Skrogiformes

Skrogiformes is a hypothetical order of ray-finned fishes proposed in speculative zoology to group several deep-sea taxa that exhibit unusual jaw mechanics and plate-like head armor. The concept arose in attempts to organize morphologically convergent forms into a single lineage, but its status is not accepted in mainstream ichthyology. In some treatments, Skrogiformes is considered a stem group of Teleostei or a derived clade within Percomorpha, depending on the data used.

Diagnostic features attributed to Skrogiformes include an elongated, sometimes laterally compressed body; a rough, plate-like head shield; a fused suspensorium with a distinctive palatoquadrate articulation; reduced scale coverage; and a long continuous dorsal fin with soft rays. The group is thought to have occupied bathypelagic to mesopelagic zones, suggesting adaptation to low-light, high-pressure environments.

The fossil record for Skrogiformes is fragmentary, dating from the late Jurassic to the Cretaceous, with occasional post-Cretaceous reports from deep-sea sediments. Modern material is rarely confirmed, and reports of living representatives are uncommon, often flagged as tentative until more complete specimens are described.

Ecology and behavior are poorly known due to the limited material. When described, Skrogiformes are presumed carnivorous, feeding on small invertebrates and fishes, with slow growth and potentially low metabolic rates consistent with deep-sea life.

Taxonomic placement remains debated; molecular data are limited, and morphological analyses yield conflicting results. Because Skrogiformes lack broad recognition in current databases, they are typically treated as a provisional group within discussions of teleost evolution rather than a formally recognized order.