Tuesday, December 16, 2014

Hey everyone,

I'm spending time at the Smithsonian National Museum of Natural History these days, and wrote a short blog post about another recent leg of the Red Sea Biodiversity Project over at the No Bones blog - why don't you go and check it out here?


Friday, October 3, 2014

Goldilocks and the three crab size classes: New paper out this week on coral guard-crabs

Remember Seabird? He was a Ph. D. student in the lab, and is now Dr. Seabird McKeon at the Smithsonian Marine Station in Ft. Pierce, Florida. A paper we co-authored on Trapezia defense against coral predators came out this week in PeerJ, and even made the front page. It's open access, so you can read it for yourself right here. These plucky little crabs defend their coral hosts against different species of corallivores, including the snail Drupella cornus, the cushion sea star Culcita novaeguineae, and the fearsome Acanthaster planci, or Crown-of-Thorns sea star (COTS if you're in the know).

Photo © David Liitschwager
The response of the four species of Trapezia we tested against these predators varied by the size of the crab species. Little Trapezia serenei and Trapezia punctimanus defended their hosts effectively against Drupella cornus (the little snail predator), but couldn't do much about the big predators. Medium sized Trapezia serenei and Trapezia bidentata could fend off Culcita novaeguineae, but didn't bother with the snail threat. And the biggest crabs, Trapezia flavopunctata, had a striking effect on their host survival in a natural experiment in Moorea, French Polynesia during an outbreak of Crown-of-Thorns sea stars.

Terrifying: Acanthaster chowing down on Pocillopora
There's also been a bit of buzz about the article on some news sites, so if popular articles are more your cup of tea, here's a few features of the article, featuring the gorgeous photography of Trapezia by David Liitschwager:

Science News
Smithsonian Magazine
Science World Report

Worm wishes,

Sunday, May 25, 2014

Not bad atoll...

The 2014 Marine Biodiversity Workshop on Magoodhoo Island, Maldives

Photo: Francesca Benzoni
This is a busy summer of fieldwork for the IZ crew: Gustav just returned from an expedition in the Philippines, Nat is off wrestling portunids in Palau and Guam, and I spent the past two weeks participating in a great workshop organized by Drs. Francesca Benzoni and Paolo Galli of the University of Milan, Bicocca.

Many invertebrate researchers from universities and museums in the Netherlands, Japan, Saudi Arabia, Italy, and the US gathered on Magoodhoo Island to document the biodiversity of the Maldives, as well as contribute lectures and practical courses to a wonderful group of Master's students.

Photo: Luis Gutierrez

The students got a taste of our team's field and curation techniques through collecting their own specimens from the local lagoon, replete with seagrass beds, a lovely fringing reef, and all the sand a sea cucumber could eat. Here are some of the students hard at work hunting for creatures in dead coral rubble and sorting the catch:

The students took to our processing techniques immediately, and documented, photographed, DNA subsampled, relaxed and preserved the specimens provided by the sorting teams like champions!

After the biodiversity sampling lecture and practical, the students filed back into the classroom for a lecture on marine annelid biology, which are my favorite group of spineless creatures. They got a thorough indoctrination lesson on the wonderful world of worm biology.

In exchange for the wonderful opportunity to interact with these very bright and eager students, the visiting researchers also sampled the local reefs during daily excursions on the dhoni, a traditional wooden Maldivian boat outfitted these days with SCUBA tank racks, diesel engines and sound systems.

Photos: Francesca Benzoni
These excursions provided us with new specimens of crustaceans, echinoderms, molluscs, and of course, annelids, for the Florida Museum Marine Invertebrate collection. I will resist the extreme temptation to show off some of the beautiful chaetopterid polychaete worms, in favor of this incredibly adorable leopard-print Indian Ocean endemic nudibranch, Chromodoris gleniei:

Stay tuned for a post on the upcoming expedition to Kavieng, Papua New Guinea!

Worm wishes,

Monday, February 24, 2014

Team Unionid

Taxonomy is a wily beast.  As François discussed in his previous post, keeping up with who is called what can be a complex issue.  Species can be synonomized with other species, moved to other genera, split from their current species into a new species (or new genus), and back again and so forth.  This can make things somewhat complicated for museum collections, especially when we receive collections that have been collected throughout history.  We get specimens that have the ID that was correct when they were collected 50 years ago, but what is the current correct name? What is the name in our database?  Is it one of those two or one of the many steps in between?  There are a (very) few groups that have current taxonomy listings on line, but we deal with so many groups from so many phyla.  It usually takes an expert, who is familiar with the current literature of their particular group to clear things up. Fortunately for us, we know an expert for one of our largest groups, the Unionidae family of freshwater mussels, and he's recruited others.

Jim Williams, Matthew Rowe, and Jordan Holcomb have been combing through countless brown shells and getting our taxonomy in order. 

To give you an idea of what "countless" means...

Yeah, you could totally count that, but multiply it by...

That's still doable, might take a while, but...

Nearly that entire aisle is Unionids, and there are even a few cabinets worth in the previous aisle.  Let's not forget the wet collection.  Below is less than half of it.

Even though they are all caught up on the current taxonomy of this group, it still isn't always as straightforward as changing all specimens of one name to another.  Here is an excerpt of an email I got from Jordan outlining the specimen labels they needed updated and printed for the Lampsilis teres/floridensis group:

We will need everything from Florida listed as Lampsilis teres to be changed to Lampsilis floridensis.  All records from Georgia except those from Walker, Chattooga, Gordon, Floyd, Bartow, Whitfield, Murray, Gilmer, Catoosa and Polk counties listed as Lampsilis teres need to be changed to Lampsilis floridensis.  Finally, all Lampsilis teres holdings in Alabama from Butler, Barbour, Chambers, Conecuh, Covington, Crenshaw, Coffee, Escambia, Dale, Geneva, Henry, Houston, Lee, Pike, and Russell counties should be changed to Lampsilis floridensis. 

And this doesn't even account for the L. teres floridensis that we had cataloged from Iowa and Arkansas, or the L. teres teres specimens that needed to become L. teres.  So it's complicated, and we are really grateful that they are willing to spend all this time and effort helping to get our collection up to date.  We're also grateful for the bribes they bring us to keep the updated labels flowing.

Unionids are a challenging group to work with, but the challenges that they present to us pale in comparison to the challenges with which humanity has presented them.  Many species are critically endangered and some are suspected to now be extinct.  As a freshwater group, they rely on many of the same waterways that we utilize for drinking water, power, recreation, and many other uses.  Pollution and habitat loss have wreaked havoc on this group that is very sensitive to changes to their ecosystem.  If you want to know more about Unionids, check out Jim's book on the Alabama mussels, and keep your eyes peeled for his next one.

:) Mandy

Thursday, February 6, 2014

Invertebrate Zoology is Nice(ville)

This past weekend we were visited by a group of high school students from Niceville, FL.  They have come to visit us every year for the past several years to get a taste of what we do, and to incorporate some of our techniques into their own projects and fieldwork.

They divided into three groups.  The first group explored the collection for a broad overview of the kind of biodiversity we have in our collection.  Of course Bathynomus giganteus, a giant isopod, was a hit.

Who could resist a face like this?

Photo from Wikipedia Commons
We had several exercises for them down in the collection.  Jenna worked with a group of students trying to sort brittle stars.  There is a group that has been historically identified as a single species, however genetics and the discerning eye of Tania (a visiting researcher) can find significant differences between several groups within the species.  We challenged the high school students to do the same, armed with Tania's genetic tree and a microscope

The students also braved the world of tunicates with Ronaldo who is visiting from Brazil.  He showed them some nice clear diagrams with taxinomically significant features highlighted.  They then looked through the microscope at a prepared specimen to see how tiny and easily confused these features really are.

Then they tried their hand at some microscope work of their own and prepared some sea cucumber ossicle slides with guidance from Starmer John and myself.  He even brought in the big fancy microscope from our office for the occasion, to demonstrate how ossicles show up under polarized light.

The second station was upstairs in the lab with Nat and Jennifer.  After explaining the PCR process and how we use it in our lab, the students all gloved up and prepared solutions for PCRing.  Since running the actual PCR is a process that takes several hours in the thermal cycler, Nat and Jennifer ran some pre-loaded gels so they could see the bands of DNA fragments of various lengths.

After their stint in the DNA lab, the students headed downstairs to work with François on aligning and cleaning DNA sequences using Geneious.  After we send our PCR products out for sequencing, the results we get back still need some hands-on attention before they are ready for prime-time, so the students got a taste of that.  François has undoubtedly spend many an hour in front of the computer with color-coded nucleotides dancing before his eyes. 

We had a great experience with the group and it's always fun to share our love of what we do, especially with potential future scientists.  In fact, you can never be too young to be engaged in invertebrate zoology...

...even if what that means for now is that you're drawing some octopus and crabs in with your flowers.

Friday, January 31, 2014

At last Mookie has a sea cucumber species named after him, let me introduce you to Phyrella mookiei

In 2010, during the sea cucumber taxonomy workshop we organized in Guam, we collected what we thought was a new sea cucumber species of the order Dendrochirotida. At least, we knew it was interesting as this order was known to have only two species in Guam, and this clearly was neither.

Back to the museum, we started to examine the specimen more closely to assign it to the appropriate genus. It soon became apparent that this species belonged to the genus called Phyrella (family Phyllophoridae). To determine if it was a new species, we first went through all species that are currently in this genus, and our species did not match any of the 4 species assigned to Phyrella. At this stage, it looked like describing this new species would have been a quick and easy side project. It was not. The paper is pretty large (40 pages), and took a long time to put together. So, what happened?

The species description turned into the revision of the Phyrella. We realized that two genera were synonym of Phyrella (Thyonidiella and Semperiella); one species that was assigned to Phyrella did not belong there (we transfered it to the genus Euthyonidiella); and that other species might actually belong to Phyrella. Making these decisions involved spending a lot of time reading through old taxonomic descriptions (most of them in German), and also examining specimens from many places (Australia, Japan, the Philippines, Panama) and type specimens that are housed in the natural history museums of Paris, Geneva, Washington D.C., Copenhagen and Perth.

If you are not acquainted with the inner workings of taxonomy you might be wondering what a "revision" is, and why we "transfer" species between genera or "synonymize" them. Taxonomy strives to create groups that reflect the evolutionary history of the species they include. In other words, the classification of a species should give you a rough idea of its position on the tree of life. In the past, the only way to estimate how species are related to each others was to find morphological characters that are shared among them. Sea cucumbers don't have many morphological characters that can be used to make these groupings. In addition, over the history of sea cucumber taxonomy, different authors had divergent opinions on which characters to use. Another problem is that many species were described based only on a few specimens so previous authors didn't appreciate the variation in these characters within a species. These factors led to a confused taxonomy with many genera that do not group related species together. A taxonomic revision fixes that, and with our paper, we clean up a little corner of the giant mess that is currently the Dendrochirotid taxonomy.

An important advantage that we now have compared to past sea cucumber workers is that we can use DNA to infer how species are related to each others. It gives us an independent line of evidence we can use to clarify the morphological characters that define genera. Our study is the first to use DNA to guide a taxonomic revision in Dendrochirotida. We learned that there is a lot more morphological variation in Dendrochirotida than was previously appreciated. For instance, before our study, all Phyrella were thought to have 20 tentacles. However, after painstakingly counting the tentacles of many specimens, it is clear that this number is variable, even within a species.

And what about the new species? Its name is Phyrella mookiei, the etymology of the paper says:
Named after Mookie, the dog of our collection assistant Ms. Mandy Bemis, because the "woolly" appearance and color of this species is similar to the soft coat of wheaten terriers, the breed to which Mookie belongs.
The timing couldn't be better as tomorrow is Mookie's birthday. Here are some pictures of Phyrella mookiei and Mookie so that you can decide for yourself of the resemblance. You can download the full article here. It's open access so feel free to distribute widely and re-use the content as you please.