Evolution: like explaining the details of a magic trick

Some people really don’t want to know in detail how evolution works.
Unfortunately, this list of people includes some professors and students of paleontology. They prefer to keep a few enigmas and mysteries in their pocket even though all workers employ the number one tool of evolutionary biologists and paleontologists, the cladogram produced by phylogenetic analysis. Their magic trick is to omit certain taxa to get or retain the traditional results they want. Some academics think their fellow workers do this to ensure publication, staying within the current orthodoxy.

Example one:
It has been nearly twenty years since Peters 2000 presented several pterosaur ancestor, each one closer to pterosaurs than the next and each one closer to pterosaurs than any tested archosaur. All traditional archosaur candidates, including Scleromochlus (Benton 1999), were tested by simple taxon addition to four previously published analyses.

  1. Has anyone adopted this hypothesis in the last twenty years? No.
  2. Has anyone tested this hypothesis? Well, Hone and Benton 2007 announced they were going to test this hypothesis, but when tentative results matched those of Peters 2000 (the only study that included all four novel taxa), they decided to delete all data from and all reference to Peters 2000 in their follow up paper (Hone and Benton 2008).
  3. My paper correcting earlier interpretations of several taxa in Peters 2000 was denied publication by referees (members of the pterosaur community). You can read those revisions here at ResearchGate.net. [This update added < 24 hours after yesterday’s post].

Sometimes I wonder if anyone else would have tested these four taxa sometime over the last twenty years if I had not done so. The odds and circumstances, I fear, don’t support that vague hope. Dr. John Ostrom also lamented this sort of situation, noting that Archaeopteryx linked theropod dinosaurs to birds a hundred years before his Deinonychus and the proliferation of feathered Chinese taxa that finally sealed the deal for most of the paleo community.

 

Example two:
Genetic studies keep coming up with odd sister taxa that don’t look like one another. Nevertheless, workers have put their faith in their parade of illogical results without batting an eyelash. They think their results reveal previously unconsidered relationships, creating greater gulfs between sister taxa that will hopefully, someday be filled by future paleo discoveries. They seem to ignore, or don’t wish to examine the bones in their cabinets, preferring instead the invisible, hopeful results of DNA codes, while publicly recognizing that genomic results rarely duplicate phenomic results.

Examples three through eighteen:

  1. In turtle studies, you won’t find Niolamia, Odontochelys, Sclerosaurus and Elginia in the same cladogram.
  2. In whale studies, you won’t find tenrecs, elephant shrews, mesonychids, hippos and desmostylians in the same cladogram.
  3. In bat studies you won’t find pangolins and their ancestors in the same cladogram.
  4. In Jurassic placental studies you won’t find rodents, carpolestids, Daubentonia and multituberculates in the same cladogram.
  5. In ichthyosaur studies you won’t find mesosaurs and pachypleurosaurs in the same cladogram.
  6. In dinosaur studies you won’t find a list of basal bipedal crocodlyomorphs in the same cladogram.
  7. In synapsid/mammal studies you won’t find a long list of amphibian-like reptiles in the same cladogram.
  8. In caseid studies you won’t find millerettids, Aclestorhinus and a long list of amphibian-like reptiles in the same cladogram.
  9. In basal mammal studies, you won’t find arboreal didelphids in the same cladogram.
  10. In Vancleavea studies, you won’t find thalattosaurs in the same cladogram.
  11. In basal archosauriform studies, you won’t find a long list of terrestrial younginid and proterosuchid specimens in the same cladogram.
  12. In pterosaur studies, you won’t find every well-known specimen, including tiny Solnhofen pterosaurs, in the same cladogram.
  13. In bird origin studies, you won’t find all 13 Solnhofen birds and pre-birds in the same cladogram.
  14. In lepidosaur studies you won’t find pterosaurs and their fenestrasaur and tritosaur ancestors in the same cladogram.
  15. In placoderm studies you won’t find catfish in the same cladogram.
  16. In snake origin studies you won’t find the quadrupedal Jurassic ancestors that link to basalmost geckos in the same cladogram.
  17. The list goes on…

If you want to see all the above omitted taxa in the same cladogram,
all you have to do is click here for the large reptile tree (1558+ taxa) where the last common ancestors of all included clades are documented and validated all the way back to Silurian jawless fish. Here taxon exclusion is minimized adding confidence to the results vs. prior studies that continue to omit key taxa.


References
Benton MJ 1999. Scleromochlus taylori and the origin of the pterosaurs. Philosophical Transactions of the Royal Society London, Series B 354 1423-1446.
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.
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.

4 thoughts on “Evolution: like explaining the details of a magic trick

  1. Hi Dave, I’ve been trying to email you about this situation.

    My recommendation is that if you want to reject the null hypothesis (“adding these taxa won’t make a difference”), you should test it. Add thalattosaurs to Vancleavea analyses, mesosaurs to ichthyosaur analyses, placoderms to catfish analyses, etc. Most phylogenetic studies include data matrices in their supplemental info, you can edit and re-run them in TNT or MacClade. It may take a while, but wouldn’t it be worth it to finally prove whether these taxa do make a difference when added to other studies? Using solely the LRT to support your classification scheme is inconclusive from an outside perspective due to its many variables, but this method tests for only one independent variable, taxa. Minimize your variables is key in the scientific method, so it can only lead to good results.

    Let me know what you find. As you say, “test, test, and test again”.

    • Neil, I appreciate what you’re saying. That’s what the LRT is all about: minimizing taxon exclusion. To your point, as mentioned above, Peters 2000 took 4 prior analyses and simply added taxa to them to recover pterosaurs apart from archosaurs. Has that changed attitudes or taxon inclusion sets over the last 19 years? No. And that work was published and peer-reviewed. Bottom line: there is heterodoxy and orthodoxy. As mentioned earlier, paleo workers are not interested in testing heterodox hypotheses, as I did in 2000. Tradition rules.

      • You have told me these things many times. I am asking you to test other analyses using a different method than your standard “compare to the LRT’s results” strategy. Are you willing to do that?

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