Subadult and adult Tropeognathus compared

Holgado and Pegas 2020 name several toothy crested rostral pieces
they assign to Anhangueridae, Coloborhynchinae and Tropeognathinae, subsets of the clade Ornithocheiridae (Seeley 1870).

More interesting due to its completeness,
was the Holgado and Pegas page-wide photo of the BSp 1987 I 47 specimen of Tropeognathus (Fig. 1, Wellnhofer 1987). Here the ’47’ specimen is compared to the larger holotype, BSp 1987 I 46, and to the smaller Scaphognathus holotype (Fig. 1, GPIB 1304, No. 109 of Wellnhofer 1975), a distant ancestor of Tropeognathus in the Large Pterosaur Tree (LPT, 251 taxa).

Quick note to readers after October 19, 2020:
Co-author Pegas sent a comment noting the 47 specimen was a typo and should be 46 instead. I asked about the scale bar differences and am awaiting that reply at present.

Figure 1. A subadult and adult specimen of Tropeognathus compared to a distant relative, Scaphognathus.

Figure 1. A subadult and adult specimen of Tropeognathus compared to a distant relative, Scaphognathus.

Holgado and Pegas provided a cladogram of a clade of pterosaurs
formerly considered Ornithocheiridae, Lanceodontia. Strangely, their outgroup is the derived istiodactylid, Lonchodraco giganteus, which we looked at earlier here and nested with the unnamed SMNS PAL 1136 specimen, which was omitted from their cladogram.

By contrast
In the LPT ornithocheirids arise from small taxa like Yixianopterus, Mimodactylus and before them the Cycnorhamphus clade and before them the tiny Late Jurassic pterosaurs, BM NHM 42735, Gmu10157, TM 13104 and three Scaphognathus specimens (109, SMNS 59395 and 110 and  of descending size. None of these are included in Holgado and Pegas.

There are quite a few nomenclature problems
in the Ornithocheridae that make the taxonomy unnecessarily confusing.

According to Wikipedia,
“Back in 1987, Wellnhofer had named a second species called Tropeognathus robustus, based on specimen BSP 1987 I 47, which is a more robust lower jaw. In 2013 however, T. robustus was considered as a species of Anhanguera, resulting in an Anhanguera robustus.” Comparing the 46 and 47 specimens (Fig. 1) show they are conspecific, or at least congeneric. This clade becomes increasingly confused with every new author or set of authors. Strange that such closely related taxa are generically split while the several dozen variations in Rhamphorhynchus and Pteranodon are ignored.

The first species of Tropeognathus mesembrinus has several synonyms.

  • Anhanguera mesembrinus (Wellnhofer, 1987)
  • Coloborhynchus mesembrinus (Wellnhofer, 1987)
  • Criorhynchus mesembrinus (Wellnhofer, 1987)
  • Ornithocheirus mesembrinus (Wellnhofer, 1987)

Ornithocheiridae Seeley 1870, named when only a few bits and pieces were known

Ornithocheiromorpha Andres et al., 2014, incorrectly nested within Pteranodontoidea.

Pterodactyloidea Plieninger, 1901, adding taxa splits up this traditional clade.

The disappearance of the naris in scaphognathid pterosaurs.

Figure 2. The disappearance of the naris in scaphognathid pterosaurs. Click to enlarge figure 1 to see the tiny naris in the subadult specimen of Tropeognathus, more sealed over in the adult.

The subadult specimen (specimen ’47’)
of Tropeognathus (Fig. 1) documents a vestige, slit-like naris that disappears in the larger ’46’ specimen. If you can’t see it here, click to enlarge.

Rostral crest
Comparing the subadult to the adult specimen (Fig. 1) demonstrates no growth in the size of the rostral crest. Rather the back half of the skull is slightly larger.


References
Holgado B and Pegas RV 2020. A taxonomic and phylogenetic review of the anhanguerid pterosaur group Coloborhynchinae and the new clade Tropeognathinae. Acta Palaeontologica Polonica 65 (X): xxx–xxx.
Wellnhofer P 1975a. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33. 1975b. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. 1975c.Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149: 1-30.
Wellnhofer P 1987. New crested pterosaurs from the Lower Cretaceous of Brazil. Mitteilungen der Bayerische Staatssammlung für Paläontologie und historische Geologie 27: 175–186; Muenchen

/wiki/Tropeognathus
wiki/Scaphognathus
wiki/Criorhynchus

 

SVP abstracts – Daylight and lowlight Solnhofen pterosaurs

Cardozo, Sobral and Rodriques 2019 bring us
a new look at the vision of Solnhofen (Late Jurassic) pterosaurs.

From the abstract:
“Recent taxonomic reviews suggest that up to twelve genera of pterosaurs might have been present there.” 
Up to? There are twice a dozen distinct Rhamph-like taxa in the first row of figure 1, ignoring the other Solnhofen ‘wastebasket’ taxa Pterodactylus, Scaphognathus, Ctenochasma, Archaeopteryx, etc.
Traditional workers don’t count the little ones. Specialists don’t look closely at all the specimens. They ignore many. Some distinct taxa are found within traditional taxa like, Pterodactylus, Rhamphorhynchus and other generic wastebaskets. According to the LPT, no two pterosaurs scoring the same except for a juvenile/adult pairing in the Rhamphorhynchus wastebasket (Fig. 1).
Figure 3. Bennett 1975 determined that all these Rhamphorhynchus specimens were conspecific and that all differences could be attributed to ontogeny, otherwise known as growth to maturity and old age. Thus only the two largest specimens were adults. O'Sullivan and Martill took the brave step of erecting a new species. The n52 specimen is at the lower right. Click to enlarge.

Figure 1. Bennett 1975 determined that all these Rhamphorhynchus specimens were conspecific and that all differences could be attributed to ontogeny, otherwise known as growth to maturity and old age. Thus only the two largest specimens were adults. O’Sullivan and Martill took the brave step of erecting a new species. The n52 specimen is at the lower right. Click to enlarge.

Cardoza et al. continue:
“Even though many have been recovered from different chronostratigraphic 
units, the high taxonomic diversity and morphological disparity still suggest specializations that reflect distinct ecological roles. An endocast analysis of Pterodactylus antiquus, together with a literature review of the anatomy and ecology of these taxa, suggest interesting niche partitions.”
“Pterodactylus, Scaphognathus, and Rhamphorhynchus were generalist taxa that lived on
coastal areas and fed on fishes and small invertebrates.”
The authors are ignoring the distinct morphologies of these three genera and are not splitting up the small, medium and large taxa. Nor are they considering the distinct niches between adults and their 8x smaller hatchlings.
The descendants of Scaphognathus.

Fig. 2. The descendants of Scaphognathus. Note the size reduction followed by a size increase.

Cardoza et al. continue:
Their niche, however, did not overlap completely: our analysis corroborates a previous study that Pterodactylus had photopic
[daylight] vision, in contrast to the scotopic [dusk/night vision] type of Rhamphorhynchus. Scaphognathus was also photopic, but the different dentition indicates it was not preying on the same items as Pterodactylus.
Other taxa have been regarded as more specialists.
“Germanodactylus has been proposed as a durophage, based mostly on the lack of teeth on the tips of the rostrum and mandible, and therefore also likely preyed on different items than Pterodactylus. Anurognathus, Ctenochasma, Gnathosaurus, and Cycnorhamphus represent highly specialized taxa. Anurognathus was probably an aerial insectivore, with moderately curved unguals that are consistent with a scansorial habit, thus suggesting it inhabited forested areas. Ctenochasma and Gnathosaurus were filter feeders and their different sizes might have prevented, at least to some extent, niche overlap. The diet of
Cycnorhamphus is more disputed: it has been proposed as a durophage, a jellyfish specialist, or a generalist feeding on fishes and insects. In any case, its uniquely curved mandible with teeth only on the distal tip implies a different feeding niche from Solnhofen generalist pterosaurs. Lastly, the endocast of Diopecephalus kochi, a taxon that has been proposed as synonymous with Pterodactylus, was analyzed but poor preservation  prevented adequate assumptions on niche specializations.”
This is a list of old news, old traditions and old excuses. Where is the original thinking? Where are the pithy insights?
“Our preliminary analyses suggest that, although the Solnhofen archipelago was a rich pterosaur site, these taxa were not in direct competition, separated either by functional
anatomy or time. More data on paleoneurology is still needed to better understand niche occupation by Pterodactylus.”
In other words, we have nothing new to say, but wanted to come to Australia to make a presentation.

References
Cardozo FG, Sobral G and Rodriques T 2019. Ecological niches among pterosaurs from the Solnhofen archipelago. Journal of Vertebrate Paleontology abstracts.

Scaphognathus soft tissue in RTI, PTM and UV

Jäger et al. 2019
present a new look at the holotype of Scaphognathus and pay homage to its first describer, Goldfuß 1831. Soft tissue is hard to see in this specimen, whether in white light, UV light or using RTI/PTM (Reflectance Transformation Imaging (see below references) and Polynomial Texture Mapping) methods.

Figure 1. Scaphognathus SIPB Goldfuß 1304a, no. 109 in the Wellnhofer 1970 catalog. Two plates drawn by Goldfuß. Color tracing here. Note the foot and prepubis were overlooked by all prior workers.

Figure 1. Scaphognathus SIPB Goldfuß 1304a, no. 109 in the Wellnhofer 1975 catalog. Plate and counter plate drawn by Goldfuß. UV images from Jäger et al. 2019. Color tracing here. Note the foot and prepubis were overlooked by all prior workers. Note the Goldfuss drawing includes ‘fluff’ over the dorsal vertebrae confirmed by Jäger et al.

Previously I reported
plumes (pycnofibers) emanating from the dorsal region of several pterosaurs, like Jeholopterus (Fig. 5), homologous with those found in Longisquama and Cosessaurus. No one supported these observations in pterosaurs until now (Fig. 2). In fact, this is one of the reasons why workers think I am ‘seeing things’ that others cannot see. So this is confirmation not only of my own observations, but also, as noted in the text, those of Goldfuiß 1833, which have been ignored until this paper.

Figure 4. Jäger et al identify this area as 'dorsal pycnofibers.'

Figure 2. Jäger et al identify this area as ‘dorsal pycnofibers.’I have attempted to trace in color the shapes I see here, Not all the plumes are identified here.

It would be worthwhile
to review Darren Naish’s blogpost that ridiculed my observations of dorsal plumes, now confirmed by several pterosaur specimens.

Figure 2. Reconstruction of Jeholopterus. This owl-like bloodslurper was covered with super soft pycnofibers to make it a silent flyer.

Figure 3. Reconstruction of Jeholopterus. This owl-like bloodslurper was covered with super soft pycnofibers to make it a silent flyer.

Phylogenetic bracketing indicates
that soft tissue fibers/plumes emanating from the dorsal region are present in a wide range of basal pterosaurs, up to the Early Cretaceous. Such plumes likely reduced the speed that these pterosaurs could fly, and reduced the noise they made while flying, as in similarly fluffy owls.

Figure 1. Click to enlarge. The origin and evolution of Longisquama's "feathers" - actually just an elaboration of the same dorsal frill found in Sphenodon, Iguana and Basiliscus. Here the origin can be found in the basal tritosaur squamate, Huehuecuetzpalli and becomes more elaborate in Cosesaurus and Longisquama.

Figure 4. The origin and evolution of Longisquama’s “feathers” – actually just an elaboration of the same dorsal frill found in Sphenodon, Iguana and Basiliscus. Here the origin can be found in the basal tritosaur squamate, Huehuecuetzpalli and becomes more elaborate in Cosesaurus and Longisquama.

We looked at this Scaphognathus specimen earlier
here when the tiny foot was first discovered. That foot was overlooked by the Jäger et al. team, but I thank them for confirming, without citation, the presence of dorsal plumes in this pterosaur.

Figure 1. Bergamodactylus compared to Cosesaurus. Hypothetical hatchling also shown.

Figure 5 Bergamodactylus compared to Cosesaurus. Hypothetical hatchling also shown. Dorsal frills are visible in the fossil of this pterosaur, too.


References
Goldfuss GA 1830. Pterodactylus crassirostris. Isis von Oken, Jena pp. 552–553.
Jäger KRK, Tischlinger H, Oleschinski G and Sander PM 2019. Goldfuß was right: Soft part preservation in the Late Jurassic pterosaur Scaphognathus crassirostris revealed by reflectance transformation imaging (RTI) and UV light and the auspicious beginnings of paleo-art. Palaeontologia Electronica: 21.3.4T
https://doi.org/10.26879/713
Wellnhofer P 1975a. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33.1975b. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. 1975c. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149: 1-30.

wiki/Scaphognathus
https://palaeo-electronica.org/-scaphognathus-in-rti-and-uv


Notes about RTI:
Bogart J 2013a. Reflectance Transformation Imaging: Guide to Highlight Image Capture. Cultural Heritage Imaging, San Francisco. http://culturalheritageimaging.org/What_We_Offer/Downloads/RTI_Hlt_Capture_Guide_v2_0.pdf
Bogart J 2013b. Reflectance Transformation Imaging: Guide to RTIViewer. Cultural Heritage Imaging, San Francisco. http://culturalheritageimaging.org/What_We_Offer/Downloads/rtiviewer/RTIViewer_Guide_v1_1.pdf

wiki/Scaphognathus

Scaphognathus wing membrane in visible light

Today a paper by Jäger et al. 1831
put the holotype of Scaphognathus (Goldfuß 1831; Late Jurassic) under various forms of illumination and re-discovered soft tissue originally noted and rarely cited.

Figure 1. Holotype of Scaphognathus GIF animation showing extent of wing membrane ignored by xx et al. 2018.

Figure 1. Holotype of Scaphognathus GIF animation showing extent of wing membrane ignored by xx et al. 2018.

Ironically
the authors ignored the most obvious aspect of the Scaphognathus soft tissue: the presence of a narrow chord wing membrane (Fig. 1), as documented by Peters (2002) and ignored ever since, per Chris Bennett’s threat, “You won’t get published, and if you do get published, you won’t get cited.”

Figure 2. Here is the Vienna specimen of Pterodactylus in situ and with matrix removed. Now compare this figure with figure 3, which shows the wings and uropatagia unfolding. There is no way to turn this into a deep chord wing membrane. And it decouples the forelimbs from the hind limbs.

Figure 2. Here is the Vienna specimen of Pterodactylus in situ and with matrix removed. Now compare this figure with figure 3, which shows the wings and uropatagia unfolding. There is no way to turn this into a deep chord wing membrane. And it decouples the forelimbs from the hind limbs.

The Vienna specimen of Pterodactylus
(Figs. 2, 3) are the prime examples of a narrow chord wing membrane, stretched between the wing tip and elbow… as in all pterosaurs that preserve soft tissue.

The Vienna Pterodactylus.

Figure 3. The Vienna Pterodactylus. Click to animate. Wing membranes in situ (when folded) then animated to extend them. There is no shrinkage here or in ANY pterosaur wing membrane. There is only an “explanation” to avoid dealing with the hard evidence here and elsewhere.

There are still no examples
of a deep chord wing membrane (attached to the ankle or tibia) preserved in any pterosaurs, as documented here, here, here and here.

References
Goldfuß A 1831. Beiträge zur Kenntnis verschiedener Reptilien der Vorwelt. Nova Acta Physico-Medica Academiae Caesareae Leopoldino-Carolinae Naturae Curiosorum, 15:61-128.
KRK Jäger, Tischlinger H, Oleschinski G, and Sander PM 2018. Goldfuß was right: Soft part preservation in the Late Jurassic pterosaur Scaphognathus crassirostris revealed by reflectance transformation imaging (RTI) and UV light and the auspicious beginnings of paleo-art. Palaeontologia Electronica 21.3.4T: 1-20. pdf
Peters D 2002. A new model for the evolution of the pterosaur wing – with a twist. Historical Biology 15: 277–301.

Updating a little Scaphognathus

When I find better data, I use it.
Case in point, the Maxberg specimen of Scaphognathus (n110 in the Wellnhofer 1975 catalog, no. 992 in the solnhofen-fossilienatlas.de catalog). My earlier data came from Wellnhofer (1991). The earlier image can still be seen by googling “maxberg specimen Scaphognathus“.

The Maxberg specimen is smaller than the holotype, but that doesn’t make it a juvenile, as Bennett (2004, 2014) proposes. Think of it as a sparrow compared to a blue jay in size relative to the larger holotype of Scaphognathus (n109, Fig. 1).

In phylogenetic analysis, the Maxberg specimen descends from the larger holotype (n109). It is similar in size, but not identical in morphology, to the SMNS 59395 specimen of Scaphognathus. The Maxberg specimen is larger than proximal descendant taxa seen here (Fig. 1). So, more than Darwinopterus, Rhamphodactylus or the Painten pterosaur, the Maxberg specimen is a transitional taxon, bridging part of the gap between the long-tails rhamphs and the short-tailed pterodacs.

Figure 1. Scaphognathians to scale. Click to enlarge.

Figure 1. Scaphognathians to scale. Click to enlarge.

I found the Maxberg specimen on the Solnhofen commercial fossil site – solnhofen-fossilienatlas.de catalog – which we looked at earlier here and here.

Figure 1. The Maxberg specimen of Scaphognathus as found at the Solnhofen commercial fossil website.

Figure 2. The Maxberg specimen of Scaphognathus as found at the Solnhofen commercial fossil website.

The photo (Fig. 1) is rather low in contrast, so the first step is to boost it (Fig. 3).

Figure 2. Same specimen, image contrast boosted.

Figure 3. Same Scaphognathus specimen, image contrast boosted. Tip of the tail has a vane-like shape.

Next step: color tracing (Fig. 4).

Figure 2. Tracing of the Maxberg specimen of Scaphognathus.

Figure 3. Tracing of the Maxberg specimen of Scaphognathus. Two odd little ellipses are traced here, both able to pass through the reconstructed pelvis exit. These could be anything. They need to be looked at more closely. Note the ilia are back shifted relative to the sacral vertebrae. Long, tail stiffening zygopophyses are visible.

Reconstruction brings it all together (Fig. 4). So much easier to deal with when not looking like a roadkill. Not sure why more pterosaur workers don’t do this.

Figure 4. The Maxberg specimen of Scaphognathus reconstructed. Even with the updates, the nesting doe not move.

Figure 4. The Maxberg specimen of Scaphognathus reconstructed. Even with the updates, the nesting does not shift. There’s something interesting going on with the nares, splitting into a primary and secondary naris. Like all Scaphognathus, this specimen has tiny feet. This is the first or maybe second stage in the reduction of the tail as all descendant taxa (Fig. 1) have an even more gracile tail.

The new image updates the old one in several subtle ways, none of which are enough to shift the nesting. There are two oval structures in the matrix. And they happen to be just the right size to be pterosaur eggs. Someone will have to take a closer look at this to determine if the bumps are pterosaurian or not. There is a symmetrical disturbance in the matrix at the tail tip that appears to represent a vane, though distinct from the more distinct tail vanes of Campylognathoides and Rhamphorhynchus.

Phylogenetically the Maxberg specimen is basal to cycnorhamphids and ornithocheirids.

References
Bennett SC 2004. New information on the pterosaur Scaphognathus crassirostris and the pterosaurian cervical series. Journal of Vertebrate Paleontology, 24: 38A
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.
Wellnhofer P 1975a. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33. 1975b. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. 1975c. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149: 1-30.
Wellnhoffer P 1991. The Illustrated Encyclopedia of Pterosaurs. London: Salamander. 192 pp.

wiki/Scaphognathus

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.

More wing and a foot added to Scaphognathus

The holotype of Scaphognathus (Goldfuss 1830) GPIB 1304, Fig. 1) is gorgeous, but incomplete. The posterior pelvis and tail are missing. So is the distal wing phalanx.

Figure 1. The holotype of Scaphognathus.

Figure 1. The holotype of Scaphognathus.

Earlier I thought the distal tibia and foot were missing, but a closer look at what remains of the left tibia left me thinking the pedal elements were all present, mixed up with the gastralia. I wouldn’t have confidence saying this except the reconstruction of the pedal elements is very much like those of other Scaphognathus specimens, like n110 and the Maxberg specimen.

Figure 2. Scaphognathus pedal elements highlighted in color. These are difficult to distinguish from gastralia.

Figure 2. Scaphognathus pedal elements highlighted in color. These are difficult to distinguish from gastralia. The reconstruction resembles the pes of other Scaphognathus specimens.

So we may have something here.

As a side note, one more wing phalanx is also added to the wing. Most of the left wing is hidden by the antebrachium and pelvis. I missed that earlier. So, here are the images.

Figure 3. Three proximal wing phalanges for Scaphognathus in red, green and blue.

Figure 3. Three proximal wing phalanges for Scaphognathus in red, green and blue.

And a new reconstruction puts it all together.

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

Figure 3. New reconstruction of Scaphognathus (n109) with the new foot and wing phalanges added. If I had imagined a foot, I would have made it larger. The metatarsus was found separated, but sister taxa have a compressed metatarsus. It is also possible that more of the proximal metatarsus is missing off the edge of the matrix, but I don’t think so. More of pedal 1.1 may be present beneath the femur to match sister taxa.

Hopefully a new basal Scaphognathus specimen will come along with a foot and wing in clear view. It is entirely possible that this “foot” is created from broken and half-sunken gastralia, but at this point, it’s worth presenting.

References
Goldfuss GA 1830. Pterodactylus crassirostris. Isis von Oken, Jena pp. 552–553.
Wellnhofer P 1975a. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33.1975b. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. 1975c. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149: 1-30.

wiki/Scaphognathus

Pterosaur Cervicals: 8 or 9?

Bennett (2004) reported, “The cervical series of the specimen (the third known Scaphognathus, SMNS 59395) consists of 9 vertebrae if the first vertebrae that bears a large rib that articulates with the sternum is interpreted as the first dorsal vertebra.”  This was a break with tradition, in which pterosaurs were considered to have 8 cervicals.

Scaphognathus SMNHS 59395

Figure 1. Scaphognathus SMNHS 59395 with cervicals colored green and orange, dorsal colored purple and blue, sternum in red. Click for more info.

Vertebra number 9 always lies completely within the torso, despite not articulating with the sternum. Hence the traditional number of 8 makes more morphological sense. Vertebra number 9 also shares more traits in common with number 10 than number 8.

Bennett (2004) reported that Pterodactylus had 7 cervicals and large [unspecified] pterodactyloids had 9 cervicals, the latter resulting from the cervicalization of the anterior two dorsal vertebrae.” Unfortunately, I can find no examples of either. Large or small, all pterosaur specimens in reptileevolution.com have 8 cervicals.

The skull of the SMNS 59395 specimen of Scaphognathus

Figure 2. The skull of the SMNS 59395 specimen of Scaphognathus with bones color coded. Note there were 4 premaxillary teeth, as in most other pterosaurs and all sister taxa, not 2 as Bennett (2004) reported.

On a side note, Bennett (2004) reported there were only two teeth in the premaxilla of SMNS 59395. I found four (Fig. 2) as in most other pterosaurs and all known sisters. I saw the specimen before it was prepared. But I was able to “see” four teeth in photos. Here Bennett (2004) might have made a different determination if he had realized that two teeth would have been autapomorphic, but no phylogenetic analysis was performed.

Prepared and unprepared images of the SMNS 59395 specimen of Scaphognathus.

Figure 4. Prepared and unprepared images of the SMNS 59395 specimen of Scaphognathus. Click to enlarge.

There’s a nice articulated wing ungual present in this undisturbed completely articulated specimen.

Finally, Bennett (2004) considered SMNS 59395 a “juvenile with unfused girdles, carpals, and tarsals.” No phylogenetic analysis was offered. Here, after phylogenetic analysis, the smaller SMNS specimen was found to be distinct in several traits from the larger No. 109 specimen, and derived taxa were smaller still. So SMNS 59395 was likely a precocious small adult, not a juvenile. A juvenile should have been virtually identical to the adult, only smaller, because that’s the pattern we see in embryos, the only pterosaurs for which we have an exact ontogenetic age – zero.

This data was gleaned from photos. Bennett (2004) had the specimen in hand. Some of these conclusions, like whether vert #9 was a cervical or a dorsal goes back to the choices we make as paleontologists. Phylogenetic analysis helps.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

References
Bennett SC 2004. New information on the pterosaur Scaphognathus crassirostris and the pterosaurian cervical series. Journal of Vertebrate Paleontology, 24(Suppl. to #3):38A.

What is Jianchangnathus?

A recent paper by Cheng et al. (2012) introduced a new basal pterosaur, Jianchangnathus robustus (IVPP V 16866). Middle Jurassic in age, Jianchangnathus shared several characters with Scaphognathus from the Late Jurassic, according to the authors. It was also compared to Fenhuangopterus, a basal dorygnathid from the same deposits at Jianchangnathus.

Jianchangnathus

Figure 1. Jianchangnathus was allied with Scaphognathus, but retains many traits of its ancestors within Dorygnathus.

A Basal Nesting in the Second Half of the Pterosauria
Here Jianchangnathus nested at the base of the Scaphognathia, essentially the second half of the Pterosauria. In this important phylogenetic site Jianchangnathus was derived from a sister to the Donau specimen of Dorygnathus, itself at the very base of the Dorygnathia and not far from Sordes, the outgroup taxon (Fig. 2). Pterorhynchus and the wukongopterids (= darwinopterids) were sister taxa.

A phylogenetic sequence that includes Jianchangnathus

Figure 2. A phylogenetic sequence that includes Jianchangnathus at the transition point between a basal Dorygnathus and Pterorhynchus + Scaphognathus. All are to scale. This is a rare instance of morphological transition in which a tiny pterosaur did not intervene.

Jianchangnathus was not originally subjected to a phylogenetic analysis, nor was it reconstructed.

The skull of Jianchangnathus with bones identified using the DGS method.

Figure 3. The skull of Jianchangnathus with bones identified using the DGS method. Here the nasal is in pink (anteriorly) and purple (posterior to the break).

Redescription Using DGS
Cheng et al. (2012) reported fusion between the premaxilla and maxilla. Here (Fig. 3) the suture is between the 4th and 5th tooth as in sister taxa. The first fang was the first maxillary tooth, as in the SMNS 55886 specimen of Dorygnathus. The dentary did not extend to the quadrate but extended posteriorly beneath posterior jugal as in sister taxa. The nasal extended to mid orbit as in sister taxa. The jugal extended to the pmx/mx suture as in sister taxa. The prefrontals were longer than originally reported. The vomers, ectopalatine and pterygoid were rod-like elements, as in sister taxa. The tip of the mandible is a double-tooth morphology.

Dorygnathus Was Barely Mentioned
The upturned premaxilla and anteriorly-oriented teeth are traits of Dorygnathus, but that taxon was not mentioned by Cheng et al. (2012) in comparison. The relatively large skull is a trait shared with Pterorhynchus and the wukongopterids. The manual and pedal element proportions are shared with sister taxa.

Maturity
Cheng et al. (2012) observed the non-fusion of the scapula and coracoid and mistakenly considered Jianchangnathus immature. In this case fusion, or a lack thereof, is a matter of phylogeny, not ontogeny. Because pterosaurs are lizards that do not follow archosaur growth patterns as discussed earlier. Sister taxa likewise do not fuse the scapula and coracoid and Jianchangnathus was similar in size to them (Fig. 2).

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

References
Cheng X, Wang X-L, Jiang S-X and Kellner AWA 2012. A new scaphognathid pterosaur from western Liaoning, China. Historical Biology iFirst article available online 29 Nov 2011, 1-11. doi:10.1080/08912963.2011.635423

wiki/Jianchangnathus