Jellynose fish
The jellynose fishes or tadpole fishes are the small order Ateleopodiformes. This group of ray-finned fish is monotypic, containing a single family Ateleopodidae. It has about a dozen species in four genera, but these enigmatic fishes are in need of taxonomic revision.
The scientific name means "Ateleopus-shaped", from Ateleopus (the type genus) + the standard fish order suffix "-formes". It ultimately derives from Ancient Greek atelís (ἆτελής, "imperfect") + pús (πούς, "foot") + Latin forma ("external form"), the Greek part in reference to the reduced pectoral and ventral fins of the jellynoses.
Description and ecology
Jellynoses are deep-water, bottom-dwelling, marine fishes. They are known from the Caribbean Sea, eastern Atlantic, the western and central Indopacific, and the Pacific coast of Central America.
Their skeletons are largely cartilage (hence "jellynose"), although they are true teleosts and not at all related to Chondrichthyes. The heads are large, with a bulbous nose, and the (usually) elongated body tapers towards the tail. Their caudal fins are very small, and except for Guentherus, it is merged with the long anal fin (which has 70 fin rays or more). The pelvic fins of juveniles have up to 10 rays, but in adults this is reduced to a single elongated ray at the throat. Again, Guentherus is an exception, retaining several fins as adults and having ventral fins that are located behind (not below) the pectoral fins. Dorsal fins tend to be high, with a rather short base (9-13 rays, but in some as few as three); they are placed just behind the head. They have seven branchiostegal rays. The species have a range of sizes, the longest reaching 2 m (6.6 ft).
