Aulopus filamentosus

Common Name

Royal Flagfin

Year Described

Bloch, 1792


Dorsal Fin: 14-16
Anal Fin: 10-13
Pectoral Fin: 12-14
Pelvic Fin: 9
Vertebrae: 47
Scales: 47-53 LL, 12 predorsal scales
Gill Rakers: 12-15 (first arch)

Body elongate and oval in cross-section, with a flattened ventrum and an arched back. Head large with a terminal mouth and pointed snout. Jaws reach well beyond middle of orbit and have multiple rows of visible teeth. Teeth on tongue and roof of mouth. Rear of mouth with two supramaxilla bones (one in synodontid lizardfishes). Eye large with a round pupil. Fins lack spines. Dorsal fin large and sail-like with a long base (male taller). Adipose fin present. Anal fin also quite tall and inserted at a level behind last ray of dorsal fin. Pelvic fin origin under dorsal fin origin. First four pelvic fin rays thickened. Pectoral fin fairly small and inserted in front of pelvic fin. Tail strongly forked. Body and head scales well developed. Bony, keeled scales on base of caudal fin.


Ground color whitish or silvery with a pearly blue sheen in life. Back yellowish-brown grading to pale on belly. There are four saddles on the body: one under dorsal fin, one on caudal peduncle, and two in between evenly spaced. A dark band across head. The saddles become distinctly darker under the lateral line and broaden into blotches. Dark saddle interrupted at lateral line and often with paired spots. Scattered golden spots on dorsum and head. Fins with many large golden spots and/or bands. Tip of dorsal fin in males with a brown blotch and some red-orange markings.


Adults range from 20cm to almost 50cm. Males and females are dimorphic.


Occurs on the bottom. Most commonly from 100-400m. Recorded to 1000m.


Florida, the Gulf of Mexico, and the Caribbean to SE Brazil. Also Bermuda.


Carvalho-Filho, A., Marcovaldi, G., Sampaio, C.L., Paiva, M.I.G., & Duarte, L.A. 2010. First report of Aulopus (Teleostei: Aulopidae) from Southwestern Atlantic, with a review of records and a key to Western Atlantic Aulopoidei species. Zootaxa, 2628(1), 27-42.

McEachran, J.D. & Fechhelm, J.D. 1998. Fishes of the Gulf of Mexico, Volume 1, Myxiniformes to Gasterosteiformes. University of Texas Press, Austin. 1004p

Other Notes

Aulopus nanae is a synonym.