Carbonodraco enters the LRT alongside Kudnu

Mann et al. 2019 bring us new taxon
Carbonodraco lundi (Fig. 1; CM 23055; Middle Pennsylvanian, Moscovian), formerly considered a type of Cephalerpeton ventriarmatum (Moodie 1912), a basal lepidosauromorph reptile close to captorhinids. The authors considered their find the oldest (Middle Pennsylvanian, Moscovian) parareptile, an invalid and paraphyletic clade in the large reptile tree (LRT, 1613 taxa).

Mann et al. start with a redescription of Cephalerpeton,
a taxon needing no such redescription. This illustrates the narrow focus of these workers and paleontologists in general. They continue to cherry-pick taxa and use freehand illustrations of reconstructions to support their views. The bones in their reconstruction do not match their tracing of the in situ bones and several bones were left unidentified.

In order to decide what a new taxon is or isn’t
there is only one way to do it. You need to add your taxon to a wide gamut phylogenetic analysis, like the LRT. Then let the software tell you what you have. The LRT minimizes bias and taxon exclusion by including such a wide gamut and large number of taxa. Mann et al. did not mention a long list of pertinent taxa in their study.

Figure 1. Carbonodraco in situ (lower right), as originally reconstructed freehand (upper right) and using DGS methods to reconstruct the skull by coloring the bone drawing.

Figure 1. Carbonodraco in situ (lower right), as originally reconstructed freehand (upper right) and using DGS methods to reconstruct the skull by coloring the bone drawing. Based on the drawings autapomorphic upper temporal fenestrae appear to be present, convergent with other clades in which this occurred.

Mann et al.
considered Carbonodraco a member of the Acleistorhinidae. That’s why they gave it a hypothetical lateral temporal fenestra, misidentified the prefrontal, did not identify the squamosal, quadratojugal, squamosal, supratemporal and postparietal in their freehand drawing. The DGS method minimizes such bias-generated errors by coloring the bones and moving them, ‘as is’, to the reconstruction (Fig. 1).

By contrast
the LRT nested Carbonodraco with Kudnu (Bartholomai 1979; Figs. 2, 3)These two nest at the base of the Pareiasauria + turtles, taxa not included in Mann et al. Both Cephalerpeton and Acleistorhinus are taxa included in the LRT and both nest far from Carbonodraco.

Figure 1. Carbonodraco enters the LRT alongside another recent addition, Kudnu, at the base of the pareiasaurs + turtles.

Figure 2. Carbonodraco enters the LRT alongside another recent addition, Kudnu, at the base of the pareiasaurs + turtles.Figure 1. Carbonodraco enters the LRT alongside another recent addition, Kudnu, at the base of the pareiasaurs + turtles.

Mann et al. are working from an old and invalidated hypothesis
when they report, “Amniotes can be divided into two major lineages, synapsids (mammals and their extinct relatives) and reptiles (crocodiles, birds, and lepidosaurs, and their eAmniotes can be divided into two major lineages, synapsids (mammals and their extinct relatives) and reptiles (crocodiles, birds, and lepidosaurs, and their extinct relatives).”

No, the LRT indicates the first dichotomy splits Archosauromorpha (including Synapsida) from Lepidosauromorpha.

Figure 1. Kudnu colorized using DGS and slight restored postcranially, shown 10x natural size at a 72 dpi standard screen resolution. Here's a taxon basal to Stephanospondylus, pareiasaurs and turtles. Prior workers excluded Stephanospondylus from their studies.

Figure 3. Kudnu colorized using DGS and slight restored postcranially, shown 10x natural size at a 72 dpi standard screen resolution. Here’s a taxon basal to Stephanospondylus, pareiasaurs and turtles. Prior workers excluded Stephanospondylus from their studies.

“The origin and early diversification of these groups are believed to have occurred during the early Carboniferous because the oldest amniotes, the reptile Hylonomus lyelli and the putative synapsid Protoclepsydrops haplous, are known from the classic locality of Joggins, Nova Scotia, Canada (313–316 Ma).”

No, the LRT indicates Silvanerpeton (Viséan, 335 mya) is the last common ancestor of all amniotes (= Reptilia).


References
Mann A, McDaniel EJ, McColville ER and Maddin HC 2019. Carbonodraco lundi gen et sp. nov., the oldest parareptile, from Linton, Ohio, and new insights into the early radiation of reptiles. Royal Society Open Science, 27 November 2019. https://royalsocietypublishing.org/doi/10.1098/rsos.191191#d3e1049

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