Navanax inermis

Navanax inermis (Cooper, 1863)

Navanax as it is even referred to in common vernacular, has from time to time found itself also in the genera, Chelidonura and Aglaja. Without question the most voracious of all eastern Pacific opisthobranchs, it is a master of sea slug stealth and attack. If you have ever observed this creature feeding in the wild or inadvertently left one in the same bucket with another critter you were delighted to collect, you will understand explicitly, by the unfortunate bystanders sudden disappearance. Navanax's keen ability to locate both a mate and prey are enabled by a pair of bristle covered "sensory mounds" on each side of the mouth. These organs are thought to be chemoreceptors capable of detecting complex sugars called mucopolysaccharides found in the slime trails produced by numerous opisthobranchs and pheromones in the slime trails of other Navanax.

This tan to black Cephalaspidean bears longitudinal yellow stripes along the edge of the parapodia. Varying yellow and blue spotting occurs over the remainder of the body. Found on mudflats, in bays and on the open coast, this species reaches 225 mm in length. Its range has recently been extended from Laguna Manuela, Mexico, throughout the Gulf of California and Nayarit, Mexico north to Bolinas Lagoon, California.

The above information courtesy of:

David W. Behrens

Author: Pacific Coast Nudibranchs
Co-Author Coral Reef Animals of the Indo Pacific
Propriator of Sea Challengers Natural History Books

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