Maxilliformes

Maxilliformes is a proposed order of ray-finned fishes that has not been definitively accepted by all ichthyologists. Historically, it was conceived to encompass a group of teleost fishes characterized by a specific arrangement of their maxillary bones, which form the upper jaw. This proposed order included families like the Cyprinidae (carps and minnows) and Catostomidae (suckers).

The concept of Maxilliformes arose from attempts to classify fish based on skeletal morphology, particularly the jaw structure. However, modern molecular and phylogenetic analyses have led to significant revisions in fish classification. Many of the taxa previously grouped under Maxilliformes are now placed within the order Cypriniformes, which is a more widely accepted and robust classification based on a broader range of evidence.

The traditional definition of Maxilliformes relied on the presence of a specific condition where the maxilla was fixed and did not participate in the protrusion of the jaw, unlike in some other fish groups. This morphological feature was considered a key diagnostic trait. Despite its historical significance in some older classification schemes, Maxilliformes is largely considered a synonym or a superseded taxonomic rank in contemporary ichthyology, with the broader Cypriniformes order being the current consensus for housing these fish groups. Research continues to refine our understanding of teleost fish phylogeny.