Bianchengichthys micros (Li et al. 2021, Latest Silurian, IVPP V27128A and B) is one of the smallest placoderms. Derived from Coccssteus, and basal to the flathead torsioned torso clade of the Devonian. Bianchengichthys has small fins and weak jaws. The oribit + naris openings are anteriorly oriented.

Bianchengichthys was reported by Li et al to be, "exquisitely preserved with mandible and paired fins. Systematically, the new taxon is close to the last common ancestor of bony and cartilaginous fishes."

Miguashaia bureaui (Schultze 1973, Cloutier 1996; Middle Devonian; up to 45cm) was traditionally considered the sister group (outgroup) of the Actinista (coelocanths). Notably Miguashaia retains a heterocercal tail and it is usually reconstructed with lobe fins (see diagram above). The maxilla was considered taphonomically missing, but the premaxilla is wide. The dentary in the reconstruction is a standard coelacanth design, not what we see in this fossil in situ.

Here this specimen is reinterpreted as a Devonian 'flounder' with a wide skull, a tremendous underbite and an torso axially rotate 90º to lie flat of the sea floor, like a flounder. Lateral fins are missing, perhaps due to taphonomy. Phylogenetically it matches larger Middle Devonian taxa lacking post-crania.

Dialipina salgueiroensis (D. markae Schultze 1968; Schultze 1992; Schultze and Cumbaa 2001; Early Devonian. 420 mya) is the earliest known bony fish known from a complete skeleton. See Miguashaia image above. It was orignally considered a palaeonisciform. Here this traditional coelacanth nests with Miguashaia and Bianchengichthys. The proposed straight traditional coelacanth tail is instead a displaced dorsal shield with a pointed posterior end. The torso is torsioned relative to the flat, wide skull, which does not resemble the skull alone shown directly above. Misidentified?

Homosteus milleri (= Homostius Traquair 1888, Middle Devonian, 27cm skull length) is a smaller flathead arthrodire with dorsal eyes related to Heterosteus.

Yinostius major (Wang and Wang 1984, Middle Devonian) is a smaller heterosteid. The flattened form of these taxa indicates a buried niche, perhaps camouflaged with sand, ready to feed on passing organisms.

Heterosteus ingens (aka Heterostius Asmuss 1856, Agassiz 1844; Early Devonian, ~6m total length, 60cm skull length) is one of the largest arthrodires, here related to Titanichthys. The jugal and preopercular were not preserved, but could be soft tissue designed to act like baleen for filtering mouthfulls of plankton-rich sea water.