Staghorn Hydrocoral, Janaria mirabilis
Staghorn Hydrocoral, Janaria mirabilis. Provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, July 2011. Size: 5.0 cm (2.0 inches). The Staghorn Hydrocoral, Janaria mirabilis (Stechow, 1921), is a member of the Hydractiniidae Family of Hydrocorals, that is known in Mexico as hydrocoral cuernos de venado. They have 3 or 4 symmetrical upright and 1 horizontal branch that are straight to slightly curved and 1.25 cm (0.5 inches) to 2.5 cm (1.0 inch) in length.
Most of the vertical branches are similar in height and structure and taper to a blunt tip that is about one-half the size of the branch at its maximum diameter. The author Julia Whitty describes this species as a “fuzzy glove of feeding polyps”. They are found on rock and sand at depths between 3 m (10 feet) and 183 m (600 feet). Living specimens are cream to beige in color. The Staghorn Hydrocoral reach a maximum height of 5.0 cm (2.0 inches).
Juvenile Staghorn Hydrocorals attach themselves to various gastropod shelled animals and overtime they totally encrust the shall and eventually erode the shell chemically. They provide homes of several living pagurid crustaceans many of which they eventually consume. They have a symbiotic relationship with the Staghorn Hermit Crab, Manucomplanus varians. Initially the hydrocoral encrusts the snail shell occupied by the hermit crab and eventually chemically dissolves the shell and the hermit crab takes up residence inside the coral colony. The crab is provided with protection by the nematocysts of the hydrocoral and the hydrocoral benefits by the hermit crab providing new food sources and a trap door that seals the Staghorn from unwanted intruders.
The Staghorn Hydrocoral is a resident of Mexican waters of the Pacific and range from Punta Tosca, Baja California Sur southward along the coast of the mainland to Guatemala. However, there are only limited to small colonies off the west coast of Baja, and they are also found throughout the Sea of Cortez.