Abel and Werneburg 2021 discuss tetrapod skulls without a valid phylogeny

Summary for those in a hurry:
Please, please, please… BEFORE you start promoting any pet hypothesis, stop what you’re doing and start with a valid cladogram.

Abel and Werenburg 2021
are “Pulling a BIG Larry Martin” by focusing their classification efforts on just the temporal region without knowing how tetrapods are interrelated.

Example 1: The authors have no idea that diapsid-grade skulls arose twice within Tetrapoda.

Example 2: The authors recognize invalid clades (e.g. Parareptilia) still taught in textbooks and lectures.

The Abel and Werenburg 2021 published cladogram
(Fig. 1) promotes many other modern myths they willingly accept without testing.

Worse yet,
no phyogenetic patterns emerge from their cladogram. Their proposal produces results no better than random scattering.

Figure 1. Cladogram from Abel and Werneburg 2021, here split in two for legibility, promotes almost every taxonomic myth while displaying their demonstrably random skull nomenclature proposal.

From the abstract:
“Here, we introduce a novel comprehensive classification scheme for the various temporal morphotypes in all Tetrapoda that is independent of phylogeny and previous terminology and may facilitate morphological comparisons in future studies.”

I know they’re trying to help, but without a valid phylogeny the authors are promoting fiction.

From the introduction:
“Additionally, the temporal region can vary distinctly in morphology among closely related taxa (Gow, 1972 [Millerettidae]; Tsuji, Müller & Reisz, 2012 [Microleter]), specimens of the same species (Cisneros, 2008 [Procolophon]; Ezcurra, Butler & Benson, 2015 [Proterosuchia]), or throughout ontogeny (Gow, 1972 [Millerettidae]; Haridy et al., 2016 [Delorhynchus]).”

All the more reason to start with a specimen-based cladogram, like the large reptile tree (LRT, 1865+ taxa) and ‘let the chips fall where they may.‘ Don’t be caught focusing your efforts on just a few traits because convergence is rampant within the clade Tetrapoda.

From the introduction:
“Here, we provide a completely new classification scheme for temporal morphology in both tetrapod groups (amphibians and reptiliomorphs), enabling us to discuss the diversity of
the temporal skull region without adding confusion by expanding or modifying the vast number of previous perspectives.”

Without a valid cladogram, Abel and Werneburg actually add confusion to current taxonomy and systematics. When two unrelated taxa (e.g. mammals and turtles; cynodonts and ichthyosaurs) have similar skull morphologies that are given the same skull description (e.g. suprafossal, suprafenestral) confusion is the result (Fig. 1). There is no need to introduce new names for convergent morphologies. We want to get away from naming non-homologous structures.

Abel and Werneburg provide a history of temporal clade nomenclature.
None of the historical references include a valid cladogram due to massive taxon exclusion, as documented by the LRT, which minimizes taxon exclusion. So this is two authors’ look at decades of mistakes without providing a solution based on rock-solid phylogeny.

Abel and Werneburg display their need for a valid cladogram
when they unambiguously state, “The ancestral morphotype of Amniota is ambiguous (Piñeiro et al., 2012) and highly dependent on the nesting of certain key clades (see Section III.1e). The ancestral amniote could have possessed a scutal skull (13 in Fig. 5), as traditionally assumed, or an infrafenestral as seen in early Synapsida and Parareptilia (e.g. Romer & Price, 1940; Cisneros et al., 2004, 2021).”

At this point Abel and Werneburg should have looked at each other and said, “What are we doing? We have no idea how reptiles are organized! Before we type another word we need to create a valid phylogeny that minimizes taxon exclusion. We need to do the work!”

It only gets worse:
more nomenclature, less clarity with every new paragraph in this paper.

If you’re a paleontologist with nothing better to do,
try producing a wide gamut phylogenetic analysis based on hundreds of taxa and traits. Take a few years off to do this. Then report what your cladogram recovers. That will help your profession and your science. Don’t focus your attention on temporal fenestrae or any other trait (e.g. ankles, scutes, wings, dorsal fins, teeth, etc.). Don’t promote old myths. Test them.

First,
establish a broad, overall view of tetrapod interrelationships. Then, with the authority your new cladogram provides, only then allow your focus to fall on smaller subsets. You’ll never have another taxonomic problem like the dozens Abel and Werneburg discuss throughout their paper. That’s essentially gossip. Step in and provide actual assistance.

You chose paleontology because you wanted to make discoveries.
Some are made in the field. Others are made in the cladogram.

References
Abel P and Werneburg I 2021. Morphology of the temporal skull region in tetrapods: research history, functional explanations, and a new comprehensive classification scheme. Biol. Rev. (2021), pp. 000–000. 1 doi: 10.1111/brv.12751

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