The BES SC 111 specimen of Macrocnemus – DGS helps reconstruct it

Previously considered (Renesto S and Avanzini M 2002) a juvenile due to its size, the BES SC 111 specimen of Macrocnemus (Fig. 1) sheds light on the origin of such diverse lineages as the Tanystropheidae (Langobardisaurus, Fig. 2) and the Fenestrasauria (Cosesaurus through the Pterosauria, Fig. 2). It also nests at the base of other Macrocnemus specimens including the oddly bizarre, Dinocephalosaurus (Fig. 3).

Figure 1. Click to enlarge. Stages in the DGS tracing and reconstruction of the the Macrocnemus BES SC 111 skull. I did not realize the the palatal bones were so visible. There's a palatine and ectopterygoid over the nasal and frontal, for instance. So earlier mistakes were made that are corrected here. The right mandible is traced here only along its ventral rim.

Figure 1. Click to enlarge. Stages in the DGS tracing and reconstruction of the the Macrocnemus BES SC 111 skull. I did not realize the the palatal bones were so visible. There’s a palatine and ectopterygoid over the nasal and frontal, for instance. So earlier mistakes were made that are corrected here. The right mandible is traced here only along its ventral rim.

Derived from
an early Triassic sister to Huehuecuetzpalli and/or Jesairosaurus, the BES SC 111 specimen seems to have at least a depression in the dorsal maxilla that will ultimately become an antorbital fenestra in the Fenestrasauria. Note the resemblance of this skull to that of Cosesaurus and Langobardisaurus (Fig. 2). They all share a retracted naris, large orbit, bent quadrate, short postorbital region and relatively short teeth.

The reduction of pedal digit 5 in all known Macrocnemus specimens demonstrates the BES SC 111 nests at the base of the Macrocnemus lineage. An unknown sister without this reduction would be basal to Langobardisaurus and the Fenestrasauria.

Figure 2. Macrocnemus BES SC 111 compared to sister taxa, Langobardisaurus, Cosesaurus and the basal pterosaur, MPUM 6009. Preserved loose, the orientation of the ectopterygoids could go either way, with the narrow tip contacting the maxilla instead, as in Dinocephalosaurus (Fig. 3).

Figure 2. Macrocnemus BES SC 111 compared to sister taxa, Langobardisaurus, Cosesaurus and the basal pterosaur, MPUM 6009. 

Figure 3. Dinocephalosaurus to scale with the largest Macrocnemus specimen and the smaller ones from figure 2.

Figure 3. Dinocephalosaurus to scale with a large Macrocnemus specimen, T4822, and the smaller ones from figure 2.

The take-away from this is: large odd reptiles sometimes have their origin in not-so-large, not-so-odd reptiles like the BES SC 111 specimen. At the same time, small odd reptiles may have the same origin. Make sure you add the plain, old reptiles to your cladograms. That’s where the spectacular taxa have their origin.

References
Li C, Zhao L-J and Wang L-T 2007A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern China and its palaeogeographical implication. Science in China D, Earth Sciences 50(11)1601-1605.
Nopcsa F 1931. Macrocnemus nicht Macrochemus. Centralblatt fur Mineralogie. Geologic und Palaeontologie; Stuttgart. 1931 Abt B 655–656.
Peyer B 1937. Die Triasfauna der Tessiner Kalkalpen XII. Macrocnemus bassanii Nopcsa. Abhandlung der Schweizerische Palaontologische Geologischen Gesellschaft pp. 1-140.
Renesto S and Avanzini M 2002. Skin remains in a juvenile Macrocnemus bassanii Nopsca (Reptilia, Prolacertiformes) from the Middle Triassic of Northern Italy. Jahrbuch Geologie und Paläontologie, Abhandlung 224(1):31-48.
Romer AS 1970. Unorthodoxies in Reptilian Phylogeny. Evolution 25:103-112.

wiki/Macrocnemus

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.

Tribelesodon/Tanystropheus: rough draft

Before the fossil named “Tribelesodon(Fig. 1) was identified as a small Tanystropheus with three-cusped teeth (Peyer 1931) it was considered a type of pterosaur with three-cusped teeth (Bassani 1886, Arthaber 1921, Von Nopcsa 1923). So it’s famous.

Figure 1. Tanystropheus (Tribelesodon specimen) from Wellnhofer 1991, part and counterpart and rough tracing.

Figure 1. Tanystropheus (Tribelesodon specimen) from Wellnhofer 1991, part, counterpart and very rough tracing.

The part and counterpart fossil (Fig. 1) of Tribelesodon was housed in Italy’s Museo di Storia Naturale di Milano before it was destroyed by Allied bombs during World War II. Thankfully, Wellnhofer (1991) provided small images of the fossil.

Figure 2. Rough comparisons of the Tribelesodon specimen assigned to Tanystropheus (Peyer 1931) compared to more complete specimens from Europe and China.

Figure 2. Rough comparisons of the Tribelesodon specimen assigned to Tanystropheus (Peyer 1931) compared to more complete specimens from Europe (MSNM BES SC 1018) and China (IVPP V 14472). The Tribelesodon specimen appears to have had a larger skull and more gracile postcrania, but otherwise closely comparable in size to the IVPP specimen.

Here, very roughly, I trace (Fig. 1) and uncoil the neck (Fig. 2) using DGS and compare it to more complete specimens from Europe and China. The Tribelesodon specimen appears to have had a larger skull and more gracile postcrania, but otherwise closely compares in size to the IVPP specimen. I’ll readily admit some bones may be misidentified and vaguely indicated, especially around the pelvis. The details, in this case, are not that important. Overall, it’s pretty obvious what we have here.

Earlier we looked at several of the largest specimens of Tanystropheus, the evolution of Tanystropheus and other topics related to this genus.

Thanks to Tracy Ford for providing me a scale bar on this specimen.

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, 111(3): 377–394.
Wellnhofer P 1991. The Illustrated Encyclopedia of Pterosaurs. Salamander Books Ltd., London. 192 pp.
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus(Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-16.

wiki/Tanystropheus

Giant Tanystropheus to scale, and a tribute to Rupert Wild

Figure 1. Click to enlarge. Four large Tanystropheus specimens in situ and reconstructed. The man silhouette  is 6 feet (1.8m) tall.

Figure 1. Click to enlarge. Four large Tanystropheus specimens in situ and roughly reconstructed. The human silhouette is 6 feet (1.8m) tall. In situ images from Wild 1974. Note the presence and absence of epipubic bones along with the variation in skull size.

Tanystropheus (Fig. 1, Middle Triassic, Europe, von Meyer 1852) was discovered in the 19th century, but not fully realized for what it was until Peyer 1931. One early specimen, named Tribelesodon, was mistaken for a pterosaur (Basani 1886, Arthaber 1921, Von Nopcsa 1923). The long neck bones were mistakenly compared to wing bones. The foot, with its long p5.1 digit, were indeed very pterosaurian in general morphology. So the taxonomic mistake had some basis.

Lesson learned here:
respected scientists can make mistakes. And these mistakes can become traditions until falsified. A reconstruction might have helped.

Peyer’s contribution
New complete skeletons of Tanystropheus described by Peyer (1931) solved the basic problem by showing the hyper-elongate bones actually belonged between the skull and torso.

Wild’s contribution
In 1974 Rupert Wild reviewed all the available material (27 specimens) of T. langobardicus. A few are pictured above (Fig. 1). Before the advent of phylogenetic analysis, Wild had the insight to label them Reptilia > Lepidosauria > Squamata > Lacertilia > Tanysitrachelida > Tanystropheidae. This is largely confirmed by the present large reptile tree. (The term “Lacertilia” includes all lizards, but not snakes, so it is a paraphyletic taxon in the large reptile tree. The term “Tanysitrachelida” (Peyer 1931) is no longer in use. Tanystropheidae includes other long-necked reptiles, such as  Langobardisaurus, Pteromimus, Tanytrachelos and Amotosaurus, all very much smaller taxa.)

To his credit,
Wild (1978) also was among the first to promote the idea that pterosaurs were not archosaurs, but something else along the lines of an eosuchian, a term little used today. Back then an Eosuchian was commonly considered a basal diapsid, like Youngina, a genus then considered close to the ancestry of both lepidosaurs and archosaurs. Now, thanks to the large reptile tree, we know that lepidosaurs and archosaurs are not related, except at a very basal reptile level. We also know that diapsids are diphyletic, having two origins. Wild’s heretical break with tradition is to be applauded. At the time closer relatives to pterosaurs, like Langobardisaurus, Cosesaurus, Sharovipteryx and Longisquama were either unknown or just becoming known.

Others
(Carroll 1989, etc.) placed Tanystropheus outside the Archosauriformes along with rhynchosaurs, which makes absolutely no sense. Still others (Renesto 2005 following tradition) placed Tanystropheus within the Protorosauria, which makes more sense, but, unfortunately, this is by untested tradition only.

Phylogenetic testing using more taxa in the large reptile tree clarifies relationships. Tanystropheidae nest between Huehuecuetzpalli Macrocnemus and Cosesaurus within the Tritosauria, outside of the Squamata.

Despite what Wikipedia tells you, phylogenetic analysis recovers Dinocephalosaurus as a convergent form derived from Macrocnemus, not directly related to Tanystropheus despite   the roughly similar appearance and size.

Earlier we looked at several solutions to the niche and posture of Tanystropheus. Here you can see the ancestry and sisters of Tanystropheus.

Here (fig. 1) we can see that some large Tanystropheus specimens had a larger skull. Others had a smaller skull. Some had epipubic bones. Others did not. More precision in creating the reconstructions might someday reveal other differences not readily visible in these roadkill fossils.

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, 111(3): 377–394.
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus(Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-16.
Wild R 1978. Die Flugsaurier (Reptilia, Pterosauria) aus der Oberen Trias von Cene bei Bergamo, Italien. Bolletino della Societa Paleontologica Italiana 17(2): 176–256.

wiki/Tanystropheus

Tanystropheidae in the sw usa – svp abstracts 2013

From the abstract
Pritchard et al. 2013 wrote: “Tanystropheids are a clade of long-necked archosauromorphs whose remains are largely restricted to marine deposits from the Triassic of Europe and Asia and almost entirely known from two-dimensionally crushed skeletons. Thus far, the occurrences of Tanytrachelos along the East Coast of the United States represent the westernmost confirmed record of tanystropheids, although unconfirmed isolated fragments have been referred tentatively to the group from localities in western North America.

“A large sample of well-preserved, three-dimensional tanystropheid fossils from the Hayden Quarry in the Upper Triassic Chinle Formation of New Mexico provides new insight into the anatomy, phylogeny, and paleoecology of Tanystropheidae. A newly constructed phylogenetic analysis of 200 characters and 45 diapsids, early archosauromorphs, and archosauriforms recovers a novel topology for basal Archosauromorpha. Tanystropheidae forms the sister taxon of a clade including Trilophosaurus, Prolacerta, and Archosauriformes. The analysis also recovers a novel subclade of small tanystropheids including Langobardisaurus and Tanytrachelos. Numerous apomorphies, including dorsoventrally flattened cervical centra and a number of tarsal characters, indicate that the Hayden Quarry tanystropheid materials belong to this subclade. Protorosaurus is recovered as the earliest diverging archosauromorph, outside of Tanystropheidae, and Prolacerta nests as the sister taxon to Archosauriformes.

“These results support the hypothesis that a long necked “protorosaur” bauplan was ancestral for archosauromorphs. Tanystropheid apomorphies identified in this analysis were subsequently used to recognize additional Norian-aged fossils from other sites in New Mexico, Arizona, and Texas. Some of these fossils had previously been attributed to drepanosaurs. The estimated body size range of western tanystropheids based on comparison with Tanytrachelos (~0.3 meters–2.0 meters) indicates that the group was a taxonomically and ecologically diverse component of western North American ecosystems. The presence of tanystropheids throughout western North America, a region that was only seasonally wet during the Norian and Rhaetian suggests that tanystropheids could adapt to a far wider range of habitats than previous records indicate.”

First of all
It’s great to see that little tanystropheids made it to SW America, along with those desert drepanosaurids.

Tanystropheus and kin going back to Huehuecuetzpalli.

Figure 1. Tanystropheus and kin going back to Huehuecuetzpalli. Apparently only forms close to Langobardisaurus and Tanytrachelos were discovered at the Hayden Quarry.

Second of all
This presumption of an archosauromorph nesting of lepidosaurs has to stop! Pritchard et al. are beating a dead horse. A larger spectrum of reptiles reveals that tanystropheids, many with ossified sterna, by the way, are lepidosaurs. This can be tested simply by including taxa, nor excluding them.

Third of all
A small langobardisaurid – tanystropheid has already been discovered in the SW USA. It is called Pteromimus. And perhaps the cervicals of Protoavis, too.

Fourth of all
We know of large Rotodactylus tracks in the SW USA that could only have been made by large relatives of Cosesaurus, to wit: tanystropheids.

To their credit
Protorosaurus and Prolacerta do indeed belong at the base of the Archosauriforms. They have long necks by convergence with tanystropheids.

However
These results do indeed support the hypothesis that a long necked “protorosaur” bauplan was ancestral for archosauromorphs. But I hope they’re not excluding the real sister taxa, like Youngina and Thadeosaurus. And bizarre bauplans, like tanystropheids, are almost always terminal, not ancestral.

References
Pritchard A, Nesbitt S, Turner A, Irmis R Smith N 2013.
Morphology and systematics of the reptile clade Tanystropheidae: implications for Late Triassic biogeography and early archosauromorph evolution. Journal of Vertebrate Paleontology abstracts 2013.

The unexpected bipedal/marine connection

Several times in the evolution of reptiles bipedal forms have phylogenetically preceded marine forms. Yes, marine forms. It’s bizarre, but true.

Here’s the list, more or less. Did I miss any?

Huehuecuetzpalli (bipedal capable) > Dinocephalosaurus (marine)
Huehuecuetzpalli, a small speedy lizard with short fore limbs and long hind limbs evolves to become Dinocephalosaurus, a giant long-necked sit-and-wait predator via Macrocnemus, something in between.

Langobardisaurus (biped) > Tanystropheus (marine)
Langobardisaurus, a small long-necked strider evolves to become Tanystropheus, a giant stand-and-wait marine predator.

Eudibamus (biped) > Claudiosaurus (marine)
Eudibamus, a small lizard-like diapsid with a long neck and long hind limbs evolves to become Claudiosaurus, a long-necked marine undulating marine predator of tiny prey. Thereafter descendants evolve to become ichthyosaurs and plesiosaurs.

Varanus (biped while fighting) > Mosasaurus (marine)
Okay, so only certain varanids only go bipedal when fighting, even so mosasaurs are giant and marine.

Scleromochlus & Terrestrisuchus (bipeds) > Metriorhynchus (marine)
Scerlomochlus, and Terrestrisuchus, tiny long-legged basal crocs evolve to become large short-paddled marine crocs, like

Storks (biped) > Penguins (marine)
Flying bipeds evolve to fly underwater.

Australopithecines (biped) > Humans (Homo, marine capable)
(grassland roamers evolve to become able to swim)

Evidently it all comes down to 
Conscious control of breathing — if you want to become a marine animal you have to hold your breath.

Not sure what the bipedal connection is with reptiles, because lots of marine reptiles never had a bipedal phase. I just wanted to throw the idea out there.

More on Humans:
Anthropologist Elaine Morgan on TED talks about the origin of bipedal humans from aquatic apes here. Step-by-step: Apes all walk bipedally when they cross streams. For insulation humans have fat migration to a subdermal position, that’s why obesity is possible for humans, not for apes. The nostrils open ventrally, keeping water out by air pressue in humans. Ape nostrils don’t keep out water, except for the proboscis monkey (the most aquatic of primates).  Ability to speak comes by way of the conscious control of their breath, according to Morgan.

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.

Blood pressure in an elevated Tanystropheus

Yesterday we looked at the possibility of underwater leaping in Tanystropheus for snatching prey and, with a little momentum, for reaching the surface for a breath.

Just like a giraffe or an upright sauropod
Tanystropheus had to have had a specialized circulatory system and a large heart in order to raise its neck. And also like a giraffe, Tanystropheus probably another sort of system to keep blood from pooling in its legs and tail whenever the neck was raised. This post was inspired by a recent one on sauropods here at PHENOMENA, a science salon hosted by National Geographic Magazine.

Tanystropheus underwater among tall crinoids and small squids.

Figure 1. 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.

That vertical pipe of a neck would have elevated the head nearly eight feet (250 cm) above the heart in the largest Tanystropheus specimens. That’s longer than the neck height of a giraffe, but far shorter than that of a large sauropod. In giraffes the heart rate is high, up to 170 bpm. We can imagine Tanystropheus might have also had an elevated heart rate, especially for a large lizard. What does this mean? Well, phylogenetically Tanystropheus was surrounded by bipeds, some of them, the fenestrasaurs, were speedy. Some of them, the drepanosaurs, were slow.

The blood pressure of a giraffe is the highest of all animals, reaching about 300 over 200 mm Hg to pump blood up a neck seven feet long to reach its brain. The blood pressure of Tanystropheus might have been a little higher.

Perhaps related – or not
If Tanystropheus fed underwater, the trachea might have been valved in order to keep an air bubble in the lungs and restricting its rise up the windpipe whenever submerged under at least eight feet of water pressure. Likewise the blood vessels might have been similarly valved to keep blood in the “upper stories.”

Few animals are comparable to a Tanystropheus and fewer of them are alive today. All hypotheses about soft tissue can only be considered guesses.

Whatever the case… not bad for a lizard.

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

Giraffe circulation pdf

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