Is Cycnorhamphus just a baby Moganopterus?

No. 

And yet, when you look at them, Cycnorhamphus has the classic (traditional, false) skull traits that mark it as a juvenile of Moganopterus (Fig. 1, shorter skull, smaller crest and larger eyes, and at 1/5 the size, Cycnorhampus would be just 1.33x larger than a Moganopterus hatchling at 1/8 the size).

So, what’s my point?

 Click to enlarge. The cycnorhamphids. Moganopterus is the largest one and has the longest rostrum, longest crest and smallest eye. Cycnorhamphus, by comparison, has juvenile features. Even smaller cycnhorhamphids also exist in this Gulliverian clade.

Figure 1. Click to enlarge. The cycnorhamphids. Moganopterus is the largest one and has the longest rostrum, longest crest and smallest eye. Cycnorhamphus, by comparison, has juvenile features. Even smaller cycnhorhamphids also exist in this Gulliverian clade. Feilongus is a transitional taxon. Or is it… a teenager??

Many are the pterosaur workers
who think tiny pterosaurs (Fig. 1) are mere juveniles, unworthy of inclusion in phylogenetic analyses. They think (without phylogenetic analysis) that baby pterosaurs had a shorter rostrum and larger eyes, which we falsified earlier several times. (In the same vein the experts should also discount small shrews, rodents and tiny ‘cute’ primates as equally unworthy to be included in mammal analyses.) My point is: size bigotry has been applied across the spectrum of pterosaurs.

If you don’t include tiny pterosaurs in analyses, as seen here, you’ll never figure out what they really are, as seen here.

Large pterosaurs with long crests evolve from smaller pterosaurs with shorter crests or no crests. That’s the way evolution works. But that fact seems to be lost on pterosaur workers who ignore tiny pterosaurs in phylogenetic analyses.

Not Boreopterids
By the way, Feilongus and Moganopterus are listed in Wikipedia and referenced in Witton (2013) as boreopterid ornithocheirids. Jaime Headden has a word to say too. Even though  Feilongus and Moganopterus are known only from skulls, when forced to nest with boreopterids, the shift adds 20 steps to the MPT in the large pterosaur tree. Adding these two to Gegepterus among the ctenochasmatids adds 27 stesp. In the large pterosaur tree, cycnorhamphids are the sisters to ornithocheirids (which include boreopterids), so these mistake are easy to make.

Long eggs are predicted for Moganopterus
Since Pterodaustro demonstrates that long rostrum taxa produce long eggs to house long rostra, it’s easy to predict that the eggs of Moganopterus will likely be long ones, as predicted here for Quetzalcoatlus.

References
Lü J-C, Pu H-Y, Xu i, WuY-H and Wei X-F 2012. Largest Toothed Pterosaur Skull from the Early Cretaceous Yixian Formation of Western Liaoning, China, with Comments On the Family Boreopteridae. Acta Geologica Sinica 86 (2): 287-293.
Bennett SC 1996. On the taxonomic status of Cycnorhamphus and GallodactylusPterosauria: (Pterodactyloidea). – Journal of Paleontology 70: 335–338.
Bennett SC 2010. The Morphology and Taxonomy of Cycnorhamphus. Acta Geoscientica Sinica 31 Supplement 1, The Flugsaurier Third International Symposium on Pterosaurs.
Jiang S-X and Wang X-L 2011. A new ctenochasmatid pterosaur from the Lower Cretaceous, western Liaoning, China. Anais da Academia Brasileira de Ciencias 83(4):1243-1249. online pdf
Quenstedt FA 1855. Über Pterodactylus suevicus im lithographischen Schiefer Württembergs. Doctoral thesis, Universität Tübingen.
Seeley HG 1870. The Ornithosauria: an elementary study of the bones of pterodactyles. – Cambridge: Deighton, Bell, & Co.: xviii + 135 pp., 12 plates.
Wellnhofer P 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133. International Dinosaur Symposium. Geological Publishing House, Beijing 195-203.

wiki/Cycnorhamphus
wiki/Moganopterus

13 thoughts on “Is Cycnorhamphus just a baby Moganopterus?

  1. “Many are the pterosaur workers who think tiny pterosaurs (Fig. 1) are mere juveniles, unworthy of inclusion in phylogenetic analyses. They think (without phylogenetic analysis) that baby pterosaurs had a shorter rostrum and larger eyes, which we falsified earlier several times.”

    First: The we you are referring to in this statement is not a plural. It is you. No one else has confirmed your results about pterosaur isometric growth.

    Second: Why does skull isometry make sense in pterosaurs? Cranial changes happen for a reason in other vertebrates during ontogeny. Usually that change is based around a change in diet…which makes sense. Smaller animals can’t eat larger things. Some animals are restricted from eating solid food (see especially mammals, but also juvenile birds that are fed with crop milk) during early ontogeny. Yes, they look cute, but is that a feature that is enhanced by non-pterosaur vertebrates in order to elicit parental care? Or is “cuteness” a response by parents to the functional restrictions on the diet of juveniles and the corresponding morphological differences? Both might be at play but I would argue the later plays a more important role since these functional restrictions are external to the organism (i.e. are forced on the juveniles by the rest of the environment).
    What is my point? Well by saying that there is no cranial allometry you are also implicitly stating that juveniles and adults were equally suited to consume their food, regardless of vast proposed size differences. I don’t see the extraordinary evidence here required to support the extraordinary claim that pterosaurs were developmentally different than any other known terrestrial vertebrate.

    • I make no comments on diet. But I refer you to previous posts that demonstrate with real fossils, that some tiny pterosaurs also had long rostra and embryos were identical enough to adults to nest with them in phylogenetic analysis.

      Real pterosaur fossils break your logic chain. Gotta deal with it. Real data, not supposition.

      The “we” refers to myself and my readers. Like when parents say, “we read that book last night.”

      • You are correct you did not explicitly mention diet but any discussion of rostrum shape is going to center around diet in vertebrates since that’s where food acquisition occurs. I am aware that small pterosaurs have long snouts. So what? So do hummingbirds. That doesn’t make them hatchling cranes or storks, even though they share the trait of long snout.
        If, as you state, pterosaurs exhibit isometric growth then you are also stating, even if you aren’t explicit about it, that hatchlings and juveniles were perfectly adapted to their food source with the same rostrum ratio as their massively larger parents. Again, this flies in the face of virtually every terrestrial vertebrate. The only confirmed embryo that I am aware of with a long snout is Pterodaustro. This is also one of the few examples of animals that would eat the same prey with as both adults and juveniles since they were filter feeders. Crainial allometry wouldn’t be needed as much here and that’s what we see. In other cases juveniles have to develop their skull differently in order to acquire adult food items (larger fish, bugs, seeds, etc.).

        Also, I didn’t comment on this one last but, “Since Pterodaustro demonstrates that long rostrum taxa produce long eggs to house long rostra, it’s easy to predict that the eggs of Moganopterus will likely be long ones, as predicted here for Quetzalcoatlus.”
        Sample size = 1. That’s not well supported. Long eggs are known from a few other (non-pterosaur) vertebrates, most notable the exceptionally short-snouted oviraptors. Correlation =/= causation. The fossil record is incomplete and our understanding of it is even more incomplete. Extrapolating from a single data point is “dangerous” and often ends up being wrong.

      • Hatchlings at 1/8 the size of their parents also have teeth 1/8 the size of their parents, so – I’m guessing – they ate different sized food. The baby ate insects of a variety of sizes, somewhere where they didn’t often fossilize, like damp leaf litter.

        With regard to Pterodaustro, the filtered food would be 8x larger relatively for the baby than the adult. I can’t say that they ate the same food, but the possibility is strong. It’s the only baby found in association with adults and juveniles of several sizes.

        You seem to be stuck on keeping a similar diet when the current evidence indicates that babies lived alone and were independent of the mother.

        Re: Moganopterus, thanks, but there are three eggs known. The second the JZMP specimen belongs to an ornithocheirid, with a medium length rostrum and it is a medium length egg. The IVPP specimen is rounder and belongs to a short rostrum anurognathid, so the pattern is present. More samples, as you indicate, would be great. It’s okay to assume patterns if you have small data points. Our sun has planets. Now we know other suns have planets, something we extrapolated long ago from a sample of one. That wasn’t so dangerous, was it? Your use of the word “dangerous” and “wrong” are samples of your bias. Relax, Rob. Just go with the data like I do. It’s okay to change your mind when new data moves the mark.

  2. Also, I am still aware I need to respond to your Scutellosaurus/Scelidosaurus post. Had some data snafus (all my Scutellosaurus codings didn’t survive my old laptop’s death) and I have been busy finishing up my two MS classes. It is coming.

  3. “Hatchlings at 1/8 the size of their parents also have teeth 1/8 the size of their parents, so – I’m guessing – they ate different sized food…You seem to be stuck on keeping a similar diet when the current evidence indicates that babies lived alone and were independent of the mother.”

    These two taken together indicate that I may not have been clear or you misunderstood my point. I 100% agree with you that hatchlings ate different things in virtually every case from whatever the adults ate. That is the crux of my point, in fact. Juveniles had to be eating different things than the adults. That is not only the crux of my argument but a big problem with your statements. If pterosaurs exhibited only isometric growth then you are saying that each life stage was well-enough adapted to the target prey of that species without any changes. The same relative beak shape that would sustain an adult pterosaur for decades on a diet of large fish (as just an example) would also be near perfect for getting the juveniles (which, without parental care, would have a high mortality rate to begin with) through their completely different life style and into adulthood.
    Snouts on animals are like tools. In your isometric hypothesis you are saying (to use an analogy) that if chopsticks work for sushi they will also work for a T-bone steak. Where is your evidence for this? You tell me to do with the data and that is what I am doing. No convincing evidence for isometric-only growth in pterosaurs means the hypothesis cannot be supported at this time.

    “With regard to Pterodaustro, the filtered food would be 8x larger relatively for the baby than the adult. I can’t say that they ate the same food, but the possibility is strong. It’s the only baby found in association with adults and juveniles of several sizes.”

    Since the filtered food would still be orders of magnitude smaller than even a hatchling Pterodaustro I think the relative sizes here have a negligible impact on the discussion.

    “Re: Moganopterus, thanks, but there are three eggs known. The second the JZMP specimen belongs to an ornithocheirid, with a medium length rostrum and it is a medium length egg. The IVPP specimen is rounder and belongs to a short rostrum anurognathid, so the pattern is present.”
    Mind e-mailing me the papers?

    “It’s okay to assume patterns if you have small data points.”
    No, it is okay to construct hypotheses based on small data sets. Those doing the hypothesizing shouldn’t be surprised if their hypothesis cannot be supported with better data.

    “Our sun has planets. Now we know other suns have planets, something we extrapolated long ago from a sample of one.”
    We didn’t extrapolate, we hypothesized. And that hypothesis was based on lots of prior experiments within our solar system that gave us a model on how planetary systems form. Once we had the technology we were able to test it, yes. And guess what? It looks like a lot of our assumptions about planetary formation are in serious need of revision. Giant gas planets with orbital periods of a few days around sun-sized stars? Stray planets drifting free of any star? Very different from what we see in our solar system.

    “Your use of the word “dangerous” and “wrong” are samples of your bias.”
    I use “wrong” as a shorthand for something is unsupported by repeated (or repeatable) scientific tests. And yes, something can be “wrong”. I have been wrong before about things both personally and things I have hypothesized and tested. I don’t see how that shows a bias. In fact I think it shows that I am willing to “change my mind” when data shows something other than what I had expected/suspected/hypothesized.
    As for “dangerous”, it is dangerous to assert that one is correct based on limited, unsupported, or untested data. Why? This is the sort of thing that leads to confirmation bias which is dangerous in science. It leads to unscientific thought processes and assertions that cannot be supported by data.

    “Relax, Rob. Just go with the data like I do. It’s okay to change your mind when new data moves the mark.”
    Do you? I’ve made very specific critiques in the past about some of the data you have used, specifically the statistical support for some of your claims. Yet have you changed your characters or taxa list based on those data? Others have pointed out problems with the data as well and you have generally been dismissive. Have you responded to any major criticism to your tree or data set in a way that significantly altered your favored tree? Mickey Mortimer did a good breakdown on your tree and errors in the coding. Those are specific and very important. He showed that your tree, when correctly coded, would change. These are specific errors that are easily correctable and verifiable. Why not adopt them? It seems (and I have made this critique before, I believe) that your “going with the data” changes only occur when it is your discovery and not something someone else has pointed out.

    • To your major points: I substantially revised my data matrix based on M. Mortimer’s comments. SMNS 12352 moved to the crocs because of it and revised those posts. M. Mortimer also added a substantial number of traits, that were, unfortunately not listed in the matrix he sent. So I can’t comment on those. I did notice that his tree found theropods to be derived, rather than basal, which is a problem which I reported. Basically our trees were the same, only his was upside-down compared to mine. Has he fixed that problem yet?

      With regard to the eggs and their contents you’ll find the images online. No one has attempted detailed drawings of the contents except yours truly. The Pterodaustro egg image is held in trust and I cannot publish it first.

      Sorry if this reply doesn’t cover all your bases. Write more shorter notes next time.

      • I have Mortimer’s matrix and I’m not sure what traits you are referring to being included post-discussion.

        “With regard to the eggs and their contents you’ll find the images online.”
        I generally don’t get my data from doing Google Image searches. Are there published papers on these eggs or are these things that you have discovered?

        “Write more shorter notes next time.”
        Sorry, I thought a detailed, line-by-line response to your post (and subsequent comments) was what you were looking for.

  4. Okay, I read through http://www.reptileevolution.com/ivpp-embryo.htm and http://www.nature.com.ezproxy2.library.arizona.edu/nature/journal/v429/n6992/pdf/429621a.pdf and other papers listed. I think that your nearly complete restoration of the IVPP V13758 embryo is vastly over-restored. Even if you have photos at 10x the resolution of the published photos I don’t see how you are making out those details. It is hard enough to make out the features that the authors ascribe to the embryo, let alone your reconstruction. Getting back to your earlier statements:
    “The IVPP specimen is rounder and belongs to a short rostrum anurognathid, so the pattern is present.”
    Except the authors A) assign it (tentatively) to an Ornithocheirid and B) caution that it can’t be readily assigned due to its immature state. I will attempt some DGS on this specimen based on the published photos (unless you have a better photo you are willing to share) and come back with my results soon. I withhold judgement on whether I will be able to make out the features you describe since the test will provide the evidence we need. I would like to know why you disagree with the authors’ assessments on the state and assignment of the embryo. I understand your argument via DGS. Is there anything else I have missed as to why you disagree with Wang and Zhou?

    • On the IVPP specimen: From the tracings I made a reconstruction. From that I scored a matrix. The results nest the IVPP embryo with the largest anurognathid, Dimorphodon(?) weintraubi, and the IVPP specimen is the latest surviving anurognathid (Cretaceous) and it has the longest metacarpals, so it looks like a short rostrum ornithocheirid at first glance. No details support that though. Remember the IVPP embryo is as large as the other anurognathid adults, which can lead to confusion (personal experience) and the search for a larger adult taxon, like an ornithocheirid, to be a parent. Key to your acceptance of isometric growth in pterosaurs is going to be Zhejiangopterus, for which we have a nice published growth series that I presented earlier in graphic form at Pterosaur Heresies (use keyword search) and here: http://reptileevolution.com/zhejiangopterus.htm

      I can also send you my original layered Photoshop files of the IVPP embryo via Internet large file sharing servers on request.

      • That would be great, I would really appreciate the files if you are willing to share them.

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