Iniopteryx rushlaui (Zangerl and Case 1973; Pennsylvanian, Late Carboniferous, 300 mya; < 50cm) nests Gregorius with pectoral fins raised to a dorsal insertion. Either these were used as secondary sexual traits some sort of remora-like hooks to attach itself to larger fish. Note the posterior jaw joint. Large claspers appear with the pelvic fins. The caudal fin is abbreviated and diph Other iniopterygids include Promexyele, Iniopera and Sibyrhynchus.

Cervifurca nasuta (Zangerl 1997; Pennsylvanian; FMNH PF13228) was described from a partial, slightly disarticulated skeleton lacking an anterior rostum.

From the Zangerl abstract: "This taxon is remarkable for its dorsoventrally flattened body habitus and probably (functionally) correlated enormous size of the pterygopodia, and for orbits that face dorsolaterad. The neurocranium is provided with very prominent nasal capsules, and the pelvic fins consist of a few very short and stout radials. Cervifurca nasuta was probably a member of the mobile benthos."

The sharp teeth, the large and laterally extended nasals are reversals to a more shark-like morphology. Note the dorsal orbits and complete circumorbital ring. Ecologically this was the most remora-like of all iniopterygians, using the pectoral fins to hold on to larger, faster, wider ranging host, upside-down or rightside-up.

Dracopristis hoffmanorum (Hodnett et al. 2021, Pennsylvanian, Early Carboniferous) The morphology of Dracopristis suggests it was a slow-moving ambush predator in shallow estuaries or lagoons. The pectoral girdle flips in this GIF animation because it appears to have been initially reconstructed upside-down. The flip elevates the pectoral fin as in inipoterygian fish, like Cervifurca, which Dracopristis resembles in most regards, other than the large dorsal spines and its 10x larger size.