The median-fin skeleton of the Eastern Atlantic and Mediterranean clingfishes Lepadogaster lepadogaster (Bonnaterre) and Gouania wildenowi (Risso) (Teleostei: Gobiesocidae).

Previous research on the osteology of the Gobiesocidae focused mostly on the neurocranium and the thoracic sucking disc (formed by the paired-fin girdles). Little attention has been paid to the skeleton of the median fins. The dorsal- and anal-fin skeleton of Lepadogaster lepadogaster and other gobiesocids (excluding Alabes, which lacks these fins) are characterized by the absence of spines, branched fin-rays, and middle radials. In gobiesocids, the distal radials never ossify and consist of elastic hyaline-cell cartilage. Gouania wildenowi is unique among gobiesocids in having further reductions of the dorsal- and anal-fin skeleton, including a notable decrease in the size of the proximal-middle radials in an anterior-posterior direction. Unlike L. lepadogaster, which exhibits a one-to-one relationship between the dorsal- and anal-fin rays and proximal-middle radials, G. wildenowi has a higher number of proximal-middle radials than distal radial cartilages and fin rays in the dorsal and anal fins. In G. wildenowi, the dorsal- and anal-fin rays do not articulate with the distal tip of the proximal-middle radials but are instead positioned between proximal-middle radials, which is unusual for teleosts. Previously unrecognized dorsal and ventral pads of elastic hyaline-cell cartilage are also present in the caudal skeleton of L. lepadogaster, G. wildenowi, and all other gobiesocids examined.