New Pterodactylus at the Field: Lauer Foundation Collection

The Lauer Foundation for Paleontology provided
this deep cut Pterodactylus to the Field Museum, Chicago, USA. The foundation number is: #LF 513. It enters the large pterosaur tree (LPT, 250 taxa) distinct from all other tested pterosaurs.

Figure 1. Pterodactylus at the Field Museum from the Lauer Collection

Figure 1. Pterodactylus at the Field Museum from the Lauer Collection

Basically it’s your run-of-the-mill Pterodactylus,
nesting pretty much in the middle of a clade that has divided into several subclades (Fig. 2) each with several members. Now there’s another PhD thesis in the making! Who wants to lump and split?

Figure 2. Subset of the LRT focusing on Pterodactylids and Pterodactylus.

Figure 2. Subset of the LRT focusing on Pterodactylids and Pterodactylus.

It’s worth noting the ribcage,
the one part of any pterosaur that gets the least attention. In many pterosaurs the ribcage forms the torso into a cylinder or a Releaux triangle (triangle with curved sides), but here, as in several anurognathids and Sharovipteryx, the ribcage has a flatter appearance, more elliptical in dorsal view, more like a flying saucer.

Figure 3. Sharovipteryx reconstructed. Note the flattened torso.

Figure 3. Sharovipteryx reconstructed. Note the flattened torso.

References
https://www.fieldmuseum.org/blog/meet-pterosaur-flock

https://www.lauerfoundationpse.org/about

Late-surviving sharovipterygids in Early Cretaceous Burmese amber

Earlier we looked at a
Oculudentavisa late-surviving cosesaur in Early Cretaceous Burmese amber. I noted it had just a few traits closer to another fenestrasaur, Sharovipteryx (Fig 2).

Figure 1. DGS tracings of two amber entombed Early Cretaceous sharovipterygids.

Figure 1. DGS tracings of two amber entombed Early Cretaceous sharovipterygids.

Today,
two unnumbered, unnamed, undescribed Early Cretaceous fenestrasaurs with even more sharovipterygid traits from the same Burmese amber. These specimens have huge eyes, a larger naris, a small antorbital fenestra, gracile postorbital bones, long cervicals with robust cervical ribs. That gray sickle-shaped area appears to represent the same sort of extendable hyoids seen in Sharovipteryx that extend the neck skin to form canard wing membranes or strakes (Fig. 2). Once again, these poor saps got their head stuck in the resin. The rest of the body was lost to the ages.

For comparison, a complete Sharovipteryx
(Fig. 2) is known from Late Triassic strata, coeval with the first pterosaurs, both derived from Cosesaurus, a lepidosaur tritosaur fenestrsaur.

Figure 3. Sharovipteryx reconstructed. Note the flattened torso.

Figure 3. Sharovipteryx reconstructed. Note the flattened torso.

References
No scale bar, No citation, No museum number, Owner unknown.

If Sharovipteryx was a glider, how did it climb trees with such tiny arms?

That’s a good question that is rarely asked.
Typically considered a hind-wing glider, Sharovipteryx (Sharov 1971) must have also been an obligate biped due to its proportions (Peters 2000). This is another form of locomotion rarely attributed to this Late Triassic Lepidosaur, Tritosaur Fenestrasaur. In the large reptile tree (LRT, 1413 taxa) Sharovipteryx was derived from a flapping, sprinting, occasionally bipedal Cosesaurus and Sharovipteryx shares many traits with pterosaurs (see below).

Today we’ll make comparisons
to an extant quadrupedal arboreal glider, Draco volans (Fig. 1).

Figure 1. Sharovipteryx alongside a photo of Draco volans. Both lepidosaurs had sprawling limbs, a long fifth toe, attenuated tail, extrademal membranes and dorsal ribs that flatten and widen its torso.

Figure 1. Sharovipteryx alongside a photo of Draco volans. Both lepidosaurs had sprawling limbs, a long fifth toe, attenuated tail and dorsal ribs that flatten and widen its torso.

Draco vs. Sharovipteryx: the similarities:

  1. sprawling limbs
  2. tendril-like toes and a long fifth toe
  3. attenuated tail
  4. dorsal ribs that flatten and widen its torso
  5. expandable hyoid for display

Draco vs. Sharovipteryx: the differences:

  1. extradermal membranes
  2. longer hind limbs (bipedal)
  3. shorter fore limbs
  4. longer cervical vertebrae
  5. 5+ sacral vertebrae
  6. longer ilia
  7. antorbital fenestra
  8. prepubes (phylogenetic bracketing)
  9. pteroid (former centrale) (Fig. 4)
  10. pedal 5.1 nearly as long as metatarsal 4 (Fig. 3)
  11. vestigial finger 5
  12. strap-like scapula
  13. stem-like coracoid (flapping)
  14. robust radius and ulna without interosseum space

Sharp-eyed readers will note
that many of the above traits are also found in pterosaurs.

Figure 2. Draco and Sharovipteryx bipedally on tree trunk, flapping its tiny arms. Hatchling Sharovipteryx between them.

Figure 2. Draco and Sharovipteryx bipedally on tree trunk, flapping its tiny arms. Hatchling Sharovipteryx between them. Several living birds are able to cling to tree trunks by their hind feet alone. Imagine the knees of Sharovipteryx bending even further, or imagine the femora further splayed to match the in situ fossil. Both configurations bring the body closer to the tree. As in pterosaurs, splayed knees can still produce a bipedal configuration because the knees bend the ankles back toward the midline.

Tradition presupposes that Sharovipteryx
was a glider. In counterpoint, Cosesaurus had uropatagia and was not a glider, but a flapping sprinter. Flapping animals do not become gliders. Gliders do not become flappers. Even so, it is good science to keep proposing alternatives for Sharovipteryx. Then we can refute, support or confirm all of the alternatives.

Tradition, in this case may be correct.
Cosesaurus
did not have membranes between its toes and it did not splay its metatarsals (Fig. 3). Nor did Cosesaurus have the limb proportions of Sharovipteryx and its several canard and strake neck membranes.

Figure 3. Sharovipteryx pes in dorsal and digit 4 in lateral view.

Figure 3. Sharovipteryx pes in dorsal and digit 4 in lateral view.

Dyke, Nudds And Rayner 2006
wrote, “Intriguingly, because of the incompleteness of the single known specimen, the evolutionary relationships of S. mirabilis remain poorly understood (Tatarinov, 1989; Unwin et al., 2001) – better preserved fossil material will be required to resolve this issue.” 

This paper followed and cited Peters 2000,
which added Sharovipteryx to four previously published phylogenetic analyses and found it nested with pterosaurs every time. It would have been so easy for Dyke, Nudds and Rayner to replicate the addition of taxa to the same four previously published analyses to confirm or refute Peters 2000. But evidently no PhD wants to confirm the work of another worker.

Later
Hone and Benton 2007, 2008 created a supertree to determine pterosaur affinities, but in the second of two papers removed all reference to Peters 2000 and removed Sharovipteryx from their taxon list.

In all prior studies
a lack of a precise tracing of the fossil and its counterpart is evidence that earlier studies did not look very closely or comprehensively at the fossil (see below).

I have seen Sharovipteryx first hand.
I keep in my file cabinet an 8.5×11-inch transparency for ready reference. The Sharovipteryx holotype fossil (Fig. 5) is nearly complete (but note the big gash in the middle) and, since I’ve actually done the phylogenetic work… well understood.

Figure 4. Sharovipteryx forelimb with digit 4 extended and flexed/folded. Note the large, deep unguals that appear to be useful, not vestigial.

Figure 4. Sharovipteryx forelimb with digit 4 extended and flexed/folded. Note the large, deep unguals that appear to be useful, not vestigial.

Dyke, Nudds And Rayner 2006
also proposed a delta-winged Sharovipteryx. They wrote, “Our novel interpretation of the bizarre flight mode of S. mirabilis is the first based directly on interpretation of the fossil itself and the first grounded in aerodynamics.” Students should be aware, not all such claims are valid. This claim, in particular, is built largely on imagination.

Figure 1. Sharovipteryx in situ. Click to enlarge. Here both plate and counter plate are shown along with a tracing based on both.

Figure 5. Sharovipteryx in situ. Click to enlarge. Here both plate and counter plate are shown along with a tracing based on both.

Hopefully the Dyke, Nudds And Rayner interpretation
will fade into the forgotten literature. The Dyke team fully imagined the forelimbs and added several membranes that are not present in the fossil while ignoring others that are present. So Dyke, Nudds and Rayner based their mathematics on an imaginary creature. We’ve seen how other scientists change/imagine morphology to fit their mathematical model. Despite the Dyke, Nudds and Rayner claim for first-hand observation, their cartoonish drawing of Sharovipteryx was based on Sharov’s freehand drawing.

What scientist concerned about their reputation would do this?
Well… Unwin, Alifanov and Benton (2003, yes Benton once again!) reprinted Sharov’s 1971 drawing, rather than create one of their own. Worse yet, Gans et al. 1987 created an even more cartoonish reconstruction, barely better than a cave drawing.

The takeaway:
As we’ve seen many times before, beware that certain PhDs sometimes do not put in the effort necessary to validate their claims. And sometimes PhDs, acting as referees, strive to ensure that contradicting hypotheses are not published.

Finally
Let’s not forget Kenneth Dial’s work with pre-volant bird chicks, able to climb steep inclines using everything they have to do it. (Video lecture 1 hour, 36 minutes).


References
Dyke GJ, Nudds RL and Rayner JMV 2006. Flight of Sharovipteryx mirabilis: the world’s first delta-winged glider. xx PDF
Gans C, Darevski I and Tatarinov LP 1987. Sharovipteryx, a reptilian glider? Paleobiology. 13: 415–426.
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Tatarinov LP 1989. [The systematic position and way of life of the problematic Upper Triassic reptile Sharovipteryx mirabilis.] Paleo. Zh. 1989(2): 110-112. [in Russian].
Unwin DM, Alifanov VR and Benton MJ 2003. Enigmatic small reptiles from the Middle-Late Triassic of Kyrgyzstan. In: Benton M.J., Shishkin M.A. & Unwin D.M. (Eds) The Age of Dinosaurs in Russia and Mongolia. Cambridge: Cambridge U. Press: 177-186.

http://reptileevolution.com/sharovipteryx.htm

Sharovipteryx dorsal plumes

Figure 1. Sharovipteryx in situ. Click to enlarge. Here both plate and counter plate are shown along with a tracing based on both.

Figure 1. Sharovipteryx in situ. Click to enlarge. Here both plate and counter plate are shown along with a tracing based on both. Note the large area missing from the plate. The specimen is virtually complete and articulated. Some beetles dot the matrix. Look closely and you’ll see where the hands are. The uropatagia (they are separate) and other soft tissue membranes are easy to see.

We looked at Sharovipteryx earlier here, here and here. Today we’l take an overall look at the plate and counter plate with a fresh tracing that reveals new, previously overlooked details, some of which are so buried they are best discovered by way of phylogenetic bracketing.

Dorsal plumes
The sister taxa of Sharovipteryx have dorsal plumes. These taxa include Cosesaurus, Kyrgyzsaurus and famously, Longisquama (Fig. 2). Dorsal plumes have never been observed in Sharovipteryx, largely because no one has looked for them and, just as importantly, they are small and hard to see because they overlap easier-to-see soft tissue. Here the plumes are best seen in the enlargement and are labeled ‘DP.’ These online images are greatly reduced from the data I was able to work from, so they may be difficult to see at web resolution (Fig. 3). If anyone is interested in seeing higher resolution images, email me.

Figure 2. The basal fenestrasaur precursors of pterosaurs, including Cosesaurus, Sharovipteryx, Kyrgyzsaurus, Longisquama and a basal pterosaur.

Figure 2. The basal fenestrasaur precursors of pterosaurs, including Cosesaurus, Sharovipteryx, Kyrgyzsaurus, Longisquama and a basal pterosaur. Click to enlarge. All basal fenestrasaurs had a lepidosaurian dorsal frill, sometimes enlarged to plumes, derived from the frill in Huehuecuetzpalli and other basal lepidosaurs.

The Prepubis
Sister taxa to Sharovipteryx also had a prepubis. This bone is essentially invisible in Sharovipteryx, but if it exists, as phylogenetic bracketing indicates, it is buried beneath the right hand, which is back by the pelvis where the prepubis articulates.

Figure 3. Sharovipteryx (Pp) prepubis possible location beneath the right fingers. The dorsal plumes (DP) are easier to see.

Figure 3. Click to enlarge. Sharovipteryx (Pp) prepubis possible location and shape – beneath – the right fingers and associated soft tissue. The coincidence is suspect (note the shape matches) but phylogenetic analysis provides Sharovipteryx with a prepubis of this size and shape. The dorsal plumes (DP) are easier to see. Numbers are fingers 1-4. Soft tissue covers most of the view here, blanketing other elements. The tracing shows more detail because it was traced from both plates, not just this one. Note the left ischium is likewise buried beneath the left uropatagium, revealed only like a child beneath a blanket. I’m sure no one would deny that Sharovipteryx had an ischium and fingers. The same must be said of a prepubis and dorsal plumes by phylogenetic bracketing.

At this size and shape
the prepubis of Sharovipteryx is proportioned relative to the femur more similar to the same bone in Longisquama and pterosaurs. The prepubis essentially extends new bone ventral to the pelvis to anchor femoral muscles of adduction.

Pelvic opening
If you want to know the maximum size for a Sharovipteryx egg, you can estimate a minor axis diameter measurement from the pelvic opening. Then figure out the appropriate size of the hatchling (Fig. 2). Note the pelvic opening of Sharovipteryx is much deeper than that of Cosesaurus, but not as deep as in MPUM 6009, a basal pterosaur. Apparently fewer larger eggs were laid by more derived fenestrasaurs, but MPUM 6009 had the deepest pelvic opening of any pterosaur.

References
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Tatarinov LP 1989. [The systematic position and way of life of the problematic Upper Triassic reptile Sharovipteryx mirabilis.] Paleo. Zh. 1989(2): 110-112. [in Russian].
Tatarinov LP 1994. Terestrial vertebrates from the Triassic of the USSR with comments on the morphology of some reptiles. In: Mazin J.-M. & Pinna G. (Eds.) Evolution, ecology and biogeography of the Triassic reptiles. Paleo. LombNew Ser. 2.
Unwin DM, Alifanov VR and Benton MJ 2000. Enigmatic small reptiles from the Middle-Late Triassic of Kyrgyzstan. In: Benton M.J., Shishkin M.A. & Unwin D.M. (Eds) The Age of Dinosaurs in Russia and Mongolia. Cambridge: Cambridge U. Press: 177-186.

wiki/Sharovipteryx

Perching Sharovipteryx

Figure 1. Sharovipteryx in various perching attitudes.

Figure 1. Sharovipteryx in various perching attitudes. Note the pancake-flat torso, the deep prepubis, the stunted pterosaur-like hands and all that soft tissue! This gracile bipedal sprinter was also a hind-wing glider after leaping into the air with those large hind limbs. This is also how small pterosaurs launched from tree trunks, with wings outstretched and powered aloft by a hind limb launch.

Sharovipteryx mirabilis (Sharov 1971) is the famous hind wing glider.

Wikipedia consideres it “a genus of early gliding reptiles.” and “Sharovipteryx is generally agreed to belong to a group of early archosaur relatives known as the protorosaurs (or prolacertiformes).”

In this age of phylogenetic analysis
such a general description is very disheartening, especially considering that four phylogenetic analyses from 15 years ago allied Sharovipteryx to Cosesaurus, Longisquama and pterosaurs (Peters 2000). Very little work has been done on this genus since then. No one has attempted a precise tracing and, of course, no one has attempted a reconstruction from that tracing. I’ll show you some new reconstructions and tracings over the next few days but you can preview them here.

Over the past decade
I have attempted to publish additional data that repaired earlier mistakes. Unfortunately every such attempt was rejected, often for vacuous reasons. This is one more such instance.

Over the next few days
we’ll take a look at the latest tracings and reconstructions from those rejected manuscripts. Here (Fig. 2), for starters, is a new reconstruction of the foot based on the in situ specimen. The original was in color and segregated using DGS.

Figure 2. Sharovipteryx foot, in situ and reconstructed.

Figure 2. Sharovipteryx foot, in situ and reconstructed. Note digit 1 is dislocated toward the ankle. Digits 2-4 likewise have their distal phalanges jammed proximally past their metatarsals. Parallel interphalangeal lines show that phalanx sets worked as sets, flexing and extending at the same line.

References
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Tatarinov LP 1989. [The systematic position and way of life of the problematic Upper Triassic reptile Sharovipteryx mirabilis.] Paleo. Zh. 1989(2): 110-112. [in Russian].
Tatarinov LP 1994. Terestrial vertebrates from the Triassic of the USSR with comments on the morphology of some reptiles. In: Mazin J.-M. & Pinna G. (Eds.) Evolution, ecology and biogeography of the Triassic reptiles. Paleo. LombNew Ser. 2.
Unwin DM, Alifanov VR and Benton MJ 2000. Enigmatic small reptiles from the Middle-Late Triassic of Kyrgyzstan. In: Benton M.J., Shishkin M.A. & Unwin D.M. (Eds) The Age of Dinosaurs in Russia and Mongolia. Cambridge: Cambridge U. Press: 177-186.

wiki/Sharovipteryx

 

Sharovipteryx Wiki just updated

Once again, like the Pterosaur Origins Wiki page, some well-meaning, but misinformed author/expert on the Sharovipteryx Wiki page claimed that I did not observe the fossil firsthand (which is false) and that my phylogenetic analysis of Sharovipteryx (still the only one in any academic publication in the last 14 years) had less validity than what paleontologists “generally agree”. Yes, in this age of verifiable nestings, can you believe this return to the vagaries of the 1960s? (Actually I think this only occurs when my name is present).

The author/expert claimed that I am not a scientist (ignoring academic publications in 6 or 7 journals now) and put his faith in Bennett’s claim made in a popular publication that my tracings were fantasies (once again, mining the wastebasket). Yes, I made those mistakes, but the new work puts all that crap in the wastebasket, where it should stay.

Wiki is generally for information, not for casting aspersions on others. So, when an alternate and testable hypothesis is presented, it is not necessary that the author of that hypothesis be trashed. Simply present the facts. Not the bias, please.

I made changes to the Sharovipteryx Wiki page that stick to the readily observable and testable facts. Let’s see if those changes stick.

If that author/expert wants to put his faith in Chris Bennett, Lord help him. Bennett has made dozens of mistakes, including purposefully creating a fantasy (by his own admission) pterosaur precursor (Bennett 2008), rather than to test any of the hundreds of currently known reptile candidates in phylogenetic analysis, as I have here. And 2008 Bennett had a short list provided by Peters (2000), which he ignored. I tested his 1996 paper by adding a few taxa. Turnabout would have been very welcome.

We’re all guilty. Let’s move forward people. Please, use the latest information and keep the focus on the taxa, not the person. I put all my data in viewable, testable photos and am more than happy to make corrections when made available.

 

Bottom Line
Sharovipteryx is a complete fossil with many uncontroversial traits shared with Cosesaurus and pterosaurs. Those traits are going unpromoted in Wiki and I think it’s because some people think I’ve poisoned the well in publishing on it without having a PhD. They have to tip-toe around my peer-reviewed publications and they have to trash me because if they started listed characters, they’d soon find out what anyone can find out. Perhaps that’s why no one had published another analysis of Sharovipteryx in the last 14 years. And it’s ripe for a revision because I made several mistakes with it, even firsthand.

Remember, Hone and Benton (2007, 2008) tossed Sharovipteryx out in their search for a pterosaur precursor. Same thinking. Same result.

If you’re thinking of Senter’s (2003) dissertation (which the Wiki author/expert cited), in which he nested Sharovipteryx with Cosesaurus, but pterosaurs with Scleromochlus, take a good look at his scorings. He gave Scleromochlus a sternal complex and a long lateral pedal digit, both of which are absent on it and any sister taxa — among dozens of other rookie mistakes.

References
Bennett S.C. 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoo. J. Linn. Soc. 118: 261-309.
Bennett S.C. 2008. Morphological evolution of the forelimb of pterosaurs: myology and function. In: Buffetaut E. and Hone D.W.E. (Eds) – Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Zit., B28: 127-141.
Peters D. 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Riv. It. Paleo. Strat. 106(3): 293-336.

 

 

Sharovipteryx skull revised

In response to an interested reader, J. Headden, I spent the day looking at and tracing the head and neck of Sharovipteryx, attempting to identify the skull parts. I used phylogenetic bracketing to determine what shapes I should be looking for, especially in the palatal elements. I present them here as large as they will show in WordPress.

Sharovipteryx in situ. See figure 2 for identification of elements and figure 3 for a reconstruction.

Figure 1. Sharovipteryx in situ. See figure 2 for identification of elements and figure 3 for a reconstruction. Lots of skin here. Note the neck skin is 6x wider than the cervicals. Stretched out by those long hyoids and this loose skin becomes a taut set of strakes, aerodynamic pitch controls. Are those pycnofibers, collagen or wrinkles on the neck? They look like fibers to me. And do you see the insect inside the antorbital fenestra? Guide graphics in figure 2.

DGS Digital Graphic Segregation
The DGS tracing (Fig. 2) reveals the elements of the crushed skull, including some palatal elements that have shifted to the side. There is a winged insect there, lacking one wing, in the antorbital fenestra. There are other insects, mostly beetles, elsewhere on the slab and the site is known for its insects. Somer workers dismiss DGS, but no one else has found the details presented here using traditional microscope, prism and pencil tools.

I wanted to present a much larger image in order for readers to determine for themselves if the neck structures were hairs, wrinkles or collagen. To my mind these are elongated fibers, overlapping others. The specimen is buried slightly in the matrix. If there are stray hairs hidden below the matrix, they have yet to be exposed.

Earlier we discussed the use of this 6x wider neck skin as an aerodynamic strake used during gliding.

Figure 2. Skull of Sharovipteryx with elements identified from figure 1. Yes that's a winged insect in the middle of the left antorbital fenestra. The hairs on the right are possible matrix artefacts, possible pycnofibers. Judge for yourself what the various fiber-like shapes represent. I think they're pycnofibers.

Figure 2. Skull of Sharovipteryx with elements identified from figure 1. Yes that’s a winged insect in the middle of the left antorbital fenestra. The hairs on the right are possible matrix artefacts, possible pycnofibers. Judge for yourself what the various fiber-like shapes represent. I think they’re pycnofibers.

Reconstruction from graphic elements
Here (Fig. 3) the colored elements are arranged according to their identities to check fit and create a reconstruction in several views.

Figure 3. Elements of Sharovipteryx skull reconstructed in palatal and lateral views. Elements identified in figure 2.

Figure 3. Elements of Sharovipteryx skull reconstructed in palatal and lateral views. Elements identified in figure 2.

Yes, there could be some mistakes. This tracing differs from prior versions. If you find problems, please alert me to them. At this point no one else on the planet has attempted a precise reconstruction of the skull of Sharovipteryx based on examination of the specimen. The fact that my reconstruction changes over time is not an indictment of DGS, but a measure of my increasing experience and judgement.

Figure 5. Reconstruction of Sharovipteryx skull in several views based on the new tracings. The dentary teeth were probably present, but not shown here.

Figure 5. Reconstruction of Sharovipteryx skull in several views based on the new tracings. The dentary teeth were probably present, but not shown here.

The new reconstruction of Sharovipteryx is similar to that of Cosesaurus and Longisquama, its phylogenetic sisters.

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
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
wiki/Sharovipteryx

Pycnofibers on Sharovipteryx – Another hairy lizard!

Yesterday we noted pterosaur-like pycnofibers (ptero-hairs) on Longsiquama. Here we find them also on Sharovipteryx (Figs. 1, 2), further cementing their relationship to pterosaurs like Sordes, Jeholopterus and others that preserve these extradermal hairs.

Figure 1. Click to enlarge. Pycnofibers (extradermal tissues) on Sharovipteryx. Formerly such hair-like extradermal membranes were recognized only in pterosaurs. Now they are in found in more basal fenestrasaurs. Surely these were no ordinary lizards! Warm-blooded? You decide. On the right the fibers are more easily seen. On the left (bottom) these are less distinct.

Figure 1. Click to enlarge. Pycnofibers (extradermal tissues) on Sharovipteryx. Formerly such hair-like extradermal membranes were recognized only in pterosaurs. Now they are in found in more basal fenestrasaurs. Surely these were no ordinary lizards! Warm-blooded? You decide. On the right the fibers are more easily seen. On the left (bottom) these are less distinct. They all criss-cross and seem “thick” to me, thicker than fur on mammals, for instance.

If these patterns were wrinkles in neck skin, they would not criss-cross as they do here. They are fiber-like or hair-like and as such may have functioned in thermoregulation, as did the extensive uropatagia behind each hind limb. More likely both were part of their elaborate displays and likely were brightly or contrasted in color and value.

Figure 2. Sharovipteryx mirabilis in various views. No pycnofibers added yet. Click to learn more.

Figure 2. Sharovipteryx mirabilis in various views. Click to learn more.

Start making Sharovipteryx hairy, guyz! It joins pterosaurs in being kinda fuzzy, especially around the neck.

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
Sharov AG 1971
. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].

wiki/Sharovipteryx

Bizarro Sharovipteryx and Bizarro Icarosaurus

This artist, Dr.Takeshi Yamada, definitely has great talent, but little sense of accuracy. Still worth looking at for the really great, live-like texture and color. Click the links to see the copyrighted images.

Sharovipteryx 1.

Sharovipteryx 2.

Icarosaurus.

Coelurosauravus.

Others

On the other hand, another artist (name unknown) has different problems with accuracy. Sadly he’s following pterosaur tradition down a very rocky road. The saggy results speak for themselves, but Dave Hone, one of the spokesmen for keeping such pterosaur traditions, discusses the various highlights and faults of the artwork.

A better wing morphology, reflecting the evidence from all known pterosaurs, can be seen here and here if anyone starts to feel the onset of confusion.

The Evolution of the Pterosaur Palate – part 1

Not much attention has been paid to the pterosaur palate.
Ever since Williston (1902) and continuing through Huene 1914, Wellnhofer (1978, 1991) and Bennett (1991, 2001a,b), the solid palatal plate in pterosaurs has been considered the palatine (Fig. 1). That’s the tradition and that’s the paradigm – but that’s wrong.

Scaphognathus palate

Figure 1. Click to enlarge. (Left) The traditional reconstruction of the palate of the pterosaur Scaphognathus (Wellnhofer 1978) in which the palatal shelf is considered the palatine bone. (Right) The heretical and recently vindicated reconstruction of the palate in which the palatine is fused to the ectopterygoid creating a L-shaped bone, the ectopalatine. The medial extent of the maxillary palate shelf is unknown. 

Not the Palatine, the Maxilla!
Virtually ignored, Newton (1888), Seeley (1901 and Woodward (1902) reported that the solid palatal plate was an outgrowth of the maxilla, not the palatine. Unfortunately, I did not know that when I reported (in Peters 2000) that the palatal plate actually originated from the maxilla. (Thought I had discovered something!) The much smaller palatine and ectopterygoid were fused to form a single L-shaped element, the ectopalatine. This was due to an ancestry among fenestrasaurs and Macrocnemus, rather than archosaurs. Even that was largely ignored until…

Reinterpretation and Vindication
Osi et al. (2010) reported, “The hard palate is formed by the extensive palatal plate of the maxilla and not by the palatine as has been generally reconstructed.”  This was well demonstrated by a 3D Dorygnathus skull (Fig. 2).

Palate of the WDC specimen of Dorygnathus

Figure 2. The Osi et al. (2010) WDC 3-D Dorygnathus palate. Click to enlarge. The non-fusion of the palatine and ectopterygoid might have signaled ontogenetic immaturity, but the specimen is half again larger than other Dorygnathus specimens. The original interpretation of the premaxilla was based on the break at mid maxilla, not the sutures, which are revised at right. The purported foramen incisivum is not found in other pterosaurs. It represents missing vomer bone. 

The Origin and Evolution of the Palatal Elements in Basal Pterosaurs
To trace the origin of the palatal elements in pterosaurs we go back to Lacertulus, a basal tritosaur from the Late Permian (Fig. 3. Lacertulus had round wide jaws with large wide elements with no maxillary component.

In Huehuecuetzpalli (Fig. 3) the snout was narrower and so were all the palate elements. In Macrocnemus, narrower still. In Tanystropheus, not so narrow, but the interpterygoid vacuity was narrow. In both of these the palatine barely contacts the ectopterygoid.

In Cosesaurus (Fig. 3) the vomer teeth were probably absent (hidden in the fossil). In Sharovipteryx the ectopterygoid and palatine were both straight and fused. The rostrum in Longisquama was narrowed and the palatal elements were reduced.

The evolution of the pterosaur palate

Figure 3. The evolution of the pterosaur palate from basal tritosaur ancestors. Note the fusion of the palatine and ectopterygoid creating the ectopalatine in adults. The non-fusion of these elements in figure 1 may represent an ontogenetic character. Not sure. Vomers in green. Palatines in blue. Pterygoids in orange. Ectopterygoids in magenta. The latter two elements are fused in Longisquama and most pterosaurs. The medial extent of the maxillary palate processes and the width of the rostral portion of the skull is unknown in specimens exposed in lateral view.

Figure 3. The evolution of the pterosaur palate from basal tritosaur ancestors. Note the fusion of the palatine and ectopterygoid creating the ectopalatine in adults. The non-fusion of these elements in figure 1 may represent an ontogenetic character. Not sure. Vomers in green. Palatines in blue. Pterygoids in orange. Ectopterygoids in magenta. The latter two elements are fused in Longisquama and most pterosaurs. The medial extent of the maxillary palate processes and the width of the rostral portion of the skull is unknown in specimens exposed in lateral view.

In the basal pterosaur, MPUM 6009, the palate did not become so narrow. Like Sharovipteryx, the anterior pterygoid was more robust, forming a “head” and the posterior portion was quite gracile. Other pterosaurs had more gracile palatal elements. A maxilla palatal process leading from the base of the ascending process connects to the palatine portion of the ectopalatine.

The solid portion of the palate
The evolution of the maxillary process of the palate would probably come later in the evolution of pterosaurs (Fig. 1), appearing in Rhamphorhynchus and, by convergence, in Dorygnathus and other pterosaurs derived from this genus or by convergence after Scaphognathus. Due to crushing, etc. the medial extent of the maxilla toward the vomers is difficult to gauge in most Triassic and early to mid-Jurassic pterosaurs, other than anurognathids) which we’ll cover in a future blog.

New Openings?
The new premaxillary openings discovered by Osi et al. (2010) were indeed novel with regard to Dorygnathus, but were also found in Rhamphorhynchus muensteri by convergence (Fig 4). They do not represent vomernasal organs, but are new structures. Only higher scleroglossan lizards have vomernasal openings. No other such openings have been reported in pterosaur ancestors or other pterosaurs. Longisquama (Fig. 2) may have had something similar my convergence (this is educated guesswork). In any case they were secondarily developed in all cases and not related to or pinched off from the choanae.

Various pterosaur palates

Figure 4. Comparing pterosaur palates. Left to right: the new WDC Dorygnathus, Rhamphorhynchus muensteri, Cacibupteryx and Dorygnathus purdoni. The pterygoid extends a process to the jugal in three of these taxa, but such a process is otherwise rare in pterosaurs.

The Fragile Stem-like Portion of the Palate
As the maxillary portion of the palate expanded, the posterior elements (palatine and ectopterygoid) become more or less smaller in all pterosaurs (Fig. 4). More later on these derived taxa.

Problems with the Supplementary Material in Osi et al. (2010)
1. Comparisons were only made to archosaurs when in fact no line up of archosaurs documents a gradual increase in pterosaurian characters. They report: “Hone and Benton (2007, 2008) provided new evidence to support the origin of the Pterosauria within Archosauria and we follow their definition here.” Unfortunately, Hone and Benton made their test by omitting the data from Peters, 2000, omitting the two fenestrasaurs closest to pterosaurs and scoring the other two for only a quarter of their available characters. Their so-called ‘test’ was no test at all, but elimination of the competition and a foregone conclusion with only one possible outcome.

Reinterpretation of purported premaxilla in Dorygnathus

Figure 5. Here I reinterpret more bones in this purported premaxilla of the WDC 3-D Doryganthus of Osi et al. (2010). Purple = maxilla. Green = vomer. Pink = nasal.

2. Osi et al. (2010 fig. 3) is a multiview photo of the premaxilla of the new specimen  (Fig. 5). Unfortunately the authors failed to recognize the pmx/mx suture essentially extending from the antorbital fenestra not quite to tooth #4. So a healthy portion of the maxilla is present here laminated to the pmx. The break occurred at the narrowest portion below the naris.

3. The sagittal rdge (SI) in the pmx is the paired, fused, anterior vomers.

4. Considering the proportions of the very elongate premaxilla, longer than in any other Dorygnathus of which I am aware, and as long as the maxilla, this is probably a derivation of Dorygnathus and sufficiently distinct to merit its own genus. I would encourage the authors to erect a new genus and perform a phylogenetic analysis of all known Dorygnathus specimens to confirm the new specimen’s closest relations. There is an unrecognized variety in Dorygnathus that needs to be explored. I don’t think this specimen is basal to any known taxa, which all have a relatively shorter premaxilla.

5. Their figure 9 misidentified the entire broken rostrum of Gnathosaurus as the premaxilla, when it should have included only the first four teeth and a long premaxillary ascending process.

6. Paradoxically, and contra the evidence of their specimen, the hypothetical  reconstructions in their figure 11 separate the palatine from the ectopterygoid, giving each a separate articulation on the pterygoid for no apparent reason, other than following the pattern seen in crocodilians. These two elements were in direct contact and fused in many taxa.

7. Figure 11 also purports to extend the premaxilla in “(B) pterodactyloid pterosaurs” to include over a dozen teeth. This is also wrong. The premaxilla in all pterosaurs includes up to 4 teeth, no more.

8. In their figure 11 the authors should have reconstructed the posterior vomers lateral to the anterior pterygoids, not medial to them. They had it right in their figure 8.

9. The authors ascribe a lateral pterygoid process contacting the jugal to all basal pterosaurs, but this process is restricted to certain Rhamphorhynchus and certain Dorygnathus by convergence.

We’ll look at anurognathid palate tomorrow…

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:
Bennett SC 1991. Morphology of the Late Cretaceous Pterosaur Pteranodonand Systematics of the Pterodactyloidea. [Volumes I and II]. – Ph.D. thesis, University of Kansas [Published by University Microfilms International/ProQuest].
Bennett SC 2001a, b. The osteology and functional morphology of the Late Cretaceous pterosaur Pteranodon. Part I and 2. General description of osteology. – Palaeontographica, Abteilung A, 260: 1-153.
Newton ET 1888. On the skull, brain and auditory organ of a new species of pterosaurian (Scaphognathus Purdoni) from the Upper Lias near Whitby, Yorkshire. Philosphoical Transaction of the Royal Society, London 179: 503-537.
Osi A, Prondvai E, Frey E and Pohl B 2010. New Interpretation of the Palate of Pterosaurs. The Anatomical Record 293: 243-258.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Seeley HG 1901. Dragons of the air. An account of extinct flying reptiles. – London, Methuen: 1-240.
Wellnhofer P 1978. Pterosauria. Handbuch der Paläoherpetologie, Teil 19.– Stuttgart, Gustav Fischer Verlag: 1-82.
Wellnhofer P 1991. The Illustrated Encyclopedia of Pterosaurs. London, Salamander Books, Limited: 1-192.
Williston SW 1902. On the skull of Nyctodactylus, an Upper Cretaceous pterodactyl. Journal of Geology 10:520–531.
Woodward AS 1902. On two skulls of Ornithosaurian Rhamphorhynchus. Annals of the Magazine Natural History 9:1.