What would turtles be, if pareiasaurs were not known?

This is lesson 3 in taxon exclusion…
to see where select clades would nest in the absence of their proximal taxa.

Two clades of turtles
(soft-shell and hard-shell) arise from two different parieasaurs (Fig. 1) in the large reptile tree (LRT, 1242 taxa).

Figure 2. Comparing the skulls of Elginia, with teeth, and the turtle, Niolamia, toothless.

Figure 2. Comparing the skulls of Elginia, with teeth, and the turtle, Niolamia, toothless.

The question is: what if pareiasaurs were never discovered?

  1. Then turtles arise from Stephanospondylus. And if that taxon is absent…
  2. Then turtles arise from limbless microsaurs (like Lysorophus and Adelospondylus ). What?? With the very weird, tube-snout soft-shell, Ocepecephalon (post-crania unknown) nesting as the basalmost turtle. And if all non-reptile tetrapods and lepidosauromorphs are absent…
  3. Then turtles arise from cynodonts, between Procynosuchus and Thrinaxodon. In that case, turtles start with Baena and Glyptops on one branch, and soft-shell turtles on the other.
  4. Removing all soft-shell turtles nests hard-shell turtles between the fish, Osteolepis, and chroniosuchids (not Eldeceeon), (when non-reptile tetrapods and lepidosauromorphs are absent as in #3), which is close to the original topology.
  5. Otherwise hard-shell turtles arise from the microsaur, Batropetes clade, with the turtle Kallokibotion at the base of the hard-shell turtles.

Does this all make sense?
No. But in the absence of pareiasaurs (and later, soft shell turtles) PAUP is going to find the least different taxa from a wide gamut list (see above).

neither Eunotosaurus nor Pappochelys were picked by PAUP, which found more parsimonious candidates elsewhere. Eunotosaurus and Pappochelys were cherry-picked taxa, promoted to be turtle ancestors by biased workers. These two taxa nested with turtles by default in the absence of more similar candidate sisters for all involved taxa.

Taxon exclusion
has been the number one problem in traditional paleontology. That’s why the LRT includes such a wide gamut of taxa. The result is a minimizing of taxon exclusion and the problems that attend it.

7 thoughts on “What would turtles be, if pareiasaurs were not known?

  1. So your whole classification is based on morphology and picturesof bones you “paint” to highlight similarities, right?

    Since evolution is mutation, mutation happens in DNA and there is no such thing as “convergent genetics” what are your arguments to say your “out of the box” classification is better and should be followed even going against most we know about tetrapod evolution?

    • DNA cannot be trusted, actually it fails sometimes, to produce what evolution is all about: a gradual accumulation of derived traits. Some examples include nesting flamingos with grebes, turtle with archosaurs, golden moles with elephants, etc. Plus, if we want to use fossils (and we do want to use fossils) we have to rely on skeletal traits. The LRT produces the gradual accumulation of traits at every branch and node. What we know about tetrapod evolution needs to fit to one rule: a gradual accumulation of traits. If you see any mismatches in the LRT, please let me know.

      • I understand, the whole scientific community people that work with Bacteria, Fungi, Algae, Plants and Animals all trust molecular data and use it as the main guide for phylogeny, but you that your picture enhancing method is better because DNA is not a good guide because evolution is about change in morphology.

        But only morphology analyzes have been proven wrong and we got into such things as species complex and cryptic species; species that look superficially similar but when you compare the DNA are quite different.

        Evolution is change, and where this changes happens? In DNA.

        Trying to solve evolution using without using DNA is like ignoring a videotape murder in favor of sticking with only the clues to the crime (morphology).

        Fossils are not the problem we can’t go molecular on them, but the rest of our LTR is completely wrong, because you completely ignore the most reliable and accepted evidence in favor of your own new and unproven method.

        In the penultimate topic of your text you say that the scientific community is biased and “cherry-picked” Eunotosaurus and Pappochelys to be primitive Turtles ignoring Pareiasaurs (which were actually included in the morpho-genetic analyzes of the last years).

        Looking how you ignore the most accepted method, with arguments such as “it fails sometimes” and because it differs from your results, the one with bias is you. This is an old tactics in rhetoric accusing your opposition of doing exactly what you do.
        Who is the most likely to be bias all scientist from major different areas your you a blogger with a proposed revolutionary method? Yes we know the answer it is supported by parsimony and Occam’s razor, and since it is the base of morphological phylogeny I’m sure you believe what I mean : )

      • Re: Turtle and pareiasaur studies… in none of the deletion tests you just read about here do turtles nest with Eunotosaurus and Pappochelys. One of those tests deleted pareiasaurs. Please keyword: “Eunotosaurus” and “Pappochelys” to view prior arguments against those taxa as turtle ancestors. Both set of authors make false assumptions regarding the supratemporal and ventral ribs. None test Sclerosaurus, Meiolania, Niolamia, Elginia and Bunostegos, proximal ancestors to turtles in the LRT.

        Re: DNA… only the expression of the DNA counts. As you know some instructions lie dormant while others are expressed.

        Re: blogger… you are treading into the ad hominem arena. Please keep to the data. Using ‘four letter words’ is inappropriate in this setting.

        Re: my results… please find the specific error with my results (i.e. taxa that should not nest together due to a better sister taxon lurking elsewhere. If you cannot do so, please say so.

  2. 01-I’m not talking about turtles and Pareiasaurs specifically, they may be in fact turtle relatives but they’d need to be archosauromorphs rather them lepidosauromorphs. The LTR also says that Sauropsida is unnatural and mammals are inside Archosauromorpha, a result never supported contrary to morphology and genetic analysis.
    The point of that part is your results are completely unorthodox going against all other previous works. I asked for your motives on why you thing your methodology is better, and specifically why you think DNA is worse than morphology; and your arguments were “DNA fails” (all methods fails sometimes) and “The LRT produces the gradual accumulation of traits at every branch and node.” all other ones produce those as well, but in molecular study those are genetic character rather them morphological ones.
    The 1st being an obvious statement and the later being “Their results differ from mine”, none is convincing.

    02-The methodology: your matrix has a great number of species included and also a good number of out-group taxa (better them many published papers); but the method you use to code things (forgot the name, sorry) is heavily criticized by other scientists and not accepted by those who look at it. Also your charter list is small and has been criticized.
    You have a small character list and those are obtained from a questionable methodology. Some of your results have never been found in any other study and some goes agains the most reliable DNA method, that you insist is unreliable but is accepted by many researches from every other area of biology.

    03-“DNA… only the expression of the DNA counts” nooooo it is the opposite, morphology only looks at the expression while DNA looks at the cause of the expressed characters. Different parts of a DNA can express a same character, that is not aomorphic it is homology and convergent; and that is why DNA is preferable over pure morphology cause it can detect the hidden homoplasy.
    Dormant parts are equally relevant because they are also part of the code that produces the species, even if they are not active they are there and tell the evolutionary story of the lineage.

    04-By bad, I should have been more specific you are a digital designer, retired paleoartist, paleo-enthusiast owner of a paleo-related blog; you cannot even call yourself an armature paleontologist because your ideas goes against the base of science, everything should be falsifiable and if proven so it should be abandoned, you insist in your method proven wrong when tested by scientists.

    05-Sorry I can’t put my money own your results because they are based on a matrix done using a questionable/not accepted method. I can not join your revolution because the cause advocated by it was defined using a refuted idea.

    • It comes down to taxon exclusion. The LRT minimizes that problem. When taxa are not excluded (Chilesaurus, for example) results match the LRT. The method is the same one used by all others: gather data in MacClade, run the data through PAUP. Everything I propose is falsifiable. Try it yourself. If I can do it, you can do it.

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