Hardtail Conger, Gnathophis cinctus
The Hardtail Conger, Gnathophis cinctus, whose common Spanish name is congrio cola tiesa, is a species in the Family Congridae, the Conger Eels, which are known collectively as congrios in Mexico. Globally, there are twenty-five species in the genus Gnathophis, two of which are found in Mexican waters, one in the Atlantic and one in the Pacific.
The Hardtail Congers have elongated narrow “eel-like” bodies. They are uniform pale gray-brown in color with a silvery mid-section. Their head is pointed with disproportionately large eyes set well on the back in their head, a horizontal mouth with bands of simple conical teeth, and an overhanging long snout that has a keel ventrally. Their anal and dorsal fins are continuous with their caudal fin. Their caudal fin has a small stiff tip (after which they are named), their dorsal fin origin is over the rear of their pectoral fins, and their pectoral fins are well-developed and end above their gill cover openings. A key to identification is their tail length which is reported to be greater than 60% of total length, however, we note that the small fish pictured below has a tail length of only 52%. They have a complete lateral line.
The Hardtail Congers reside buried within coastal sandy bottoms at depths from 30 to 1,200 feet and reach a maximum length of 42 cm (17 inches). They are a rare and poorly studied species and as such very limited information is available about their behavioral patterns.
In Mexican waters the Hardtail Congers are found in all waters of the Pacific with the exception that they are absent from the extreme northern portion of the Sea of Cortez.
The Hardtail Conger is most likely confused with the Needletail Conger, Rhynchoconger nitens (small beady black eyes).
The Hardtail Conger is small, exceedingly rare, and of limited interests to most.