Hone et al. 2020 vs. Rhamphorhynchus

Long one today.
Summary, for those in a hurry:
Hone et al. 2020 bring us their views
on Rhamphorhynchus ontogeny (= growth from hatchling to adult). Unfortunately, this study is based on several invalid assumptions. Lacking a phylogenetic context, Hone et al. made the mistake of comparing small adults to large adults. No juveniles were tested. Subsequent ontogeny comparisons to birds and bats were thus rendered moot.

Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row.

Figure 2. Rhamphorhynchus specimens to scale based on results from the LPT. No two are alike — except the juvenile Vienna specimen and the adult n81.

Before we get started, you might remember:

  1. A competing paper has been online for 2 years: ‘First Rhamphorhynchus juvenile recovered by phylogenetic analysis’ in which only one juvenile/adult pairing was found among all 31 specimens shown in figure 1. Among the rest, no two are alike. The small ones in the top row are not juveniles, but phylogenetically miniaturized adult basal Rhamphorhynchus species. (Perhaps someday, someone will re-name them all appropriately.)
  2. All pterosaurs (so far tested) develop isometrically (with the exception of tapejarid crests) because that’s what lepidosaurs do.
  3. Hatchling pterosaurs are typically 1/8 as tall as adults.
  4. Only hatchlings of a certain minimum size can fly. Hatchlings below this hypothetical size risk desiccation due to a high surface-to-volume ratio. That’s when quadrupedal locomotion enters pterosaur clades. Extradermal soft tissue that limits desiccation first appears on tiny, flapping pre-pterosaurs like Cosesaurus.
  5. New pterosaur clades often begin with a series of phylogenetically miniaturized transitional taxa (as in Fig. 1). This only appears in phylogenetic analyses when small and large taxa are analyzed together. That has not happened yet in published analyses because other workers make the same mistake as they consider small adult taxa to be mismatched juveniles (thereby destroying the Hone et al. isometry hypothesis).

The Hone et al. 2020 paper was announced today on
Dr. Hone’s email list. After a short comparison to Pteranodon, Hone continues:
“However, if we turn to Rhamphorhynchus we have only a fraction of the number of specimens but pretty much all the other issues are absent. They also cover a near order of magnitude in size with everything for animals of c 30 cm wingspan up to nearly 2 metres and include everything from putative hatchling-sized animals to a couple of genuine outliers that are much bigger than other known individuals.”

A good sample of Rhamphorhynchus taxa are shown above (Fig. 1) in phylogenetic order. Note this genus has its genesis as a phylogenetically miniaturized series following Campylognatoides in the large pterosaur tree (LPT, 250 taxa). The sole juvenile shown above is the Vienna specimen, nesting with one of the ‘genuine outliers that are much bigger.’ This adult and juvenile pairing nest together with virtually identical scores, despite the great difference in size.The LPT was able to lump and split all tested Rhamphorhynchus taxa. So it can be done. Hone et al. omitted this all important step and ruined their paper.

Hone continues:
“The numbers of course are not tiny, well over 100 good specimens, and that alone would make them an exceptional sample of most terrestrial Mesozoic archosaurs.”

Our first red flag! Hone et al. do not realize that when taxa are added, pterosaurs move over to lepidosaurs. On another note: relative to ‘100 good specimens’, 31 are shown above (Fig. 1).

Hone explains
that Wellnhofer (1975) featured 108 specimens. Hone’s group looked at 129, but, as Hone confesses, “The ‘real’ total is actually a little lower.” Oddly, in the text of the paper, Hone et al. report testing 135 specimens of R. muensteri.

Hone continues:
“This post inevitably marks the publication of an analysis of growth in Rhamphorhyunchus. In a lot of ways, this mirrors Chris Bennett’s fantastic 1995 paper on this genus where he convincingly demonstrated that all specimens belonged to a single species and not multiple ones as previously thought, and part of his arguments for doing this looked at the relationships between various elements based on Wellhofer’s dataset.”

Our second red flag! Bennett’s 1995 paper likewise did not include a phylogenetic analysis. When several specimens of Pteranodon were added to the LPT, no two nested together as conspecific taxa (Fig. 2). Small specimens were closer to the genesis of Pteranodon following Germanodactylus. Large specimens split into several clades.

Figure 2. The Tanking-Davis specimen compared to other forms. Specimen w and specimen z appear to be the closest to the Tanking-David specimen. Specimen 'w' = Pteranodon sternbergi? USNM 12167 (undescribed). Specimen 'z' = Pteranodon longiceps? Dawndraco? UALVP 24238. Click to enlarge.

Figure 2. The Tanking-Davis specimen compared to other forms. Specimen w and specimen z appear to be the closest to the Tanking-David specimen. Specimen ‘w’ = Pteranodon sternbergi? USNM 12167 (undescribed). Specimen ‘z’ = Pteranodon longiceps? Dawndraco? UALVP 24238. Click to enlarge.

Hone is delighted to announce
“Chris’ point [in Bennett 1993, 1995] was that while there were some discreet clusters of specimens (which he attributed to year classes) most of the alleged differences between the putative species vanished when you put them on a graph and the rest were classic ontogenetic traits like the fusion of the pelvis in large individuals of big eyes in small ones. So while he didn’t really deal with growth as such, he was already showing similar patterns to what I and my coauthors confirm now – Rhamphorhynchus was weirdly isometric in growth.”

Our third red flag! Dr. Hone does not appear to realize that ALL pterosaurs  develop isometrically during ontogeny. They do this because pterosaurs are lepidosaurs. By contrast, archosaurs develop allometrically. I’m also going to throw in the objection that a graph or two (as in Bennett 1993, 1995, Hone et al. 2020] is no substitute for a thorough phylogenetic analysis.

Hone continues:
“In other words, in the case of the vast majority of their anatomy, young animals are basically just scaled down adults.”

This is an odd statement to make considering the fact that Hone et al. are looking at phylogenetically miniaturized adults (Fig. 1) and regarding them as juveniles. That Hone considers the little specimens, “basically carbon copies of the adults” makes one question the precision of their observations. They did cherry-pick two similar taxa (Figs. 3, 4), avoiding the wider variation of other specimens. A competing online analysis (subset Fig. 5) was able to split and lump all Rhamphorhynchus specimens.

For comparison, Hone et al. also looked at ontogeny in bats,
noting hand/wing development accelerated close to sexual maturity (= shortly after weaning). He notes, “This is the pattern we would expect.”

Our fourth red flag! Since Hone et al. have blinded themselves to the possibility that pterosaurs are lepidosaurs (Peters 2007) they don’t look at lepidosaurs for comparison. Here’s why they should: pterosaurs hatch with adult proportions from leathery eggs held within the mother’s body longer than in any archosaur.

Hone continues:
“Birds are functionally poor analogues of pterosaurs but are much closer phylogenetically and are the only other powered flying tetrapod so we also looked at some existing datasets for them too.”

More traditional myth perpetuating here. I find this all so disheartening. Colleagues, just add taxa. If I can do it as an outsider, you can do it as a PhD. Do not be afraid to do the work of constructing a cladogram.

Hone continues:
“If you grow isometrically you wings will get longer and wider but your weight will increase much faster since you as a whole will get longer and wider and deeper. Birds increase penumaticity as they grow and there’s evidence this is the case in other pneumatic clades too and if so for pterosaurs, then the mass increase in adults would also be offset somewhat by a proportionally lower mass in adults for a given volume than juveniles.”

Very good point. But I’m ot sure of any pneumaticity studies comparing hatchling and adult pterosaurs.

Hone continues:
“Precociousness has been suggested in pterosaurs before based on the evidence for them flying while young, but it has also been challenged. It suggested that to be flying at that size would require a huge amount of effort and this would leave little energy for growth.”

Wait a minute! Didn’t he just say the weight would increase by the cube in adults? That means juveniles were that much lighter.

Hone continues:
“That’s largely true, but overlooks that there could be post hatching parental parental care. That is normal for archosaurs (including dinosaurs) and we would expect it for pterosaurs.”

If only pterosaurs were archosaurs, but at this point they still nest with lepidosaurs. Most lepidosaurs fend for themselves after hatching, and if pterosaur hatchlings could fly, then they would be able to fly off on their own shortly after hatching. Best not to ‘expect’ anything without a valid phylogenetic context, evidently lacking in Hone et al. 2020.

Hone continues:
“So in short, Rhamphorhynchus is perhaps the best pterosaur for large studies about populations and growth and this genius at least grew isometrically, and this may or may not be the same for other pterosaurs.”

But for the present, every pterosaur known from embryo, juvenile and adult shows strict isometric growth (except for tapejarid crests).

“But it does imply that young pterosaur could fly, and fly well.”

Sadly, Hone et al. seem to be looking at small adults (Fig. 1) and calling them ‘young’. Of course these adult pterosaurs can fly well!

Apparently Hone et al. are comparing linear measurements and graphing them. That method produced false positives for Bennett 1995. There is no substitute for phylogenetic analysis.

In this topsy-turvy world of pterosaurs,
myths are popularized by PhDs while comprehensive phylogenetic analyses compiled by amateurs are ignored and suppressed. Not sure why this problem is not more widely recognized. For other missteps made by Dr. Hone with regard to pterosaurs, click here or use the keyword ‘Hone’ for that long list.

Moments ago the paper itself arrived.
In my morning email was a message from Dr. Hone: “Attached” along with a PDF of their Rhamphorhynchus paper. Two sets of graphs are present, but only a single figure combining bat allometry and Rhamphorhynchus isometry (isolated in Fig. 3).

Figure 3. Image from the only non-graph figure in Hone et al. 2020. Identification and permission note from that caption. Compare these taxa to those in figures 1 and 4.

Figure 3. Image from the only non-graph figure in Hone et al. 2020. Identification and permission note from that caption. Compare these taxa to those in figures 1 and 4.

Figure 4. Lateral view of Hone et al. 2020 Rhamphorhynchus taxa taken from ReptileEvolution.com (Fig. 1).

Figure 4. Lateral view of Hone et al. 2020 Rhamphorhynchus taxa taken from ReptileEvolution.com (Fig. 1). Hone et al. cherry-picked these two somewhat similar by convergence taxa assuming the smaller one was a juvenile of the other other. Phylogenetic analysis separates these two (see Fig. 1). Note the differences in pedal element proportions.

From the paper:
“We test whether pterosaurs show a similar pattern of rapid forelimb growth during post‐hatching/ontogeny to that of bats and birds, and thus infer when in ontogeny R. muensteri would have become volant.”

Sounds laudable. Let’s see how they do it.

From the paper:
“All Rhamphorhynchus specimens from Bavaria are now considered a single species (Bennett 1995).”

No. That’s why figure 1 was created and a phylogenetic analysis of pterosaurs was run (subset Fig. 5), to see how specimens could be lumped and separated. Like Hone et al., Bennett likewise eschewed the use of phylogenetic analysis. Sadly, Hone et al. adopted without further consideration Bennett’s invalid assumption, rather than testing Rhamphorhynchus with a phylogenetic analysis.

Figure 4. Subset of the LRT focusing on Rhamphorhynchus.

Figure 5. Subset of the LRT focusing on Rhamphorhynchus.

From the paper:
“Four lines of evidence suggest that the smallest R. muensteri specimens were very young animals and potentially hatchlings.

  1. Histology reveals incomplete ossification of long bones in the smallest specimens tested (Prondvai et al. 2012),
  2. A disproportionate number of known specimens are small, consistent with high juvenile mortality (Bennett 1995; Hone & Henderson 2014)
  3. Late‐stage embryos of pterosaurs had well‐developed, ossified wings (Wang & Zhou 2004; Codorniú et al. 2018)
  4. and finally while few fossilized pterosaur embryos are known, the ratio by which adults are larger than embryos (Lü et al. 2011; Wang et al. 2017) is similar to the size ratio between the largest R. muensteri specimens and the smallest.”

Incomplete ossification: the smallest specimen studied by Prondvai et al. (2012) was BSPG 1960 I 470a = n9 (Figs. 1, 5) is also the second most primitive tested specimen (next to n28) in a phylogenetic miniaturization series that began with Campylognathoides. Among the neotonous / juvenile traits retained was incomplete ossification of the long bones. Lacking a phylogenetic context, neither Prondvai et al. nor Hone et al. were aware of the miniaturized adult status of n9.

Figure 5. the B St 1960 I 4709A specimen of Rhamphorhynchus is the first and one of the smallest phylogenetically miniaturized specimens.

Figure 5. the B St 1960 I 470a specimen of Rhamphorhynchus (at right)  is the second most primitive and one of the smallest phylogenetically miniaturized specimens attributed to Rhamphorhynchus. One of the neotonous traits was incomplete ossification. Hatchlings were 1/8x the size of adults, similar to house flies in size.

Disproportionate number of specimens are small: lacking a phylogenetic context, Hone et al. were not aware of the phylogenetic miniaturization that preceded the evolution of larger Rhamphorhynchus specimens. In the LPT only one Rhamphorhynchus specimen is a valid juvenile nesting with larger adults.

Late‐stage embryos of other pterosaurs had well‐developed, ossified wings: So did miniaturized adults.

Size ratio of largest R. muensteri specimens to smallest similar to embryo vs adult sizes in other pterosaurs: lacking a phylogenetic context, Hone et al. were not aware of the phylogenetic miniaturization that preceded the evolution of larger Rhamphorhynchus specimens. Hone et al. made the mistake of labeling small adults as juveniles. Notably, Hone et al. did not try to match their purported juveniles with adults phylogenetically. Other tiny Rhamphorhynchus specimens have juvenilized proportions (smaller rostrum, larger orbit), but these were ignored by Hone et al., who cherry-picked two comparative taxa out of 135.

From the paper:
“We tested for isometric versus allometric growth across 135 specimens of R. muensteri using bone length and composite measures (e.g. total wing length and total leg length) relative to: (1) total body length, from rostrum tip to the end of the tail; (2) skull length; and (3) humerus length.”

Lacking a phylogenetic context (available online for several years), Hone et al. made the mistake of comparing adults to adults. No juveniles were tested. Subsequent comparisons to birds and bats were thus rendered moot.

From the paper:
“Our results suggest that even the smallest Rhamphorhynchus had adult skeletal proportions and thus wings sufficient for flight.” This confirms the conclusions of Peters (2018) using a phylogenetically validated juvenile Rhamphorhynchus, rather than a dataset full of large and small adults.

From the paper:
“Wang et al. (2017) noted that in embryos of the pterodactyloid Hamipterus, although there was greater ossification of the limbs and vertebrae than the head, including of the shafts of longbones, there was limited ossification of some other parts of the skeleton that may have related to flight. They hypothesize in this case that hatchlings may have been able to walk before they could fly, though still imply relatively early flight for these animals.”

These were not hatchlings, but embryos still developing within the egg, within the mother in the tradition of lepidosaurs.  Eruptive gases killed flocks en masse. Details here.

From the paper:
“Pterosaurs, like almost all other archosaurs, probably provided parental care (Witton 2013), and precocial flight need not preclude this possibility.” 

This is myth. We’ve known since Peters 2007 that adding taxa moves pterosaurs to nest within Lepidosauria.

From the paper:
“Thus, while Rhamphorhynchus apparently flew at a young age, such volant offspring may have plausibly received parental care, including provisioned food, as they became independent foragers.” 

There is no evidence for this bit of speculation. But it cannot be ruled out. According to Gans 1996, “Many aspects of reptilian reproductive patterns prove to be vagile among the vertebrates. Reversals complicate, and may even invalidate, the characterization of broad trends. Furthermore, the 7000 species of reptiles show dozens of modes that seem to enhance the fitness of their offspring, thereby providing a vast opportunity of testing the reality of these adaptations.”  (‘vagile’ = able or tending to move from place to place or disperse)

In summary:
Hone et al. assumed that phylogenetically miniaturized adults at the genesis of Rhamphorhynchus were juveniles. While testing small adults against large adults (Figs. 1–5) the authors determined that Rhamphorhynchus ontogeny proceeded isometrically.

Ironically this confirms earlier findings by Peters (2018 and elsewhere in this blog) using the only known phylogenetically validated juvenile and a matching adult Rhamphorhynchus. As longtime readers know, all other pterosaurs develop isometrically because they are lepidosaurs arising from taxa close to late-surviving Huehuecuetzpalli, known from matching juvenile and adult specimens.

Dr. Hone needs to show more leadership. He needs to create reconstructions of the specimens under study so visual comparisons can be made by his team and readers. Roadkill specimens are too difficult to compare otherwise. He also needs to run a phylogenetic analysis to determine interrelationships between pterosaur taxa and within all amniotes to see where pterosaurs nest. At present he’s perpetuating old myths and traditions that were invalidated twenty years. He’s that far behind the times.

I’ll never forget the day several decades ago
when Dr. Kevin Padian and Dr. Chris Bennett told me, “nothing can be known about a taxon until it is put into a phylogenetic context.” I took that advice to heart. That is why the LRT and LPT now include more than 2000 taxa.


References
Bennett SC 1993. The ontogeny of Pteranodon and other pterosaurs. Paleobiolgy 19(1):92-106.
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.
Gans C 1996. An overview of parental care among the Reptilia. Advances in the Study of Behaviour 25:145–157.
Hone DWE, Ratcliffe JM, Riskin DK, Hemanson JW and Reisz RR 2020. Unique near isometric ontogeny in the pterosaur Rhamphorhynchus suggests hatchlings could fly. Lethaia. Paywall access here.
Hone 2020. Email post. How to grow your dragon – pterosaur onotgeny [sp]
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D 2018. First juvenile Rhamphorhynchus recovered by phylogenetic analysis. PDF here.
Prondvai E, Stein K, Ösi A, Sander MP 2012. Life History of Rhamphorhynchus Inferred from Bone Histology and the Diversity of Pterosaurian Growth Strategies. PlosOne. online pdf
Wellnhofer P 1975a-c. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149:1-30.

wiki/Rhamphorhynchus

https://pterosaurheresies.wordpress.com/2012/03/23/not-another-rhamphorhynchus-growth-series-without-a-phylogenetic-analysis/

 

New Rhamphorhynchus at the Field: Lauer Foundation Collection

The Lauer Foundation for Paleontology provided
this deep cut Rhamphorhynchus (Fig. 1) to the Field Museum, Chicago, USA. The foundation number is: #LF 1182. Photoshop helps get rid of the surface and deep cuts to see the bones without those distractions.

Figure 1. Another deep cut Solnhofen fossil from the Lauer Collection at the Field Museum, Rhamphorhynchus.

Figure 1. Another deep cut Solnhofen fossil from the Lauer Collection at the Field Museum, Rhamphorhynchus.

Due to its generic look,
the Lauer Foundation specimen enters the large pterosaur tree (LPT, 250 taxa) somewhere in the middle of this genus, distinct from all others, between the ROM specimen (first row, far right, Fig. 2) and the Imhof specimen (second row, far left, Fig. 2).

Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row.

Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row. Click to enlarge.

This wonderful and complete specimen
nests in the middle of the tested Rhamphorhynchus (Fig. 2) specimens (Fig. 3), outside the clade of the largest specimens (including the large and only juvenile, the Vienna specimen row 2, second from right)..

Figure 4. Subset of the LRT focusing on Rhamphorhynchus.

Figure 3. Subset of the LPT focusing on Rhamphorhynchus.

References
https://www.fieldmuseum.org/blog/meet-pterosaur-flock
https://www.lauerfoundationpse.org/about

A Jurassic squid choking hazard for Rhamphorhynchus

Hoffmann et al. 2020 reported in no uncertain terms,
“Pterosaurs ate soft-bodied cephalopods (Coleoidea).”

Immediately after, Hoffmann et al. dialed it back a bit,
when they wrote, “Here, we report the first evidence of a failed predation attempt
by a pterosaur on a soft-bodied coleoid cephalopod.”

Based on size alone,
the squid (PIMUZ 37358) was more than a mouthful according to this ‘to scale’ diagram (Fig. 1)…at least more than a stomachful.

Ask yourself:
could a Rhamphorhynchus of that size (none were larger) eat a squid of that size? Did the pterosaur fail at predation? Or did it change its mind after biting the squid out of curiosity or boredom and losing a tooth in the process?

Figure 1. Plesioteuthis squid in situ with tooth. Reconstructions of Plesioteuthis (above) and the n81 specimen attributed to the largest known Rhamphorhynhcus, which has a matching tooth. The question is: could that pterosaur eat that squid? Or did it change its mind after biting the squid?

Figure 1. Plesioteuthis squid in situ with tooth. Reconstructions of Plesioteuthis (above) and the n81 specimen attributed to the largest known Rhamphorhynhcus, which has a matching tooth. The question is: could that pterosaur eat that squid? Or did it change its mind after biting the squid? At the very top is the hard tissue gladius of the squid to scale. That’s a hard part that would have been especially hard to swallow.

You be the judge.
Hoffmann et al. 2020 have provided the pertinent information. Above are the predator and “prey” to scale. Other Rhamphorhynchus specimens are smaller, and the tooth could have fallen from a different alveolus (a larger tooth) on a smaller specimen. Lots of variables and unknowns here. Also consider the difficulty of swallowing that long gladius, a hard part homologous with the cuttle bone in a cuttlefish.

In any case,
watch what headline you put on your paper. Here the authors went for maximum impact. If, like these authors, you have to dial it back in the second sentence of your abstract,  maybe a more conservative headline should reflect that assessment. After all, a dietary mainstay is indeed different than a curious nibble… and relative size matters.

We looked at other pterosaur choking hazards
earlier here. Pterosaurs likely swallowed their prey whole. There is no indication that they tore squids apart, creating bite-sized pieces. Likewise there is no indication that pterosaurs were able to expand their stomach to accommodate oversize prey (Fig. 1).


References
Hoffman R, Bestwick J, Berndt G, Berndt R, Fuchs D and Klug C 2020. Pterosaurs ate soft-bodied cephalopods. http://www.nature.com/scientificreports (2020) 10:1230 | https://doi.org/10.1038/s41598-020-57731-2

First non-pterodactyloid pterosaurian trackways ever described? …No

Updated April 18. 2020
The four-fingered manus tracks (identified below out of context as a rhamphorhynchid pes track) belong to a tenrec, not a pterosaur. Details here. 

Mazin and Pouech 2020
report on basal pterosaur tracks from the “Pterosaur Beach of Crayssac” (Upper Jurassic), which they consider novel.

From the abstract:
“New discoveries on the ichnological site known as “the Pterosaur Beach of Crayssac” (lower Tithonian, Upper Jurassic; south-western France) answer the question of terrestrial capabilities of non-pterodactyloid pterosaurs. If the terrestrial type of locomotion of pterodactyloid pterosaurs has been solved from ichnological evidence for more than twenty years, no tracks and trackways referable to non-pterodactyloid pterosaurs have ever been described.”

Not true. Peters 2011 included several anurognathid tracks and matched them to trackmakers (Fig. 1). We looked at the so-called ‘Sauria aberrante‘ from Patagonia earlier here in 2011.

Digitigrade pterosaur tracks

Figure 1. A pterosaur pes belonging to a large anurognathid, “Dimorphodon weintraubi,” alongside three digitigrade anurognathid tracks and a graphic representation of the phalanges within the Sauria aberrante track.in

Continuing from the abstract:
“Thus, the debate on terrestrial capabilities of these non-pterodactyloids was based on morpho-functional studies, with the main conclusion that those pterosaurs were arboreal dwellers and bad walkers.”

Not true. Peters 2000a, b, 2011, demonstrated a bipedal ability in pterosaurs superior to that of extant bipedal lizards, (e.g. Chlamydosaurus).

The ‘bad-walker myth’ results from mythology promoted by Unwin and Bakhurina1994 with regard to several misinterpretations of Sordes pilosus. including the invalid binding of the hind limbs with a uropatagium along with the invalid continuation of the brachiopatagium trailing edge to the ankle.

Dimorphodon pes with shadows.

Figure 2. Dimorphodon pes with shadows. Pedal digit 5 can swing beneath the metatarsus. Note elevated proximal phalanges.

“Six trackways referable to three non-pterodactyloid new ichnotaxa, maybe closely related to Rhamphorhynchidae, are described in this work. Their study leads to the conclusion that grounded non-pterodatyloids, at least during the Late Jurassic, were quadrupedal with digitigrade manus and plantigrade to digitigrade pes.”

This confirms work by Peters 2000a, b, 2011.

“They were clearly good walkers, even if hindlimbs are supposed to be hampered by the uropatagium, what could have constrained the terrestrial agility of these animals.”

A single binding uropatagium is a myth invalidated several years ago. See above.

“Thus, from ichnological evidence and contrary to the current hypotheses, non-pterodactyloid pterosaurs seem to have been good walkers even though their trackways are very rare or unidentified to date.”

This also confirms work by Peters 2000a, b, 2011.

Cosesaurus matched to Rotodactylus from Peters 2000.

Figuue 3.  Cosesaurus matched to Rotodactylus from Peters 2000.

Continuing from the abstract:
“This rarity could be due to behaviour rather than to functional capacities, many non-pterodactyloids being considered both littoral fishers and arboreal or cliff dwellers. However, the concept of non-pterodactyloid “good climbers and bad walkers” has to be modified to “good climbers and rare walkers”, unless many non-pterodactyloid ichnites have yet to be discovered.”

Many non-pterodactyloid ichnites have been discovered (Fig. 1). Unfortunately, they have been ignored and omitted by authors, including Mazin and Pouech. It’s never a good time to remember Dr. S. Christopher Bennett’s infamous threat, “You will not be published. And if you are published, you will not be cited.”

Pes of Rhamphorhynchus and matching track

Figure 4. Crayssac track different from all others. Inset: Pes of Rhamphorhynchus muensteri JME-SOS 4009, no. 62 in the Wellnhofer catalog. NOTE ADDED APRIL 18, 2020. The Martin-Silverstone paper (link above) identifies this as a manus track. It belongs to a tenrec, not a pterosaur. 

This used to be considered
crankery. Now they confirm the heretical hypotheses, but claim them as their own.

Unique among Rhamphorhynchus specimens, Rhamphorhynchus muensteri (Wellnhofer 1975) JME-SOS 4009, no. 62 in the Wellnhofer catalog has a long digit 4.

Figur 5. Unique among Rhamphorhynchus specimens, Rhamphorhynchus muensteri (Wellnhofer 1975) JME-SOS 4009, no. 62 in the Wellnhofer catalog has a long digit 4.

BTW
Earlier a published Craysaac a basal pterosaur track was matched to the pes of a particular Rhamphorhynchus (no. 62, JME-SOS-4009; Figs. 4, 5) in a 2011 blogpost on digitigrade pterosaur footprints. I heard of the Crayssac rhamph-tracks years ago and am glad to see their present publication. Still awaiting the paper. When it comes: more details.

NOTE ADDED APRIL 18, 2020. The Martin-Silverstone paper (link above) identifies this as a manus track. It belongs to a tenrec, not a pterosaur.

Cosesaurus and Rotodactylus, a perfect match.

Figure 6. Cosesaurus and Rotodactylus, a perfect match. Elevate the proximal phalanges along with the metatarsus, bend back digit 5 and Cosesaurus (left) fits perfectly into Rotodactylus (right).

We also have tracks made by pre-pterosaur fenestrasaurs.
Rotodactylus, UCB 38023, Moenkopi Formation (Peabody,1948; Peters, 2000a; Figs. 3, 6)


References
Casamiquela RM 1962. Sobre la pisada de un presunto sauria aberrante en el Liassico del Neuquen (Patagonia). Ameghiniana, 2(10): 183–186.
Mazin J-M and Pouech J 2020. The first non-pterodactyloid pterosaurian trackways and the terrestrial ability of non-pterodactyloid pterosaurs. Geobios 16 January 2020. PDF
Peabody FE 1948.Reptile and amphibian trackways from the Lower Triassic Moenkopi formation of Arizona and Utah.  University of California Publications, Bulletin of the  Department of Geological Sciences 27: 295-468.
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. 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.

Sauria aberrante MLP 61-IX-4-1 (Casamiquela, 1962)
Track D, Sundance Formation (Harris and Lacovara, 2004)
Track C, Sundance Formation (Harris and Lacovara, 2004)

https://pterosaurheresies.wordpress.com/2012/03/02/the-case-against-bipedal-pterosaurs

https://pterosaurheresies.wordpress.com/2011/08/09/pterosaurs-bipedal-quadrupedal-or-both/

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.

More evidence for a narrow chord wing membrane in pterosaurs

Unidentified by a museum number
this beautifully complete and articulated Solnhofen (Late Jurassic) Rhamphorhynchus specimen (Figs. 1, 2) preserve outlines of soft tissue, including a narrow-chord wing membrane (supporting Zittel 1882; Schaller 1985; Peters 2002; contra Unwin and Bakhurina 1994; Elgin, Hone and Frey 2011).

Figure 1. Rhamphorhynchus specimen preserving soft tissue, including a narrow-chord wing membrane. For details see figure 2.

Figure 1. Rhamphorhynchus specimen preserving soft tissue, including a narrow-chord wing membrane. For details see figure 2.

A closer view reveals a wing-tip ungual
(Fig. 2) better presented when Photoshop increases the contrast in the photo. Note: the other wingtip is more buried. This one less so. You’re still seeing the matrix over the wingtip ungual. The preparators did not excavate the entire wingtip from either wing.

Also worthy of note:
the propatagium extends to the deltopectoral crest, not to the neck. Pedal digit 5 is not connected to the uropatagia or any other membrane. And there is no single deep chord uropatagium extending between the legs. The toes are also webbed in other specimens. Here those webs are covered by the brachiopatagium.

Figure 2. Closer view of the specimen in figure 1 with overlays showing the various membranes and wingtip ungual.

Figure 2. Closer view of the specimen in figure 1 with overlays showing the various membranes and wingtip ungual, here a little bit buried along with the tip of m4.4, probably expanding the apparent size of the wing tip, just as burying an arrowhead necessitates using more mud to cover the edges and smooth out the edges.

As documented
earlier, the deep chord wing membrane is never found in pterosaurs. Both Unwin and Bakhurina 1994 and Elgin, Hone and Frey 2011 used cartoonish outlines to fudge their data. And when Elgin, Hone and Frey 2011 could not fudge their data (e.g. the Zittel wing), their desperation to avoid confirming Peters 2002 forced them to claim ‘membrane shrinkage‘ when there was none. I’m not sugar-coating this. This is what some paleontologists do in the present age. Be ready for it when you enter this field.

Click to animate. This is the Vienna specimen of Pterodactylus, which preserves twin uropatagia behind the knees.

Click to animate. This is the Vienna specimen of Pterodactylus, which preserves twin uropatagia behind the knees.

Is this a case of confirmation bias?
Yes. But I have yet to see any examples that confirm any other interpretation. Please send them if you have them.

References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111. doi: 10.4202/app.2009.0145
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Prondvai E and Hone DWE 2009. New models for the wing extension in pterosaurs. Historical Biology DOI: 10.1080/08912960902859334
Schaller D 1985. Wing Evolution. In: Hecht, M., Ostrom, J.H., Viohl, G. and Wellnhofer, P., eds, The Beginning of Birds. Proceedings of the International Archaeopteryx Conference, Eichstätt 1984, (Freundes Jura Museum, Eichstätt),pp. 333–348.
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.
Zittel KA 1882. Über Flugsaurier aus dem lithographischen Schiefer Bayerns. Palaeontographica 29: 7-80.

http://reptileevolution.com/pterosaur-wings.htm
http://reptileevolution.com/pterosaur-wings2.htm
http://reptileevolution.com/rhamphorhynchus-wings.htm

 

Those two Houston Rhamphorhynchus specimens

Two Rhamphorhynchus specimens
housed in the Houstom Museum of Natural History were recently traced and reconstructed (Figs.1-5) I don’t know the museum numbers, but a request is in. Here we’ll refer to them as the wet wing specimen and deep cut specimen for reasons that will become obvious.

Figure 1. The HMNS wet wing specimen of Rhamphorhynchus. Note the narrow chord wing membranes and the perfect layout of the specimen, almost as if it was rebuilt.

Figure 1. The HMNS wet wing specimen of Rhamphorhynchus. Note the narrow chord wing membranes and the perfect layout of the specimen, almost as if it was rebuilt.

The wet wing specimen
was preserved in three dimensions, ventral view exposed. The matrix looks very odd for Solnhofen limestone. All the parts are laid out almost perfectly, as if they were shifted to their in vivo positions. The wing membranes are not like those of the Zittel specimen. They look like they were created out of wet matrix then allowed to set.  I didn’t know if this specimen is a chimaera or not so I ran the traits through phylogenetic analysis. Evidently it is not a chimaera because few to no traits are odd for its nesting.

Figure 2. The HMNS (1862?) wet wing specimen reconstructed.

Figure 2. The HMNS (1862?) wet wing specimen reconstructed.

The caption for the wet wing specimen is more confusing than informative. The text carries the flavor of HMNS curator and famous author/paleontologist, Dr. Robert Bakker.

Figure 3. The HMNS (1862?) wet wing specimen of Rhamphorhynchus along with its caption, rewritten in text below.

Figure 3. The HMNS (1862?) wet wing specimen of Rhamphorhynchus along with its caption, rewritten in text below.

The caption reads, “Bat-wings with Super-fingers. Pterodactyls first evolved in the Triassic, long before birds acquired their wings. Instead of feathers, ‘dactyls used bat-style wing of strong, elastic skin that stretched from the hand to the ankle.

Bats use four fingers to support their wings. ‘Dactyls are simpler.; the leading edge of the wing is connected to a single enlarged digit.

Breast-bones for Flight Power
‘Dactylus evolved wide breastbones and enlarged flanges for the chest muscles that powered flight. Extra strength came from the hind limb, which flapped up and down with each stroke.

Leading edge Flap and Trail-rudder
‘Dactyls evolved a ‘leading-edge flap,” similar to what is seen on modern airplanes. A spike of bone on the wrist could tighten a narrow strip of of wing skin along the front of the main wing and turn it up or down to manipulate lift and speed.

Rhamphorhynchus and other long-tailed ‘dactyls had a rudder built into the tail. Long, thin bone rods stiffened when the tail muscles tightened, while other muscles near the hip could flip the tail in any direction.”

Good grief!
This has to be confusing to the museum visitor. To look at it, the wing membranes clearly reach the elbows, not the ankles. On a more academic vein, the tail vane acted more like an arrow vane, keeping the tail in line while in the air, and acting like a secondary sexual trait while on the ground. It was not a rudder. Rudders rotate on an axis close to their maximum width. The leading edge “flap”in the text is the propatagium and was not manipulable. That’s an idea that has dropped out of favor, but once was out there. The propatagium simply opened taut whenever the wing fingers was extended. It prevented overextension of the elbow and a strong airfoil shape. And finally, cartoon characters are ‘Dactyls,’ not museum exhibits. It was cute when Bakker did it in his book. Not so much anymore, especially when the ‘Dactyl’ is not a pterodactyl-grade pterosaur.

Figure 4. The HMNS deep cut specimen of Rhamphorhynchus with tracings.

Figure 4. The HMNS deep cut specimen of Rhamphorhynchus with tracings on a more typical Solnhofen matrix bed .his specimen was deeply buried.

The HMNS deep cut specimen
This is a more typical Solnhofen matrix presentation and there is no doubt that all the bones were uncovered in their original positions from a single specimen. Imagine how little of this specimen was exposed on the surface when first discovered. As mentioned earlier, preparators know exactly where to dig in Solnhofen strata because the buried specimen produces a ghost-like bump in the upper bedding planes.

Figure 6. The HMNS deep cut specimen of Rhamphorhynchus reconstructed. Note the clear differences, showing the two Houston specimens were not conspecific.

Figure 6. The HMNS deep cut specimen of Rhamphorhynchus reconstructed. Note the clear differences, particularly in the feet and hands, showing the two Houston specimens were not conspecific.

Phylogenetic nesting sites
Neither of these two specimens are identical to any of the previously nested specimens in the large pterosaur tree/cladogram (awaiting museum numbers before that gets updated). The wet wing specimen nests with the Imhoff (with fish) specimen alongside the giant Rhamphorhynchus specimens, n81 and n82 (in the Wellnhofer 1975 catalog) and the Vienna juvenile earlier identified by phylogenetic analysis.

The deep cut specimen nests with the dark wing specimen of Rhamphorhynchus and its clade members, including the Washington University specimen here in St. Louis.

These specimens have not been published yet, so there are no references today.

July 8, 2016:
Dr. Bob Bakker at the HMNS wrote, “You can quote me as stating that the narrow wing, carved in relief, has no biological reality. And please do pass on to your readers that there is an etiquette to follow when publishing on specimens on public view. Art pieces are treated the same way.”

I wrote to the HMNS prior to the post seeking museum numbers regarding the display pterosaurs with no reply. If a specimen is on display, I take it that it is a specimen that will not be published or has already been published. More of a show piece. Apologies were offered.

Nesting the Zittel wing of Rhamphorhynchus in the large pterosaur cladogram

Traditionally
the well-preserved Zittel wing (Fig. 1; Zittel 1882) had been assigned to Rhamphorhynchus gemmingi, of which n74 (TM 6922/6923) is the holotype.

Figure 1. The Zittel wing of Rhamphorhynchus is traced here. It nests not with R. gemmingi specimens, but with R. muensteri specimens.

Figure 1. The Zittel wing of Rhamphorhynchus is traced here. It nests not with R. gemmingi specimens, but with R. muensteri specimens. Click to enlarge. Both manual digit 5 and ungual 4.5 are present here along with wonderful shallow chord wing membrane tissue and propatagium.

I wondered if
the wing specimen had enough character traits to nest it in the large pterosaur cladogram. There it nests between the famous ‘dark wing’ specimen (JME Sos 4784, also famous for soft tissue preservation) and the MTM V 2998.33.1 specimen (Fig. 2), both assigned to R. muensteri. The Zittel wing is a little larger than both.

Figure 2. The Zittel wing specimen B St 188 II 8 nests between the 'dark wing' JME specimen and the MTM specimen, both in the Rhamphorhynchus muensteri clade.

Figure 2. The Zittel wing specimen B St 188 II 8 nests between the ‘dark wing’ JME Sos 4784 specimen and the MTM V 2998.33.1 specimen, both in the Rhamphorhynchus muensteri clade. This is a portion of a larger image.

You might recall
that Elgin, Hone and Frey (2010) dismissed the Zittel wing because it did not fit into their deep chord paradigm, but suffered from ‘shrinkage’. That is bogus thinking. More on pterosaur wings here and here. All known pterosaur specimens preserving wing membranes do so following the Zittel wing pattern. That’s a fact that other workers attempt to dismiss. 

References
Elgin RA, Hone DWE and Frey E 2010. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica in press. doi: 10.4202/app.2009.0145
Goldfuss A 1831. Beiträge zur Kenntnis vershiedener Reptilien der Vorwelt. Nova Acta Academiae Leopoldinae Carolinae, Breslau and Bonn, 15: 61-128
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Tischlinger H and Frey E 2002. Ein Rhamphorhynchus (Pterosauria, Reptilia) mit ungewöhnlicher Flughauterhaltung aus dem Solnhofener Plattenkalk. Archaeopteryx, 20, 1-20.
Wellnhofer P 1975a-c. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149: 1-30.
Zittel KA 1882. Über Flugsaurier aus dem lithographischen Schiefer Bayerns. Palaeontographica 29: 7-80.

wiki/Rhamphorhynchus

Rhamphorhynchus n28: unidentified food mass? or overlooked egg in the abdomen?

Figure 1. Rhamphorhynchus intermedius (n28) reconstructed.

Figure 1. Rhamphorhynchus intermedius (n28) reconstructed.

Rhamphorhynchus intermedius (Koh 1937, n28 in the Wellnhofer 1975 catalog) is a well preserved basal specimen (derived from the C3 specimen of Campylognathoides) with a mass inside of its torso, only part of which has been identified as a Solhnhofen fish (Figs. 2,3).

Figure 2. Wellnhofer 1991 illustrates the abdominal mass as part of a fish and other unidentified elements.

Figure 2. Wellnhofer 1991 illustrates the abdominal mass as part of a fish and other unidentified elements.

The rest of the abdominal mass
is unidentified (Fig. 2). Wellnhofer 1991 considered it food. Considering its shape, size and placement, I wonder if the posterior mass is actually a nearly full term egg (Fig. 3). I don’t think it makes much sense to consider such an abdominal mass as “unidentified food” when no other known specimen has a similar mass of undigested food. That would mean the stomach could expand to fill the abdomen. Usually the only thing that crowds out other organs and air sacs is an egg or a number of eggs in other reptile taxa. Check out this kiwi X-ray for an extreme example.

Figure 3. Skeletal elements of Rhamphorhynchus intermedius (n28) along with an ingested fish and what appears to be a possible egg.

Figure 3. Skeletal elements of Rhamphorhynchus intermedius (n28) along with an ingested fish and what appears to be a possible egg. Note the overlapping sets of gastralia. It looks like the jaws of the fish are displaced here. Wellnhofer did not see the large eyeball identified here. Note the left scapula and coracoid are inverted. There sternal complex has a similar unexpectedly bumpy texture as the purported egg.

Rhamphorhynchus intermedius
is a medium-sized Rhamphorhynchus nesting at the very base of the clade between the larger Campylognathoides and the smaller Bellubrunnu. Thus it is a transitional taxon, step one in an extreme example of phylogenetic miniaturization. No one understood this nesting prior to the phylogenetic analysis documented at ReptileEvolution.com because no one included a long list of Rhamphorhynchus specimens in analysis prior to or since. I’d like to encourage other pterosaur workers to do so and test this hypothesis of relationships.

Texture
The “egg” has an odd texture, but then so does the sternal complex. Not sure why.

Previous examples?
Two smaller examples of “something else” in the abdomen of – or just aborted from the abdomen – other specimens of Rhamphorhynhcus can be seen here and here.

References
Koh TP 1937. Unterscuchungen über die Gattung Ramphorhynchus. – Neues Jahrbuch Mineralogie, Geologie und Palaeontologie, Beilage-Band 77: 455-506.
Wellnhofer P 1975a-c. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149: 1-30.

wiki/Rhamphorhynchus

Four new Rhamphorhynchus specimens added

Over the weekend
I added four new Rhamphorhynchus specimens to the large pterosaur tree (subset Fig. 1). Once again, each is distinct from one another and no two match in all traits…

Figure 1. Rhamphorhynchus cladogram with four new taxa.

Figure 1. Rhamphorhynchus cladogram with four new taxa.

…except
the one-third-size juvenile, commonly called “The Vienna specimen” NHMW 1998z0077/0001, which nests with the adult largest Rhamphorhynchus of all, BMNH 37002, n82 in the Wellnhofer 1975 catalog.

Fig. 5. Rhamphorhynchus specimens that have been bitten and fossilized with Aspidorhynchus, a Solnhofen fish of 60cm length.

Fig. 2. Rhamphorhynchus specimens that have been bitten and fossilized with Aspidorhynchus, a Solnhofen fish of 60cm length.

The four new specimens
include two specimens caught in the jaws of Late Jurassic fish (Fig. 2), the Imhof specimen and WDC CSG 255. Also included are BRI010, again from the Imhof collection and TMP 2008.41.0001, a sister to the dark wing specimen. The latter three bridge the gap between the n81 and n82 rare giants and the smaller more typical specimens, like the dark wing specimen, JME SOS 4784. The Imhof specimen nests basal to the giants.

Are all Rhamphorhynchus specimens congeneric? Or conspecific?
No. Many look similar, but on closer examination, or phylogenetic analysis, the differences are manifold, contra Bennett 1995.

  1. Some adults are tiny, others are mid-sized, and a few are relative giants
  2. Some have a short rostrum, but most do not.
  3. The finger and toe patterns vary greatly. The free finger sizes vary, too.
  4. Sternal complex shapes vary greatly.
  5. Some have a robust cervical series. Others do not.

Some things do not change between specimens

  1. The wing membrane has a shallow chord at the elbow, as in all pterosaurs.
  2. The nares and antorbital fenestra are both small
  3. The humerus is relatively short and the torso long such that when tucked posteriorly the elbow is still several vertebrae away from the anterior ilium.
  4. The teeth lean anteriorly
  5. The metatarsals spread and pedal digit 5 is relatively short.
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 3. Prior to today’s additions, these were the taxa included in analysis. 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. Click to enlarge with new taxa added. 

Many of these things don’t become apparent
until you can see the whole lot reconstructed at one glance, or in phylogenetic analysis where you really do pay attention to details that lump and split clades and nodes.

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.
Smith-Woodward A 1902. On two skulls of the Ornithosaurian Rhamphorhynchus. Annals and Magazine of Natural History, London, (7) 9:1-5.
Wellnhofer P 1975a-c. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149:1-30.

wiki/Rhamphorhynchus