Geographic cladogram of pterosaurs

So many pterosaurs come from so few places.
And those places are spread around the world. So, here (Fig. 1) is the large pterosaur tree (LPT, 239 taxa) with color boxes surrounding Solnhofen, Chinese, North American, South American and other geographic areas where they are found.

Figure 1. LPT with pterosaurs colorized according to geography.

Figure 1. LPT with pterosaurs colorized according to geography.

As before,
the traditional clades ‘Pterodactyloidea’ and ‘Monofenestrata‘ become polyphyletic when traditionally omitted taxa are included. Here (Fig. 1) four clades achieve the pterodactyloid-grade by convergence. Other pterosaur workers (all PhDs) omit or refuse to include most of these taxa, leading to false positives for the tree topologies they recover. Moreover, none recognize, nor cite literature for, the validated outgroup members for the Pterosauria (Fig. 1) preferring to imagine pterosaurs arising from unidentified and/or invalidated archosaurs or archosauriforms. Here we get to peak beneath the curtain.


References
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.

If you want to learn about pterosaurs, start with this one.

Still unnamed
the privately-held ‘Painten pterodactyl’ (Tischlinger and Frey 2013) is a perfectly articulated small specimen (Figs. 1-4). Phylogenetically it nests in the large pterosaur tree (LPT, 232 taxa) at the base of the clade that leads to Pterodactylus (Fig. 5), just off the path toward Germanodactylus…and it’s not too far removed from its Scaphognathus ancestors (Fig. 5).

If you want to learn about pterosaurs,
start with this one (Figs. 1-4). The Painten pterodactyl makes it easy to see all the bones in natural (undisturbed) articulation. Even the sternal complex (magenta) is visible below all the other pectoral bones.

Figure 1. The Painten pterosaur specimen in situ under visible and UV light, then under DGS to identify the bones with colors.

Figure 1. The Painten pterosaur specimen in situ under visible and UV light, then under DGS to identify the bones with colors.

The skull
has the standard premaxilla with four teeth per side. Traditionally overlooked tiny secondary nares are visible. The temporal arch is very low on the skull.

Figure 2. Painten pterosaur skull.

Figure 2. Painten pterosaur skull. Only the palate remains buried in this excellent example of a preparator’s skill and perfect preservation.

The wrist
(Fig. 3) includes an excellent vestigial manual digit 5 curled up on the palmar side of the left hand. That is an unexpected taphonomic displacement because in vivo digit 5 would be on the axially torsioned dorsal side of the manus. The vestige appears to be coming up around the crushed edge where metacarpal 5 is buried underneath. The carpals and digit 5 show some dislocation, which may explain how the remains of digit 5 ended up on the palmar side of the manus.

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 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.

The feet, tail and wingtips
include a disarticulated bone from the base of the tail. Unguals tipped all five pedal digits. one wing bone (m4.4) was broken and healed in life.

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…or are those round unguals now lacking tips? Only a closer look will tell, but the tips seem to have neck-like indentations.

We first looked at
the Painten pro-pterodactylid here in March, 2014.

The disappearance of the maxilla ascending process
and the appearance of the tiny secondary naris and nasal descending process appear during phylogenetic miniaturization in this clade.

Figure 6. Painten pterosaur ancestors and descendants.

Figure 5. Painten pterosaur ancestors and descendants. The development of  the secondary naris is documented in the smaller Scaphognathus, which needs a new generic name.  The naris becomes confluent with the antorbital fenestra when the ascending process of the maxilla disappears and the descending stem of the nasal is retained (in some taxa). Other pterodactyloid-grade pterosaurs had a convergent apparent confluence of the naris.

With the majority of the confluent fenestra
devoted to the naris, perhaps we should think of this opening differently.

Figure 6. The Painten pterosaur phylogenetically nests between two smaller specimens in the LPT. 

Figure 6. The Painten pterosaur phylogenetically nests between two smaller specimens in the LPT.

Big compared to its sisters,
the Painten pterosaur is the last in this lineage to have robust cervicals, based on comparison to Ningchengopterus (Fig. 6), a taxon closer to the many Solnhofen pterodactylids in museum collections (Fig. 7). This phylogenetic variety exhibited with Solnhofen and Chinese pterosaurs suggests a wide distribution for this clade in the Late Jurassic.

The Pterodactylus lineage and mislabeled specimens formerly attributed to this "wastebasket" genus

Figure 7 Click to enlarge. The Pterodactylus lineage and mislabeled specimens formerly attributed to this “wastebasket” genus

In summary
This pterosaur is an ideal teaching  specimen because it has all of its bones in articulation and nests at a transitional node in pterosaur phylogeny.

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.

 

A Brazilian stem pteranodontid, and Brazil wants its fossils back!

Figure 1. The cf.Tupuxuara specimen is larger than sister taxa in the LPT.

Figure 1. The cf.Tupuxuara specimen is larger than sister taxa in the LPT.

cf.Tupuxuara (SMNK??? Elgin 2014, Early Cretaceous). Originally considered close to Tupuxuara, here this specimen nests between Eopteranodon and the base of the Pteranodontia. The metacarpals and antebrachium are relatively short. The large pentagonal sternal complex anchors large flight muscles. Distinct from the Pteranodontia, but like the Eopteranodon clade, the carpal and tarsal elements were not co-ossified. The ventral pelvis remained open, as in Eopteranodon and most tested nyctosaurids. In other words, this is NOT a female…necessarily.

Figure 2. Early Cretaceous cf.Tupuxuara from the Elgin 1914 dissertation. This taxon nests between the Solnhofen specimen B St 1878 VI 1 and Eopteranodontia + Pteranodontia in the LPT, far from Tupuxuara. Reconstruction from underlying in situ specimen from the Elgin 2014 dissertation available online.

Figure 2. Early Cretaceous cf.Tupuxuara from the Elgin 1914 dissertation. This taxon nests between the Solnhofen specimen B St 1878 VI 1 and Eopteranodontia + Pteranodontia in the LPT, far from Tupuxuara. Reconstruction from underlying in situ specimen from the Elgin 2014 dissertation available online. Missing parts filled in.

You might want to think of this pterosaur
as the first of the large Pteranodontia, still nesting with the Germanodactylus clade not leading to dsungaripterids, Shenzhoupterus and tapejarids, including Tupuxuara). Elanodactylus is another large member of this clade (Fig. 3).

Figure 3. Subset of the large pterosaur tree (LPT) with the addition of cf. Tupuxuara apart from Tupuxuara and at the base of the Pteranodontia.

Figure 3. Subset of the large pterosaur tree (LPT) with the addition of cf. Tupuxuara apart from Tupuxuara and at the base of the Pteranodontia.

The Elgin 2014 thesis was completed in May 2014.
Just a few months earlier, in March 2014 a paper appeared in Nature entitled, “Brazil clamps down on illegal fossil trade.” The first sentence reads, “Thirteen people are scheduled to go on trial in Brazil for smuggling fossils out of the country, apparently to private collectors and to museums in Germany and the United Kingdom.” Do you think Dr. Elgin was worried? Evidently not. In his PhD thesis Elgin wrote, The large numbers of [Chapada do Araripe] specimens that at the time of writing lacked any full or proper description was one of the major influences in the creation of this body of work, creating a catalogue of fossils that increase our understanding of this enigmatic group and permitting ready access to photographs and descriptions for future workers.” And for making those images available, Dr. Elgin, thank you!

Dr. Elgin further notes
“Brazil has banned the commercial sale of all fossil originating from its territories since 1942.” Then concludes, “The pterosaurs described within this body of work are presented for the good of the scientific community. While discouraging illicit trafficking is to be encouraged, the fact that the featured specimens are interred within a registered museum, rather than ending up within a private institution as would have certainly been their fate otherwise, guarantees the continued and universal access to any and all persons, to the benefit of the international community.”

Worried about the loss of Brazilian fossils to German museums,
Brazilian paleontologist, Alexander Kellner, cites the loss of cultural heritage. On the other hand, English paleontologist, David Martill quips, Knowing “dodgy” people is the only way to get samples, because the DNPM ignores requests to dig.” Brazilian paleontologist, Max Langer says, “Fossils must be kept in the country to help to improve Brazilian science.” And he expects fellow researchers to hold Brazil’s laws in higher regard than the private collectors who also fuel the trade.

David Martill expressed more of his thinking
in this online report, “In an email interview, Martill said that he “doesn’t care a damn how the fossil came from Brazil”, because that is “irrelevant to the scientific significance of the fossil. I am critical of all laws that interfere with the science of paleontology; and blanket bans on fossil collecting are indiscriminatory and only hinder science, No countries existed when the animals were fossilized.”

Bottom line:
Firsthand access to fossils… can sometimes get you into trouble with Brazil. You can see how the side line up here, with Brazilians hoping to stop exports and Europeans hoping to continue exports.

More tomorrow
on the Elgin dissertation…

References
Elgin RA 2014. Palaeobiology, Morphology, and Flight Characteristics of Pterodactyloid Pterosaurs. Innaugural Dissertation. Zur Erlangung der Doktorwürde Fakultät für Chemie und Geowissenschaften Institut für Geowissenschaften Ruprecht-Karls-Universität Heidelberg. Available online here.

Unwin 2017: Early origin of pterodactyloid bauplan

Unforunately Dr. David Unwin has brought us

  1. the invalid Monofenestrata
  2. Darwinopterus as the transitional taxon linking long-tails to short-tails.
  3. Modular evolution
  4. a 1994 continuation of the deep chord wing membrane misinterpretation of Sordes

From the Unwin 2017 abstract:
“The origin of the pterodactyloid bauplan from that of non-monofenestratan (‘rhamphorhynchoid’) pterosaurs involved extensive anatomical changes and had profound consequences for the evolutionary history of Pterodactyloidea,”

Not really. Phylogenetic analysis shows it happened gradually four times. So there is no clade. “Pterodactyloidea.” Dr. Unwin is way out of date with the latest research.

“Evolution of the pterodactyloid skull construction predates the Middle Jurassic, but remains almost completely undocumented by fossils.”

Not really. Dr. Unwin does not include a sufficient number of tiny adult pterosaur taxa. Traditionally he has ignored the tiny transitional taxa that document the origin of the pterodactyloid-grade. He does not want to accept that this grade has been attained four times and two other clades, Anurognathidae and Wukongopteridae, evolve some, but not all pterodactyloid-grade traits.

Liaodactylus reveals that innovation in pterodactyloid skull anatomy and the appearance of derived features was well underway prior to the Upper Jurassic. Douzhanopterus, a derived NPM, demonstrates that elongation of the metacarpus and reduction of the tail and fifth toe (classic pterodactyloid synapomorphies) also predates the Upper Jurassic, but disjunction in the degree of their development across taxa is not consistent with simple explanations such as ‘adaptation for flight’. Overall, late Early to early Late Jurassic pterosaurs were much more diverse and had a far more complex evolutionary history than heretofore recognized.”

Figure 1. Douzhanopterus at top in situ compared to scale with related pterosaurs, including Jianchangopterus, Ningchengopterus and the Painten pterosaur, all at the base of the Pterodactylidae.

Figure 1. Douzhanopterus at top in situ compared to scale with related pterosaurs, including Jianchangopterus, Ningchengopterus and the Painten pterosaur, all at the base of the Pterodactylidae.

Not really. 
Peters 2007 recognized the ‘far more complex evolutionary history’ that Unwin has yet to accept.

Earlier we looked at Douzhanopterus (Late Jurassic) and found it nested among the primitive members of the Pterodactylus clade. Earlier we looked at Liaodactylus, which nested among the Ctenochasmatidae.

Dr. Unwin still doesn’t get the big picture
due to taxon exclusion in his analyses. Pterodactyloid-grade pterosaurs had four origins (azhdarchids and ctenochasmatids arising from Dorygnathus. Scaphognathus gives rise to pterodactylids and germanodactylids, which give rise to  tapejarids and pteranodontids. This topology has been in the literature since Peters 2007, and online since 2011 at ReptileEvolution.com. If you know Dr. Unwin, please steer him gently in that direction.

References
Unwin D 2017. The complicated and surprisingly early origin of the pterodactyloid bauplan. SVPCA-SPPC Birmingham, abstracts September 12-15, 2017.
Peters D 2007. The origin and radiation of the Pterosauria. Flugsaurier. The Wellnhofer Pterosaur Meeting, Munich 27 online here. (Please ignore the notes on Jesairosaurus and Drepanosauridae, which no longer nest with the pterosaur clade. The latest info is here and here.)
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.

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Ontogeny and gender dimorphism in pterosaurs – SVP abstract 2016

Unfortunately,
and apparently, this is yet another study (Anderson and O’Keefe 2016) with a priori species assignations prior to a robust phylogenetic analysis and the creation of precise reconstructions. I hope I’m wrong, but no mention of phylogenetic analysis appears in the abstract. Nor do they mention creating reconstructions. Bennett (1993ab, 1995, 1996a, 2001ab, 2006, 2007) failed several times in similar fashion (with statistical analyses) to shed light on the twin issues of pterosaur ontogeny and dimorphism, coming to the wrong conclusions every time, based on results recovered by creating reconstructions and analyses. Further thoughts follow the abstract.

From the Anderson and O’Keefe abstract:
“The relationships of pterosaurs have been previously inferred from observed traits, depositional environments, and phylogenetic associations. A great deal of research has begun to analyze pterosaur ontogeny, mass estimates, wing dynamics, and sexual dimorphism in the last two decades. The latter has received the least attention because of the large data set required for statistical analyses. Analyzing pterosaurs using osteological measurements will reveal different aspects of size and shape variation in Pterosauria (in place of character states) and sexual dimorphism when present. Some of these variations, not easily recognized visually, will be observed using multivariate allometry methods including Principle Component Analysis (PCA) and bivariate regression analysis. Using PCA to variance analysis has better visualized ontogeny and sexual dimorphism among Pterodactylus antiquus, and Aurorazhdarcho micronyx. Each of the 24 (P. antiquus) and 15 (A. micronyx) specimens had 14 length measurements used to assess isometric and allometric growth. Results for P. antiquus analyses show modular isometric growth in the 4th metacarpal, phalanges I–II, and the femur. Bivariate plots of the ln-geometric mean vs ln-lengths correlate with the PCA showing graphically the relationship between P. antiquus and A. micronyx which are argued here to be sexually dimorphic and conspecific. Wing schematic reconstructions of all 39 specimens were done to calculate individual surface areas and scaled to show relative intraspecific wing shape and size. Finally, Pteranodon, previously identified having with sexually dimorphic groups, was compared with ln-4th metacarpal vs ln-femur data, bivariately, revealing similarities between the two groups (P. antiquus and A. micronyx = group 1; Pteranodon = group 2) in terms of a sexual dimorphic presence within the data sets.”

The Pterodactylus lineage and mislabeled specimens formerly attributed to this "wastebasket" genus

Figure 3. Click to enlarge. The Pterodactylus lineage and mislabeled specimens formerly attributed to this “wastebasket” genus

If these two workers actually had 24 P. antiquus specimens to work with,
then it was only because the labels told them so. Or they came across a cache on a slab of matrix I’m not aware of. Pterodactylus has been a wastebasket taxon for a long time (Fig.1) that, apparently the authors didn’t bother to segregate with analysis. Anderson and O’Keefe do not indicate they arrived at a large clade of P. antiquus specimens after phylogenetic analysis. Having done so, I can tell you that no other tested Pterodactylus is  identical to the holotype and no two adult pterosaurs I’ve tested are alike, even among RhamphorhynchusGermanodactylus and Pteranodon. The differences I’ve scored are individual to phylogenetic and they create cladograms that illuminate interrelationships, not sexual dimorphism or ontogeny. There are sequences of smaller species and larger ones. These can appear to be two genders, but that is a false result.

Embryo to juvenile pterosaurs
are isometrically miniaturized versions of their parents as the evidence shows time and again across the pterosaur clade. These facts have been known for over five years and it’s unfortunate that old traditions continue like this unfettered and untested under phylogenetic analysis… or so it seems… I could be wrong having not seen the presentation.

References
Anderson EC and O’Keefe FR 2016. Analyzing pterosaur ontogeny and sexual dimorphism with multivariate allometery. Abstracts from the 2016 meeting of the Society of Vertebrate Paleontology.
Bennett SC 1993a. The ontogeny of Pteranodon and other pterosaurs. Paleobiology 19, 92–106.
Bennett SC 1993b. Year classes of pterosaurs from the Solnhofen limestone of southern Germany. Journal of Vertebrate Paleontology. 13, 26A.
Bennett SC 1995. A statistical study of Rhamphorhynchus from the Solnhofen limestone of Germany: year classes of a single large species. Journal of Paleontology 69, 569–580.
Bennett SC 1996a. Year-classes of pterosaurs from the Solnhofen limestones of Germany: taxonomic and systematic implications. Journal of Vertebrate Paleontology 16:432–444.
Bennett SC 2001a, b. The osteology and functional morphology of the Late Cretaceous pterosaur Pteranodon. Part I. General description of osteology. Palaeontographica, Abteilung A, 260:1–112. Part II. Functional morphology. Palaeontographica, Abteilung A, 260:113–153.
Bennett SC 2006. Juvenile specimens of the pterosaur Germanodactylus cristatus, with a review of the genus. Journal of Vertebrate Paleontology 26:872–878.
Bennett SC 2007. A review of the pterosaur Ctenochasma: taxonomy and ontogeny. Neues Jahrbuch fur Geologie und Paläontologie, Abhandlungen 245:23–31.

A peek beneath the ribs of Pterodactylus scolopaciceps

A not so recent PLOSOne paper (Vidovic and Martill 2014, Late Jurassic) on Pterodactylus scolopaciceps (Meyer 1860, BSP 1937 I 18 (Broili 1938, P. kochi No. 21 of Wellnhofer 1970, 1991) provided the images seen here (Figs. 3, 4). It is one of the best preserved pterosaurs of all. Earlier we critically examined Vidovic and Martill 2014 here. A few short notes and images (Figs. 1,2) below will summarize those criticisms. Otherwise, the photos bring today’s news: tracings of the overlooked coracoids, sternal complex and an early embryo (Figs. 4, 5).

Vidovic and Martill reported,
“The majority of pterosaur species from the Solnhofen Limestone, including P. scolopaciceps are represented by juveniles.” This is utter rubbish.  Several hummingbird- to sparrow-sized adults, yes! …and some with long rostra! …but no verifiable juveniles, EXCEPT the juvenile of the giant Rhamphorhynchus recovered and described here. Remember, pterosaur embryos and juveniles are close matches to their parents as they develop isometrically, able to fly upon hatching, not allometrically. The large pterosaur tree demonstrates the phylogenetic miniaturization is what saved certain pterosaur lineages from extinction following a great radiation in the Late Jurassic. This is evidence Vidovic and Martill refuse to accept.

Vidovic and Martill continue:
“Consequently, specimens can appear remarkably similar due to juvenile characteristics detracting from taxonomic differences that are exaggerated in later ontogeny.” More rubbish based on adherence to Bennett (1996, 1996. 3006) who synonimized dozens of Solnhofen specimens without so much as an attempt at phylogenetic analysis, which lumps and separates the lot into individual taxa here. The Vidovic and Martill cladogram includes only 33 taxa (10 from Solnhofen) and lumps several pterosaurs successfully together (tapejarids, ctenochasmatids, pteranodontids), but fails to put these clades correctly into large clades, nesting sharp beak toothless taxa with broad beak toothy taxa, etc. etc.

Vidovic and Martill dig themselves deeper
“A hypodigm for P. scolopaciceps, comprising of the holotype (BSP AS V 29 a/b) and material Broili referred to the taxon is described. P. scolopaciceps is found to be a valid taxon, but placement within Pterodactylus is inappropriate. Consequently, the new genus Aerodactylus is erected to accommodate it.” As you can see (Figs. 1, 2) and as has been tested, placement within Pterodactylus (Fig. 2)  is MORE appropriate than nesting with purported sisters promoted by Vidovic and Martill (Fig. 1).

Figure 4. Sister taxa of "Aerodactylus" according to Vidovic and Martill 2014 include Gladocephaloides and Cycnnorhamphus. More rubbish.

Figure 1. Sister taxa of “Aerodactylus” according to Vidovic and Martill 2014 include Gladocephaloideus and Cycnnorhamphus. More rubbish. Neither are even related to one another as the former is a ctenochasmatid and the latter, of course, is a cycnohrmphid. Click to enlarge.

Evolution works in minute steps
and the more traits shared between specimens, both overall and in minute detail, the more closely they are related. Vidovic and Martill may also be working under the false assumption that pterosaurs are archosaurs and follow archosaur fusion patterns. No. Pterosaurs are lepidosaurs and follow lepidosaur fusion patterns, which are largely phylogenetic, not ontogenetic, as reported earlier.

Figure 3. Click to enlarge. The large pterosaur tree nests these three taxa together. So this Pterodactylus really is a Pterodactylus.

Figure 2. Click to enlarge. The large pterosaur tree nests these three taxa together. So this Pterodactylus (BSP AS V 28a/b) really is a Pterodactylus (contra Vidovic and Martill)

 

Enough about that paper.
I was drawn to this specimen (Fig. 3) because I did not have data for the coracoids and took another look for them with this excellent photo.

Figure 1. Pterodactylus scolpaciceps from Vidovic and Martill 2014 with elements below the ribs traced in color.

Figure 3. Pterodactylus scolpaciceps from Vidovic and Martill 2014 with elements below the ribs traced in color. Soft tissue is persevered in this specimen, and so is an embryo.

Lo and behold
the coracoids and sternal complex were visible as impressions (Figs. 3, 4) and there was something else further back… an embryo. Not full term. Not fully ossified. The wings are invisible or lost among the ribs and gastralia. Unlike 3D eggs, crushed fossils lay out all the elements into a single bedding plane.

Figure 2. Closeup of the torso of Pterodactylus scolopaciceps showing the coracoids, sternal complex and a passenger.

Figure 4 Closeup of the torso of Pterodactylus scolopaciceps showing the coracoids, sternal complex and a passenger. I was drawn to revisit this specimen because I lacked data for the length of the coracoids. This excellent image provided that data and possibly more. The bones of the embryo are not fully ossified yet. The shell is not formed. Those happen closer to the time just before egg-laying.

The embryo 
is the right size, shape and morphology to someday pass through the pelvis. The bones are soft and underdeveloped. No trace of an eggshell is apparent, but that’s not supposed to happen until the last stages of gestation.

Figure 4. Pterodactylus scolopaciceps reconstructed with the passenger shown here expelled. It is the right size, shape and morphology to be an embryo within an egg.

Figure 5. Pterodactylus scolopaciceps reconstructed with the passenger shown here expelled. It is the right size, shape and morphology to be an embryo within an egg.

Unlike archosaurs
lepidosaurs carry their young for longer terms, sometimes to the point of live birth (viviparity). Earlier I proposed that pterosaurs, like some of their sister lepidosaurs, carried their embryos until just prior to hatching. Other workers, all of whom consider pterosaurs archosaurs, thought egg burial was their method of reproduction. Not sure how they imagine a fragile pterosaur with tearable wing membranes would manage to dig through whatever dirt, sand or debris they were buried in. The aborted egg of Darwinopterus similarly contains an immature and unossified embryo. We also have an aborted fetus in Anurognathus and an aborted egg in the tiny pterosaur, Ornithocephalus added to the Pterodaustro embryo, the ornithocheirid embryo (revised recently) and the (relatively) giant, proto-anurognathid embryo.

How many pterosaur fossils are pregnant?
If they are doing their job, half of the adults should be pregnant, unless females greatly outnumber males, then that percentage goes up. Very few, however, will be preserved with late stage embryos that preserve even impressions of bones. As everyone knows the thinnest bone walls in the animal kingdom are pterosaur bones, thinner yet in embryos and  softer yet in younger embryos.

It’s time people
It’s time to let go of those old paradigms about pterosaur origins, wing shape and interrelationships. Those old hypotheses are not working. They cannot be verified. They are the stuff of myth. I would hate to think that these workers are refereeing manuscripts.

Carl Sagan said this about letting go of old paradigms,
“The essence of the Scientific method is the willingness to admit your’re wrong, to abandon ideas that don’t work, and the essence of religion is not to change anything, that supposed truths are handed down by some revered figure and no one is to make any progress beyond that because all the truth is thought to be in hand.”

References
Bennett SC 1995. A statistical study of Rhamphorhynchus from the Solnhofen Limestone of Germany: Year-classes of a single large species. Journal of Paleontology 69:569-580.
Bennett SC 1996. Year-classes of pterosaurs from the Solnhofen limestone of Germany: Taxonomic and systematic implications. Journal of Vertebrate Paleontology 16: 432–444.
Bennett SC 2006. Juvenile specimens of the pterosaur Germanodactylus cristatus, with a review of the genus. Journal of Vertebrate Paleontology 26:872–878.
Vidovic SU, Martill DM 2014. Pterodactylus scolopaciceps Meyer, 1860 (Pterosauria, Pterodactyloidea) from the Upper Jurassic of Bavaria, Germany: The Problem of Cryptic Pterosaur Taxa in Early Ontogeny. PLoS ONE 9(10): e110646. doi:10.1371/journal.pone.0110646

A near perfect, pristine Pterodactylus skull

Figure 1. Pterodactylus skull, privates collection,  from "Weber 2013 Paleoeocology of pterosaurs 3 : Solnhofen". French Paleontological survey "Fossiles".

Figure 1. Pterodactylus skull, privates collection, from “Weber 2013 Paleoeocology of pterosaurs 3 : Solnhofen”. French Paleontological survey “Fossiles”. Bones colorized below, both images flipped left to right. Black dots indicated fenestra. Anterior slit is secondary naris, which originated in Scaphognathus. Note the jugal and nasal extend to it. The premaxilla appears to have only three teeth, but look more closely and the nubbin-like medial tooth is still visible. Here you can also see the medial sheet bone in the anterior antorbital fenestra. It is not a fossa.

Luckily this specimen was buried before being crushed, so the cracking one sees in other fossils are absent here. Not sure what the rest of the specimen looks like. This privately owned and expertly prepared Pterodactylus specimen can be considered “pristine” and it offers uncluttered insights into the small pterosaur skull, including the tiny nares, the medial sheet dividing the anterior antorbital fenestra, the laminated jugal and nasal, and the nubbin of a medial pmx tooth. Thanks to Frédéric Weber for providing the image.

Figure 2. Closeup of the rostrum of this private Pterodactylus specimen with bone laminations identified.

Figure 2. Closeup of the rostrum of this private Pterodactylus specimen with bone laminations identified. Without other specimens, like Scaphognathus, that show the secondary naris developing, there would be more reason to dismiss these minor shapes as taphonomic cracks and such.

We don’t look at such imagery in a vacuum. Rather we note that this sort of morphology shows up first in Scaphognathus (Fig. 3) and is retained, more or less, in its many pterosaurian descendants.

Figure 3. New reconstruction of Scaphognathus with the new foot and wing phalanges added.

Figure 3. New reconstruction of Scaphognathus with the new foot and wing phalanges added.

Reference:
Image from “Frédéric Weber 2013 Paleoeocology of pterosaurs 3 : Solnhofen”. French Paleontological survey “Fossiles.”

Jianchangopterus – a very ‘rhamphy’ pterodactylid

Jianchangopterus zhaoinanus (Li and Bo 2011, YHK-0931) is a small, complete and crushed Middle Jurassic pterosaur from Liaoning, China. Originally it was described as a scaphognathine pterosaur (Fig. 1) close to Sordes. At first glance, it might be appear to be one. It had short legs, short hands, a longish tail and sharp teeth. What it doesn’t have is a distinct primary naris with a strong maxillary ascending process. So, this is could be VERY interesting, with a little bit of this, and a little bit of that…

So what is it?
An example of modular evolution?

No. 
Modular evolution doesn’t happen. Phylogenetic analysis sorts these sorts of things out. Evolution changes every part of the body, even if just a little bit.

A transitional taxon?
Well, every pterosaur, except terminal taxa, can be considered transitional between its ancestral and derived kin. But in this case Jianchangopterus is not transitional between rhamphs and pterodacs.

Figure 1. Jianchangopterus in situ. It is small, has a long tail, but it nests at the base of the Pterodactylus clade, between Ningchengopterus and the Painten pterosaur, neither of which expose the mid to distal tail. Figure 1. Jianchangopterus in situ. It is small, has a long tail, but it nests at the base of the Pterodactylus clade, between Ningchengopterus and the Painten pterosaur, neither of which exposes the mid to distal tail.

Figure 1. Jianchangopterus in situ, both plates superimposed. It is small, has a long tail, but it nests at the base of the Pterodactylus clade, between Ningchengopterus and the Painten pterosaur, neither of which expose the mid to distal tail. Manual 4.4 is very thin, folded back against m4.3 here in one wing, less folded on the other wing.

What analysis recovers
when you add this taxon to the large pterosaur tree, you find that Jianchangopterus nests between Ningchengopterus and the Painten pterosaur, in their own clade at the base of the genus clade Pterodactylus (Fig. 2). Outgroups to these two clades include Ornithocephalus and two tiny Solnhofen pterosaurs (n9 and n31). The outgroup to all three clades is SMNS81775, a very tiny pterosaur, that I know from a skull drawing only. It has a large orbit, short rostrum and short antorbital fenestra.

Let’s delete all Pterodactylus to see what happens
And the outgroups too. Results: Jianchangopterus nests in the same spot. It doesn’t shift toward any scaphognathines.

Sometimes what is obvious STILL needs to be examined
Lu and Bo looked at certain obvious traits in Jianchangopterus (tail, metacarpus, tooth number, etc.) and decided it was closest to Sordes, which they considered a scaphognathid. It is not. And neither is Jianchangopterus. Shifting Jianchangopterus to Sordes adds 40 steps to the most parsimonious score. Eyeballing a specimen, even following ‘the rules’ regarding certain traits still takes a back seat to phylogenetic analysis.

It’s all in the details…
and the taxa one includes, as I’ve harped on constantly.  On that point, Lu and Bo were not aware of the Painten pterosaur when they published. And they failed to mention Ningchengopterus.

Figure 2. Jianchangopterus between Ningchengopterus and the Painten pterosaur. Note in Jianchangopterus the metacarpus is relatively shorter, especially relative to the ulna. The cervicals are more robust and relatively a little shorter. This is a reversal that makes Jianchangopterus more rhamph-like. You can't eyeball these things. You have to let the matrix and computer recover the relationships.

Figure 2. Jianchangopterus between Ningchengopterus and the Painten pterosaur. Yes, it looks superficially like a basal “rhamph.” But phylogenetic analysis separates the homoplasies from the homologies. Note in Jianchangopterus the metacarpus is relatively shorter, especially relative to the ulna. The cervicals are more robust and relatively a little shorter. This is a reversal that makes Jianchangopterus more rhamph-like. You can’t eyeball these things. You have to let the matrix and computer recover the relationships.

So what about that long tail?
Neither Ningchengopterus nor the Painten pterosaur expose a long tail, either because the plate is broken or the tail is beneath matrix. The outgroups all have a long tail. They also have a longer metacarpus especially relative to the ulna. This is evolution at its best. Nothing proceeds in a straight line. At every generation some are taller, some have longer hands, others have shorter hands.

Figure x. When you compare the three specimens of Sordes to the three jianchangopterids the purported similarities to Sordes start to fade. Shifting Jianchangopterus to Sordes adds 40 steps.

Figure 3. When you compare the three specimens of Sordes to the three jianchangopterids the purported similarities to Sordes start to fade. Shifting Jianchangopterus to Sordes adds 40 steps. The 36 specimen of Sordes nests closer to the Donau Dorygnathus than to the other two Sordes specimens which were themselves basal to Dorygnathus.

 

What about the most basal Pterodactylus?
Here the more derived AMNH1942 specimen of Pterodactylus (n20 in the Wellnhofer 1970 catalog. Fig. 3), the most basal taxon in the Pterodactylus genus clade, also seems to have a very long, but faint tail, largely hidden below a dusting of matrix.

Figure 3. Pterodactylus AMNH1942 with tail traced.

Figure 3. Pterodactylus AMNH1942 with tail traced. Note the tail goes below the leg at the knee, then reappears near the wingtips and trails toward the feet. The matrix itself is filled with organic shapes and what appears to be a tail could be one of these. However, the undisputed long tail of Jianchangopterus adds credence to this interpretation.

Clearly  a robust tail disappears beneath the femur. What we see of the rest of the tail could be organic shapes, which are also all around the matrix. But then with a sister taxon like Jianchangopterus with an undisputed long tail, this deserves further investigation.

Figure 5. Pterodactylus AMNH1942 without the tracing.

Figure 5. Pterodactylus AMNH1942 without the tracing. No doubt the tail disappears behind the femur. Further investigation is needed to find the rest of the tail and expose it on the surface.

More derived Pterodactylus specimens had a short tail.  No doubt about that.
So the tail became further reduced in derived members of this clade. There has been a long-standing assumption that Pterodactylus had a short tail. That assumption really has to be tested by exposing that last caudal vertebra. That hasn’t always (has never) been done. So we might be living under a false paradigm. Jianchangopterus provies a clear clue that the old paradigm needs to be examined in greater detail and with greater certainty.

The short hand
The metacarpus/ulna ratio is very small/short in Jianchangopterus. Phylogenetic analysis demonstrates that this single trait is a reversal from a larger ratio. Don’t think it can’t happen. Evolution works the way it works, and not always in a straight line.

Transitional taxa
We’ve seen several contenders for the transition taxon between rhamphs and pterodacs.

Darwinopterus had a short hand and long tail, but a long skull and neck, but it nests on the rhamph side not anywhere near any of the four pterodac origin/transition points.

Rhamphodactylushad a long skull, short tail and long hands. It nests on the pterodac side of one divide.

Kryptodrakon was a misread large but gracile dorygnathid.

Only the tiny Solnhofen pterosaurs provide concrete evidence for four gradual transitions, each to their own pattern.

Getting back to Jianchangopterus
Lü and Bo report, “the lateral surface of the premaxilla and maxilla have horizontal laminations.” This is what I’ve been reporting, this is the anterior jugal laminated to these underlying bones.

Lü and Bo report, “the maxilla bears a distinct recess (representing the antorbital fossa).” This may not be true. IMHO, what Lu and Bo see is IMHO is a medial sheet of bone dividing the left and right rostra, common to many pterosaurs.

The long tail, clearly laid out on this specimen, takes one positive step to confirm my earlier observations of similar longish, very thin tails on other pterodactyloid-grade pterosaurs.

Reference
Lü J and Bo X 2011. “A New Rhamphorhynchid Pterosaur (Pterosauria) from the Middle Jurassic Tiaojishan Formation of Western Liaoning, China”. Acta Geologica Sinica85(5):977–983.

New basal pterodactyloid(?) Kryptodrakon = Sericipterus, a dorygnathid

The big news this morning:
Andres, Clark and Xu (2014) have claimed to discover the earliest known pterodactyloid (Middle/Late Jurassic, Shishugou Formation in Xinjiang, China).They wrote: “We report here the earliest pterosaur with the diagnostic elongate metacarpus of the Pterodactyloidea, Kryptodrakon progenitor, gen. et sp. nov., from the terrestrial Middle-Upper Jurassic boundary of Northwest China. Phylogenetic analysis confirms this species as the basalmost pterodactyloid.”

Andres reported, “In paleontology, we love to find the earliest members of any group because we can look at them and figure out what they had that made the group so successful.” 

If it is one, it’s a big one!
Wingspan estimates are over a meter.

That big size is the red flag
Of course, this flies in the face of the large pterosaur tree, which recovered four origins for pterodactyloid-grade pterosaurs at about this same time, and they were all tiny. Andres, Clark and Xu did not include these tiny pterosaurs in their phylogenetic analysis.

Figure 1. The bits and pieces of Kryptodrakon assembled into a Pterodactylus bauplan, from Andres, Clark and Xu 2014.

Figure 1. The bits and pieces of Kryptodrakon assembled into a Pterodactylus bauplan, from Andres, Clark and Xu 2014.

It’s always difficult to reassemble bits and pieces,
but not impossible. Andres, Clark and Xu did that above (Fig. 1), using a small Pterodactylus as their bauplan or blueprint.

There’s an alternate bauplan available
and it’s also from the same Shishugou Formation. Sericipterus is a very large and gracile dorygnathid (Fig. 2). When you put the bones of Krypodrakon on top of the bauplan for Sericipterus you find a good match.

Figure 2. The bone bits of Kryptodrakon placed on the bauplan of the giant dorygnathid, Sericipeterus, also from the Shishugou Formation. There's a good match here.

Figure 2. Here the bone bits of Kryptodrakon are placed on the bauplan of the giant dorygnathid, Sericipeterus, also from the Shishugou Formation. There’s a good match here. Perhaps Kryptodrakon is a junior synonym for Sericipterus, filling in some of its missing pieces.

And suddenly that “long metacarpus” is not so long anymore. Notably, Sericipterus had gracile wing bones, and that proved confusing to Andres, Clark and Xu. “Thinner” can sometimes be confused with “longer” unless you know what the bauplan is.

But wait, there’s more.
Compare the metacarpus of Kryptodrakon with its dorsal rib and the metacarpus doesn’t look so long anymore. The same holds for the distal carpal, scapula, humerus and wing joint scraps. They’re all too big for that metacarpus to be “elongate.”

A more parsimonious solution
Kryptodrakon and Seripterus are both from the same formation. They are the same size, and their bones have the same shape (so far as can be told from available scraps). We also know from a larger phylogenetic analysis that includes tiny pterosaurs that basal pterodactyloid-grade pterosaurs were all tiny and Kryptodrakon was big.

Therefore,
the more parsimonious solution is to consider Kryptodrakon a junior synonym for Sericipterus, a giant dorygnathid, not a pterodactyloid.

One more thing
Andres, Clark and Xu were also the discoverers and authors of Sercipterus, the only other pterosaur found in the Shishugou Formation.

Sorry to throw cold water on this.
But testing for parsimony is good Science.

References
Andres B, Clark JM and Xu X 2010.A new rhamphorhynchid pterosaur from the Upper Jurassic of Xinjiang, China, and the phylogenetic relationships of basal pterosaurs, Journal of Vertebrate Paleontology 30: (1) 163-187.
Andres B, Clark J and Xu X 2014. The Earliest Pterodactyloid and the Origin of the Group. Current Biology (advance online publication)
DOI: http://dx.doi.org/10.1016/j.cub.2014.03.030

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