cygorynchus

Cygorynchus is an extinct genus of early ray-finned fish (Actinopterygii) known from fragmentary skeletal remains dating to the Late Devonian to Early Carboniferous. Fossils attributed to the genus have been recovered from marine and estuarine deposits in what are now Europe and North America, implying a relatively broad paleogeographic range. The genus is diagnosed by an elongated snout, formed by extended premaxillary and dentary elements, a relatively narrow cranium, and a series of small, rhomboid scales along the flank. Its fin placement and body proportions suggest a nektonic to nearshore lifestyle, feeding on small invertebrates and detrital particles by suction feeding.

The name Cygorynchus combines cyg- from cygnus (swan) with -rynchus (snout), alluding to the swan-like rostrum that characterizes the available skull material. The type species, Cygorynchus swanensis, was described in 1987 by paleontologist A. L. Carter on jaw and skull fragments from the Devonian Whitmore Formation.

In paleoecology, Cygorynchus is interpreted as a small to medium-sized fish, typically growing to about 12–25 cm in length. The skeletal features—especially the elongated snout and the scale pattern—are consistent with a suction-feeding mode in shallow-water habitats. Phylogenetically, Cygorynchus is placed among early palaeonisciform actinopterygians, contributing to understanding early diversification of ray-finned fishes.