Sea snails and electric flame scallop. Part 17 of my documentary, "Mucky Secrets", about the fascinating marine creatures of the Lembeh Strait in Indonesia. Watch the full 90-minute documentary at http://www.youtube.com/watch?v=nJMZ6reOB0E
As we continue to examine molluscs (mollusks, Mollusca) in this documentary series, we take a quick look at the electric flame scallop (Ctenoides ales), otherwise known as the "disco clam", "fire clam" or "electric clam". The flame scallop is a type of bivalve (Bivalvia). It appears to emit luminescent electrical pulses, but actually it is rolling and unrolling the edges of its mantle, revealing special particles that simply reflect light. The display is thought to attract phytoplankton as food and perhaps frighten off predators like crabs and shrimps.
We then turn our attention to sea snail (gastropods, Gastropoda). The grey bonnet (Phalium glaucum) is a typical sea snail. It has a protective, coiled shell that it can withdraw its entire body into. It glides over the substrate on its large, muscular foot, and at the rear we see the operculum, a hard lid that is used to close the opening of the shell after the snail withdraws into it. Two simple eyes peer out from under the front of the shell, and important sensory feedback also comes from the two tentacles. To one side is the inhalent siphon, a tube that the sea snail uses to draw in water for respiration.
The anatomy of another gastropod, the vomer conch (Euprotomus vomer), is different. Its mouth is much more obvious, at the end of a long protrusion called a proboscis. It is strictly a herbivore, and it uses the proboscis for locating and eating algae growing in the sand. It's eyes are much more prominent too, at the end of long stalks, and jutting out from these stalks are two highly sensitive tentacles. Rather than gliding, it uses its operculum to drag itself along the bottom in a lurching motion.
Conchs are a popular food, and their shells have symbolic and religious significance in some cultures. They have been used for everything from musical instruments, to weapons, to ink holders.
We then encounter a whitespotted hermit crab inhabiting an empty cone shell. The main sensory device of cones like the ivory cone (Conus eburneus) is the siphon itself which contains highly sensitive chemoreceptors. If it detects suitable prey the cone will unleash a harpoon from its proboscis containing a highly venomous neurotoxin, powerful enough to kill humans.
There are English captions showing either the full narration or the common and scientific names of the marine life, along with the dive site names.
The full Mucky Secrets nature documentary features a huge diversity of weird and wonderful marine animals including frogfish, nudibranchs, scorpionfish, crabs, shrimps, moray eels, seahorses, octopus, cuttlefish etc..
Thanks to Kevin MacLeod of http://www.incompetech.com for the music track, "Scheming Weasel (slower version)", which is licensed under a Creative Commons Attribution 3.0 Unported license.
Thanks to the staff and keen-eyed divemasters of Two Fish Divers (http://www.twofishdivers.com), for accommodation, diving services and critter-spotting.
The video was shot by Nick Hope with a Sony HVR-Z1P HDV camera in a Light & Motion Bluefin HD housing with Light & Motion Elite lights and a flat port. A Century +3.5 diopter was used for the most of the macro footage.
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Full list of marine life and dive sites featured in this video:
00:00 Flame Scallop, Ctenoides ales, Nudi Retreat
00:29 Grey Bonnet, Phalium glaucum, TK 2
01:23 Vomer Conch, Euprotomus vomer, Jahir
02:28 White-spotted Hermit Crab, Dardanus megistos, Two Fish Divers house reef
02:40 Ivory Cone, Conus eburneus, TK 2
03:03 Nudibranchs, Hypselodoris bullocki & Glossodoris cincta, Aer Perang
03:08 Nudibranch, Doto sp., Nudi Retreat