Magnificent Hermit Crab, Trizopagurus magnificus

Magnificent Hermit Crab, Trizopagurus magnificus. Photograph taken in the greater Zihuatanejo area, Guerrero, March 2020. Photograph courtesy of Ron Woheau, Zihuatanejo, Guerrero.

General information: The Magnificent Hermit Crab, Trizopagurus magnificus (Bouvier, 1898), is a member of the Diogenidae Family of Hermit Crabs, that are also known as the Spotted Hermit Crab and in Mexico as cangrejo ermitaño and ermitaño punteado. They use discarded shells for their homes to avoid predation and wave action. Reproduction involves separate sexes but a small number are hermaphrodites. The females incubate fertilized eggs that are attached to their pleopods (swimming legs) until hatching into larvae. The Magnificent Hermit Crab has been poorly documented and poorly studied and very little is known about their behavioral patterns and life span.

Identification: The Magnificent Hermit Crab are easy to recognize due to their red eyes and red antennae and antennules, black legs and equal-sized, hoofed claws with orange and white spots. Their carapace is fused to all thoracic segments with white to orange blotches, they have 19 segments (5 cephalic, 8 thoracic and 6 abdominal), jointed appendages, and stalked eyes. Their carapace has been reported to be up to 1.9 cm (0.7 inches) in width. The juveniles have a hard exoskeleton that is molted during growth; long setae are present on the chelipeds.

Habitat and Range: The Magnificent Hermit Crab is a resident of Mexican waters of the Pacific Ocean and ranges from the southern Sea of Cortez, southward along the coast of the mainland to Guatemala, southward to Ecuador and the Galápagos islands, and Malpelo islands off Columbia. They are found in rocky areas within the intertidal zone to depths up to 20 m (66 feet). They are known to associate with Pocillopora Coral.

Diet:  The Magnificent Hermit Crab is an omnivore that consumes algae, cyanobacteria and detritus and are most active at night. In turn they are subject to predation by shore birds and invertebrates and are strongly influenced by wave action.

Conservation status: The Magnificent Hermit has not been formally evaluated from a conservation status.  However, they are common and of limited interest to most and should be considered to be of Least Concern.

Synonyms:  Clibanarius chetyrkini and Clibanarius magnificus.