Endoskeletal structure in Cheirolepis (Osteichthyes, Actinopterygii), an early ray-finned fish

CT-scanned Cheirolepis trailli specimens from late Eifelian Achanarras Limestone preserve a mosaic of early ray-fin characters, including an imperforate propterygium and hyomandibular shaft plus peg-and-socket scales; the specimens neither define the global actinopterygian first appearance nor represent a demonstrated direct ancestor.

Cheirolepis trailli is an early actinopterygian represented in the cited study by several named Scottish museum specimens rather than one composite individual.

The scanned Cheirolepis material comes from the late Eifelian Achanarras Limestone and correlated Scottish localities; no global distribution is inferred.

The CT study resolves anatomy but does not directly establish diet, detailed habitat niche, swimming performance or trophic guild.

Named Cheirolepis specimens preserve an imperforate propterygium and hyomandibular shaft plus peg-and-socket scales among a broader early ray-fin character mosaic.

The displayed 390.4–388.1 Ma interval bounds the cited late Eifelian Scottish sample and is not a global actinopterygian first appearance.

The evidence-linked Actinopterygii navigation envelope starts at 390.4 Ma, the older edge of the late Eifelian interval represented by CT-scanned Cheirolepis trailli specimens, and extends to living ray-finned fishes at 0 Ma; it is not a global class FAD or a claim that Cheirolepis was a direct ancestor.

The Early actinopterygian evidence route navigation entity is source-linked only to the named specimen, dataset and analysis dossiers already cited by its range ledger. Its displayed span is a study-bounded route or sample envelope, not a biological taxon, ancestor sequence, global FAD/LAD or exact origin interval.