Longtail Jawfish

Longtail Jawfish, Lonchopisthus sinuscalifornicus

The Longtail Jawfish, Lonchopisthus sinuscalifornicus, whose common Spanish name is bocón cola larga, is a species in the Jawfish or Opistognathidae, known collectively as bocónes in Mexico. Globally, there are only five species in the genus Lonchopisthus, two of which are found in Mexican waters, one in the Atlantic and one in the Pacific.

The Longtail Jawfish have elongated tapering bodies. Their head and body are tan or cream in color. Their body has thin blue bars at the front, a large intense blue-violet ocellus spot on the gill cover, and scattered blue spots behind the gill cover. Their anal and dorsal fins have a central row of blue spots and their pectoral fins are violet. They have a large bulbous head with large eyes that are set high on each side of the head and a large mouth that opens at the front and extends to the rear of the eyes. Their anal fin has three spines and 17 rays; their caudal fin is very long and thin (after which they are named); and their dorsal fin has 11 spines and 18 rays. The lateral line is only present on the first half of their body. They are covered with scales.

The Longtail Jawfish are found in relatively shallow water and live buried in sandy substrates at depths up to 175 feet. They reach a maximum length of 30 cm (12 inches). They live in elaborate burrows that are self-constructed by utilizing their mouths and powerful jaws to excavate sand, small stones, and medium-sized rocks and that they feed primarily on benthic and planktonic invertebrates. In addition, like other Jawfish, it is assumed that they exhibit the unusual habit of oral egg incubation.

In Mexican waters of the Longtail Jawfish have a limited distribution being found in the lower two-thirds of the Sea of Cortez and along the coast of the mainland south to Guatemala. They are absent from the extreme northern portions of the Sea of Cortez and from the entire west coast of Baja.

The Longtail Jawfish cannot be confused with any other species due to its unique markings.

The Longtail Jawfish are too small and too obscure to be of interest to most.

Longtail Jawfish, Lonchopisthus sinuscalifornicus. Fish provided by the commercial fishermen of Bahía Kino, Sonora, March 2015. Length: 21 cm (8.3 inches). Photo and identification courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.