‘Preener’
Mithraculus cinctimanus crab on Ricordea florida corallimorphs
Music, Video, and Aquarium
2010 Coral Morphologic

Shown above is a 1cm Mithraculus cinctimanus, commonly known as the banded clinging crab. Typically this species is known to live in association with a variety of Caribbean sea anemone species. However, several years ago we noticed that juvenile and sub-adult banded clinging crabs seemed to prefer the protection amongst Ricordea florida polyps in the wild. When they are small, like this one, the carapace (shell) of the crab is nearly entirely covered by a fuzzy red algal camouflage. As they get larger (up to 25mm) they lose much of this hairy coat, revealing a striking white and maroon patterned exoskeleton.

The video shows the crab alternating between preening its own algae covered carapace and the fluorescent tentacles of the Ricordea florida on which it lives. It is possible that the crab may ingest some of the polyps’ mucus as an occasional food source. The video was sped up considerably (9x). At normal speed the polyps appear static, but at this speed the regular hydraulic undulations and contractions of the R. florida polyps are clearly visible.

‘Unidentified Ricordea Shrimp’
Unidentified commensal shrimp on Ricordea florida corallimorphs
Music, Video, and Aquarium
2010 Coral Morphologic

Shown above is the first documented video of a currently unidentified shrimp commensal with Ricordea florida corallimorphs. The nearly invisible shrimp measures only 9mm in total length. The ricordea polyp is about 30mm in diameter for comparison. We first reported and photographed this shrimp in October 2009. Subsequently, we sent a preserved specimen to taxonomist Dr. Richard Heard at the Gulf Coast Research Laboratory. Dr. Heard was unable to match the specimen with a described shrimp species. We will be sending additional specimens in the near future to confirm this shrimp’s newness to science.

‘Cleaner Pt. 2’
Periclemenes pedersoni shrimp on Ricordea florida corallimorphs
Music, Video, and Aquarium
2009 Coral Morphologic

Here a 2 centimeter Periclemenes pedersoni shrimp is seen perched on its host colony of fluorescent orange Ricordea florida corallimorphs. Pederson’s shrimp are native to Floridian and Caribbean waters, and are found in symbiotic association with a variety of sea anemone and corallimorph species. Pederson’s shrimp live amongst the tentacles of these animals, immune from their sting. They act as ‘cleaners’ of much larger fish. The shrimp wave their antennae and swim in a characteristic swaying motion to signal that they are ‘open for business’. Fish seem to learn and remember the specific location of these ‘cleaning stations’, returning as needed for service. When not removing parasites from fish, these shrimp will forage for bits of food amongst its host’s tentacles and spend time preening itself, as can be observed in the video. Pederson’s shrimp form monogamous mated pairs that will live together on same host. These shrimp are quite territorial, fighting fiercely with its own kind if another Pederson’s shrimp tries to take up residence on its anemone or corallimorph. If an ‘unmated’ shrimp tries to take up residence too close to an established territory, the invader will usually be dissuaded through threat displays and physical harassment.

Pederson’s shrimp are closely related to the spotted cleaner shrimp (Periclimenes yucatanicus) featured last month.