Invertebrates in the news #3 - A new tree of life for the Arthropods

You may not have heard of the word "arthropod" but you are certainly familiar with at least some members of this group: the insects. While insects make arthropods the most diverse phylum, arthropods also contains many other groups. Arthropods can be tiny (fleas) or fairly large (lobsters). They live in a variety of habitats: from the polar waters (krill) to the top of the trees (beetles) through arid deserts (scorpions).

On top of this diversity, arthropods are also economically important. For instance, mosquitoes carry the parasite which causes malaria, bees pollinate many of the fruits we eat, and the fruit fly is a model organism for genetic and medical research. Understanding how different groups of arthropods are related helps understand their evolution.

Scientists have been trying for a long time to understand how the different groups of arthropods are related to each other using morphological characters. This is not an easy task because arthropods are an ancient group. They appeared some 550 million years ago and all the extant groups were formed at least 200 million years ago. This is plenty of time to accumulate morphological differences which may mask the true relationships among extant groups.

This week, the journal Nature published a study that used an unprecedented amount of information found in DNA to understand how the major groups of arthropods are related. The results elucidate some long-debated issues about the relationships among various groups of arthropods. I highlight here two main findings.

Simplified Arthropod phylogeny based on Regier et al (2010)

First, the authors confirm the results of previous DNA-based studies showing that the myriapods (the group which includes the centipedes and the millipedes) are not directly related to insects, and thus, that these two groups invaded land independently. It has been proposed that myriapods and insects were closely related because they both used special organs to breathe air. Furthermore, the myriapods are not directly related to the Chelicerata (spiders, scorpions, horseshoe crabs, mites, ticks) but belong to the Mandibulata (all the other arthropods).

A pycnogonid from Lizard Island, Australia

Second, the closest relatives to the insects are a group of rare arthropods that the authors grouped under the new name of Xenocarida ("strange shrimps"). This new group unites two classes of arthropods that have only been recently described. In particular, the Remipedia were described in the 1980's and are only known from a few places (the Bahamas, the Canary Islands, Mexico and Cuba) where they live in caves. This illustrates the issue of what is called "taxon sampling" when scientists try to infer the relationships among organisms. If the authors didn't include these groups, the conclusions of their study would have been different, and some other arthropod group would have been mistaken for being the closest relatives of insects. Furthermore, it also illustrates the importance of habitat conservation and field work to preserve and discover species that can help unraveling the tree of life.

Link to the study:

• Regier et al, 2010. Arthropod relationships revealed by phylogenomic analysis of nuclear protein-coding sequences. Nature.

More blog articles about the study:

• The most ambitious arthropod phylogeny yet -- by Alex Wild at Myrmecos blog
• Blind Cousins to the Arthropod superstars -- by Carl Zimmer at The Loom

New Arrivals

After the grant report was due, we all heaved a sigh of relief but didn't stop to rest on our laurels. Instead we hit the ground running. Sarah and Jenna pitched in to help me take care of some of the stuff on and around my desk, mostly the ever-growing piles of re-IDs. Thanks goodness for their help...

Am I laughing or crying behind subsample mountian? It could go either way. Oh the humanity! But we finished the grant right? Why is my pile of re-IDs still growing? Pictured below is why.

Art has abandoned the Nart consortium and joined the Shrimp Mafia. He has recruited Sammy DeGrave and Ivan Marin to work with him on shrimp identifying. They will be visiting us for several weeks.

Remember that little trip to Heron Island that Rob, Sea, and François went on? Well those specimens (seven buckets worth) arrived from Australia to make the week more interesting. Since it was so long in transit without ethanol it needed our immediate attention. Jenna did the lion's share of the unpacking and rehousing.

But I (along with Sarah, not pictured--don't worry, I make up for it later) totally helped.

There was so much material that we had to make multiple trips to the offsite ethanol storage facility (hereafter known as the Ethanarium) to refill our supply back at the range. Here is Sarah multitasking by refilling our ethanol carboy and getting a tricep workout.

Sarah has also been doing some work in the lab with Jodi, a grad student in Entomology/Nemotology who is doing some land snail work with John. Even though we send much of our DNA work to the Smithsonian, for our more immediate and smaller-scale needs we can still do extractions here. Sarah has been showing her our procedures.

Plus, we also rested on our laurels. In the picture below you can see the celebratory feast we prepared and a portion of the celebrants (from right to left): John, Nat, Gustav, Sarah, Sea, Mika. But what's that poking out from behind the tree?

Puppies! It was also Mookie's birthday on Feb 1st. End of grant and puppy birthday, what better reason to feast! Gustav, Sarah, and I all brought our pups: Puka, Motu, and Mookie.

Now back to work!

:) Mandy

Invertebrates in the news #2 - David Liittschwager's images in National Geographic

For this second edition of invertebrates in the news, I chose to follow up on a previous post. In early December, Seabird reported on David Liittschwager's visit in Moorea. As announced at the time, the pictures he took during his visit are published in the February issue of National Geographic.

The photographs illustrate a feature article written by E. O. Wilson that emphasizes how important -- and yet little known -- are the small organisms that live in the soil, in the sea, around us. To unravel some of this diversity, David Liitschwager went to six different ecosystems around the globe, and carried with him a green metal-frame cube. At each location, he observed and took pictures of all the organisms he found in his one cubic foot cube. For each location, there is also a video showing how he proceeded.

If so many forms of life can fit into one cubic foot, it means that in order to fully appreciate the diversity of life one must also look closely for the smaller organisms.

Grant-ed

We (meaning Gustav) had a grant report due on January 31st so we have spent the past few weeks making sure that we had dotted and crossed our i's and t's respectively. A grant report is often required at the end the term of a grant, and it is our opportunity to show the funding agency how the money was spent and how we kept all the promises that we outlined in the original grant application. In our case this called for some last minute plating just to make extra sure that we would have as many as we promised. Lots of people got in on the act. Jenna is a veteran plater, and you've already seen her mad skills immortalized in digital format. Less accustomed to plating, but still lending much-needed manpower to the task, is the Nat/Art consortium which we have named Nart. Nart tag-teamed several arthropod plates.

Because mollusc shells are sometimes broken (either accidentally or by necessity) to get a subsample of the animal's tissue, we photograph the specimen before sampling so we have a photo voucher of the intact animal. Sarah is the speediest photographer in the west so she often manned the photo station.

While some of us spent countless hours plating, it wasn't the only activity in the range. It's a new semester so Gustav put out the call, "CUKE TEAM! ASSEMBLLLLLLLE!" is what I'm sure the email said. And assemble they did. Here they are meeting to discuss strategy. I'm pretty sure that the strategy involves a lot of ossicle slide preparation on the part of Julie, Laura, and JD.

Several members of our lab also went to the Florida Union of Malacologists meeting in Sanibel this past weekend. John, Gustav, Fred, Jim, and Chelsey all presented talks. They are also featured in the group photo, along with several people whom you might recognize from their visits to the museum.

In the face of the plating challenge, I have been neglecting my desk for the past week. Emails with work requests have piled up as well as boxes of vials and supsample tubes to be cataloged or renamed in the database. This is what faced me on February 1st.

To those who would be tempted to suggest that my desk always looks like this I would argue that flinging accusations around doesn't empty my desk any faster, and if you're not part of the solution then you're probably part of the problem. Even though February has just begun, we have quite a month lined up. Stay tuned.

:) Mandy

Invertebrates in the news #1 - Bdelloid rotifers & Corynactis viridis

To keep you entertained about invertebrates when we are not in the field, I will write regularly about invertebrates that made the news recently. On the menu today: a summary of a story published today about rotifers and a video of a tiny sea anemone.

How do bdelloid rotifers do without sex?

There are less than 1% of all animal species that don't use sex at all to reproduce. And, for most of them it seems that they gave it up fairly recently. This suggests that, in the long run, species that do not use sex to reproduce end up extinct. By not reproducing sexually, species accumulate deleterious mutations, and cannot exchange mutations that could help them to adapt to changes in their environment -- such as new diseases.

Bdelloid rotifers are an exception, as it seems that they have been reproducing strictly asexually for tens of millions of years. A study published today in the journal Science by Wilson & Sherman sheds some light on the cause of this exception.

Bdelloid rotifers are microscopic animals that live in any kind of moist habitat all around the globe. In addition to their mode of reproduction, bdelloid rotifers are also exceptional in their ability to stay alive out of the water for up to 9 years (at any of their life stages). This ability might be one of the factors explaining why they do well without sex.

The authors of the study showed that staying out of the water for a few weeks reduced drastically the number of individuals killed by a pathogenic fungus. By staying dry for an extended period of time, they can get rid of the the fungus and reduce the selective pressure that these pathogens impose to these asexual rotifers.

More info on the ScienceNOW website and in the original paper.

Video of Corynactis viridis

Have a look at this video of this small sea anemone feeding on plankton. Note how it can change the shape of its tentacles and its mouth (in the center). This video has been filmed under fluorescent light and is played 1200 times faster.

'Corynactis viridis' from MORPHOLOGIC on Vimeo.

Welcome 2010

New year, new semester, and we are all back in Gainesville. And we have already had visitors. Carole Marshall is here looking at our collection of specimens from the Lake Worth/Peanut Island area. She has been diligently photographing shells from our dry collection. We have over 3500 from that area so she has had her work cut out for her.

Harry Lee came back to reprise his role of expert IDer, this time applying his skills to the snail family Terebridae.

We realized that with these new IDs, this will probably be the next group slated for subsampling and plating. A little recon revealed that many of these specimens are small and/or tightly retracted. I think next time we might suggest to Gustav a nice slug family that we should subsample. Dorididae anyone? Well, small and retracted isn't so bad right, at least they're not bivalves, those might present a real challenge. Oh right...

We've been doing the bivalves. I was manning the photo station yesterday when Nat saw me photographing the lovely Lioconcha pictured above. What does its pattern remind you of? If you said "a phylogeny" then you might need to spend a little less time with Geneious (I'm looking at you Nat).

It's true, we're still hooked on Geneious. Below, Jenna is giving Nate an adamant lesson, but they both look pleased with his Geneious-learning acumen.

Now that the semester has started again, the Cuke Team will be reassembled. Julie was previously pictured doing some solo work on ossicle slides, but now she will have company. You last saw JD working with Jenna at Geneious, but that was merely in order to add to his skills as a Cuke Team member. Here he and Laura cuke it up, preparing still more ossicle slides of the sea cucumber family Synaptidae.

Also, Sarah is back from Moorea, but she just can't seem to let go. She has spent much of her time lately compiling the field data into a spreadsheet that can be imported into the Biocode database. The massive collection effort in Moorea is part of the large, three-year Biocode project which aims to document the entire diversity of the island. All the data must be in exactly the right format and Sarah has spent countless hours staring at error messages trying to make it so. She seems so happy, it must be just like being back in the islands!

Art just got back from Ecuador, but I can tell that he was missing work while he was on vacation because he dove right back into drawing Alpheid details. Art has several new species that's he's in the process of describing for publication. It must be keeping him pretty busy because the packages arriving from Amazon.com have slowed to a trickle.

New for 2010, division uniform? Either that or Jenna, Sarah, and I are psychic. There's no other possible explanation for the teal shirts we all decided to wear on the same day this week.

Happy New Year everyone!

:) Mandy

Goodbye Derek!

I realize that it has been far too long since the last HQ update but in my defense, we have only recently returned from break, and our computers underwent some IT voodoo that rendered them problematic for a few days. Only one short week into the new year and we lost Derek. We knew it was coming, and we are excited for him about his internship on Dauphin Island, but we'll miss him nonetheless. Today, in his honor, we listened to the internet radio station he created and his favorite song "Party in the USA." Feel free to play "It's so hard to say goodbye to yesterday" while you look at the pictures below.

We briefly shared Derek with Invert Paleo, but even before then Derek dove in to help them with their tray delivery.

Ok, so Derek is wearing the same sweater in all the pictures below. They weren't all taken on the same day, it's just cold in the range! Here he is sorting through an incoming collection, or is it specimens to plate? I can't be sure.

Pictured below is part of Derek's adventure IDing portunid crabs. He looks happy, this one must have keyed out nicely.

And this is from his last day, still diligently working on the photographs of the specimens that will be sent away for DNA sequencing.

I did not get any pictures of the goodbye potluck that we had, maybe because I was too busy eating. We might have lost Derek, but the others of us who were scattered far and wide (Moorea, Ecuador, Oregon, China) have begun making their way back to us. François is the last holdout, extending his holiday until the last possible minute, and maybe just a little beyond. I know they have calendars in France, François! 2010 here we come!

Plate-tacular-stravaganza

These past few weeks have been very plate-centric. Jenna and Derek have be photographing and subsampling bivalves from the ethanol collections. Nat has dipped his toes into the arthropods, and I have been hammering away at the echinoderm tissues pulled from the cryofreezer. The details are hazy, but I'm pretty sure I dreamed the other night about affixing the small adhesive labels to the subsample vials. In the picture below Jenna's purple gloves demonstrate her dedication to both sterile subsample conditions and a festive work environment. Ok, the purple ones were on sale last time we bought gloves.

So why isn't Nat wearing purple gloves? Somewhere he must have found a stash of the older latex gloves, but you can see his dedication to office-festiveness in the classy pink fingernail polish at his workstation. We use this to denote which specimens have been subsampled. It looks like Nat has chosen "A Dozen Rosas," I usually opt for "Fuchsia Fever."

Machel also joined us in the lab. She and Nat must have heard that I was thinking of heading up to the grad student offices to try and get a photo of them in their natural habitat for the blog. François escaped back to France for the holidays before I had fully committed to the expedition.

Plate-frenzy and ID frenzy go hand in hand. Below, John is identifying some bivalves to add to the queue of specimens to be sampled. He and Gustav have been making sure we don't get bored, run out of things to do, or see anything other than bivalves seared into our retinas when we close our eyes.


That's right, Gustav is back from Moorea (again), and you know what that means...buckets! Buckets and buckets of baggies and vials of specimens that need to be rehoused and stabilized in ethanol. I got a picture of a portion of it.

Processing the specimens fixed in ethanol goes fairly smoothly, but the ones which are formalin fixed require a little extra attention since it is a more hazardous material. Like a responsible scientist, Nat took a few bags over to the fume hood in the herpetology range to safely drain the formalin and replace it with ethanol. I hope you're looking Department of Environmental Health and Safety!

Processing buckets means we use hundreds and hundreds of small wet vials. We have many sizes, but these are the most popular. Just to give you an idea, we buy several cases at a time, several times a year. Each case contains 750 vials. In this next picture Derek is replenishing the lid stash.

At our last discussion-group meeting of the year (pictured below), Nat gave a practice presentation of a talk he will be giving in January on Myxozoa. "Myxozoans," you're thinking, "are those cnidarians like corals and jellyfish or more closely related to the bilateria such as worms?" Good questions, Nat's master's research brings us a few steps closer to the answers we seek.

Happy Holidays!

:) Mandy

Tonna perdix eating Stichopus sp.

Not many animals are known to eat sea cucumbers. There is a good reason. Most of them have chemicals in their body, which probably doesn't taste too good but more importantly may intoxicate the potential predators.

Humans have found a way to deal with these toxins. In the preparation of the bêche-de-mer, sea cucumbers are boiled for a long time which breaks down these chemicals.

If toxicity is a good way to avoid generalist predators, other animals have evolved to become specialists and can deal with the cocktail of toxins found in the skin and organs of sea cucumbers. In coral reefs, among the specialist predators, Tonna perdix is known to feed regularly on sea cucumbers, and in particular, on the species of the genus Stichopus.

After finding a Tonna perdix during a reef walk on Heron Island, I decided to keep it in a tank hoping to observe its feeding behavior. A few days later, Rob brought me back some Stichopus (that I can't identify to the species level) and decided to put it in the tank with the Tonna perdix. Before the Stichopus even touched the bottom of the tank, the Tonna perdix became really active. After a few minutes crawling around the tank, Tonna perdix used its proboscis to detach its prey from the wall of the tank, and in just a few seconds, the gastropod extended its proboscis around the sea cucumber swallowing it whole. Holly Heiniger had her camera with her to record this.

Sea cucumbers have also evolved ways to escape predation. In particular, Stichopus can shed its body wall to only leave pieces of it to the predator. However, in this case, the attack was so fast that the sea cucumber didn't seem to have any time to escape.

Visiting Artist: David Liittschwager

The Moorea Biocode project is currently hosting the photographer David Liittschwager (http://www.liittschwager.com/). His amazing works have been showcased in the book "Archipelago: Portraits of Life in the World's Most Remote Island Sanctuary", which he co-authored with Susan Middleton. He has a few projects he is working on that document coral reef organisms, so he is collaborating with the Marine Invertebrate Group of the Biocode project and the Invertebrate Zoology department of the Florida Museum of Natural History. He has spent the last week or so taking the most interesting and beautiful creatures from our collections into a lab-turned-studio and coming out with intensely detailed portraits of a fauna rarely seen, let alone celebrated.

One of his projects will be coming out in the February issue of National Geographic.

It has been a treat having him around, lending an artistic perspective to a world view dominated by scientists.

-Seabird

New Genus!

Sarah McPherson has become our expert in collecting the hidden organisms in the vast areas of sand around Moorea. The habitat is one that is frequently overlooked, and turns up all manner of surprises. You will see her patiently fanning, stirring up huge clouds of sediment, and revealing one pale tan critter after another. After today's dive she came back with a collecting bag full of creatures new for the project including one inconspicuus, transparent, Alpheid shrimp. Art Anker, a post doc in the Paulay lab and one of the few world experts in the identification of shrimp in this group, was on hand to announce that Sarah had found a very special shrimp. Not just a new species, but a new genus! He also promised to name it after her.

-Seabird

Packing up, moving on...

Rob has a distinctive packing style

Our three weeks in Australia have ended, so we are packing up all of the specimens, and shipping them back to the Florida Museum of Natural History.

Packing, itself, is a long drawn out affair- all the containters need to be drained of Ethanol, then packaged together with other specimens, heatsealed into a plastic bag, and then packaged into small barrels. With over 2000 specimens, it takes HOURS. But if it means that they make it back to the museum safely, it is time well spent.

The trip was interesting in terms of what was on the island, and what wasn't. As expected, rarity was the rule, and some groups that we expected to be common were all but absent. Unlike many places in the Indo-Pacific, the coral genus Pocillopora was largely absent from the area- and certainly not a reef dominant group, as it is in Moorea. The same could be said of many types of Sea Cucumbers. Parasitism of echinoderms and crustaceans was common.

The large scale questions remain: What drives these patterns of diversity? Why is this place different from others?

-Seabird

Preparations, Celebrations, and Geneious Fever

Another busy week! François has returned to us from Heron Island and Gustav has left us to return to Moorea (he might be on a plane right now). While he was here he entered into an ID frenzy. The first group he tackled was the gall crabs, Cryptochiridae, which live in coral. It's hard to detect the frenzy in the picture below, but it is there. And yes, that is Jenna in the background still toiling away at Geneious. Lest you think she is a Geneious slave, I'll have you know that not only has her tether recently been lengthened, but we also unchained her completely last weekend so she could spend Thanksgiving with her family.

Don't be alarmed, but Geneious Fever has spread from Jenna and JD to the office I share with John. Because his back is to me, I can't see the glassy-eyed stare that is characteristic of Geneious Fever, but the beautifully aligned and colorful DNA sequences on his computer screen give away his condition.

We've also spent some time gathering supplies for Gustav to take with him back to Moorea. A sampling is in the photo below.

Now I realize that to the untrained eye, this assortment of equipment might look vaguely suspicious, but don't worry, the scientific eye can discern that this stuff looks...ok it looks hilariously suspicious, that's why we took a picture of it! But Gustav should have no trouble at the airport, not only does he have museum credentials, but he also has a beard and an accent. In reality, what looks like three sticks of dynamite is actually a battery for an underwater vacuum and the white cylinder is its case. The bags of expensive looking white powder contain the salt magnesium chloride. This substance is used to relax mollusks before preserving them. Relaxing them has a dual purpose, it acts like an anesthetic so it is more humane than just plopping them in ethanol, and it causes them to release their body out of their shell. Some gastropods and most bivalves can be difficult to preserve without relaxing because they seal themselves in their shell and end up rotting because the ethanol can't penetrate.

In the picture below Derek is working on the construction of the battery case. It has been quite a project, and although Derek did most, if not all, of the actual construction of the case, I have a proprietary sense of pride and feel I really contributed to it's construction since I wielded the pcard that made the purchasing of the components possible.


This week the GRR (Genetic Resources Repository) division of the musuem celebrated its 20,000th accession, so they threw a party to celebrate. The GRR is responsible for managing the tissue subsamples for the museum division's wet collections. Our division felt especially proud since we contributed over 54% of the subsamples and the 20,000th lot was an isopod from our collection. Chelsey, Derek, and I posed with the cryofreezer...

...but not before stuffing our faces with cake! While Pam cut the cake Lorena opened the freezer for us to see. This picture was taken after the freezer was open for a while and so it didn't capture the huge billow of steam when the freezer is first opened. Very dramatic!

Now we'll get back to work on the next 20,000!

:) Mandy

Museum Happenings

It's been a relatively busy week at HQ. In addition to lending field support to our agents throughout the globe (Australia, New Zealand, Moorea) with supplies and data entry, we kept up a brisk pace of other activities as well.

In the picture below, Jenna is spreading the Geneious love. She is now so skilled in the program that she is sharing her knowledge with others. JD is hanging on her every word. Also, Julie is delighted by ossicles, the calcarious particles in the skin of sea cucumbers. She is preparing slides so the ossicles can be viewed under a microcscope. They are often a diagnostic character in distinguishing species.

John is taking a break from the land snails of Madagascar to ID some snails that were given to us from marine lakes in the Pacific. Not to worry, the 10,000 lots of land snails that recently arrived from Madagascar will not let themselves be forgotten. They have numbers on their side and know that John needs them for his PhD work.

Before we put tissue samples in plates to be sent off and sequenced, it is helpful to have an accurate ID on the specimen, so Gustav called for backup. Harry Lee is an expert malacologist whom Gustav recruited to help us ID to species some of the snail families in our collection.

Jada and Anthony are plating some some her Moorea specimens for sequencing. Not pictured, the actual plates. I think they're hidden behind a bag of subsample vials.

This was Walter's highly anticipated vermetid ID-stravaganza. As you can see it was well attended, even though it was postponed until Thursday due to schedule conflicts. These worm snails can be easily confused, not only between species, but with other families of snails such as the Turritellidae, and even with actual worms, a completely different phylum (Annelida). We are now armed with the necessary arsenal to fend off such mis-IDs.

We have a shortened week due to the Thanksgiving holiday. After gorging ourselves on turkey we'll be ready to spring back into action. Or if not spring, at least sluggishly haul ourselves up to our desks.

:) Mandy