Assassin Worm

The Marine Invertebrate Team of Biocode has been joined by Dr. Jon Norenburg, a specialist on Nemertean worms from the Smithsonian Institution (http://invertebrates.si.edu/staff/norenburg.cfm). During a recent outing to a shallow area in the lagoon, he found a small, pale Nemertean in his samples of the sand. It didn't look like anything special until he got it under a microscope, when the eyes at the tip of the snout were visible.

It turns out that it belongs to a group of nemertean worms that are active predators on crustaceans such as crabs. The original discovery of the group was made in Panama where a researcher studying the behavior of fiddler crabs repeatedly saw crabs suddenly freak out, making erratic motions. When he waded through the mud to get the crabs, they had been emptied- sucked dry. It turns out that a nemertean was lurking in the sand. When it detected the shadow of a crab passing overhead, it would harpoon it with a sharp stylet borne on its proboscis, enabling delivery of a dose of neurotoxin.

The worm secretes, through the same hole, digestive enzymes into the prey, rapidly liquifying the internal tissues. It then sucks out the resulting soup, leaving nothing but the exoskeleton sitting on the mud.

Now we know they are in Moorea. Crabs be warned!

-Seabird

Jurassic Scallops

We spent most of the afternoon in Opunohu bay, brushing the underside of reef overhangs and cavelets with a brush and collecting the stuff that fell off. It is mucky work, stirring up clouds of silt and urchin spines. The results however are worth it. These habitats hold all sorts of specialities, some of which are limited to very specific areas of the reef.

This parthenopid crab matches the silt and algae covering the rocks perfectly, but fell into the net when brushed off.

The real find of the search were of propeamusid bivalves called Chlamydella. These little "proto-scallops" are living fossils that had their glory days back in the Mezozoic. During the Jurassic these were one of the dominant bivalve groups, before being replaced by modern scallops. Now, they survive only in the deep oceans, and in caves, where they have taken on a miniaturized existence. Like many other cave taxa, they brood their eggs, instead of releasing them into the water column, and have young that crawl away to set up shop near their parents.

-Seabird

Getting Muddy with Art

Arthur Anker, a Postdoctoral Researcher with the FLMNH Invertebrate Zoology department, has a knack for finding the unnoticed things, the creatures that everyone else somehow misses. Here in Moorea, French Polynesia, Art has specialized in the muddy, mucky habitats that most marine biologists wouldn't stick a toe in. Art, however, thrives here, and has brought back a steady stream of new records, new species, and just plain amazing animals that don't seem to live anywhere else. Tools of the trade include a "Yabbie Pump" for pumping small animals from shrimp burrows, a range of fine dipnets, and the patience to work in two feet of muddy water for most of the day.

A few of Art's finds follow, but many more can be found on his flickr stream.

http://www.flickr.com/photos/artour_a/

-Seabird

Flat spell=opportunity.

The swell on the North side of Moorea has dropped to almost nothing. These days of flat, glassy water are very rare here, and allow us to get into some remarkable places. The 'avas' or small channels that funnel water off of the reef crest are rarely searchable, as is the reef flat itself. These 'crash zone' habitats are home to some of French Polynesia's endemic species, including a species of Coral Guard Crab, Trapezia globosa, that is found nowhere else. This habitat is among the most likely places to find new species in any coral reef ecosystem due to the extreme inaccessibility.

-Seabird

Bluewater

Dr. Steve Haddock of MBARI (www.mbari.org/staff/haddock) has joined the Marine Invertebrate Biocode Team to explore the gelatinous zooplankton, or 'gelata' of the pelagic, open water habitat that surrounds Moorea. After bringing the scientific divers up-to-speed on the specialized equipment and methods used to dive safely and productively in this 'extreme' habitat, Steve has immersed us in a completely blue world with a seemingly alien fauna. At a second glance however, most of these animals have relatives or connections much more familiar to us.

Pteropods for example, are highly modified gastropods, or snails- some of which have given up their shells in trade for a 'flying' lifestyle, with two beating fins or wings. Salps are the open ocean forms of ascidians ("sea squirts") that use the powerful water pumping system evolved originally for filter feeding, for 'jet propulsion' in the open waters.

The system truly belongs to the jellies- both the Medusae ("jellyfish") and the Ctenophores ("comb jellies"). In the deep water, without obstacles to bump into, the jellies have taken on a diversity of form unrivaled in the blue. Some are 'traditional' and have a rounded body with hanging tentacles. Others are not so conservative, and resemble nothing so much as actively moving lotus blossoms, fanning open 'petals' as they drop and recoil tentacles in an effort to catch even smaller members of this world.

-Seabird

Good Night for the Marine Biocode Team.

The Marine Invertebrate Biocode Team did the first of this collecting season's night dives tonight, bringing back a rich assemblage of nocturnal animals from the reefs surrounding Moorea.

Several beautiful crustaceans were new for the inventory, including a species of Slipper Lobster (Scyllaridae: P.holthuisi), and two species of Swimming crab (Portunidae), while others were much more cryptic, including two species of Decorator Crab (Majidae) and a Penaeid shrimp.

Conditions were exceptionally calm, allowing the divers to get into the 'avas' or shallow water channels that run through the reef. Under normal conditions, this would be near-suicidal, so the fauna represented in these areas are under-represented in museum collections. The team spent most of the dive working very small areas of habitat, finding 'rare' and undescribed taxa and completely unknown ecological patterns among the cephalaspidean gastropods, brittlestars, xanthid crabs. Everyone is ready to spend all the time we can diving at night and taking advantage of the beautiful weather.

-Seabird

Meeting the Alis

Two of the most active Invertebrate teams in the world had a chance to collaborate over the last few days. The R.V. Alis, and a team from Paris Museum led by Dr. Phillip Bouchet arrived in the Society Islands to do surveys of the deep-water fauna. The Biocode Marine Invertebrate team, led by Dr. Gustav Paulay was invited to use the samples to further the efforts to understand the fauna of French Polynesia. The first day held surprises for everyone as the deep-water dredges came back on board with a sparse but novel fauna.

Among the finds were a hermit crab that has just about lost its shell: it wears a miniscule clam to cover its miniaturized abdomen. In its crab-like shape, this new species is unlike any other hermit known. Other hermit crabs collected do not use a shell for covering their abdomen, but instead are covered by zoanthids (a cnidarian related to anemones and corals).

Other treasures were several deep-water sea cucumbers unknown from the area which will be useful in FLMNH's efforts to genetically sequence and understand the relationships in this enigmatic group of echinoderms.

-Seabird