Archive for March, 2010

‘The Lynx Nudibranch’

Monday, March 29th, 2010

‘The Lynx Nudibranch’
Phidiana lynceus (Lynx Nudibranch) on Spondylus americanus oyster
Music, Video, and Aquarium
2010 Morphologic Studios

Last week we spent a moment making eyes with the oyster (Spondylus americanus). This week we’ll spend a moment with a diverse community of animals and plants that have colonized the upper shell of the very same oyster. Towards the left of the frame is a small colony of flower-like animals known as hydroids. Hydroids are most closely related to jellyfish, but instead remain attached to the reef their whole lives (unlike a jellyfish). But, like the jellyfish, hydroids can pack a powerful stinging punch. The brown, daisy-like creatures seen growing here on the oysters’s back are one such type of hydroid, Myrionema amboinense. This hydroid species derives its brown coloration from the symbiotic zooxanthellae (dinoflagellate ‘algae’) stored in its tissues. The ability to gain nutrition from both prey capture and photosynthesis, allows these hydroids to grow and colonize quickly. The sting from these hydroids is considerably more powerful than that of most corals. The gray, lumpy knobs on the back of the oyster shell are zoanthid polyps, close cousins of the sea anemones. However, these zoanthids are no match against the powerful sting of the hydroids. The zoanthids have all but acknowledged defeat by the encroaching stingers by simply closing up; effectively handing over control of the oyster shell to the hydroids.

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‘Oyster Vision’

Monday, March 22nd, 2010

‘Oyster Vision’
Spondylus americanus oyster
Music, Video, and Aquarium
2010 Morphologic Studios

Here we look into the face of the thorny oyster (Spondylus americanus).  Unlike most shallow-water oyster species, the thorny oyster is a solitary creature that lives permanently cemented to the deeper coral reef.  Its fleshy mantle is adorned with sepia-toned psychedelic camouflage that can vary widely from one individual to the next.   The rim of the mantle is lined with dozens of eyes that stare out into the depths.  These eyes are quite simple, only detecting changes in light that might suggest an incoming predator.  If a threat is detected, the oyster will quickly snap its two shells together, sealing the animal inside with its two powerful adductor muscles.  It is the adductor muscle that people eat when they eat ‘oysters on the half shell’.  Oysters are filter feeders, spending their time siphoning water through gills that strain out particulate matter. As seen in the film, the oyster periodically expels waste and water with a quick contraction of its adductor muscles.

In the second installment (next week) we will explore the upper shell of the oyster and the community of organisms that has colonized it.

‘Transparency’

Monday, March 15th, 2010

‘Transparency’
Unidentified shrimp on unidentified Ricordea polyp
Music, Video, and Aquarium
2010 Morphologic Studios

In the second installment of the ‘Unidentified Ricordea Shrimp’ series we find the (previously featured) unidentified Ricordea shrimp upon an unusual host.  While it is is most certainly on a Ricordea polyp, we are not convinced that it is in fact Ricordea florida. Over the years, we have noticed several key morphological and physiological differences that suggest that there are two genetically distinct morphs of Ricordea florida. For practical purposes, we have been referring to the morph of Ricordea seen here (under 470 nm light) as ‘inshore ricordea’…

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‘The Arrow Crab’

Monday, March 8th, 2010

‘The Arrow Crab’
Stenorhynchus seticornis or ‘Arrow Crab’ guarding a cave entrance
Music, Video, and Aquarium
2010 Morphologic Studios

Take a moment to look into the compound eyes of the arrow crab (Stenorhynchus seticornis)… If NASA is looking for a robot capable of navigating rocky planetary terrain, the arrow crab would be a perfect organism to model it after. In the video we look down the sharp, pointed rostrum (‘nose’) of an arrow crab as it appears bobbing in space. In reality, its spindly, spider-like legs are holding it anchored like a sentinel, guarding the opening of a small cave.

Arrow crabs are an abundant species on Floridian reefs, living perched near cracks and crevices in coral heads where they can retreat if threatened. Their pointed rostrum, triangular body, and protruding eyes gives this crab the appearance of a predatory lizard fish that can dash away at a moment’s notice. Instead, the arrow crab is rather slow moving, relying on the fact that the paucity of meat inside the spiny, twig-like exoskeleton of the arrow crab makes it unappetizing to a would-be-predator. This unique anatomical configuration likely explains their abundance in the wild.

Like other decapod crustaceans, the arrow crab has 10 legs (8 walking legs, and 2 pincers or ‘chelipeds’ properly). However, if you look carefully, you’ll notice that this particular crab is missing the last leg on the right side of its body. Fortunately, crustaceans are capable of regrowing amputated legs. Only a few hours after it was filmed, this arrow crab molted, and as if by magic, regenerated its tenth limb.