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
Bock W 1952. Triassic reptilian tracks and trends of locomotive evolution. Journal of Paleontology 26(3):395-433.
Olsen PE 1979. A new aquatic eosuchian from the Newark Supergroup Late Triassic-Early Jurassic) of North Carolina and Virginia. Postilla 176: 1-14.