New Painten “Pro-Pterodactyloid”

A new, excellently preserved and unnamed private specimen has been published by Tischlinger and Frey (2013). It comes from the Latest Kimmeridgian of the Jurassic, just before the last age of the Jurassic, the Tithonian. The specimen is owned by a private research institute headed by Birgit Albersdörfer.

Figure 1. The Painten pterosaur (privately owned) from Frey and Tischlinger 2013. Excellent preservation and preparation here.

Figure 1. The Painten pterosaur (privately owned) from Frey and Tischlinger 2013. Excellent preservation and preparation here.

From their abstract: The new specimen provides evidence of a late stage of a gradual evolution from the basal pterosaur construction (the so-called ‚rhamphorhynchoid‘ grade) to a pterodactyloid one. — The Painten pro-pterodactyloid demonstrates the evolutionary pathway towards a pterodactyloid flight configuration, which is characterized by the reduction of the fifth pedal ray (digit), shortening of the tail and the elongation of metacarpal IV with respect to the humerus to more than 70% of the length of the latter.”

Figure 2. Click to enlarge. Painten pterosaur compared to phylogenetic sister taxa. Ornithocephalus and SMNS 81775 are the basal taxa here. Note that while everything else grows on derived taxa, the metacarpus stays the same size. The large size of the Painten pterosaur, along with the greater length of pedal digit 3 and the brevity of the metacarpus sets it apart in its own clade, of which this the first known representative. Larger than its relatives, this is an unlikely juvenile (contra Hone, see below).

Figure 2. Click to enlarge. Painten pterosaur compared to phylogenetic sister taxa. Ornithocephalus and SMNS 81775 are the basal taxa here. Note that while everything else grows on derived taxa, the metacarpus stays the same size. The large size of the Painten pterosaur, along with the greater length of pedal digit 3 and the brevity of the metacarpus sets it apart in its own clade, of which this the first known representative. Larger than its relatives, this is an unlikely juvenile (contra Hone, see below).

Tischlinger and Frey considered the Painten pterosaur “the last step on the long road from a basal pterosaur to the pterodactyloid.” (translated from the original German). They described it thoroughly.

Unfortunately, no phylogenetic analysis was provided.
So I provide one. Placing the Painten pterosaur into the large pterosaur tree nests it as a very basal Pterodactylus, between the very tiny SMNS 81775 specimen and Ningchengopterus, both basal to all valid Pterodactylus genera and all very much within this particular pterodactyloid-grade clade that began several nodes earlier. So the Painten pterosaur is a transitional specimen of sorts (aren’t they all? except for the terminal taxa) but only transitioning between the tiny Scaphognathus descendants and the genus Pterodactylus. Even so, several autapomorphies are present like the presence of a pedal digit 3 longer than pedal digit 2 and a very short prepubis.

The problem is
There are so many pterosaurs that converge on the morphology of Pterodactylus that aren’t really related to Pterodactylus that this genus has become a wastebasket taxon and is need of a big revision. All problems are solved with phylogenetic analysis, but no one, apparently, is interested in doing this.

The other problem is
Because they have not included multiple specimens from single genera and tiny pterosaurs most pterosaur paleontologists are still stuck in the old paradigm that all pterodactyloid-grade pterosaurs had a single common origin creating a monophyletic clade. Phylogenetic analysis shows this is not true. There were four convergent origins for the pterodactyloid grade. This is why the putative Painten transitional taxon looks so different from the putative Darwinopterus transitional taxon. They are not related to one another, but represent different clades. On the same subject from another point-of-view, Tischlinger and Frey hoped to nest their new pterosaur based on the old “rules” about which traits defined a basal pterosaur and which traits defined a pterodactyloid. You can’t do that. That’s putting the cart before the horse. You have to use a phylogenetic analysis and let the data and the analysis tell you how the traits are ordered. The order of longer and shorter traits may be more complex than the old “rules” indicate. They don’t always proceed in a step forward – step forward progress. You have to take what Nature gives you, and not try to pigeonhole new finds into old clades.

The third problem is
The belief in the mosaic pterosaur, one under modular evolution in which some body parts are advanced while others are not. Again, this is an illusion based on two few taxa in the analysis.

Let’s look at the Painten pterosaur in more detail.

Figure 4. The feet and tail of the Painten pterosaur with colors applied to bones. One loose proximal tail bone (red) is displaced at left. Left manual 4.4 is broken and re-healed in a jagged fashion. The wing tips are large, pulley-like joints. The wing unguals (dark blue) are displaced.

Figure 4. The feet and tail of the Painten pterosaur with colors applied to bones. One loose proximal tail bone (red) is displaced at left. Left manual 4.4 is broken and re-healed in a jagged fashion. The wing tips are large, pulley-like joints. The wing unguals (dark blue) are displaced.

Pedal digit 5 is rarely so wonderfully preserved (Fig. 3). Note the distal tip of p5.2. It has a joint surface, but the next phalanx, the ungual, is not readily observable.

However, if we take a closer look the ungual is there on both feet (Fig. 4), on edge on the left foot and flattened on top of mt5 on the right foot. Along the same lines the wingtips (m4.4) appear to also have joint surfaces, but no unguals. The left ungual has been displaced and now appears at mid phalanx of m4.4. The right ungual is nowhere to be seen, perhaps as a result of the breakage of the phalanx, or simple taphonomy or burial.

Tischlinger and Frey note that pedal digit 5 could be used for “tensioning the tail wing membrane (uropatagium), but to a very limited extent.” Unfortunately only one specimen has been promoted to link pedal digit 5 to the uropatagium, the holotype of Sordes, and that is a misidentification. No pterosaurs link pedal digit 5 to the uropatagium, but Sharovipteryx does.

Figure 3. The wrist of the Painten pterosaur. Here the vestige of manual digit 5 (blue) is clearly visible on the palmar side of the left wrist.

Figure 5. The wrist of the Painten pterosaur. Here the vestige of manual digit 5 (blue) is clearly visible on the palmar side of the left wrist.

Manual digit 5 is usually disturbed during taphonomy.
Here it is (in dark blue) undisturbed, but curled, on an axially rotated metacarpus. The undisturbed pteroid is articulated to the radiale. The extensor tendon process is not coosified to m4.1. The fingers are all rotated into the plane of the substrate. In vivo they would have pointed palmar side down, as in other tetrapods.

Transitional?
Tischlinger and Frey agree with the Darwinopterus transitional hypothesis, which is falsified when more taxa are included in analysis. They consider the Painten pterosaur, with it’s short tail and short pedal digit 5, to be the next step from Darwinopterus toward the pterodactyloid grade. These are traits that Darwinopterus had not acquired.

If you think the consensus is correct on this issue, remind yourself that Tischlinger and Frey merely accepted the findings of others, despite the red flags and oddities. I test issues using established methods, like phylogenetic analysis. I don’t have to make up excuses for data or imagine the evolution of body plans because all that comes from the order of the nodes in the recovered trees.

That’s good Science, right? Repeat the experiment if you don’t agree, then let me know if you come up with something different.

Tischlinger and Frey discuss various ways or paths by which the rhamph body plan evolved to become the pterodac body plan, but this is all simple dreaming without a large phylogenetic analysis of the Pterosauria. This the -only- method by which you can actually trace the appearance and subsequent modification of the various traits in much greater resolution, precision and verifiable validity.

Finally, if Rhamphodactylus, Darwinopterus and the Painten pterosaur were indeed phylogenetic sisters representing closely related steps in the evolution of the pterodactyloid grade, shouldn’t they look more alike (Fig. 5)? Phylogenetic analysis indicates they were not related, only convergent.

Figure 5. The Painten pterosaur, Darwinopterus and "Rhamphodactylus" to scale showing their variety and their transitional status.

Figure 5. Three putative transitional pterosaurs. The Painten pterosaur, Darwinopterus and “Rhamphodactylus” to scale showing their variety and transitional status. These three are not related to one another, but acquired similar traits by convergence.

The Painten pterosaur is still very special
The Painten pterosaur is a transitional taxon leading to higher Pterodactylus specimens. It also represents a new clade in the pterosaur bush that had its own traits. Unlike other sister taxa pedal digit 5 is longer than the others. The middle dorsal vertebrae are compressed to be much shorter than the anterior and posterior verts, creating a shorter torso. The prepubis is remarkably tiny. The teeth are more needle-like than those of others.  Pedal digit 5 is more robust than in sister taxa.

Postscript
Dave Hone in his Archosaur Musings Blogpost described the Painten pterosaur as a “small, juvenile animal.” He did not say why, or to which adult it would be most closely associated. Hone may have followed the old paradigm that states a large orbit and unfused extensor tendon process are juvenile traits. He may not be aware that phylogenetic analysis (the large pterosaur tree) demonstrates that both are phylogenetic, rather than ontogenetic in nature.

Hone reported, “The fifth toe also seems to be something of an intermediate – it is not a small nub like the pterodactyloids, but nor is the second phalanx that long and it’s not curved either as in other basal forms.” Evidently he was not aware of the many pterodactyloids with longer lateral toes, often tucked beneath the other four. The relative shortness of metacarpal 4 was noted by both Tischlinger and Frey and Hone which they considered intermediate trait between shorter rhamphs and longer pterodacs. Unfortunately that assumes linear progression in evolution, which is not born out when phylogenetic analysis shows that more basal taxa had relatively longer metacarpals. We have to avoid wishful thinking and rigorously test all such “eyeball” assumptions.

References
Tischlinger H and Frey E 2013.  Ein neuer Pterosaurier mit Mosaikmerkmalen basaler und pterodactyloider Pterosauria aus dem Ober-Kimmeridgium von Painten (Oberpfalz, Deutschland) — A new pterosaur with mosaic characters of basal and pterodactyloid pterosauria from the Upper Kimmeridgian of Painten (Upper Palatinate, Germany) Archaeopteryx 31:1-13.

Bennett 2014: Lumping Scaphognathus

Among paleontologists we have lumpers and splitters. Dr. S. Christopher Bennett is definitely a lumper. That’s not necessarily a bad thing, but sometimes, ironically, it blinds one to the subtle but important differences that are key to understanding relationships. In his latest paper he takes another look at the SMNS 59395 specimen of Scaphognathus.

From the Bennett 2014 abstract: “A new complete and fully articulated juvenile specimen of the rhamphorhynchoid pterosaur Scaphognathus crassirostris from the Upper Jurassic Solnhofen Limestone of southern Germany is only the third known specimen of the species. The specimen is described and compared to the other two specimens. Based on the comparisons, the skull of Scaphognathus is reinterpreted as having two premaxillary, six maxillary, and five dentary teeth per jaw side, and a broad boat-shaped snout. Scaphognathus is compared to Jianchangnathus robustus, and revised diagnoses of the genus and family are presented. In addition, the position of the cervico-dorsal transition in the vertebral column of pterosaurs is reviewed, and an apparent constraint to nine cervical vertebrae is noted.”

The SMNS 59395 specimen of Scaphognathus. Even numbered neck vertebrae are pink. Note the ninth has dorsal ribs that extend into the chest cavity despite the fact that they do not contact the sternal complex. The ninth vert is also much smaller than #8.

Figure 1. Both images from Bennett 2014. The SMNS 59395 specimen of Scaphognathus. Even numbered neck vertebrae are pink. Note the ninth has dorsal ribs that extend into the chest cavity despite the fact that they do not contact the sternal complex. The ninth vert is also much smaller than #8. That’s why I say pterosaurs had eight cervical vertebrae, not nine. The ninth is inside the torso.

It all depends on how you count that 9th vert.
Bennett considers it a cervical because the ribs do not contact the sternal complex. I consider it a dorsal vertebrae because the ribs are long, completely embedded in the torso and the vertebra is more similar in size and shape to #10 than #8.

Only two pmx teeth?
Bennett 2014 also reports that this specimen had but two premaxillary teeth (Fig 2). Four is the typical number and four teeth are visible here, but Bennett calls two of the teeth “replacement” teeth, even though both are close to one longer tooth. Two teeth would be an autapomorphy for most pterosaurs with teeth. No other pterosaurs have just two premaxillary teeth. IMHO, four teeth mean four teeth, especially if the pattern matches other pteros.

Figure 3. Scaphognathus SMNS 59395 with anterior skull bones colorized. There are four teeth there. Are two replacement teeth? That would be an autapomorphy.

Figure 2. Scaphognathus SMNS 59395 with anterior skull bones colorized. There are four teeth there. Are two replacement teeth? That would be an autapomorphy. Here we see the anterior naris dividing. Descendants had both widely divided. The anterior one I call the secondary naris. 

Lumping another genus into Scaphognathus
Bennett 2014 revised the genus Scaphognathus to include the former Jianchangnathus robustus, which he renamed S. robustus. Phylogenetic analysis in the large pterosaur tree does not support this name change. Nor does analysis support the juvenile status of the smaller Scaphognathus specimens. If Jianchangnathus is within the genus Scaphognathus then all of the wukongopterids and Pterorhynchus must also be included, but Bennett doesn’t report that.

According to Bennett (2014) the clade Scaphognathidae HOOLEY 1913,  includes these genera.

  1. – Dorygnathus WAGNER 1860,
  2. – Scaphognathus WAGNER 1861
  3. – Sordes SHAROV 1971

Unfortunately, this is not a monophyletic clade as phylogenetic analysis shows. Any clade that includes Sordes must also include all pterosaurs other than basal eudimorphodontids (with multi cusp teeth) and dimorphodontids. Any clade that includes Dorygnathus also includes all azhdarchids and pre-azhdarchids, ctenochasmatids and pre-ctenochasmatids.

References
Bennett SC 2014. A new specimen of the pterosaur Scaphognathus crassirostris, with comments on constraint of cervical vertebrae number in pterosaurs. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 271(3): 327-348.

NOT a new Zhenyuanopterus: XHPM1088

Very, very close, but no cigar.

And not a juvenile either.
A new paper by Teng et al. (2014) reports on a small partial Zhenyuanopterus (XHPM1088, Fig. 1) that does quite fit the morphology of the holotype. No worries. They said it was a juvenile with some odd sorts of allometry going on.

I hate to say it, but we can blame Chris Bennett for this bit of wishful thinking as his 1995 and 1996 papers on Solnhofen pterosaurs opened the doors to letting almost any small specimen become the juvenile of any somewhat similar, but much larger specimen based on the false notion of allometry during ontogeny. Several specimens falsify that little fantasy, including all the embryos now known.

Phylogenetic analysis would have put a stop to such nonsense, but no analysis was undertaken, either in 1995, 1996 or 2014.

Figure 1. XHPM1088 in situ. Only the posterior half is preserved here.

Figure 1. XHPM1088 (mistakenly referred to Zhenyuanopterus) in situ. Only the posterior half is preserved here.

Here’s the problem
The new specimen has a relatively long and robust tail (15 caudals) and a more robust forelimb than hindlimb, plus a Yixian Formation (Early Cretaceous) locality. These facts identified this pterosaur as Zhenyuanopterus to its authors. With identical length ratios between the humerus and femur, Teng et al. thought growth was isometric in these bones, but not others. The scapula has an odd sort of shape otherwise found only in Zhenyuanopterus. However the coracoid was not the same shape or size ratio (Fig. 1). They thought the length of the coracoid would slow dramatically during growth compared to other bones, not realizing that taxa just outside of Zhenyuanopterus (i.e. Boreopoterus, Arthurdactylus, Fig. 2) had a similar long, straight coracoid. They also blamed the coracoid length problem on the holotype of Zhenyuanopterus, saying it was not well-preserved and giving it a longer redicted length based on XHPM1008. That’s not good Science, especially when the coracoids are well preserved and articulated in the holotype.

Unfortunately
Teng et al. thought one of the unique characters of Zhenyuanopterus was its small feet, but the reality is ALL ornithocheirids (more derived than the JZMP embryo) had tiny feet.

Figure 2. The partial pterosaur XHPM1088 to scale with Boreopterus and Zhenyuanopterus and also scaled up to a similar humerus length with Zhenyuanopterus.  Note the coracoids don't match. This is one of the few pterosaurs in which the tibia is shorter than the femur. Boreopterus is similar in this regard.

Figure 2. Click to enlarge. The partial pterosaur XHPM1088 to scale with Boreopterus and Zhenyuanopterus and also scaled up to a similar humerus length with Zhenyuanopterus. Note the coracoids don’t match. This is one of the few pterosaurs in which the tibia is shorter than the femur. Boreopterus is similar in this regard.

A beautiful illustration of Zhenyuanopterus is included in the paper (Fig. 3) sadly flawed by bat-like, deep chord wing membranes and an odd sort of hanging posture for a pterosaur, especially one with such small feet. Some traditions are very hard to kill.

Zhenyuanopterus-illustration

Figure 3. Zhenyuanopterus illustration by Zhao Chuang, a very talented artist. Sadly the wing membranes are wrong and the hanging posture is unlikely based on the tiny feet.

I encourage pterosaur workers
to start putting bones together in reconstructions, then adding new taxa to good phylogenetic analyses before assigning a juvenile status to a small pterosaur that doesn’t match a large one. Here’s a new genus that Teng et al. could have named, but didn’t.

Reference
Teng F-F, Lü J-C, Wei X-F, Hsiao Y-F and Pittman, M 2014. New Material of Zhenyuanopterus (Pterosauria) from the Early Cretaceous Yixian Formation of Western Liaoning. Acta Geologica Sinica (English) 88(1):1-5.

Archaeopteryx vs pterosaurs: speciation? or variation? Plus an interclavicle question.

I read this today on Wiki/Archaeopteryx: “Recently, it has been argued that all the specimens belong to the same species, however, significant differences exist among the specimens. In particular, the Munich, Eichstätt, Solnhofen, and Thermopolis specimens differ from the London, Berlin, and Haarlem specimens in being smaller or much larger, having different finger proportions, having more slender snouts lined with forward-pointing teeth, and possible presence of a sternum. These differences are as large as or larger than the differences seen today between adults of different bird species, however, it also is possible that these differences could be explained by different ages of the living birds.”

Figure 1. Archaeopteryx size graphic from Wikipedia.

Figure 1. Archaeopteryx size graphic from Wikipedia created by Matt Martyniuk. Very informative. Size matters!

If that is all that separates one Archaeopteryx from another, it really is time to take another look at pterosaurs.
There are so many Pterodactylus, Pteranodon, Rhamphorhynchus, Germanodactylus, Darwinopterus, etc. etc. etc. that given the same splitting/lumping parameters someone is going to have to come up with a slew of new names.

The problem is, who has the authority?
And if anyone does have the authority, who will recognize, follow and support that authority? That time may have already passed when there were fewer workers setting standards in paleontology. Back in the 1970s the work by Wellnhofer on Solnhofen pterodactyloids (1970) and non-pterodactlyloids (1975) is encyclopedic and widely cited. I’m not sure that someone else in the present day such authority because the professional vacuum that existed then is not present today.

The answer is:
A grad student for his/her PhD dissertation might have no authority, but that doesn’t matter. These least likely candidates are incredibly talented, but largely lacking in experience, which sometimes works to their advantage. And they are always looking for large projects to tackle. This task is enormous and will involve a lifetime of study and restudy. So, maybe the parameters are not narrow enough for a decent thesis.

I suppose lumpers will always fight splitters, and vice versa, like two parents trying to name one child.

>>>>>>>>>

On a side note:
Did early amniotes and their outgroups fuse the coracoid and interclavicle? I am having a difficult time locating coracoids, at the same time that the interclavicle appears to be “amply endowed,” if you know what I mean. Here’s an example in Brouffia: (Fig. 2) and Gephyrostegus (Fig. 3). Please send literature refs if you have them.

Figure 2. Brouffia. Is the coracoid fused to the over robust interclavicle, as it would seem? Lit refs please!

Figure 2. Brouffia. Is the coracoid fused to the over robust interclavicle, as it would seem? Lit refs please!

Figure 3. This Gephyrostegus interclavicle looks suspiciously tripartite. Are coracoids fused here?

Figure 3. This Gephyrostegus interclavicle looks suspiciously tripartite. Are coracoids fused here?

The new Changchengopterus(?) and its affinity to wukongopterids

Figure 1. Left: the holotype of Changchengopterus. Right: The larger referred specimen that does not nest with Changchengopterus. The similarities are uncanny, but phylogenetic analysis broadly separates these two despite the missing skulls.

Figure 1. Left: the holotype of Changchengopterus. Right: The larger referred specimen that does not nest with Changchengopterus. The similarities are uncanny, but phylogenetic analysis broadly separates these two despite the missing skulls. At first I thought we had a juvenile and adult, but analysis removed that possibility.

A new headless pterosaur referred to Changchengopterus and compared to wukongopterids was published a few years ago (Zhou and Schoch 2011, Fig. 1). Soft tissue was preserved in abundance (Fig.2).

Figure 1. PMOL specimen referred to Changchengopterus. Soft tissue colorized.

Figure 2. Click to enlarge. PMOL specimen referred to Changchengopterus. Soft tissue colorized. Note the multiple vanes along the length of the tail, as in Pterorhynchus.

When I ran the new Changchenopterus in the large pterosaur tree it nested not with the old Changchengopterus, but between Pterorhynchus and the wukongopterids (Fig. 2).

Figure 2. Subset of the large pterosaur tree nesting the two Changchengopterus specimens. The new one, in yellow, does not nest with Changchengopterus, but with basal wukongopterids.

Figure 3. Subset of the large pterosaur tree nesting the two Changchengopterus specimens. The new one, in yellow, does not nest with Changchengopterus, but with basal wukongopterids.

Figure 4. PMOL specimen pelvis. Top: original interpretation with fused puboischium. Middle lowrez photo from paper. Adding color overlays to identify bones reveals a longer prepubis and split puboischium.

Figure 4. PMOL specimen pelvis. Top two: original interpretations with fused puboischium. They don’t quite match. Middle: lowrez photo from paper. Adding color overlays to identify bones reveals a longer prepubis and split puboischium. Note broken left ilium.

Zhou and Schoch (2011) reported on the many similarities to the wukongopterids and the PMOL specimen comes from the same Late Jurassic locality and formation.

Slight change to the pelvis
One small change from the original interpretation is presented below with regard to the length of the prepubis and the splitting of the ventral pelvis (Fig. 4). Sister taxa do not have a fused pubis/ischium and neither does the PMOL specimen. Nevertheless, it’s easy to see how, with all the other broken bones, the original interpretation was made.

DGS again
This is an example of DGS enhanced by using phylogenetic analysis (which is part of the process). When you find autapomorphies in your analysis, go back to the data to see if it can be interpreted along the lines of sister taxa. If so, it is probably so.

Because analysis uses so many traits to nest taxa the few mistakes one makes in interpretation should not greatly affect the recovered tree. Loss of resolution typically means a mistake was made. Fix the mistakes and the resolution will typically improve.

So, observe. Interpret. Insert data. Analyze (compare to putative sisters). Double check autapomorphies. Make repairs.

References
Zhou C-F and Schoch RR 2011. New material of the non-pterodactyloid pterosaur Changchengopterus pani LÜ, 2009 from the Late Jurassic Tiaojishan Formation of western Liaoning.  N. Jb. Geol. Paläont. Abh. 260/3, 265–275 published online March 2011.

A longer snout for “Rhamphodactylus”

Earlier we looked at a new specimen (BSPG 2011 I 133) that was promoted without being given a new genus or species. It was nicknamed, “Rhamphodactylus,” because it seemed to bridge the gap between Rhamphorhynchus and Pterodactylus (or long tails and short tails, if you wish).

I looked for the mandible
It was there, but I didn’t see it. Phylogenetic analysis revealed several apparent autapomorphies (like antorbital fenestra covers the majority of the rostrum). So, I took another look and found faint traces of the missing elements after enhancing the contrast with Photoshop (Fig. 1). See if you can see them. This is where you need to dig into the matrix to reveal the bones.

Figure 1. Revealing the anterior rostrum and mandible in "Rhamphodactylus". This completes the specimen (see figure 2).

Figure 1. Revealing the anterior rostrum and mandible in “Rhamphodactylus”. This completes the specimen (see figure 2).

So with these additions, the reconstruction of “Rhamphodactylus” is essentially complete and far fewer autapomorphies plague its nesting in the analysis.

Figure 2. "Rhamphodactylus" reconstruction. While it looks like a Pterodactylus, it nests between Dorygnathus and protoazhdarchids.

Figure 2. “Rhamphodactylus” reconstruction. While it looks like a Pterodactylus, it nests between Dorygnathus and protoazhdarchids.

This is indeed something of a transitional taxon, but transitional between Dorygnathus + the tiny TM10341 and Beipiaopterus, at the base of the protoazhdarchid line. The skull of “Rhampodactylus” is likely a good substitute for the missing skull of Beipiaopterus.

References
Rauhut OWM 2012. Ein “Rhamphodactylus” aus der Mörnsheim-Formation von Mühlheim. Freunde der Bayerischen Staatssammlung für Paläontologie und Historische Geologie e.V., Jahresbericht und Mitteilungen 01/2012; 40:69-74.  online here.

News story in German

 

 

 

The Humble Origins of the Ornithocheiridae

Earlier we looked at a tiny pterosaur attributed to Pterodactylus” pulchellus at the British Museum of Natural History (NHM  42735) and its ancestry to cycnorhamphids and ornithocheirids. We also looked at the tiny Nohra ornithocheirid from Lebanon. Today we’ll look at these taxa to scale (Fig. 1).

Figure 1. Click to enlarge. The origin of the Ornithocheiridae begins with tiny  "Pterodactylus" pulchellus and continues with the much larger Yixianopterus and the hypothetical adult to the JZMP embryo. Then a size reduction (or is it a juvenile?) to the Nohra Lebanon pterosaur followed by Haopterus, itself about seagull-sized. Thereafter ornithocheirids get larger.

Figure 1. Click to enlarge. The origin of the Ornithocheiridae begins with tiny “Pterodactylus” pulchellus and continues with the much larger Yixianopterus and the hypothetical adult to the JZMP embryo. Then a size reduction (or is it a juvenile?) to the Nohra Lebanon pterosaur followed by Haopterus, itself about seagull-sized. Thereafter ornithocheirids get larger.

From humble beginnings
P. pulchellus (Late Jurassic, Solnhofen) is about as tiny as pterosaurs get. Yet it had already developed traits that put it at the evolutionary crossroads that produced cycnorhamphids in the Solnhofen and yixianopterids (basal ornithocheirids) in the Yixian formation (Early Cretaceous) of China. Other than this specimen, ornithocheirids are curiously absent from the Solnhofen, but by the early Cretaceous they had spread worldwide.

Yet another size reduction – or is it a juvenile?
The Nohra specimen from Lebanon is oddly smaller than its phylogenetic sisters. The only thing holding us back from calling it a juvenile is the relative rarity of juveniles in the fossil record and the presence of small Haopterus ( Fig. 1) as a sister taxon. At this point the Nohra specimen testifies to the unexplored variety in morphology and size that pterosaurs present us.

You can see more ornithocheirids to scale here.

Cearadactylus and the importance of adding taxa to family trees

A recent paper by Vila Nova et al. (2014) on the ornithocheirid pterosaur Cearadactylus atrox (Fig. 1) corrects earlier errors and posits a phylogenetic position for it. 

Figure 1. Cearadactylus atrox.

Figure 1. Cearadactylus atrox correctly reconstructed, as Vila Nova et al. 2014 reconstruct it.

Originally the premaxilla was reconstructed as the dentary tip and vice-versa. The Vila Nova paper corrects this by flipping those rostral elements back the way they should be.

The problem with Vila Nova et al. is a reliance on traditional family trees
that include Pteranodon (Fig. 2) as sister taxa to ornithocheirids. This is based on the purported shared trait of a warped deltopectoral crest, and that’s about it. And the design of those warps share nothing in common. The rest of their bodies  share traits that are common to many or most pterosaurs. Think about it. Anhanguera (Fig. 2) a close relative of Cearadactylus) is a giant Scaphognathus. Pteranodon is a giant Germanodactylus.

Figure 2. Cearadactylus, Anhanguera and Pteranodon compared. The inset compares the humerus of Anhanguera and Pteranodon.

Figure 2. Cearadactylus, Anhanguera and Pteranodon compared. The inset compares the humerus of Anhanguera and Pteranodon. Think about it. Anhanguera is a giant Scaphognathus. Pteranodon is a giant Germanodactylus.

Who would match these two??
After all, Pteranodon has a long sharp toothless beak, nothing like what you see in Cearadactylus (Fig. 2). Here (Fig. 3) are the trees that Vila Nova et al. employed.

Figure 2. Cearadactylus family trees employed by Vila Nova et al. 2014. Inclusion of Pteranodon and Nyctosaurus is incorrect when more taxa are added (Fig. 4).

Figure 3. Cearadactylus family trees employed by Vila Nova et al. 2014. Inclusion of Pteranodon and Nyctosaurus is incorrect when more taxa are added (Fig. 3).

Missing from the Vila Nova tree are all the basal ornithocheirids, like Haopterus, Arthurdactylus and the rest shown here (Fig. 4). Also missing, if you’re going to include Pteranodon and and Nyctosaurus are all the basal Germanodactylus and tiny pterosaurs arising from Scaphognathus, including the last common ancestor of Pteranodon and Cearadactylus: the tiny pterosaur specimen TM13104.

Figure 3. The pterosaur subset of the large reptile tree showing the nesting sites of Cearadactylus (yellow) and Pteranodon and Nyctosaurus (black arrows) so far apart.

Figure 3. The pterosaur subset of the large reptile tree showing the nesting sites of Cearadactylus (yellow) and Pteranodon and Nyctosaurus (black arrows) so far apart.

Adding taxa, especially tiny taxa, is key to the understanding of pterosaur interrelationships. Traditional trees are good starts, but they must be expanded.

Otherwise you get strange bedfellows that nest together without sharing very many traits.

References
Dalla Vecchia FM 1993. Cearadactylus? ligabuei, nov. sp., a new Early Cretaceous (Aptian) pterosaur from Chapada do Araripe (Northeastern Brazil)”, Bolletini della Societa Paleontologica Italiano, 32: 401-409.
Leonardi G and Borgomanero G 1985. Cearadactylus atrox nov. gen., nov. sp.: novo Pterosauria (Pterodactyloidea) da Chapada do Araripe, Ceara, Brasil. Resumos dos communicaçoes VIII Congresso bras. de Paleontologia e Stratigrafia, 27: 75–80.
Unwin DM 2002. On the systematic relationships of Cearadactylus atrox, an enigmatic Early Cretaceous pterosaur from the Santana Formation of Brazil. Mitteilungen Museum für Naturkunde Berlin, Geowissenschaftlichen Reihe 5: 1239–263.
Vila Nova BC, Kellner AWA, Sayão JM 2010. Short Note on the Phylogenetic Position of Cearadactylus Atrox, and Comments Regarding Its Relationships to Other Pterosaurs. Acta Geoscientica Sinica 31 Supp.1: 73-75.
Vila Nova BC, Sayão JM , Neumann VHML and Kellner AWA 2014. Redescription of Cearadactylus atrox (Pterosauria, Pterodactyloidea) from the Early Cretaceous Romualdo Formation (Santana Group) of the Araripe Basin, Brazil, Journal of Vertebrate Paleontology, 34:1, 126-134.

wiki/Cearadactylus

New Pterosaur Tree – Andres and Myers 2013

Pterosaur worker, Brian Andres, has produced a larger pterosaur tree than prior efforts by combining those prior efforts (Fig. 1). This was part of his 2010 PhD dissertation. The Wiki version (easier to read) can be seen here. I understand this tree will appear in a forthcoming (2014) volume entitled, “The Pterosauria.” Hope it avoids all past pitfalls, but judging by this tree (Fig. 1) and the description of the volume (“important new finds such as Darwinopterus“) we are due for another few years in the “dark ages.”

Sorry about that, kids. l’m really trying to fix things here by pointing out obvious errors.

According to Wikipedia
Andres’ phylogenetic analysis combines data mainly from three different matrixes: Kellner’s original analysis (2003) and its updates (Kellner (2004), Wang et al. (2005) and Wang et al. (2009)), Unwin’s original analysis (2003) and its updates (Unwin (2002), Unwin (2004), Lu et al. (2008) and Lu et al. (2009)) and previous analyses by Andres et al. (2005), Andres and Ji (2008) and Andres et al. (2010). Additional characters are taken from DallaVecchia (2009), Bennett’ analyses (1993-1994) and various older, non-phylogenetic, papers.

Figure 1. Click to enlarge. Pterosaur family tree produced by Andres 2010 and in press. Color added to show clades according to the large pterosaur tree that included several specimens of certain genera and included tiny pterosaurs, lacking here.

Figure 1. Click to enlarge. Pterosaur family tree produced by Andres 2010 and in press. Color added to show clades according to the large pterosaur tree (that included several specimens of certain genera and included tiny pterosaurs, lacking here). The indigo bar by Eosipterus indicates one specimen is indeed a ctenochasmatid, but the other is a germanodactylid, as we covered earlier. So, specimens are needed here, not just genera.

It’s big but still incomplete
Andres’ taxon list excludes distinct variations within certain genera, like Dorygnathus and Scaphognathus, that proved important in the large pterosaur tree. Andres’ taxon list also excludes all tiny pterosaurs. Those likewise proved important in the large pterosaur tree.

Strange bedfellows
The Andres’ tree nested several taxa that also nest together in the large pterosaur tree. However, the Andres tree also produces several nesting partners that don’t look alike. They don’t share many traits. For instance, Andres tree nests the basal anurognathid Dendrorhynchoides with the germanodactylids (Fig. 2) at the base of the “pterodactyloidea.” Few pterosaurs are so different from one another. It seems improbable that one would evolve from the other. In the large pterosaur tree this transition actually was several convergent transitions — and all sister taxa document a gradual accumulation of derived traits — not the skull-jarring leap shown here (Fig. 2).

Figure 3. According to Andres these two pterosaurs are sisters. This, obviously, is erroneous.

Figure 2. According to Andres these two pterosaurs are sisters. This, obviously, is erroneous.

Andres tree also nests the dorygnathid, Parapsicephalus (= Dorygnathus) purdoni with Dimorphodon (Fig. 3). Again, these two share very few traits. Click on the links above to see and read about pterosaurs that are more similar to these two, and you’ll see what I mean.

Figure 4. According to Andres, these two pterosaurs are close sister taxa. According to the large pterosaur tree, they nest far apart.

Figure 3. According to Andres, these two pterosaurs, Dorygnathus and Dimorphoson, are close sister taxa. According to the large pterosaur tree, they nest far apart.

There are several other misfits in the Andres tree, as shown by the various color codes (Fig. 1) that represent clades in the large pterosaur tree. For instance, Andres tree doesn’t recognize that azhdarchids and chaoyangopterids evolved from protoazhdarchids, like Beipiaopterus and Huanhepterus.

Some highlights
Andres tree does not put darwinopterids at the base of the “pterodactyloidea” but between Sordes and Changchengopterus and close to Scaphognathus. This is very close to results of the large pterosaur tree (Fig. 4).

Figure 1. Click to enlarge. Unwin and Lü note a resemblance between Darwinopterus and Germanodactylus. And that is certainly so, but only by convergence. Phylogenetic analysis indicates a closer relationship between the descendants of Scaphognathus and Germanodactylus. Arrows indicate phylogenetic order. Here the long neck evolved first with a smaller skull. Then the skull became longer in the lineage of Darwinopterus.

Figure 4. The evolutionary lines that gave rise to Germanodactylus and Darwinopterus according to the large online pterosaur tree by yours truly. Small changes, gradual accumulations of derived traits are shown here. No strange bedfellows.

Andres nests the Triassic Raeticodactylus and Preondactylus at the base of the Pterosauria. While MPUM6009 is ancestral to both, these nestings are not bad (Fig. 5).

The origin of the Pterosauria from basal Fenestrasauria

Figure 5. The origin of the Pterosauria from basal Fenestrasauria. This image is not current, but will update when enlarged. Note: Euparkeria is not involved here.

Some lowlights
Andres tree nests most ornithocheirids following the pteranodontids (Fig. 6). This means large teeth reappeared on a broad rostrum evolving from a toothless sword-like rostrum. Sharp rostrum germanodactylids make better ancestors for pteranodontids and scaphognathids make better ancestors for ornithocheirids via Yixianopterus (Fig. 6). The warp in the humerus deltopectoral crest is distinct in ornithocheirids and pteranodontids and evolved convergently.

Figure 6. Left - evolutionary lineage according to Andres in which toothless pteranodontids give rise to toothy ornithocheirids. On the right, corrected lineages for each.

Figure 6. Click to enlarge. Left – evolutionary lineage according to Andres in which toothless pteranodontids give rise to toothy ornithocheirids. Right –  corrected lineages for each clade.

At the base of the pterosaurs Andres uses the derived erythrosuchid, Euparkeria, which shares no traits with pterosaurs. He would have been better off using a tritosaur or fenestrasaur, but chose to ignore the literature on pterosaur origins (Peters 2000, 2002, 2007).

Andres nests anurognathids with darwinopterids in a false clade, “monofenestrata” in which the naris and antorbital fenestra are supposed to be confluent, evidently based on the bogus reconstruction of Anurognathus by Bennett 2007, which we dismantled earlier here and here.

Some thoughts
Since so many pterosaurs are preserved in a crushed fashion it is imperative that they be reconstructed in order to ascertain the identification of bony elements. Few other workers attempt this and Andres is not known for doing so.

It is also imperative that pterosaur workers know what a pterosaur is. Phylogenetic analysis (Peters 2000, 2007 and online studies) and character analysis (Peters 2013) demonstrate pterosaurs are not related to archosaurs, like Euparkeria, but to tritosaur fenestrasaurs.

Finally it is imperative that pterosaur workers employ the tiny pterosaurs in their analyses. The family tree will never make sense and will never produce gradual accumulations of derived characters unless the tiny pterosaurs are included.

References
Andres BB 2010. Systematics of the Pterosauria PhD dissertation. Yale University, 2010, 366 pages; 3440534
Andres B and Myers TS 2013. Lone Star Pterosaurs. Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 103: Issue 3-4, p 383-398.
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Peters D 2000. 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 2013. A gradual accumulation of pterosaurian traits within a series of Lepidosauriformes. Rio Ptero Symposium 2013.

wiki/Phylogeny_of_pterosaurs 

Pteranodon – Chimaeras and Fakes – part 2

Go to the KU natural history museum at the University of Kansas at Lawrence and downstairs you fill find a spectacular mounted Pteranodon (KU VP 2212)  in all of its glory. You might be disappointed only by the lack of a traditional long or tall crest on the cranium.

Figure 1. A Pteranodon chimaera created from the bones of several species. KU VP 2212.

Figure 1. A Pteranodon chimaera created from the bones of several species. KU VP 2212.

Upon closer inspection — It’s not just one specimen, but many
Created, like a Frankenstein monster from the dead bodies of several individuals and probably different species, the KUVP 2212 mounted specimen (Fig. 1) is nevertheless spectacular to behold. Be wary though of using all of its bits and pieces in phylogenetic analysis for therein lies madness. They say this specimen is a composite, or chimaera, of twenty specimens. Even the two feet came from different individuals (Fig. 2), at least one of which was flat-footed, distinct from other Pteranodon pedes.

Figure 2. A reconstruction of the chimaera that is KU VP 2212. Created from several individuals and several species, this mounted specimen cannot be used in toto in phylogenetic analysis.

Figure 2. A reconstruction of the chimaera that is KU VP 2212. Created from several individuals and several species, this mounted specimen cannot be used in toto in phylogenetic analysis.

The skull
belongs to a mid-sized species near the node at which the tall-crested P. sternbergia clade split from the long-crested P. ingens clade. Compared to other more complete specimens, like the Triebold specimen (Fig. 3), the skull of the KU specimen is inappropriately small. Earlier we looked at an artist who reconstructed his Pteranodon with a too small skull. Wonder if this was the inspiration?

The Triebold Pteranodon, one of the most complete ever found. The metacarpals are quite a bit longer here. So is the beak.

Figure 2. The Triebold Pteranodon, one of the most complete ever found. Compare the proportions with KU VP 2212, which is a next of kin phylogenetically (at least with regards to the skull.) This specimen is basal to the P. sternbergia clade of tall crested Pteranodon.

The flat foot of the KU specimen
belongs to a member of the P. sternbergia clade because another member, the Alberta Pteranodon, has similar proportions.

My what big arms you have!
The monster antebrachiumu of the KU specimen belong to the P. ingens clade, which also have digitgrade pedes.

The very short femur
means it probably belonged to a smaller, generally more primitive species of Pteranodon, like P. occidentals. The lack of more than a few reasonably complete Pteranodon specimens hinders more precise identification. Not sure yet about the field notes for the KU specimen. There is no paper focused on just it.

Complete specimens are hard to come by.
Museums needed large spectacular mounts to drive in their audience. The old way of thinking was: “Why not create a chimaera? After all, who’s going to know?”

It’s not exactly deception,
but creating a chimaera display mount is a practice from the past that hopefully will no longer be considered viable as interest in these fossils and their phylogeny becomes more serious.

I’ll tackle another Pteranodon chimaera as #7 in this series.

A paper written on fossil fakes is online here.