Flugsaurier 2018: ‘Young istiodactylid’ nests with tall pterodactylids in the LPT

Flugsaurier 2018 opens today, August 10,
and the abstract booklet is out. So it’s time to take a look at some of the news coming out of that Los Angeles pterosaur symposium. Since the purpose of the symposium is increase understanding of pterosaurs, I hope this small contribution helps.

Figure 1. The Erlianhaote specimen attributed by Hone and Xu 2018 to istiodactylidae nests in the LPT with the large derived pterodactylids.

Figure 1. The Erlianhaote specimen attributed by Hone and Xu 2018 to the clade Istiodactylidae (within Ornithocheiridae) nests in the LPT with the large derived pterodactylids. Note the un-warped deltopectoral crest and lack of a deep cristospine, along with the long legs and short wings.

Hone and Xu at Flugsaurier 2018
describe, “An unusual and nearly complete young istiodactylid from the Yixian Formation, China (Fig. 1). The specimen shows the characteristic istiodactylid cranial features of tooth shape and enlarged nasoantorbital fenestra. However, it has proportionally large hindlimbs and wing proportions that are similar to those of azhdarchids. This has led to suggestion that the specimen may be a composite and that only the cranial material is istiodactylid. Preparation work around some key parts revealed no inconsistencies in the matrix or evidence of glue. The specimen is held in the Erlianhaote Dinosaur Museum, Erlianhote, China.”

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3).

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3). Note the antorbital fenestra becomes longer with larger size in this clade. The teeth are similar to those in istiodactylids.

Reconstructed as is
(Fig. 2) and added to the large pterosaur tree (LPT, 233 taxa, not yet updated due to no museum number nor genus name) the young ‘istiodactylid’ nests as a large derived pterodactylid. 13 steps separate this taxon from the Istiodactylus clade.

Ornithocheirids,
like Istiodactylus (Figs. 3, 4) and the SMNL PAL 1136 specimen (Fig. 5), share a very large wing finger, a short metacarpus, a warped deltopectoral crest, small free fingers and deeply keeled sternal complex not found in the Erlianhote specimen.

Figure 3. Istiodactylus has a shorter neck, longer wing finger and deep cristospine, among other traits not found in the new Erlianhaote specimen.

Figure 3. Istiodactylus has a shorter neck, longer wing finger and deep cristospine, among other traits not found in the new Erlianhaote specimen.

Figure 4. Istiodactylus sinensis is an istiodactylid from China sharing few traits with the new Erlianhaote specimen. Note the warped deltopectoral crest not warped in the new specimen.

Figure 4. Istiodactylus sinensis is an istiodactylid from China sharing few traits with the new Erlianhaote specimen. Note the warped deltopectoral crest not warped in the new specimen. Manual 4.1 is shorter than in other well-known istiodactylids.

The largest ornithocheirid

Figure 5. The unnamed largest ornithocheirid, SMNK PAL 1136, nests with Istiodactylus.

Figure 6. The Erlianhaote pterodactylid reconstructed in several views.

Figure 6. The Erlianhaote pterodactylid reconstructed in several views. The imagined (gray) areas of the skull here were imagined as an istiodactylid, but the better restoration is shown in figure 2.

It’s better not to eyeball certain specimens.
Sometimes you have to run them through a phylogenetic analysis to find out what they are. That’s what the LPT is for. It minimizes taxon exclusion and handles convergence.

Pterosaurs are still lepidosaurs.
So they follow lepidosaur fusion patterns, which follow phylogeny. Hone and Xu made the mistake of imagining pterosaurs might have archosaur fusion patterns that follow ontogeny.

Why am I not at Flugsaurier 2018?
In addition to about a dozen reasons that I can list later, or your can guess now, I can be more helpful and timely here.

References
Andres B and Ji Q 2006. A new species of Istiodactylus (Pterosauria, Pterodactyloidea) from the Lower Cretaceous of Liaoning, China. Journal of Vertebrate Paleontology, 26: 70-78.
Bowerbank JS 1846. On a new species of pterodactyl found in the Upper Chalk of Kent P. giganteus). Quarterly Journal of the Geological Society 2: 7–9.
Bowerbank JS 1851. On the pterodactyles of the Chalk Formation. Proceedings of the Zoological Society, London, pp. 14–20 and Annals of the Magazine of Natural History (2) 10: 372–378.
Bowerbank JS 1852. On the pterodactyles of the Chalk Formation. Reports from the British Association for the Advancement of Science (1851): 55.
Hone DWE and Xu 2018. An unusual and nearly complete young istiodactylid from the Yixian Formation, China. Flugsaurier 2018: the 6th International Symposium on Pterosaurs. Los Angeles, USA. Abstracts: 53–56.
Hooley RW 1913. On the skeleton of Ornithodesmus latidens. An ornithosaur from the Wealden shales of Atherfield (Isle of Wight)”, Quarterly Journal of the Geological Society, 69: 372-421
Howse SCB, Milner AR and Martill DM 2001. Pterosaurs. Pp. 324-335 in: Martill, D. M. and Naish, D., eds. Dinosaurs of the Isle of Wight, The Palaeontological Association
Wang X, Rodrigues T, Jiang S, Cheng X and Kellner AWA 2014. An Early Cretaceous pterosaur with an unusual mandibular crest from China and a potential novel feeding strategy. Scientific Reports 4 : 6329, pp. 1-9. | DOI: 10.1038/srep06329
Witton MP 2012. New Insights into the Skull of Istiodactylus latidens (Ornithocheiroidea, Pterodactyloidea). PLoS ONE 7(3): e33170. doi:10.1371/journal.pone.0033170

wiki/Istiodactylus

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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.

 

New name and a name resurrection for two Solnhofen pterosaurs

Vidovic and Martill 2017
propose new and resurrect old generic names for two Solnhofen pterosaur specimens. Both are good and needed based on an earlier abstract (Peters 2007) and tree topology published here six years ago at ReptileEvolution.com in the large pterosaur tree (LPT, 232 taxa).

Unfortunately
Vidovic and Martill remain completely in the dark regarding pterosaur ontogeny. As we learned earlier here, here and here from several adult and juvenile specimens, pterosaurs juveniles and embryos had adult proportions and that’s why they were mechanically able to fly shortly after hatching. Vidovic and Martill report, “It is difficult to distinguish ‘G. rhamphastinus’ (Fig. 3 from the holotype of D. kochi (Fig. 2) other than by using size-related criteria.” And, “juvenile pterosaurs with small crests have been identified.”

Also unfortunately,
Vidovic and Martill still consider pterosaurs to be derived archosaurs or archosauriforms. They report, “A cladistic analysis of the Pterosauria, including all the taxa discussed here, was performed. The analysis included 104 operational taxonomic units (OTUs) comprising 99 pterosaurs and five archosauriforms as an outgroup.” We have to ask ourselves, how long will pterosaur workers remain in the dark on these basic questions that were answered years ago? Look here, here (Peters 2000, 2007) and here.

Pterodactylus wastebasket
Vidovic and Martill write: “Until relatively recently, the genus Pterodactylus Cuvier, 1809 had been a wastebasket taxon that has included many diverse pterosaurs, including some that are now recognized as basal nonpterodactyloids.” We looked at the Pterodactylus wastebasket here in 2011 (Fig. `1).

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

Figure 1. Click to enlarge. The Pterodactylus lineage and mislabeled specimens formerly attributed to this “wastebasket” genus

Wellnhofer 1970
provided catalog numbers for dozens of Solnhofen specimens. Since those numbers are simpler than their museum numbers that’s how they are named (Figs. 2, 3) at ReptileEvolution.com.

basal germanodactylids

Figure 2. Basal Germanodactylia, Three taxa preceding Germanodactylus rhamphastinus: No. 6, No. 12 and No. 23, the last renamed Diopecephalus kochi. These are all adults.

No. 23 — BSP AS XIX 3 — Diopecephalus kochi (formerly Pterodactylus kochi).
(Fig. 1, left). Seeley had it right originally. Vidovic and Martill correct a century of error when they report, “The holotype of ‘P. kochi’ was considered to belong to a distinct genus by Seeley (1871), which he  unambiguously named Diopecephalus Seeley, 1871.”

No. 64 — B St AS I 745  —
Altmuehlopterus (formerly Germanodactylus) rhamphastinus

Vidovic and Martill reported, “Many phylogenetic studies demonstrate that the two species of Germanodactylus nest together (Kellner 2003; Unwin 2003; Andres & Ji 2008; Lu et al. 2009; Wang et al. 2009; Andres et al. 2014) in a monophyletic clade, but a more focussed analysis by Maisch et al. (2004) demonstrates the genus to be paraphyletic. Maisch et al. (2004) created the nomen nudum Daitingopterus, intended for the reception of ‘G. rhamphastinus’ by placing the name in a table with no specific reference to a specimen.”

Figure 3. Germanodactylus rhamphastinus, No. 64 in the Wellnhofer 1970 catalog.

Figure 3. Germanodactylus rhamphastinus, No. 64 in the Wellnhofer 1970 catalog. Vidovic and Martill renamed this specimen Altmuehlopterus, which is fine and appropriate.

The LPT separates A. (G.) rhamphastinus from G. cristatus by two taxa.

Problems with the Vidovic and Martill 2017 tree:

  1. Lagerpeton nests with Marasuchus, both as proximal outgroups to the Pterosauria. Totally bogus. Tested, validated, real outgroups are listed here. The Fenestrasauria (Peters 2000) is overlooked in the text and references.
  2. Preondactylus and Austriadactylus nest as basalmost pterosaurs. Bergamodactylus, the basalmost pterosaur in the LPT, is excluded.
  3. Only one specimen each of Dorygnathus and Scaphognathus are employed. The LPT shows two clades of pterodactyloid-grade pterosaurs arise from various specimens of Dorygnathus while two others arise from tiny Scaphognathus specimens experiencing phylogenetic miniaturization.
  4. As a result (perhaps) toothy ornithocheirids nest with toothless pteranodontids. In the LPT ornithocheirids arise from equally tooth cycnorhyamphids while shartp-face pteranodontids arise from similar germanodactylids.
  5. The Darwinopterus clade nests as the proximal outgroup to the traditional Pterodactyloidea, when the LPT shows it to be a sterile clade with some pterodactyloid-grade traits.
  6. Altmuehlopterus (formerly Germanodactylus) rhamphastinus nests with G. cristatus
  7. Diopecephalus kochi nests with Pterodactylus antiquus.
  8. Those are the big problems. There are more, but I want to keep it pertinent.

Vidovic and Martill provide clues to their observational problems
when they note, “The genera Pterodactylus and Diopecephalus are remarkably similar.” No they aren’t! Species within the Pterodactylus clade are not even that similar!

Re: Germanodactylus and Pterodactylus,
Vidovic and Martill write: “We agree that some of the differences could be ontogenetically variable and perhaps vary between sexes, so in 1996 it seemed possible that the two species could be at least congeneric.” They disagree with the “common opinion” that the two are distinct genera. Let’s go with the evidence of a large gamut phylogenetic analysis — not opinion — or any analysis lacking so many pertinent taxa.

Vidovic and Martill 2017 rename G. rhamphastinus
Altmuehlopterus rhamphastinus. That’s good. It is generically distinct from its proximal relatives in the LPT. They report, “This name is presented as an alternative to the geographically significant name Daitingopterus (Maisch et al., 2004) which is a nomen nudum.” Not sure how all that falls. I’ll leave such issues to the PhDs.

If you like long nomenclature puzzles
you’ll like Vidovic and Martill 2017. They do a good job of running down all the names that prior workers gave to these century-old specimens. Beware that they are clueless as to the origin of pterosaurs, the ontogeny of pterosaurs and previous work on the phylogeny of pterosaurs based on a much larger taxon list of ingroup and outgroup taxa.

References
Peters D 2000. A redescription of four prolacertiform genera and implications for pterosaur phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106: 293-336
Peters D 2007  The origin and radiation of the Pterosauria. Flugsaurier. The Wellnhofer Pterosaur Meeting, Munich 27. Abstract online here.
Vidovic SU and Martill DM 2017. The taxonomy and phylogeny of Diopecephalus kochi (Wagner, 1837) and ‘Germanodactylus rhamphastinus’ (Wagner, 1851). From: Hone DWE., Witton MP and Martill DM (eds) New Perspectives on Pterosaur Palaeobiology. Geological Society, London, Special Publications, 455, https://doi.org/10.1144/SP455.12
Wellnhofer P 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133.

wiki/Pterodactylus
wiki/Germanodactylus

Douzhanopterus: Not the pterosaur they think it is + overlooked wing membranes.

A new paper by Wang et al. 2017
describes a ‘transitional’ pterosaur (Figs. 1,4) that was purported to link long-tail basal pterosaurs to short-tail derived pterosaurs (Fig. 2).

Unforunately this pterosaur does not do that.
No one single pterosaur can do that (see below, Fig. 3). But the new pterosaur is a new genus with a set of unique traits that nests at the base of the Pterodactylus clade, the Pterodactylidae, not the base of the so-called ‘Pterodactyloidea.’

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 (Wang et al. 2017) at top in situ compared to scale with related pterosaurs, including Jianchangopterus, Ningchengopterus and the Painten pterosaur, all nesting at the base of the Pterodactylidae.

Douzhanopterus zhengi (Wang et al. 2017; STM 19–35A & B; Late Jurassic, Fig. 1) originally nested (Fig. 2) between the Wukongopterids (Wukongopterus, Darwinopterus, Kunpengopterus.) and the Painten pterosaur (Fig. 1) and the rest of the purported clade Pterodactyloidea, beginning with Pterodactylus antiquus. Unfortunately, this is an antiquated matrix based on Wang et al. 2009 modified from Andres et al. 2014 with additional taxa. Unfortunately it includes far too few additional taxa and it produces an illogical cladogram in which clade members recovered by the large pterosaur tree (LPT) become separated from one another.

Figure 2. Basal portion of a cladogram provided by Liu et al. but colorized here to show the division of clades recovered in the LPT.

Figure 2. Basal portion of a cladogram provided by Wang et al. but colorized here to show the division of clades recovered in the LPT. Note that dorygnathids are basal to all derived cyan taxa and Scaphognathids are basal to all derived amber taxa.

As readers of this blogpost know
there was not one origin to the ‘Pterodactyloidea” clade, there were four origins to the pterodactyloid grade: two out of two Dorygnathus specimens and two out of small Scaphognathus descendants (subset of the LPT, Fig. 3). Once again, taxon exclusion is the problem in Wang et al. 2017. Too few taxa were included and many key taxa were ignored.

Should we get excited about the length of the tail
or the retention of an elongate pedal digit 5? No. These are common traits widely known in sister taxa and too often overlooked by pterosaur workers.

I understand the difficulties here.
Wang et al. saw no skull (but see below!) and the rest of the small skeleton is rather plesiomorphic, except for those long shins (tibiae). Even so, plugging in traits to the LPT reveals that Douzhanopterus is indeed a unique genus.

Figure 3. Subset of the LPT focusing on Pterodactylus with Douzhanopterus at its base.

Figure 3. Subset of the LPT focusing on Pterodactylus with Douzhanopterus at its base. Many of these taxa were not included in the Wang et al. 2017 study, but not the proximity of the Painten pterosaur, similar to the Wang et al study.

Here Douzhanopterus nests
in the LPT as a larger sister to Jianchangopterus (Lü and Bo 2011; Middle Jurassic; Fig. 1) at the base of the Pterodactylidae. These are just those few taxa closest to the holotype Pterodactylus and includes the Painten pterosaur, as in the Wang et al. study. Here that pterosaur was likewise demoted from the base of the Pterodactyloidea to the base of the Pterodactylidae.

Figure 4. Douzhanopterus in situ, original drawing and color tracing showing the overlooked soft tissue membranes and skull. Click to enlarge.

Figure 4. Douzhanopterus in situ, original drawing and color tracing showing the overlooked soft tissue membranes and skull. Click to enlarge.

Wang et al. overlooked
the skull and soft tissue membranes (Fig. 4) that are readily seen in the published in situ photo image. Click here to enlarge the image. These shapes confirm earlier findings (Peters 2002) in which the wing membranes had a narrow chord + fuselage fillet and were stretched between the elbow and wingtip, not the knee or ankle and wingtip. The uropatagia were also had narrow chords and were separated from one another, not connected to the tail or to each other, contra traditional interpretations.

DGS
This is what Digital Graphic Segregation is good for. I have not seen the specimen firsthand yet I have been able to recover subtle data overlooked by firsthand observation. The headline for this specimen should have been about the wing membranes, not the erroneous phylogenetic placement.

References:
Andres B, Clark J and Xu X 2014. The earliest pterodactyloid and the origin of the group. Curr. Biol. 24, 1011–1016.
Lü J and Bo X 2011. A New Rhamphorhynchid Pterosaur (Pterosauria) from the Middle Jurassic Tiaojishan Formation of Western Liaoning, China. Acta Geologica Sinica 85(5): 977–983.
Peters D 2002.  A New Model for the Evolution of the Pterosaur Wing – with a twist.  Historical Biology 15: 277–301.
Wang X.Kellner AWA, Jiang S and  Meng X 2009. An unusual long-tailed pterosaur with elongated neck from western Liaoning of China. An. Acad. Bras. Cienc. 81, 793–812.
Wang et al. 2017. New evidence from China for the nature of the pterosaur evolutionary transition. Nature Scientific Reports 7, 42763; doi: 10.1038/srep42763

wiki/Jianchangopterus
wiki/Ningchengopterus
wiki/Douzhanopterus (not yet posted)

Full scale models from the vault

Back in the day
when I was writing and illustrating dinosaur books (1988~1992) I also built a few full scale models that I intended to use as subjects for paintings and museum displays. Here are most of them. Other models include the pterosaur skeletons you can see here.

Figure 1. Brachiosaurus skull, carved out of wood. Full scale.

Figure 1. Brachiosaurus skull, carved out of wood. Full scale.

At this point in my life
(1990s) the work (paintings / illustrations) was considered ‘acceptable.’ Even my papers were ‘acceptable.’ Unfortunately, when I started applying phylogenetic analysis to taxa and discovering new and overlooked relationships (published at ReptileEvolution.com, ) my work and manuscripts were no longer considered ‘acceptable,’ despite the fact that early discoveries made here are being re-discovered and validated years later by PhDs.

FIgure 2. Camarasaurus baby model. Full scale.

FIgure 2. Camarasaurus baby model. Full scale.

This Dimorphodon
(Fig. 3) was among the first of the models, based on Kevin Padian’s 1983 running illustrations.

Figure 3. Dimorphodon skull with dog hair for pycnofibers.

Figure 3. Dimorphodon skull with dog hair for pycnofibers.

Not sure why I produced this plesiosaur
because it took up a bunch of garage space and only entertained the mailman. Ultimately it was purchased by the AMNH, but never put on display. Where it is now is anyone’s guess.

Figure 4. Plesiosaur model. Full scale.

Figure 4. Plesiosaur model. Full scale. See figure 5 for the face.

Much of this plesiosaur
was fashioned at the late Bob Cassilly studios, who was a famous St. Louis sculptor and founder of The City Museum. Bob contacted me after seeing my book, Giants, because he had been commissioned to produce some of the giant marine animals pictured therein. Through that friendship in the 1990s, I was able to study specimens, including Sharovipteryx and Longisquama, from the traveling Russian Dinosaur Exposition that came to the City Museum for their first stop.

Figure 5. Plesiosaur model head detail. Full scale. Teeth are tree thorns.

Figure 5. Plesiosaur model head detail. Full scale. Teeth are tree thorns.

Among the smaller full scale models
is this sparrow-sized Pterodactylus in a bipedal pose (Fig. 6), ready to take flight.

FIgure 6. Pterodactylus scolopaciceps (n21) model. Full scale.

FIgure 6. Pterodactylus scolopaciceps (n21) model. Full scale. Later I learned that this genus was plantigrade (flat-footed), when quadrupedal. This one is about to take flight from a bipedal configuration. Digitigrady at this instance would have given Pterodactylus a bit more power in its initial leap during take-off.

And based on the evolution book

From the Beginning, these three (Fig. 7) are fleshed out steps in the evolution of tetrapods, cynodonts, mammals and man. Ichthyostega is a bit out of date now.

Figure 7. Ichthyostega, Osteolepis and Thrinaxodon, all more or less ancestral to humans. Full scale.

Figure 7. Ichthyostega, Osteolepis and Thrinaxodon, all more or less ancestral to humans. Full scale.

References
Padian K 1983. Osteology and functional morphology of Dimorphodon macronyx (Buckland) (Pterosauria: Rhamphorhynchoidea) based on new material in the Yale Peabody Museum, Postilla, 189: 1-44.

The carpus (wrist) of Pterodactylus scolopaciceps

Earlier we looked at the pectoral girdle of Pterodactylus scolopaciceps  BSP 1937 I 18 (Broili 1938, P. kochi n21 of Wellnhofer 1970, 1991).. And even earlier we looked at that elusive (they say it doesn’t exist!) manual digit 5. Today, some more thoughts on that wonderful wrist… (Fig. 1).

Figure 1. The wrist of Pterodactylus scolopaciceps BSP 1937 I 18 (Broili 1938, P. kochi n21 of Wellnhofer 1970, 1991). Manual digit 5 is a vestige, but it is there.

Figure 1. The wrist of Pterodactylus scolopaciceps BSP 1937 I 18 (Broili 1938, P. kochi n21 of Wellnhofer 1970, 1991). Manual digit 5 is a vestige, but it is there.

Manual digit 5
is here. So is metacarpal 5 and distal carpal 5

Figure 1. The wrist of Pterodactylus scolopaciceps BSP 1937 I 18 (Broili 1938, P. kochi n21 of Wellnhofer 1970, 1991). Manual digit 5 is a vestige, but it is there.

Figure 2. The wrist of Pterodactylus scolopaciceps BSP 1937 I 18 (Broili 1938, P. kochi n21 of Wellnhofer 1970, 1991). Manual digit 5 is a vestige, but it is there.

Metacarpals 1-3
are not pasted onto the anterior (during flight) face of the big metacarpal 4 as tradition dictates. Here mc1-3 are in their natural positions for tetrapods, palmar side down. Only metacarpal 4 is axially rotated so the wing finger folds (flexes) and extends in the place of the hand like bird and bat wings do. That means only metacarpal 3 attaches to metacarpal 4, mc2 lies between 1 and 3 and 1 hangs out in front.

Fingers 1-3
are dislocated and axially rotated anteriorly. In life they palms of the fingers would have been ventral, just like metacarpals 1-3 — not flexing anteriorly as they do here after crushing. Note the fingers are all disarticulated at the knuckle, which was a very loose joint, enabling 90 degrees of extension dorsally (in flight) or laterally (while quadrupedal for walking. Moreover, digit 3 was able to flex in the plane of the wing, like the wing. That produces manus impressions in which digit 3 is oriented posteriorly. That’s very weird for most tetrapods, but common in pterosaurs, as it indicates the quadrupedal configuration was achieved secondarily from an initial bipedal configuration.

Of added interest here….
Note the sawtooth posterior edges of the forelimb, hand and finger four where the wing membrane was attached, fed and enervated. Note also the large extensor tendon distal to the preaxial carpal. It is rarely preserved.

The preaxial carpal and pteroid
as you might remember, are former centralia having migrated to the outside (Peters 2009). We looked at analogous migrations here.

Radius and ulna
as in birds and bats, there is no pronation or supination in the pterosaur wrist and forearm. The elements are too close together to permit this. And that’s a good thing to keep the wing in the best orientation for flight. Bats and birds don’t twist their forearms either.

As you already know, every body part that disappears
goes out with a vestige.

References
Broili F 1938. Beobachtungen an Pterodactylus. Sitz-Bayerischen Akademie der Wissenschaten, zu München, Mathematischen-naturalischenAbteilung: 139–154.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Wellnhofer P 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133.

wiki/Pterodactylus

Pterodactylus n15 reconstructed using digital graphic segregation (DGS)

The nearly perfect specimen
(plate and counter plate) of the  BSP AS V 29a/b specimen of Pterodactylus (n15 in the Wellnhofer 1970 catalog, Fig. 1) is today’s subject.

Figure 1. Click to enlarge. The plate and counter plate of the BSP AS V 29a/b specimen of Pterodactylus with color overlays of the bones and visible soft tissues.

Figure 1. Click to enlarge. The plate and counter plate of the BSP AS V 29a/b specimen of Pterodactylus (n15) with color overlays of the bones and visible soft tissues. Click to enlarge. Now, does not this method improve on just about all others as far as identifying and delineating the skeletal elements? 

DGS
Digital Graphic Segregation has been unfairly maligned by some workers, embraced by others. Here (Fig. 1) is a great example of bone tracing, not only the easy ones on top (left side elements), but also the more difficult ones below (right side elements).

Figure 1. Click to enlarge. The plate and counter plate of  the BSP AS V 29a/b specimen of Pterodactylus with color overlays of the bones and visible soft tissues.

Figure 1. Click to enlarge. The plate and counter plate of the BSP AS V 29a/b specimen of Pterodactylus with color overlays of the bones and visible soft tissues. Click to enlarge.

This specimen appears to have a naris separated from the reduced antorbital fenestra by a stretch of soft tissue, (here colored green, like the maxilla).

Figure 3. Pterodactylus specimen BSP AS V 29a/b, n15 in the Wellnhofer 1970 catalog torso.

Figure 3. Pterodactylus specimen BSP AS V 29a/b, n15 in the Wellnhofer 1970 catalog torso. Yes, there’s a little sternal complex inside all those ribs and gastralia. I don’t see a fetus in this one. Click to enlarge.

 

Yesterday we looked at another specimen of Pterodactylus in which the dorsal and sacral vertebrae of the fetus were visible in ventral view. Those vertebrae looked like a series of tiny bow ties. In the n15 specimen the same pattern is visible due to crushing.

Figure 3. Colored elements of Pterodactylus specimen BSP AS V 29a/b.

Figure 4. Colored elements of Pterodactylus specimen BSP AS V 29a/b. I might not have gotten everything right, but this is more than one usually gets in a published tracing. 

This basic Pterodactylus
had been mistakenly reassigned to Aerodactylus by Vidovic and Martill 2014. Still not sure why considering it nests within Pterodactylus in the large pterosaur tree.

Figure 5. Pterodacatylus specimen BSP AS V 29a/b reconstructed from DGS tracing (fig. 4).

Figure 5. Pterodacatylus specimen BSP AS V 29a/b reconstructed from DGS tracing (fig. 4). Quadrupedal or bipedal, pterosaurs could do it all. 

Considering the width of those gastralia
this pterosaur, like so many others, appears to have had a more flattened (wider) torso than traditionally reconstructed. Now, does not this method improve on just about all others as far as identifying and delineating the skeletal elements?

References
Meyer H 1860. Zur Fauna der Vorwelt: Reptilien aus dem lithographischen Schiefer des Jura in Deutschland und Frankreich. Frankfurt. 1–84.
Vidovic SU and 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

wiki/Pterodactylus