Straight out of Star Wars: Satyrichthys, the armored sea robin

One of the strangest fish in the sea
is the armored sea robin, Satyrichthys (Fig. 1). Based on phylogenetic bracketing, that’s the palatine + lacrimal + jugal + postorbital creating a face mask of bony armor. Ancestral taxa, like the sea robin, Prionotus (Fig. 4) and the thread fin, Polydactylus (Fig. 3), have progressively smaller circumorbital bones.

Figure 1. Satyrichthys skull with DGS applied and overall diagrams. That preoperculum spike is shared with Prioonotus (Fig. 5).

The Satyrichthys skull
(Fig. 1) looks strikingly like a Star Wars Legion T-47 Airspeeder (Fig. 2) IMHO. In paleontology, we call this an unrelated ‘convergence.’

Figure 2. Star Wars air speeder model.

Satyrichthys rieffeli (originally Peristethus rieffeli Kaup 1859, 1873; Kawai T 2013; Fig. 1) is the extant armored sea robin with massively developed external palatine + lacrimal + jugal + postorbital extending far anterior to the small, weak, mouth.

Phylogenetically that face-mask started off innocently enough
as a circumoribital ring (palatine + lacrimal + jugal + postorbital) with a slight bump to the front on Polydactylus (Fig. 3). That ring evolved to cover more and more of the face (e.g. Prionotus, Fig. 4) until it became an all enclosing mask, as in Satyrichthys (Fig. 1).

Figure 3. Primitive Polydactylus skull has only a small, fused circumorbital ring. The former lacrimal is here the palatine given comparisons to outgroup Seriola zonata (Fig. 5). 

Polydactylus oxtonemus (Girard 1858; up to 23cm, some species up to 2m; Fig. 3) is the extant Atlantic threadfin. A perciforme (perch family), here Polydactylus (above) is also a shallows-dwelling relative of the sea robin Prionotus (below). Note the five thread-like rays/feelers anterior to the pectoral fin arising from the coracoid. These drag along the sea floor sensing prey. A second dorsal fin and forked tail distinguish this taxon from its sisters.

Figure 4. The sea-robin, Prionotus, has a more extensive circumorbital ring/face-mask. The palatine here may instead by relegated to just the ventral rim of the naris if the lacrimal extends anteriorly, as in Satyrichthys.

Prionotus evolans (Linneaus 1766; 40cm; Fig. 4 is the extant striped sea robin, a scorpionfish that uses a set of finger-like flexible spines (homologous with the thread fin fins (Fig. 2) of its large pectoral fin to walk on the seafloor. With a long straight snout, it looks more like it’s barracuda-like relatives, but descends from a last common ancestor, the banded rudderfish, Seriola zonata (Fig. 5). We looked at missing cheekbones in the banded rudder fish earlier here.

Figure 5. Gregory 1933 did not illustrate a jugal and lacrimal for Seriola zonata, but the cladogram indicates they should be there. We find them in the photo. Note the anteriorly projecting palatine retained in derived taxa like Satyrichthys.

The phylogenetic connection of rudder fish, threadfins and sea robins
appears to be a novel hypothesis of interrelationships. If you know of a prior citation, please let me know so I can promote it.

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References
Girard CF 1858. Notes upon various new genera and new species of fishes, in the museum of the Smithsonian Institution, and collected in connection with the United States and Mexican boundary survey: Major William Emory, Commissioner. Proceedings of the Academy of Natural Sciences of Philadelphia. 10: 167-171.
Kaup JJ 1859. Description of a new species of fish, Peristethus rieffeli. Proceedings of the Zoological Society of London, 1859, 103–107, 8 pl.
Kaup JJ 1873. Über die Familie Triglidae nebst einigen Worten über die Classification. Archiv für Naturgeschichte, 39, 71–93.
Kawai T 2013. Revision of the peristediid genus Satyrichthys (Actinopterygii: Teleostei) with the description of a new species, S. milleri sp. nov. Zootaxa, 3635 (4): 419–438.
Linnaeus C von 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Linneaus C von 1766. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio duodecima, reformata. pp. 1–532. Holmiæ. (Salvius)
Sulak KJ 1975. The systematics and biology of Bathypterois (Pisces, Chlorophthalmidae) with a revised classification of benthic mystophiform fishes. University of Miami Press, 398 pp. also:  Galathea Report. 1977; 14:49pp.

wiki/Polydactylus
wiki/Flying_gurnard
wiki/Triglidae-SeaRobin