Histology and morphology of the scales in some extinct and extant teleosts
Scale morphology and histology of some fossil and extant teleosts, as well as some stem group teleosts such as Pachycormiforms, are compared. Basal teleosts have lepidosteoid type scales, although cycloid scales appear at the †Leptolepis coryphaenoides level. Pachycormiforms have mainly lepidosteoid scales, but amioid type scales also occur within this clade, confirming that pachycormiforms are not teleosts. An osteoglossid type of scale is defined, based on morphological and histological characters and is considered a derived feature within teleosts.