Elgin 2014 PhD dissertation: nits and picks, part 2

Yesterday we looked at
a misidentified pterosaur specimen from the State Museum of Natural History Karlsruhe (SMNK) that wasn’t a Tupuxuara, as originally considered by then PhD candidate, now Dr. Ross Elgin. Consider that blogpost an unlabeled part 1.

Today, in part 2,
we’ll take a look at several other aspects of the Ross Elgin 2014 PhD dissertation that deserve credit and discredit. 

FIgure 1. GIF animation of image from Elgin 2014 comparing wing membrane configurations and a more accurate rendition of what Peters 2002 proposed. See text for list of issues here.

FIgure 1. GIF animation of image from Elgin 2014 comparing wing membrane configurations and a more accurate rendition of what Peters 2002 proposed and Elgin distorted. See text for list of issues here. In reality, like birds, the wings and hind limbs are decoupled. Most pterosaur workers don’t believe the data.

Elgin mistakenly reported,
“The primary flight membrane is reconstructed with an ankle attachment of the trailing edge, a configuration that was never fundamentally altered throughout the evolutionary history of the group.” Elgin ignored the bipedal origin of the Pterosauria, and ignored the narrow-chord wing membrane data that attends every pterosaur fossil that preserves wing membranes, perhaps on the advice of his mentors. And he ignored, or distorted, what Peters 2000 actually proposed for a wing membrane and bone orientation in pterosaurs (Fig. 1).  This may be what happens when you have to feed the fever dreams of a teacher rather than recording actual data. Elgin reported, “I am indebted to both David Hone and Eberhard “Dino” Frey for the opportunity to undertake this project and continue my work on the enigmatic and curious group of animals known as pterosaurs.”

Solutions to problems with Figure 1.

  1. The scapula/coracoid should rotate laterally, as in all articulated fossils
  2. The elbow should angle further posteriorly, as in all articulated fossils (+ in birds and bats)
  3. The pteroid should point to the deltopectoral crest, as in all articulated fossils
  4. The free fingers should point ventrally (in flight). Crushing typically rotates the narrow claws anteriorly.
  5. Metacarpals 1-3 should line up anteriorly, not stack themselves against mc4
  6. Manual 4.4 should articulate at an angle to m4.3, deepening the wing tip
  7. The propatagium should extend only to the deltopectoral crest
  8. The brachiopatagium should stretch between the wingtip and elbow with a fuselage fillet to distal thigh, as in all articulated fossils
  9. The thigh should be more meaty based on the long anterior ilium
  10. The femur should extend laterally to form a horizontal stabilizer (and note the sprawling lepidosaur orientation!)
  11. The femur should be flipped, as shown in Elgin’s figure 3 below.
  12. The uropatagia do not extend to the tiny tail, as in all articulated fossils. Elgin’s essentially creates a single uropatagium, which is a decades-old false paradigm.

If the above illustration by Elgin 2014 looks familiar
it’s because we looked at it earlier here, after publication of Elgin, Hone and Frey 2011. Also check out all the images on this ReptileEvolution page. You might remember these authors employed the fiction of ‘wing membrane shrinkage’ to explain the data, instead of just accepting the data, as is. We have evidence of pterosaur ancestors with wings decoupled from the hind limbs, so there was never a gliding transitional phase. Flapping preceded flying.

Along the same lines
Hone and Benton (2007, 2008); and Nesbitt and Hone (2010a, b) preferred to see things their own way, rather than strict adherence to the data. So, maybe young Elgin was unduly influenced by his professors and mentors.

Elgin introduced us to
Microtuban altivolan, which he described as a non-azhdarchid azhdarchoid. In the large pterosaur tree (LPT, 1189 taxa) Microtuban indeed nests at the base of the azhdarchid clade, arising from certain dorygnathids, a relationship Elgin never tested.

Elgin suggested a possible sexual dimorphism,
“where the pelvic girdle lacks a symphysis and remains open even in large adults is observed within Coloborhynchus robustus.” (Fig. 2) Let’s blame this one partly on his teachers, and partly on sloppiness. The base of the pterosaur pelvis opens and closes in phylogenetic patterns, not gender patterns. That tricked up Bennett, too, and Elgin’s teachers followed Bennett’s mistakes. On the sloppiness point, the open pelvis of C. robustus is missing its ventral and posterior borders, exactly the bones needed to join the ischia together (Fig. 2). It doesn’t look like Elgin was cheating. He must have thought he was not cheating. But he was cheating by changing points of view, changing scales and not adding back missing bone to follow generic patterns. This was all resolved with a little tracing in Adobe Photoshop, the paleontologists’ best friend.

Figure 1. Elgin compared these two Coloborhynchus pelves together, but failed to align them, scale them and add back missing bone.

Figure 2. Elgin compared these two Coloborhynchus pelves together, but failed to align them, scale them and add back missing bone.

Elgin was also tricked by
traditional archosaur patterns and paradigms in ontogeny. He expected sutures to close at adulthood. This tricked up Bennett, too. Instead, since pterosaurs are lepidosaurs, sometimes they do, sometimes they never do, and sometimes they fuse sutures before maturity and reading their final size. It’s all phylogenetic, not ontogenetic with lepidosaurs, including pterosaurs.

Figure 2. Coloborhynchus robustus (bones and outlines from Elgin 2014) compared to C. spielbergi (b&w). Notes added.

Figure 3. Coloborhynchus robustus (bones and outlines from Elgin 2014) compared to C. spielbergi (b&w). Notes added.

Elgin described and did not illustrate the missing wing finger:
“The wing finger phalanges in almost all pterosaurs are similar in form with expanded proximal and distal margins, the shafts of which show various degrees of curvature. Those preserved in SMNK PAL 1133 are not exception and agree well with other descriptions of pterodactyloids.” This description can only be the result of naiveté and inexperience. In reality phalanx proportions change between genera and species. It would have been helpful to see the wing finger of C. robustus since the C. spielbergi wing finger is missing.

Elgin 2014 mistakenly considered

  1. pterosaurs to be archosauromorphs.
  2. anurognathids to be basal pterodactyloids
  3. Darwinopterus to be ‘an animal intermediate’ linking basal to derived pterosaurs

These issues are resolved and settled
here and here when you add more taxa. It’s good for science to be critical. If nothing else this blog will hopefully show all readers that published scientific text and figures can sometimes include errors that can be exposed and corrected by colleagues.

It’s not okay
to disfigure the figures of other workers and then claim that’s the essence of their work (contra Fig. 1). We’ve seen this before with other PhDs.

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
Elgin RA 2014. Palaeobiology, Morphology, and Flight Characteristics of Pterodactyloid Pterosaurs. Innaugural Dissertation. Zur Erlangung der Doktorwürde Fakultät für Chemie und Geowissenschaften Institut für Geowissenschaften Ruprecht-Karls-Universität Heidelberg. Available online  here.
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Nesbitt SJ and Hone DWE 2010a. An external mandibular fenestra and other archosauriform character states in basal pterosaurs. Palaeodiversity 3: 225–233
Nesbitt SJ and Hone DWE 2010b. An external mandibular fenestra and other archosauriform character states in basal pterosaurs. Palaeodiversity 3: 225–233





15 thoughts on “Elgin 2014 PhD dissertation: nits and picks, part 2

  1. Surely you must realize that just because you find a different topology, the phylogeny is not “resolved and settled?” Not only do those studies of yours remain unpublished outside of summaries in Prehistoric Times, so that the vast majority of pterosaur workers don’t think they’ve even presented in a venue that deserves to be engaged with. But literally every professional in the field disagrees with you, and every one of them who has examined your analysis says it’s fatally flawed. These don’t make your ideas incorrect, but being universally and strongly discounted is basically the opposite of “resolved and settled.” You, by definition, can never resolve or settle a phylogenetic issue- the very act requires a change in opinion of other parties.

  2. Where is the fatal flaw? Is it because I have included more taxa?
    Literally every professional? Where is the correspondence? I have not seen it.
    And then details, Mickey. Where are the facts and figures?

    • My point here is that it doesn’t even matter why everyone else disagrees with you. Even if your results were correct and everyone else was wrong to criticize them and your methods, the phylogenetic issues would not be resolved or settled. For an issue to be settled and resolved, the disagreeing parties have to settle for a resolution. They have to stop disagreeing. And you know that at least some professional pterosaur workers (Elgin, Hone, Naish, etc.) disagree with your result that pterosaurs are outside Archosauromorpha. Because this disagreement exists, by definition the issue has not been resolved or settled.

      • That’s one definition. But by that definition the ‘fact’ that the Earth is a sphere is not resolved or settled because there are some folks out there who still believe the world is flat. (Recent news on the one-man rocket story who flew to 1800 feet, case in point). On the day that Elgin, Hone and Naish, etc. employ the taxa in question, we’ll review this discussion. Until then… go with tested results, not faith/belief/tradition, even if promoted by PhDs.

      • You can’t evade your mistake that easily. I stated “professionals in the field” and “professional pterosaur workers” are what matters in a scientific resolution involving pterosaurs. But no professional in a field involving planetary shape thinks the Earth is flat, regardless of the opinion of laymen. So the shape of the Earth is scientifically resolved.

        Do you honestly think Elgin, Hone, Naish et al. are equivalent to flat earthers in their ignorance of the subject and that archosauromorph pterosaurs are as likely as a flat Earth?

  3. PS. With so many studies published online, why don’t you accept results published online at ReptileEvolution.com and PterosaurHeresies? You also know that results published years ago here have been duplicated by others recently. You know that whenever I find a valid error here it is corrected. Next time you talk to ‘literally every professional’ ask them where their pterosaur reconstructions are… and why they omit long lists of taxa.

    • Because I know you don’t fix the most important valid errors- those of your methodology. Whether it’s interpreting DGS results, forming characters in a way that makes it impossible for PAUP to interpret them, not including any of the proposed conflicting characters, etc.. Which is also what every professional who has looked at your data says.

      To phrase this in a way that hopefully makes it obvious- you have always treated things as if we think your problem is only ‘garbage in, garbage out’. You ask what miscodings (garbage in) exist in your matrix, and what “mismatched sisters” (garbage out) exist in your tree. But the larger issue is that the machine you’re placing garbage into is itself made of garbage, so can never give you good results. And yet you refuse to try to fix that machine, by modifying and adding characters.

      Until you fix that machine, you will never get defensible results, no matter how many codings you fix or how many taxa you add.

  4. You’re blackwashing again. And creating a false premise, even in your own mind. There is some vague hope within you that bad scores/codes/characters are messing things up… yet you cannot tell me which taxa should not nest together as a result. Sure the LRT and LPT are less than perfect. But that’s okay. We’re dealing with majority/minority issues here. I find bad scores all the time and make corrections. There’s a great feedback loop when you check your results and scores. The results still yield taxa that display a gradual accumulation of traits, generally with high Bootstrap scores, echoing evolutionary events. If you don’t like a character, leave it out and recheck your new results. Don’t leave out a taxon, unless it is poorly represented.

    • It’s not blackwashing to say your method that nobody else utilizes is incapable of giving you accurate cladograms. Your method also gives ME bad cladograms.

      My Lori matrix is 700 characters, three times as many as yours. And I’ve scored it for every single Mesozoic theropod that’s not just known from fragments. 600 or so compared to your ~120, five times as many as you. Nothing suprageneric, plus you and I basically agree about what counts as a Mesozoic theropod, so you can’t say I’m analyzing lepidosauromorphs with archosauromorphs or something to ruin my result.

      My 700 characters are taken from Theropod Working Group analyses, which were designed to determine coelurosaur relationships. And they recover what I think are excellent maniraptoriform relationships, but as you move towards the base things get weird. Coelurosaurian ceratosaurs, a big Carnosauria including tyrannosaurids, diphyletic megaraptorans, etc.. Some groups are still normal, but some have odd inclusions, or novel arrangements of taxa. I’d also say my mpts “display a gradual accumulation of traits” and have sisters that don’t look out of place, even outside Coelurosauria.

      Sounds familiar, right? Just like your LRT with its 228 characters taken from basal amniote analyses. You apply those to birds or mammals or amphibians or lizards or whatever, and you get weird results with some traditional aspects. You don’t get Cetacea or Galliformes or a thousand other groups because the characters found to support them were not in your amniote list, just like I didn’t get Tetanurae or Megaraptora in their traditional form because the Theropod Working Group never tried to deal with those parts of the tree and I haven’t added characters from Carrano et al. (2012), Novas et al. (2013), etc.. And my scores are extremely accurate and characters mostly well formed, so it doesn’t matter if you only fix your codings and character formulations. Your trees would still be bad like mine are, for a more basic reason.

      Neither you nor I nor anyone else will ever get defensible cladograms for group X by using a few hundred characters designed to create a cladogram of group Y. It doesn’t matter how many taxa we add, or if my codings are accurate, or if the sisters look good, or your bootstraps are high, or the traits gradually accumulate, or my characters are formulated well. If you scored tetrapods and I scored theropods for Conrad’s squamate characters we’d get trees that are weird in new ways, and if we did so for Zack’s mammal characters we’d get new trees that are weird in yet other ways. That’s part of why my non-coelurosaur topology is almost entirely different from yours in its weird aspects.

      If you were right that a few hundred characters could be used to reliably generate tetrapod relationships in any portion of the tree as long as taxon sampling is high, then our Mesozoic theropod trees would match. But they don’t, because neither of us included many relevant characters for non-maniraptoriform theropods. I recognize this and have limited the matrix to Ornitholestes and taxa closer to birds for the Lori manuscript. You should recognize it too so that the LRT can be more than ‘look at what happens when I add every tetrapod to a 228 character matrix intended for basal amniotes’.

  5. Excellent arguments, Mickey, but it avoids the question: which two taxa are mismatched on the LRT and where should they nest instead? How many times have I asked for this? To your point: no one else is using the LRT because it has not been published in an academic journal. And finally, I publish (online) results that I get, encouraging others to replicate taxon lists. If my theropods could use a shakeup, please suggest five or six that I need to add and we’ll see what happens.

    • How many times have I told you that “which two taxa are mismatched on the LRT?” is a pointless question to ask? At least once in this post- “You ask what miscodings (garbage in) exist in your matrix, and what “mismatched sisters” (garbage out) exist in your tree. But the larger issue is that the machine you’re placing garbage into is itself made of garbage, so can never give you good results.”

      And I just said “It doesn’t matter how many taxa we add” yet you say “please suggest five or six that I need to add.”

      No one can fix your problem by adding taxa. You can code every taxon for three times as many characters (as shown by my Lori analysis) and it doesn’t matter. Similarly, suggesting where your results are wrong is futile because your process can never work (ditto for correcting codings). It’s not you that’s the problem, it’s the process. I could code your taxa for your characters, or 300 characters from any other study and the results would be on average bad. Nobody could code a few hundred characters across all of Tetrapoda and get a good result. It doesn’t work and will never work. Can never work. Everyone would get a result, but it’s on average a bad result.

      That’s why nobody else is doing this. Why isn’t everyone interested in phylogenetics just plugging every taxon into a few hundred character matrix and claiming success? Because it doesn’t work.

      We might as well be saying “You’re throwing stones into mud and expecting a good result.” “Ah, but which muddy stones are mismatched?” “Throwing stones into mud will never give good results, it doesn’t matter how they emerge.” “Ah, but which stones have I colored incorrectly before throwing them into mud?” “Again, once they go through mud you can’t get good results.” “Ah, but which additional stones should I throw into mud?” “No, it doesn’t matter how many stones you throw, the mud ruins them all.” “Ah, you’re blacklisting me by saying my stones can never be good.” “No, if anyone throws stones through mud like that, they’ll get bad results too.” “Excellent arguments, but which two stones are mismatched and which additional stones should I throw into mud?” “…”

  6. re: Do you honestly think Elgin, Hone, Naish et al. are equivalent to flat earthers in their ignorance of the subject and that archosauromorph pterosaurs are as likely as a flat Earth?

    Yes, but limited to the subjects reported here. Please keyword any of their names in this blog over the last seven years and the reasons why can be read at your leisure.

    • So just to make sure, you believe “archosauromorph pterosaurs are as likely as a flat Earth?” That is a subject reported here often, after all….

      • I keep looking for a paper that nests pterosaurs with archosauromorph taxa that share pterosaur traits, and a better (more parsimonious) suite of traits than those published here and in Peters 2000. Even pterosaur workers claim pterosaurs arose without obvious precedent. Send me the paper that tests all relevant taxa with precise tracings/reconstructions (Senter did a poor job) and I’ll make the necessary changes here.

        And re: characters vs. taxa. I encourage you to repeat the experiment, come to me with solutions and chill out.

      • I agree analyses on the archosauromorph side aren’t great, but do you believe “archosauromorph pterosaurs are as likely as a flat Earth?”

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