‘The Lettuce Slug’
Elysia crispata on Halimeda opuntia
Music, Video, and Aquarium
2010 Morphologic Studios

Lettuce sea slugs (Elysia crispata) are a commonly found in protected nearshore Floridian waters where green macroalgae proliferates. They belong to a clan of sea slugs, the sarcoglossans, that are characterized by their ‘sap-sucking’ feeding habits of algae. These slugs slowly patrol mangrove roots and rocks searching for green algae upon which they feed. They store some of the chloroplasts from eaten algae in their tissue, giving it the green coloration. The chloroplasts continue to function, providing the slug with photosynthetic energy. The ruffles along the back of the lettuce sea slug are called parapodia, and help provide more surface area for the chloroplasts to inhabit. They also camouflage the slug amongst the leafy algae that they live amongst. It is very easy to swim past a lettuce nudibranch without ever noticing it.

The scrolled rhinophores (antennae) on the head of the lettuce sea slug help detect the chemical fingerprints of their preferred algal species. If you look carefully, just behind the rhinophores, you’ll notice the small black eye spots that act as rudimentarly eyes to detect changes in light and dark.

The macroalgae featured in the film is Halimeda opuntia, (named after its resemblance to the prickly pear cactus Opuntia sp. ). It is unique amongst green algae in that it produces a semi-rigid, calcareous skeleton. In fact, the dead ‘leaf’ fragments of Halimeda spp. algae are a more significant producer of coral reef sand than the corals themselves. It is not uncommon to find lettuce sea slugs on Halimeda opuntia algae, as it frequently lives amidst the softer green algae that the lettuce sea slugs prefer.

‘Complex Nano’
Music by Space Voodoo Crystal
Video and Aquarium
2010 Morphologic Studios

Above is a short video featuring a glow-in-the-dark perspective of the 5-gallon ‘Complex Nano’ reef aquarium. A daylight photo of this aquarium is featured in the April/May – 8th Anniversary Issue of Marc Ecko’s Complex Magazine (see below). By comparing the two differently illuminated versions of this nano reef, the true fluorescence of the corallimorphs and zoanthids immediately becomes apparent. The fluorescent pigments of the corallimorphs and zoanthids are preferentially activated under the 470 nm blue wavelength LED lighting used in the video. Notice that the normally bright orange coloration of the clownfish (Amphiprion ocellaris) appears nearly black in the film.

Both of the fish in the aquarium are captive-raised by the Harbor Branch Oceanographic Institute’s ornamental aquaculture subsidiary ORA. ORA has been a leader in this field, and we stand fully committed to the further development of  aquacultured ornamental marine fish species. You’ll notice that the normally three-striped clownfish has an unusual cross-pattern on one side. This is the result of selective breeding on ORA’s part.  In recent years, clownfish hatcheries have developed all black, white, orange, and ‘Picasso’, variations of the standard ‘Nemo’ through patient breeding and selection.

The other fish in the aquarium is an orchid dottyback (Pseudochromis fridmani). Wild versions of this fish tend to be more fiesty and territorial, whereas hatchery-raised fish tend to be more gregarious and better suited for life in a community reef aquarium.

Note the commensal (and nearly translucent) Pederson’s cleaner shrimp (Periclimenes pedersoni) on the fluorescent orange (Ricordea florida) corallimorphs in the video.

Click here for a complete species and hardware list

Special thanks to Patrick Albertson (article author) and Space Voodoo Crystal (soundtrack)

‘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.

‘Purple Forest’
Decorator Crab (Microphrys bicornuta) on Asparagopsis taxiformis algae
Music, Video, and Aquarium
2010 Morphologic Studios

This week’s video features an aquascape comprised of the beautiful purple macro algae  Asparagopsis taxiformis. However, if you pay close attention to the left 1/3 of the screen, you’ll notice something… moving with claws… Nestled amongst the algae is a perfectly camouflaged decorator crab (Microphrys bicornuta).  Keep paying attention… at 26 seconds into the clip you’ll notice a tiny isopod crustacean float by in the current and descend helicopter-style right onto the crab’s back. The unsuspecting isopod has no idea that it has landed upon an algae covered beast. Furthermore, it appears that the crab is not aware of the unexpected visitor until the isopod begins to explore its decorated exoskeleton.  50 seconds into the clip the isopod meets its fate with a few swift snatches of the crab’s claws.  Without missing a beat, the crab continues scavenging amongst the rocks and algae.  And life on the reef goes on…

Decorator crabs are amazing creatures in that they pick up pieces of their surrounding habitat and place them on their carapace (back, exoskeleton) in order to blend into their surroundings.  Decorator crabs that live amongst sponges decorate with sponges, those that live amongst zoanthids use zoanthids, and so on. This instinctual logic is truly remarkable.  The  crab in the video has attached small pieces of the Asparagopsis upon itself, and as a result is all but indistinguishable from its surroundings.

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