Tyrannosaur feature scales?

[DefinitelyNOTDilo]

I recall hearing mention of feature scales in the tyrannosaur skin impressions we've found, but I haven't found any good images of the impressions, or mentions of feature scales. Feature scales being larger scales interspersed within the smaller scales ala carnotaurus (though likely not as large.) If they are present, I'm surprised more people have talked about it, as it would imply that most theropods had them seeing as abelisaurs and tyrannosaurs diverged very early, and would make the occasional larger scales present in models from HLG and pnso more than just speculation.

[Faelrin]

This paper from Hendrickx et al, and its supplemental material are worth taking a look at, as far as current theropod (non feather) integument goes:

https://docentes.fct.unl.pt/sites/default/files/omateus/files/hendrickxetal.2021.morphologyanddistributionofscales.pdf

Of particular interest (and for posterity's sake):

Skin is known from a number of later-diverging tyrannosaurids, including Albertosaurus sarcophagus, Daspletosaurus torosus, Gorgosaurus libratus, Tarbosaurus baatar, and Tyrannosaurus rex, all of which indicate a solely squamous integument contrary to some previous speculations (Bell et al., 2017; Figs 11 and 12). These typically consist of polygonal basement scales from regions of the tail or underbelly in Gorgosaurus libratus (Fig. 11A), Albertosaurus sarcophagus (Fig. 11B–F), and Daspletosaurus torosus (Fig. 12A), whereas those in Tarbosaurus are reputedly smaller and pebbly (Currie, Badamgarav & Koppelhus, 2003; Bell et al., 2017; Fig. 12B, C). Feature scales have only been described in Albertosaurus where they are associated with the gastral ribs, forming small (7 mm diameter), conical, and corrugated scales (Fig. 11B). Reticulate scales are also present on well preserved footprints attributed to T. baatar from the Nemegt Formation in Mongolia (Currie, Badamgarav & Koppelhus, 2003; Fig. 12H–L), and a bag of smooth skin under the jaws was also reported in this taxon (Carpenter, 1997, 1999). Tyrannosaurus appears to have had a unique configuration of epidermal scales formed of tiny (≤1 mm) polygonal scales that were arranged into triangular or quadrangular clusters separated by epidermal midrib and primary and secondary epidermal veins (Bell et al., 2017; Fig. 12D–G). This arrangement persists in all areas where skin is preserved, including on the neck, pelvis, and tail, suggesting that this pattern of epidermal midrib and veins was consistent across the body (Appendix S3.5).

The material with the feature scales, is described in both the paper and supplement material to have come from a specimen TMP 1994.186.0001. The paper also includes an image of this patch of skin (Fig. 11).

Edit: Ceratopsians are also known from a mix of pebbly basement scales and feature scales as described in this paper by Bell et al, though it differs from one to another, and the material is pretty limited as well, so there could be even more variation out there then what we currently have. Maybe within stegosauria as well, but I haven't done much research in this regard, but I do recall coming across a paper regarding stegosaur integument that I'll need to dig for again at some point.