Private Pterodactylus with extensive soft tissue

www.solnhofen-fossilienatlas.de is a private project building a internet-data-base of the Fossils from Solnhofen with pictures and descriptions. Today we’ll look at their Pterodactylus #1359.  The specimen is housed in a private collection, not Fossnet.

Figure 1. Fossnet Pterodactylus 1359.

Figure 1. Fossnet Pterodactylus 1359. Such soft tissue preservation is very rare. The question is, do these wing membrane attach to the ankles? Or do they attach to the elbows? Matrix tone changes are due to placing higher resolution images on top of the basic overall image.

The first thing you’ll notice is all that soft tissue, especially the wing membranes and uropatagia. There’s even little strip of hard tissue at the trailing edge behind m4.2. Despite the preservation of the most fragile tissue, the humerus is practically gone, leaving only an impression.

Figure 2. Fossnet Pterodactylus 1359 with soft tissues colorized.

Figure 2. Fossnet Pterodactylus 1359 with soft tissues colorized. Here the uropatagia (orange) are distinct from the two wing membranes (green, brown). Here the wing membranes attach to the elbow contra all those workers who assert without evidence that the wing membrane attached to the ankles. The inner membrane creates a fuselage fillet from elbow to knee/mid-thigh.

DGS (colorized tracing) helps segregate one membrane from another, clarifying the apparent overlaps. This specimen leaves little doubt that the wing membrane was stretched between the elbow and wingtip. There is no membrane present leading toward the tibia, as in ALL other known pterosaurs and CONTRA Elgin, Hone and Frey (2008) and all similar traditions repeated by the current consensus represented academically by Witton, Unwin, Bennett, etc. Still waiting here for one wing membrane undeniably attached to one tibia. All prior candidates were dismissed here.

Figure 3. Fossnet Pterodactylus compared to two other related specimens. Note the differences in various bone shapes.

Figure 3. Click to enlarge. Fossnet Pterodactylus compared to two other related specimens. Though very much alike, note the differences in various bone shapes. These differences split specimens into species. Note the size of the feet is similar despite the varying heights of these pterosaurs.

While some workers consider all Pterodactylus conspecific, those same workers have not reconstructed them, nor have they performed phylogenetic analyses to lump and split therm. Sometimes that’s all you have to do to understand the situation. But most pterosaur scientists do not take this very simple and basic step (Fig. 4).

Figure 4. Closeup of the private Pterodactylus with extensive wing membrane preservation.

Figure 4. Closeup of the private Pterodactylus with extensive wing membrane preservation. The humerus, based on an impression of a humerus, is quite short, which makes this specimen distinct, if valid. Also atypical is the alignment of pedal digits 2-4.

So, yes, it’s a Pterodactylus.
But the species is not quite the same as any species previously described.

References
Elgin RA, Hone DWE, and Frey E. 2011.The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111 doi:10.4202/app.2009.0145 online pdf

Arguments against the Rhynchosaur/Rhynchocephalian Rhylationship

Tradition used to say
that rhynchosaurs were related to rhynchocephalians. Then about forty years ago Carroll and Benton changed everything — without phylogenetic analysis or providing a closer outgroup relative. They said it was so  — and it was so!

Carroll (1988) revisiting Carroll (1977) reported, “It was long thought that rhynchosaurs were closely related to modern sphendontids not the basis of general similarities of the skull and dentition. The common presence of primitive features such as the lower temporal bar only points to their common origin among early diapsids. Although the dentition appears to be vaguely similar, it is fundamentally different. Sphenodontids have only a single row of acrodont teeth in the maxilla, but rhynchosaurs have multiple rows of teeth set in sockets. Sphenodontids have a second row of teeth in the palatine, but this bone is edentulous in the rhynchosaurs. What appear to be long premaxillary teeth in the rhynchosaurs are actually processes from the premaxillary bones. Sphenodontids have true premaxillary teeth.”

Problem is, the rhynchosaur outer tooth row is indeed the maxilla (Fig. 1), the inner row is [surprise!] the palatine, as in rhynchocephalians, especially Priosphenodon. That the palatine fuses to the maxilla does not take away the identity of either. Thus, the palatine is not edentulous in rhynchosaurs.

The premaxillary is also toothless in Priosphenodon, currently considered a rhynchocephalian. Mesosuchus is considered a proto-rhynchosaur, not a rhynchocephalian, yet it has socketed teeth on the premaxilla. So there’s a transition zone developing between rhynchosaurs and rhynchocephalians, which are distinct, but decidedly related — because — no other taxa are closer to them than these two are to each other in the large reptile tree.

Benton (1983) reported, “Rhynchosaurs have no special relationship with the sphenodontids. The supposed shared characters are either primitive (e.g. complete lower temporal bar, quadratojugal, akinetic skull, inner ear structure, 25 presacral vertebrae, vertebral shape, certain character of limbs and girdles) or incorrect (e.g. rhynchosaurs do not have acrodont teeth, the ‘beak-like’ premaxilla of both groups is quite different in appearance, the ‘tooth plate’ is wholly on the maxilla in rhynchosaurs but on maxilla and palatine in sphenodontids).”

Benton did not realize the lower temporal bar was derived in sphenodontians. Early lepidosaurs don’t have it.

Acrodont teeth are also derived from socketed teeth, so all sphenodontids had to do was stop fusing their teeth to their skull in order to go back to the socketed teeth found in rhynchosaurs. Rhynchosaurs stop fusing their ankles and stop fusing their teeth to their jaws. That’s just what they do.

Figure 1. Rhynchocephalian and Rhynchosaur palates. That's Priosphenodon in the middle leading to Mesosuchus and Howesia, to Trilophosaurus and Azendohsaurus and rhynchosaurs. That's where the palatine grows as large as and alongside the maxilla. In derived taxa these two bones fuse creating the illusion that the maxilla has the entire tooth pad. Look at those palatine stems on Priospbenodon, which really come out on rhynchosaurs.

Figure 1. Rhynchocephalian and Rhynchosaur palates. That’s Priosphenodon in the middle leading to Mesosuchus and Howesia, to Trilophosaurus and rhynchosaurs. That’s where the palatine grows as large as and alongside the maxilla. In derived taxa these two bones fuse creating the illusion that the maxilla has the entire tooth pad. Look at those palatine stems on Priospbenodon, which really come out on rhynchosaurs.

The beak-like premaxillae look a little different in rhynchosaurs and rhynchocephalians, but no other reptiles have anything closer in appearance. If you can find one, please let me know. It’s not among the tanystropheids or protorosaurs. They don’t look anything like rhynchosaurs.

Benton did not realize that the palatine fuses to the maxilla in rhynchosaurs and both include socketed teeth. And we can see the evolution of one to another, especially in transitional taxa like ClevosaurusMesosuchus and Priosphenodon.

In those early days, before computer-assisted phylogenetic analysis, Benton and Carroll eye-balled taxa and made decisions. Nowadays, those decisions have become traditions so rhynchosaurs are not longer in the same inclusion sets as rhynchocephalians — until reptileevolution.com came along.

Darren Naish (DN) aid it best in his blog on rhynchosaurs, “When the jaws are closed, these tusk-like premaxillae fit in between the dorsally curved anterior tips of the dentaries.” Funny thing, the rhynchocephalian, Priosphenodon, has those.

DN: “Mesosuchus and Howesia would have superficially resembled big lizards or tuataras in proportions.” Well, these traits also go into phylogenetic analyses — if allowed to do so.

DN: Numerous studies published since the 1980s have shown that rhynchosaurs and the members of the tuatara clade were not really closely related (R. Burckhardt had argued as early as 1900 that the supposedly similar premaxillary beaks of tuatara and rhynchosaurs were actually completely different). Tuatara and kin – now termed the Sphenodontia* – are lepidosaurs (and hence close to squamates), while rhynchosaurs are archosauromorphs: part of the same group as archosaurs and their relatives. Archosauromorpha has been defined as a branch-based taxon that includes all taxa closer to Protorosaurus than to Lepidosauromorpha** (Dilkes 1998, p. 528) and autapomorphies of the clade include slender cervical ribs, a notch on the leading margin of the interclavicle, and an ilium with a small anterior and large posterior process (Dilkes 1998).

Okay, again, no phylogenetic analysis here. Just eyeballing. it. Slender cervical ribs are also found in Tritosaurs. A notch on the leading margin of the interclavicle is also found on xxx. An ilium with a small anterior and large posterior process is also found in sphenodontids.

Benton 1985 performed an early cladistic analysis, though apparently not with a computer as no data matrix was presented. The following traits were considered to ally rhynchosaurs with other archosaurmorphs. I abbreviate where possible.

Character list C: Archosaurornorpha

(1) Premaxilla extends up behind naris. NOT in rhynchosaurs.

(2) Nares elongate and close to midline. Also in Clevosaurus.

(3) Quadratojugal located mainly behind the lower temporal
fenestra. Also in Sphenodon. If a lower temporal bar is present, it is formed largely by the jugal, and the squamosal has a short ventral process.

(4) Loss [fusion] of the tabulars. Also in Sphenodon.

(5) Stapes without a foramen. ??

(6) Vertebrae not notochordal. Sphenodon and geckos retain notochordal vertebrae. This trait is invisible in most reconstructions.

(7) Transverse processes on dorsal vertebrae project as distinctive narrow elongate processes. NOT in Mesosuchus, present in Hyperodapedon. 
(8) Cleithrum absent. Also ABSENT in Sphenodon.

(9) No entepicondylar foramen in the humerus. NOT in lizards.

(10) Loss of foramen in carpus between ulnare and intermedium. Also ABSENT in lizards.

(11) Presence of a lateral tuber on the calcaneum. NOT in Hyperodapedon.

(12) Complex concave-convex articulation between the astragalus and
calcaneum. Most lepidosaurs have a fused ankle, but some do not. 

(13) Fifth distal tarsal lost. ALSO absent in Hyperodapedon.

(14) Fifth metatarsal hooked without lepidosaur specializations. NOT in Hyperodapedon. A hooked 5th metatarsal is present in Sphenodon.

Character list M: Rhynchosauria
(1) Premaxilla bearing a small number of acrodont teeth, or none at all (Fig.8D, E). Also in Priosphenodon

(2) Single median naris. Good trait.

(3) Fused parietals. Not described for Priosphenodon.

(4) Presence of three proximal tarsals, with the centrale closely associated with the astragalus

Character list N: Rhynchosauroidea

(1) Premaxilla beak-like and lacks teeth.
(2) Parietal foramen absent.
( 3 ) Teeth have ankylothecodont implantation. Rhynchosauroid teeth are implanted in deep sockets and fused to the jaw by bone of attachment. They show a mixture of the characters of acrodont and thecodont teeth (See not far from sphenodontids)
(4) Batteries of functional teeth on the maxilla and dentary. As in Priosphenodon to a lesser extent. 

Figure 1. Noteosuchus is considered a basal rhynchosaur, but it nests with the rhynchocephalian, Sapheosaurus. hmmm.

Figure 2. Noteosuchus is considered a basal rhynchosaur, but it nests with the rhynchocephalian, Sapheosaurus. hmmm.

And the latest news
When you add Noteosuchus (Fig. 2), the earliest known rhynchosaur, to the mix, it nests with Sapheosaurus, a derived rhynchocephalian. This gives us our best clue as to what the skull of Noteosuchus looks like using phylogenetic bracketing. I’d like to get better data on Sapheosaurus if available, especially of the skull.

References
Benton M J 1983. TheTriassic reptile Hyperodapedon from Elgin: functional morphology and relationships. Phil. Trans. R. Soc. Lond. B 302, 605^717. Carroll, R. L. 1988 Vertebrate paleontology and evolution. New York: W. H. Freeman & Co.
Carroll RL 1977. The origin of lizards. In Andrews, Miles and Walker [eds.] Problems of Vertebrate Evolution. Linnean Society Symposium Series 4: 359–396.
Carroll RL 1988. Vertebrate Paleontology and Evolution. W. H. Freeman and Co. New York.

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.

Pulling Bavarisaurus out of the belly of Compsognathus

Figure 1. Click to enlarge. The little Jurassic lizard Bavariasaurus was found inside the belly of the little Jurassic dinosaur, Compsognathus. But it is not the same genus as the holotype.

Figure 1. The little Jurassic lizard Bavariasaurus was found inside the belly of the little Jurassic dinosaur, Compsognathus. Illustration by Franz Nopcsa 1903.

As everyone knows, one Jurassic lizard, Bavarisaurus macrodactylus (Figs. 1-4, = Homoesaurus macrodactylus Wagner 1852, Hoffstetter 1964; length: ~20cm, (Lower Tithonian), Solnhofen), was found inside the belly of a small Jurassic dinosaur, Compsognathus (BSPHM AS-1-563). All curled up like the good meal it was, Bavarisaurus has been added to various lepidosaur phylogenetic analyses, but, to my knowledge, it has not been reconstructed in the literature. However, Tracy Ford did a good job here.

Figure 2. Like Michelangelo removing the excess marble, I removed every trace of Compsognathus, leaving nothing but Bavarisaurus in step 1.

Figure 2. Like Michelangelo removing the excess marble, I removed every trace of Compsognathus, leaving nothing but Bavarisaurus in step 1.

Not sure how much good this will do, but I took all the bones I could see and segregated from the dinosaur bones (Fig. 2), then rearranged them as well as I could (Fig. 3). Seems like Bavarisaurus had quite a long tail when it is all stretched out! Looking at the maxilla and mandible you’ll notice the teeth don’t match. Small triangle-shaped teeth are on the dentary, but posteriorly-oriented narrow, sharp teeth appear on the maxilla. The presumes that I have the maxilla correctly oriented.

Figure 3. Click to enlarge. Moving the bones of Bavarisaurus into a reasonable reconstruction is step 2.

Figure 3. Click to enlarge. Moving the bones of Bavarisaurus into a reasonable reconstruction is step 2.

The next step was to tentatively nest the elements phylogenetically, then clean them up in a better presentation in dorsal and lateral views (Fig. 4). A final scoring of elements nests Bavarisaurus more securely.

Figure 2. Click to enlarge. Cleaned up reconstruction of the former Bavarisaurus (cololizard at present). Gray areas added based on sister taxa. This is a tritosaur.  Note the large naris bounded ventrally by the maxilla. The ventral pelvis is shallower. I don't understand the pterygoid morphology anteriorly. The upper and lower teeth don't match. That's a red flag, but it is the only data available.

Figure 2. Click to enlarge. Cleaned up reconstruction of the former Bavarisaurus (cololizard at present). Gray areas added based on sister taxa. This is a tritosaur.  Note the large naris bounded ventrally by the maxilla. The ventral pelvis is shallower. I don’t understand the pterygoid morphology anteriorly. The upper and lower teeth don’t match. That’s a red flag, but it is the only data available.

Bavarisaurus is another tritosaur. 
And that’s why it nests uncertainly at the base of the Squamata in prior analyses that did not include any or many other tritosaurs — because it doesn’t nest in the Squamata. In the large reptile tree Bavarisaurus nests between Meyasaurus and the Dahugou lizard + Lacertulus, not far removed from Dalinghosaurus, which it resembles by convergence.

So based on the presence of Lacertulus in the Late Permian, something very much like Bavarisaurus originated in the Permian and continued to the Late Jurassic where we find the first and last of this genus inside the ribcage of Compsognathus.

References
Evans SE, Raia P and Barbera C 2004. New lizards and rhynchocephalians from the Lower Cretaceous of southern. Italy. Acta Palaeontologica Polonica 49:393–408.
Hoffstetter R 1964. Les Sauria du Jurassique supérieur et specialement les Gekkota de Baviére et de Mandchourie. Senckenberger Biologische 45, 281–324.
Nopcsa F 1903. Neues ueber Compsognathus. Neues Jahrbuch fur Mineralogie, Geologie und Palaeontologie 16: 476-494.
Wagner A 1852. Neu-aufgefundene Saurier, Uberreste aus dem lithographischen Schiefern und dem obern Jurakalke: Abhandlungen der Bayerischen Akademieder Wissenschaften Mathematisch-naturwissenschafliche Kl, 3(6): 661-710.

Tsk. Tsk. New Cosmos rehashes 25-year-old evolution sequence from old Cosmos

Figure 1. Cosmos logo

Figure 1. Cosmos logo

In part 2 of the new 13-part Cosmos series with Neil DeGrasse Tyson, they presented a wonderful panorama of evolution — until they came to the end where they re-presented Carl Sagan’s original cartoon evolution of humans from single-cell organisms.

As one who has written a book on the subject, From the Beginning, the story of human evolution (Peters 1991), and constructed a website on the subject, ReptileEvolution.com, I know the sequence from 25 years ago should not include tunicates or any sessile organisms, spiny sharks and sphenacodonts. Too bad the producers did not update that.

We know better now.
After all, the WHOLE POINT of the new Cosmos is to UPDATE the old stuff!!!

The other minor problem showed Dimetrodon at the Permo-Triassic extinction event, which is not true.

References
Peters D 1991. From the Beginning, The Story of Human Evolution. Little Brown.

 

Gardiner 1982 – a radical hypothesis on reptile relationships

From the Gardiner 1982 abstract:
“The traditional palaeontological view that the mammals separated from the ‘reptiles’ before the origin of all other living amniotes is challenged. A radical alternative hypothesis, based on a character analysis of living tetrapods, is elaborated in which birds are considered the sister-group of mammals, crocodiles the sister-group of those two, chelonians the sister-group of those three, and squamates + Sphenodon the sister-group of those four. The living Amphibia are hypothesized to form a natural group and to be the sister-group of the Amniota. Further, I conclude that the Anapsida, Diapsida and Synapsida are paraphyletic or grade groups and no unique statements can be made about their structure.”

Dr. Brian Gardiner was the professor who exposed the Piltdown man scandal as the work of a student. He teaches vertebrate paleontology at King’s College, University of London and is an expert on fossil fishes and amphibians, and advisor on paleontology to the Natural History Museum in London. He helped write a dinosaur book. While his alternative relationships paper has been cited, it has rarely been supported, even by the Feduccia clade. The Gardiner hypothesis is not supported by the large reptile tree.

The Gardiner 1982 hypothesis was based only on living taxa, thus birds and mammals, both warm-blooded, were grouped together. Originally it was Richard Owen’s idea, as he lumped birds and mammals in the Haemothermia (= Haematothermia).

Gardiner also nested pterosaurs with birds, but not sure how that was pulled off.

Gardiner did make at least two observations that are true based on relationships recovered by the large reptile tree: 1. The traditional palaeontological view that the mammals separated from the ‘reptiles’ before the origin of all other living amniotes is challenged. 2. Anapsida, Diapsida and Synapsida are paraphyletic or grade groups. Earlier we talked about the closure of the diapsid openings in mesosaurs. Earlier we talked about the diphyletic Diapsida. Earlier we talked about the origin of diapsids from basal synapsids, all based on the evidence of the large reptile tree.

I haven’t seen the paper.

Witmer’s View of Gardiner
In Perspectives on Avian Origins Lawrence Witmer writes, “Most of Gardiner’s data came from soft anatomy, although he did consider a few fossil groups.”

Gauthier on Gardiner
Gauthier (1986) praised Gardiner for his cladistic methodology but faulted him for his grasp on the morphology and literature.

Feduccia on Gardiner
In Descent of Birds, Allan Feduccia wrote a short note on Gardiner’s work, reporting it illustrates many of the difficulties inherent in phylogenetic analysis.” As everyone knows, Dr. Feduccia is not a fan of phylogenetic analysis. He’s one of the last stalwarts holding out on the “birds are dinosaurs” work that has been so well supported with phylogenetic analysis.

But wait, there’s more:

From the Gardiner 1993 abstract:
“An exhaustive parsimony analysis of amniote phylogeny using 97 characters has substantiated the hypothesis that mammals and birds are sister groups. This deduction is further supported by parasitological and molecular evidence. The presumed importance of “synapsid” fossils in amniote phylogeny is questioned and it is concluded that they represent a transformation series which, when broken down into constituent monophyletic groups, does not support the separation of the Mammalia from the remainder of the amniotes. Fossil members of the Haematothermia include pterosaurs and “dinosaurs” (both stem-group birds) and Dinocephalia, Dicynodontia, Gorgonopsida and Therocephalia (all stem-group mammals). The Dromaeosauridae are the most crownward stem-group birds and the Morganucodontidae the most crownward stem-group mammals.”

Naish’s view of Gardiner and Løvtrup:
“According to this haematotherm model, birds and mammals are sister-taxa, united by their endothermy, fully divided heart, respiratory turbinates, nerve and vascular characters, and so on. The best known proponent of this concept has been Brian Gardiner; he published a few reasonably lengthy papers on the subject in high-impact journals, the best known of which is Gardiner (1982). Unfortunately, Gardiner has since become best known for this above all else, whereas his writings on vertebrate phylogeny in general, Piltdown, and on Darwin’s correspondence should be better known. 

“Danish embryologist Søren Løvtrup published on the hypothesis a few years earlier (Løvtrup 1977), and later published a paper further supporting the proposal (Løvtrup 1985)*. Both Løvtrup and Gardiner cited and discussed observations made by John Ray in 1693 and Owen in 1866, both of whom supported the idea of a bird-mammal group that did not include other tetrapods (yes, I said 1693 and 1866). Neither Løvtrup nor Gardiner used Owen’s term Haematothermia; instead, they went with the alternative spelling Haemothermia. * I have only recently become aware of the fact that Løvtrup is best known as a staunch critic of evolutionary theory; he has argued that evolution does not proceed as proposed by Darwin, instead occurring via substantial saltational events known as macro-mutations. As was later discussed by a whole string of authors (e.g., Gauthier et al. 1988a, b, Kemp 1988, Benton 1985, 1991), one can only conclude that birds and mammals are especially close relatives within Tetrapoda by ignoring and excluding a vast amount of contradictory data. Løvtrup and Gardiner both ignored fossils, relied predominantly on soft tissue characters, and included only a handful of characters (literally, three or four) that contradicted their favoured topology and supported the traditional one: neither author included or discussed the huge number of bony and soft tissue characters that unite crocodilians and birds, for example. Furthermore, nearly all of the haematotherm ‘synapomorphies’ could be shown to be more widely distributed than proposed, non-homologous, or just plain wrong (e.g., Benton 1985, pp. 103-106).

In summary, Brian Gardiner had his blinders on, refusing to consider all of the evidence. His referees also had their blinders on, for whatever reason, as they approved the manuscript. The good thing is his work was discussed, reviewed and refuted for good reason.

References
Gardiner, B. G. 1982. Tetrapod classification. Zoological Journal of the Linnean Society 74, 207-32.
Gardiner BG 1993.
Haemotothermia: Warm-blooded amniotes. Cladistics 9(4):369-395.
Gauthier, J. A., Kluge, A. G. & Rowe, T. 1988a. Amniote phylogeny and the importance of fossils. Cladistics 4, 105-209.
Naish D 2012. The Haematothermia Hypothesis – Tetrapod Zoology, Scientific American blog 2012/10/03.
Witmer LM 1991. Perspectives on Avian Origins p 427-466. in Shultze H-P and Trueb L eds. Origins of the Higher Groups of Tetrapods: Controversy and Consensus

Benton 1985 on pterosaurs

Benton 1985 was an early cladistic analysis done without a published matrix. Benton nested pterosaurs between Rhynchosaurs and Younginiforms + Lepidosaurs (that’s a stretch!). He did not report which pterosaur(s) he used in analysis.

Benton wrote: “Pterosaurs have typically been regarded as archosaurs that had their ancestry among the thecodontians (e.g. Romer, 1966; Wellnhofer, 1978). However, Wild (1978) has described two late Triassic genera on the basis of good material (Eudimorphodon, Peteinosaurus) , and he has made the proposal that the pterosaurs arose directly from ‘eosuchians’ and are not true archosaurs. Pterosaurs possess an antorbital fenestra, but Wild (1978: 247) considered that this may be a convergence. Further, Wild ( 1978: 246-253) reviewed numerous similarities between the early pterosaurs and various ‘eosuchians’ and differences from early thecodontians. The characters shared with Youngina, Prolacerta and others are all primitive to diapsids as a whole, except for the reduced quadratojugal, the ossified sternum, the ‘hooked’ 5th metatarsal, and the 3-pointed teeth seen in Eudimorphodon.

Until Peters 2000, Wild (1978) was the sole voice doubting the affinity of pterosaurs with archosaurs. Neither Wild nor Benton realized that the diapsid configuration arose twice in reptile phylogeny, as shown by the large reptile tree because their test did not include primitive reptiles.

Benton wrote: “Pterosaurs display all of the characters of the Neodiapsida as far as can be determined, except B2 (ventral processes on parietals) and B6 (emarginated quadrate). They show some archosauromorph synapomorphies (C4-10), but lack others: C1-3, 11-14. Pterosaurs share two characters with the Lepidosauromorpha: the single ossified sternum, and specialized sternal attachments for the ribs. The most parsimonious position for the pterosaurs at present is within the Archosauromorpha, as sister-group to all other archosauromorphs. Further work is needed on this question as well as on the suggestion that Pterosauria are the sister-group of Aves (Gardiner, 1982).”

Benton, to his credit, at least gave a nod to the lepidosauromorph traits. He noted pterosaurs shared 6 archosauromorph traits, but lacked 7 others.

According to Benton, archosauromorph traits shared with pterosaurs:

C4. Loss of tabulars. Benton notes they are also lost in lepidosaurs.

C5. Stapes without a foramen. I don’t think stapes have ever been identified in pterosaurs, but living lepidosaurs retain a heavier stapes with a foramen, according to Benton. Huehuecuetzpalli, at the base of the Tritosauria, does not show a foramen, but then it is only partly exposed.

C6. Vertebrae not notochordal. Benton notes that Sphenodon and geckos retain notochordal verts. Reynoso (1998) reports that Huehuecuetzpalli had amphicoelous verts, a trait shared with pterosaurs.

C7. Transverse processs on dorsal vertebrae project as distinct narrow elongate processes. Benton’s samples are all large reptiles. We don’t see these on pterosaur ancestors until Macrocnemus and all of its descendants among the tritosaurs.

C8. Cleithrum absent. Also absent on Huehuecuetzpalli. 

C9. No entepicondylar foramen in the humerus. Benton notes that lizards lose this too. Huehuecuetzpalli retains one. Cosesaurus does not have one.

C10. Loss of foramen in carpus between ulnare and intermedium. Benton notes this is lost in Squamata.

So that’s his list. Not much to say the least. I was hoping for more.

According to Benton, archosauromorph traits lacked in pterosaurs include:

C1. Premaxilla extends behind naris. Benton is wrong here, but Huehuecuetzpalli shares this trait.

C2. Nares elongate and close to midline. Benton is wrong here. Huehuecuetzpalli shares this trait.

C3. Quadratojugal (if present) located mainly behind the lower temporal fenestra. Benton is wrong here, but the same morphology is present in Cosesaurus.

C11. Presence of a lateral tuber on the calcaneum. Benton is correct! But no lateral tuber is found on Huehuecuetzpalli. 

C12. Complex concave-convex articulation between the astragalus and calcaneum. Correct, but the same is found on Huehuecuetzpalli.

C13. Fifth distal tarsal lost. Correct, but the same is found in Huehuecuetzpalli.

C14. Fifth metatarsal hooked without lepidosaur specializations. These include: ‘hooked’ in two planes. According to Benton mt5 bears specialized plantar tubercles, and it passes into the tarsus over the proximal end of the 4th metatarsal. Benton may be right. In any case pterosaurs and Huehuecuetzpalli have the same kind of mt5. In Pteranodon the metatarsus is reduced to being hooked in one plane.

Benton did not realize the rampant homoplasy in the reptilia.
The HI (Homoplasy Index) of the large reptile tree is over 0.90. So, exceptions and convergences abound within the reptilia. Very few traits are found in one and only one clade.

Benton mentioned Cosesaurus briefly, noting in the original description a long antorbital fossa (but he quoted the original French). He lumped it with Malerisaurus in “Prolacertiformes, incertae serdis”, not realizing that Cosesaurus was a tritosaur, along with Macrocnemus, Tanystropheus and Tanytrachelos, which he also considered prolacertiformes. Longisquama and Sharovipteryx, the two taxa closest to pterosaurs, were not considered.

The Gardiner (1982) paper mentioned by Benton has been largely ignored, and for good reason. Not sure why it was even included, but then, we’re talking about 1985 here. We’ll look at Gardiner 1982 tomorrow.

Bottom line:
With wrong, tenuous and convergent evidence Benton 1985 found pterosaurs nested outside the archosauromorpha. Later workers, who merely looked at the conclusions without questioning the evidence, accepted Benton’s conclusion. And look where that has brought us.

Later Hone and Benton (2007, 2009) applied the same lax interest and disposal of data to show that pterosaurs probably nested close to archosauromorphs after deleting the only competing candidate taxa. We looked at those problems in detail here.

I think it all comes down to conservatism. The same sort of conservatism that dismissed Wagner’s (and others) hypothesis on continental drift, Heyerdahl’s hypothesis on western migration to Polynesia and the static, earth-centered universe. Those days are not yet over.

References
Benton MJ 1985. Classification and phylogeny of the diapsid reptiles. Zoological Journal of the Linnean Society 84: 97-164.
Carroll RL 1977. The origin of lizards. In Andrews, Miles and Walker [eds.] Problems of Vertebrate Evolution. Linnean Society Symposium Series 4: 359 -396.
Carroll RL 1988. Vertebrate Paleontology and Evolution. WH Freeman and Company.
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.
Reynoso V-H 1998. Huehuecuetzpalli mixtecus gen. et sp. nov: a basal squamate (Reptilia) from the Early Cretaceous of Tepexi de Rodríguez, Central México. Philosophical Transactions of the Royal Society, London B 353:477-500.

Variation in Three Sordes Specimens

Uropatagium of Sordes according to Sharov 1971 and Unwin/Bakhurina 1994.

Figure A. Uropatagium of Sordes according to Sharov 1971 and Unwin/Bakhurina 1994.

Despite it’s fame and antiquity
(some 40 years after discovery) very little has been published on the first hairy pterosaur, Sordes pilosus (Sharov 1971). We’ve seen photos of three (Figs. 2, 4, 6) of the eight or nine reported specimens and Sharov’s original illustration of the holotype (Fig. A). Then there’s my own published tracing (Peters 2002) based on photos of the holotype (PIN 2585/3, Fig. 2). Other workers (Elgin et al. 2011, Unwin and Bakhurina 1994, Wellnhofer 1991) have simply lifted or retraced Sharov’s tracing of the bones and membranes, which are a little cartoony at best.

Three years ago,
for the Sordes webpage of reptileevolution.com I took the easy road out and created a chimaera, adding the head of 2585/25 (Figs. 3, 4) to the headless holotype 2585/3 (Figs. 1, 2). That’s not a good practice. In doing so one assumes that each of the contributing specimens is conspecific. That’s almost never true in pterosaurs as work with Rhamphorhynchus, Dorygnathus, Germanodactylus, Pteranodon, and Pterodactylus has already demonstrated.

Today we’ll reconstruct the three specimens (PIN 2585/3, PIN 2585/25 and a third unidentified specimen) that have been published as photos to compare and contrast them.

Figure 1. Sordes holotype 2785/3. The skull is perhaps present, but so degraded it must be considered unknown.

Figure 1. Sordes holotype PIN 2585/3. The skull is perhaps present, but so degraded it must be considered unknown. Here it is grayed out to show it is poorly known and the skull reconstruction makes it a chimaera.

The holotype PIN 2585/3 (Figure 1). is complete, but lacking a skull.

Figure 2. Sordes holotype, PIN 2585/3. Soft tissue in abundance, but the skull is largely gone.

Figure 2. Sordes holotype, PIN 2585/3. Soft tissue in abundance, but the skull is largely gone. Click to see where the displaced radius and ulna are.

The PIN 2585/3 holotype is the only Sordes specimen for which bones were identified, which is key to specimens that preserve so much camouflaging soft tissue. The displaced arm bones that dragged the wing membrane back to the hind limbs are shown here.

Figure 2. The PIN 2585/25 specimen of Sordes. This is the specimen that shows the skull in lateral view.

Figure 3. The PIN 2585/25 specimen of Sordes. This is the specimen that shows the skull in lateral view. Scale unknown.

The second specimen PIN 2585/25 also has a short torso, in this case subequal to the skull. No soft tissue here, but a great view of the skull in lateral view.

Figure 4. Sordes specimen PIN2585/25. No soft tissue here.

Figure 4. Sordes specimen PIN2585/25. No soft tissue here.

The third specimen (no number known so far) has lots of hair, but preserves the skull in ventral view. You can still see the buried side from the inside through the mandibles,  so you can still get close on skull reconstruction.

Figure 3. PIN specimen number unknown. Scale unknown. This is the specimen that shows the  mandible in ventral view with a fish alongside.

Figure 5. PIN specimen number unknown. Scale unknown. This is the specimen that shows the mandible in ventral view with a fish alongside.

The third specimen has a longer torso, longer than the skull. The shape of the humerus is different. The wing is relatively short. The teeth are smaller. So is the antorbital fenestra.

Figure 4. The third Sordes specimen PIN number unknown. That is a small fish in the middle. Lots of soft tissue here.

Figure 6. The third Sordes specimen PIN number unknown. That is a small fish in the middle. Lots of soft tissue here.

The third specimen (Fig. 6) includes a fish alongside and lots of hair. The radius and ulna are largely buried beneath the dorsal vertebrae with only the ends exposed.

Figure 8. The three Sordes specimens. Scale for right specimen only. Others scaled to matching skull lengths.

Figure 7. The three Sordes specimens. Scale for right specimen only. Others scaled to matching skull lengths. Missing tails here are missing in the fossils. The humerus is different in each specimen.

Putting all the Sordes specimens together (Fig. 7, sorry no scale here as scale bars are unknown for two of the specimens). This form of presentation makes it easier to see the differences and similarities.

Phylogenetic analysis nests all three Sordes specimens very close to the basalmost Dorygnathus, the Donau specimen (Fig. 9). Actually, for one of them, a little too close.

Figure 8. The Donau specimen of Dorygnathus is very close to Sordes.

Figure 8. The Donau specimen of Dorygnathus is very close to Sordes.

Like the tall third specimen of Sordes, Dorygnathus has a longer torso, but not a larger sternal complex, which remains a small triangle. So, the small sternal complex that characterizes Dorygnathus (easy to distinguish from broad-chested Rhamphorhynchus), originated with Sordes.

References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeonntologica Polonica 56(1): 99-111.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15: 277–301.
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].
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.

wiki/Sordes

Reconstructing Sharov’s Longisquama

My detractors often point to my discovery of the second half of Longisquama as pure fantasy.

So let’s pretend
that the back half of Longisquama was never present in the fossil. Pretend, like Jimmy Stewart in a Wonderful Life, that I was never born.

Now the onus
goes back to all the pterosaur workers who still refuse to examine the very pterosaurian traits of Longisquama, as traced by Sharov (1970, Fig. 1). Those traits are still there, whether I point them out or not.

Figure 1. Longisquama as traced by Sharov 1970. Workers have been searching for the predecessor of pterosaurs. Why didn't they look here?

Figure 1. Click to enlarge. Longisquama as traced by Sharov 1970 above, reconstructed below using DGS to move Sharov’s lines around. Workers have been searching for the predecessor of pterosaurs. Why don’t they look here? According to Sharov Longisquama has a sternal complex (he saw the displaced, fused clavicles, but not the sternum they rimmed), antorbital fenestra, long 4th finger (the actual 4th finger is much longer) and membranes trailing the forelimbs, not to mention a strap-like scapula and elongate coracoid. What more could you want? Alongside, not to scale, long-necked Sharovipteryx and short-necked MPUM6009, a basal pterosaur. Yellow displaced “plumes” are actually the tibia and femur, so the hind legs have been seen, just misidentified.  Those two bumps on the head are really a displaced parietal rimming upper temporal fenestrae. A little more resolution would clear this up.

So many fantasy creatures
have been built around the idea of Longisquama (just Google it), but no one has taken Sharov’s blueprint and put the bones back into their in vivo positions — until now (Fig. 1). When you repeat this experiment, you will also get something that can be input into phylogenetic analysis. And the rest (the blue areas) can be guesstimated based on phylogenetic bracketing. Almost all other artists put much smaller hind limbs on Longisquama, but that’s not what close relatives have (Fig. 1).

Like a basal pterosaur Longisquama has this suite of characters:

  1. an antorbital fenestra
  2. a large orbit
  3. multicusped teeth
  4. short neck (eight cervicals)
  5. 9th vert has short rib, 10th vert has rib that contacts sternal complex
  6. strap-like scapula
  7. narrow coracoid
  8. sternal complex (clavicles wrapped around sternum + interclavicle)
  9. parallel ulna and radius
  10. asymmetric manus with short digit 5
  11. structured membrane trails forelimb (proto-wing)
  12. small membrane precedes forelimb (proto-propatagium)

Everything else we’ll call guesswork
based on phylogenetic bracketing, which is, by definition, extremely conservative. Phylogenetic bracketing gives Longisquama long hind limbs, uropatagia, an attenuated tail and a short mt5 + elongated p5.1, just like it’s sisters.

Sharov’s traits alone
are enough to call this specimen out as the best candidate for pterosaur kinship — and yet — it’s been ignored and dismissed for forty years — even with that PR bump in 2000 and 2002. With such data widely available, does anyone else think it is very odd that professionals who write pterosaur books (Wellnhofer, Witton and Unwin) and other professors (Bennett, Padian, Hone, etc. etc.) claim we don’t know the ancestry of pterosaurs? Or am I the only one who finds this odd and unsettling?

I can understand why they would ignore me, a published amateur widely despised and ridiculed. But why ignore Sharov?

Evidently it’s a mind set.
And it’s hard to break, even with Sharov’s own images. He saw what I saw. I just added details.

New tracings of Longsiquama

Figure 2. Click to enlarge. New tracings of Longsiquama (B) soft tissues and (C) bones.

If you want to learn more details about the Longisquama fossil, find them here.

 

Figure 3. Click to enlarge. If you still don't like Longisquama, there's more where that taxon came from. Any one of these will nest closer to pterosaurs than any archosauromorph. Here's Kyrgyzsaurus to scale alongside other basal fenestrasaurs, Cosesaurus, Sharovipteryx and Longisquama. Kyrgyzsaurus likely was a biped with long legs. We know from the shape of its coracoids that it was a flapper.

Figure 3. Click to enlarge. If you still don’t like Longisquama, there’s more where that taxon came from. Any one of these will nest closer to pterosaurs than any archosauromorph. Here’s Kyrgyzsaurus to scale alongside other basal fenestrasaurs, Cosesaurus, Sharovipteryx and Longisquama. Kyrgyzsaurus likely was a biped with long legs. We know from the shape of its coracoids that it was a flapper.

References
Bennett SC 2008. Morphological evolution of the forelimb of pterosaurs: myology and function. Pp. 127–141 in E. Buffetaut & D.W.E. Hone (eds.), Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Zitteliana, B28.
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 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15: 277-301.
Senter P 2003. Taxon Sampling Artifacts and the Phylogenetic Position of Aves. PhD dissertation. Northern Illinois University, DeKalb, IL, 1-279.
Senter P 2004. Phylogeny of Drepanosauridae (Reptilia: Diapsida) Journal of Systematic Palaeontology 2(3): 257-268.
Sharov AG 1970. A peculiar reptile from the lower Triassic of Fergana. Paleontologiceskij Zurnal (1): 127–130.

A tall, thin Rhamphorhynchus: CM11427

A recent paper
by Hone et al. (2013) documented the pterosaurs of the Carnegie Museum in Pittsburgh, Pennsylvania. It’s good to see good pterosaurs shown in detail.

Figure 1. The CM11427 Rhamphorhynchus specimen at the Carnegie Museum. Above with membranes and bones traced. Scale bar = 10 cm.

Figure 1. The CM11427 Rhamphorhynchus specimen at the Carnegie Museum. #59 in Wellnhofer 1975. Above with membranes and bones traced. Scale bar = 10 cm.

CM11427 is presented in ventral view and missing just some tail, wing tip and there’s no trace of the sternal complex and coracoids. Not sure why Hone et al. report the presence of a “well ossified sternum.” It should be present in ventral view, but I don’t see it and they don’t describe it. Maybe they meant pterosaurs in general have a well-ossified sternum (actually a sternal complex with clavicles and interclavicle incorporated.)

I traced wing membranes.
Hone et al. reported, “Padian and Rayner (1993: table 1) intimated that the wing membrane of CM 11427 is discernable via grooves or impressions in the matrix associated with the specimen. This is almost certainly correct.” Their statement does not give me great confidence that they either confirm or refute earlier observations. They only seem to be bowing to earlier authority with words like “intimated” and “almost” giving them room to back out, but they did mention matrix “wrinkles” that point to the wing tip. Wrinkles are good. The wing membrane is difficult to see, but wrinkles in the matrix are evidence.

This would have been a great specimen to show the wing membrane attachment to the lateral tibia, as Hone as previously reported, but they were not able to show it. Maybe they couldn’t, but, like me, thought they should.

Following Bennett
Hone et al. report, “Moreover, here and below, we follow Bennett (1995) in considering all known specimens of Rhamphorhynchus to be referable to R. muensteri, with smaller supposed ‘species’ representing earlier ontogenetic stages of this taxon.”

That’s why we should look at two reconstructions side by side (Fig. 2) to see if they are indeed conspecific.

Figure 2. Click to enlarge. CM11427 specimen to scale with the darkling specimen. Make up your own mind if these two are conspecific.

Figure 2. Click to enlarge. CM11427 specimen to scale with the darkling specimen. Make up your own mind if these two are conspecific. Maybe one is just taller with different ulnar, pedal and other proportions.

Proportions are not readily apparent in a crushed roadkill fossil, but immediately pop out in reconstructions. I encourage pterosaur workers to trace and reconstruct their specimens to reveal this otherwise hidden data. Here There are not too many differences, but overall the Carnegie specimen is taller, but without a larger skull or hind limb. The radius and ulna are much longer and the mandible is not so curved.

Hone et al. report a fish in the gut of Rhamphorhynchus behind the right elbow, between the ribs and gastralia. It’s a little mashed up now. They weren’t able to identify it. I could only see a strong string of vertebrae.

Figure 4. Left: Right pes dorsal view of CM11427 compared to the "darkling" specimen pes on right. Not quite the same proportions on each of the phalanges.

Figure 4. Left: Right pes dorsal view of CM11427 compared to the “darkling” specimen pes on right. Not quite the same proportions on each of the phalanges. Compare p1.1 to p2.1 to p.3.1. Digit 4 is overall longer on the CM specimen. The metatarsals are similar.

This specimen nests at the base of R. longiceps, one branch away from R. muensteri.

References:
Hone DWE, Habib MB and Lamana MC 2013. An annotated and illustrated catalogue of Solnhofen (Upper Jurassic, Germany) pterosaur specimens at Carnegie Museum of Natural History. Annals of Carnegie Museum 82(2): 165-191.