More on the life appearance of Dunkleosteus

[Halichoeres]

Russell Engelman follows up his paper last year, using regression analysis to argue for a shorter stouter Dunk, with another examining the constraints on appearance that can be inferred from the limited material available. This paper is unusual, though not unique, in having paleoartists explicitly included as its intended audience.

There's a strong bias in which bits of Dunkleosteus preserve, but there are a lot of specimens, some of which preserve a decent amount of three dimensional data. Some of what Engelman points out was knowable from previously published work, but some of it is definitely a refinement. One thing that surprised me was the following: "Whether the sclerotic ring of Dunkleosteus terrelli was visible in life is unclear." I have always argued for these being internal eyeball structures, as has Mark Witton, among others. But according to Engelman, their texture leaves some room for ambiguity.

Anyway, here's a visual summary of the arguments herein:
Do:


Don't:


Open access in Palaeontologia Electronica: https://palaeo-electronica.org/content/2024/5307-dunkleosteus-reconstruction

[Faelrin]

I mean looking at the front armored half, it really does make a lot more sense that it would be on the shorter side. I'm glad to see the reconstruction further refined as well.

I find the schlerotic ring thing interesting. Maybe Schleich made the right call after all? Though the rest of it is much outdated though.

In any case I hope someone gives this fish an updated figure based on this newer reconstruction. I think Eikoh's strangely comes the closest from the looks of it.

There's also a new reconstruction in the paper of Coccosteus cuspidatus. First time I've seen that genus with a fluked tail. I'll have to dig into that more, as I'm surprised to see it. The paper also includes an image with the potential size disparity of the tail and body length. Certainly worth sharing here:



I think the old Kaiyodo Dinotales figure might safely fall into this potential body size range. The Favorite I think it is a tad too long. That said, the Eikoh, Kaiyodo Dinotales, and Favorite are probably the only ones to come close (with also getting the fluked tail right as well). PNSO's also gets the fluked tail right, but is obviously way too long (and was suspected of such before Engelman's first paper on this dropped). Paleozoo's 2019 model may also qualify as coming close, but is certainly the least distributed among all these options.

Edit: There's also an ontogeny series included in the paper, which is the first time I've seen that for Dunkleosteus. Really fascinating.

[Halichoeres]

Yeah, the Coccosteus tail was a bit of a surprise to me too.

The Kaiyodo Dunkleosteus from 20 years ago is really remarkable and shows just how much biological intuition their sculptors had.

[JimoAi]

Is there smaller species of dunkleosteus within the genus as to allow the Kaiyodo one to pass as it

[stargatedalek]

Is there smaller species of dunkleosteus within the genus as to allow the Kaiyodo one to pass as it

The issues with the Kaiyodo aren't size, but rather the armor being on top of the skin (whether it was visible or not, it should not be sitting above the skin) and IIRC the gill position?

All the same, it would probably do fine as a stand in for Coccosteus. At least from a distance.

*edit*
Looking at it again, the gill is along the right piece of armor (I think) but that armor is extended further than it should be.

[Turkeysaurus]

So he is still short and fat guy.

[Halichoeres]

So he is still short and fat guy.

This is the same researcher who inferred the chunky dunk from a model based on other fishes' body shape. So it's more like he's building on that foundation, and filling in other details of appearance that are at least partially independent of the overall body shape. It's an elaboration rather than a new data point.