Dunkleosteus: still not short and deep (with sharp fin tips)

Engelman 2024 wrote,
“Multiple lines of evidence (trunk armor shape, head proportions, OOL, entering angle, position of the fin bases, etc.; see present study and Engelman, 2023b) suggest
Dunkleosteus had a relatively stocky body plan with a deep trunk.”

This is called doubling down on a bad bet because we have post-crania for Dunkleosteus-like placoderms in Amazichthys (Fig 1), something Engleman 2024 and Engleman 2023 chose not to compare in graphic fashion, as shown below.

Figure 2. Freehand images from Engelman 2023 compared to scale with images that add the post-crania of Amazichthys to the skull of Dunkleosteus bringing the estimate of length back to 5m. ” data-image-caption=”

Figure 2. Freehand images from Engelman 2023 compared to scale with images that add the post-crania of Amazichthys to the skull of Dunkleosteus bringing the estimate of length back to 5m.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/02/dunkleosteus.size588.jpg?w=166″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/02/dunkleosteus.size588.jpg?w=565″ tabindex=”0″ role=”button” class=”size-full wp-image-76442″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2023/02/dunkleosteus.size588.jpg” alt=”Figure 2. Freehand images from Engelman 2023 compared to scale with images that add the post-crania of Amazichthys to the skull of Dunkleosteus bringing the estimate of length back to 5m.” width=”584″ height=”1058″ />

Figure 1. Freehand images from Engelman 2023 compared to scale with images that add the post-crania of Amazichthys to the skull of Dunkleosteus bringing the estimate of length back to 5m.

Engelman 2023 reported,
“Large arthrodires (Dunkleosteus, Titanichthys) were much smaller than previously thought and vertebrates likely did not reach sizes of 5 m or greater until the Carboniferous. Lengths of 5–10 m are commonly cited, but these estimates are not based on rigorous statistical analysis. Applying this method to Dunkleosteus terrelli results in much smaller sizes than previous studies: 3.4 m for typical adults (CMNH 5768) with the largest known individuals (CMNH 5936) reaching ~4.1 m.”

Engelman 2024 concluded,
“The length of the body, shape of the trunk, and location of the dorsal and pelvic fins is
well constrained by the comparative anatomy of arthrodires.”

Engelman 2024 took 79 pages to explain his hypothesis. Again.
It only took 57 pages the first time.

One graphic
(Fig 1) showing one arthrodire Engelman was familiar with is all one needs to debunk the single Engelman 2023, 2024 hypothesis.

Time to move on, Engelman. Two papers making the same mistake twice on the same subject without addressing the Amazichthys in the room (Fig 1) is enough.

References
Engelman RK 2023. A Devonian Fish Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes for Dunkleosteus terrelli (Placodermi: Arthrodira). Diversity 15: 318, 57pp.
Engelman RK 2024. Reconstructing Dunkleosteus terrelli (Placodermi: Arthrodira): A new look for an iconic Devonian predator. Palaeontologia Electronica, 27(3):a45.
https://doi.org/10.26879/1343  
palaeo-electronica.org/content/2024/5307-dunkleosteus-reconstruction

Body length estimates for Dunkleosteus