Monday, December 24, 2012

Summer's here!

 Last week it was humid, rainy, and cool -
well cool for Panama.

Just like that!  It's summer.    

And this week it is bright, blue and breezy.
It’s always confusing here when we talk about summer.  The gringos usually mean June-August, the summer holidays for universities in the north; the summer field season for hard-working graduate students; the busy season for the field stations. 

But here, for Panamanians, summer starts in the weeks before or after Christmas.  It’s not a date you can find in the calendar. There’s no gradual spring warming.  It switches almost from one day to the next. 

What happens is this…..the Inter-Tropical Convergence Zone (ITCZ) is a thin strip of low pressure between two areas of high pressure, one in the subtropical part of the northern hemisphere and the other in the southern hemispheres.  You can see the ITCZ from satellite photos.  It’s the band of clouds and storms swirling around the equator.  During the dry season the northern hemisphere areas of high pressure push the ITCZ south keeping it south of Panama and we get blue skies and breezy dry days.  The rest of the year it is closer to us and keeps things wet and cloudy.
Red arrow points to us in Panama, orange arrows show the
line of clouds and rain.  Photo from NASA.

Biologically this has large effects.   In the dry season it doesn’t rain for weeks or even months.  Trees lose their leaves. Dry grassy areas burn.  Residents spend time watering their lawns. 

For us marine biologists things are different. The strong winds cause upwelling of cool water, so it’s cold for marine life in Panama.  Plankton blooms in the Bay of Panama. Tuna and dolphins arrive to take advantage of the little fish that thrive in upwelling.  And the animals we work on in the intertidal have to cope with wild fluctuations between the cold water and the scorching sun as the tide goes in and out.

Click for more information about the ITCZ in the news

Saturday, December 15, 2012

Grey-necked Wood Rails

I’ve been trying for a few months – with no success - to photograph a grey-necked wood rail (Aramides cajaneus).

Or perhaps I should say I’ve been wanting to photograph them, but my efforts so far – occasionally wandering around outside with my point-and-shoot camera in hand - have not been adequate for the task.  But today I decided to get serious.

These silly-looking birds are some of my favorites.  You would never know they are there until they pop, unexpected for such large birds, out of the undergrowth. They strut out with their tail pointed straight up, looking both jaunty and alarmed.  They are absolutely charming.  Early in the mornings and on grey drippy days you can hear them calling.  A loud, complicated squawky cackle (listen here).  

Plenty of other animals sit still for their portraits in rail habitat  

Grey-necked wood rails are easy to see at the Bocas del Toro Research Station and I want to add them to the iNaturalist list we have been developing for the local plants and animals. Last time I was here I saw 4 – a mother and 3 almost full-grown chicks-walking single file along the fence at the end of the property.  They must have known I didn’t have my camera.  Later, on the same trip, they walked out from under the dining hall, only feet from where I was hosting a VIP.  They must have know I wasn’t prepared.

So I was ready. Getting up early, covered in long sleeves and mosquito repellent (dawn and dusk; you might find rails but you will certainly find sand flies, and mosquitos), I positioned myself on the corner ramp of our new dormitory building.  And waited… and waited…  Nothing.

I returned to the house, showered, looked out of the window and there they were!  Just long enough for me to fire off a couple of shots through the dirty window as they darted into the undergrowth laughing at me.

For more information about the rails click here.

Monday, December 3, 2012

Discovering the Newest Calyptraeid Species - Part 2 - Can we name it?

Finding something you think is new is the easy part.  Then the work really begins.  Before any species can be named it is important to demonstrate that it does not already have a name.  This sounds straightforward but it’s actually a lot like historical detective work.  Frustrating, fascinating, and under-appreciated by people who don’t do it themselves.

The type shells of two of the species described in 
the 1800s, kept at the British Museum and kindly 
photographed for us by their staff.  They look as 
good as new, you'd never guess they are almost 
200 years old!  From Veliz et al. 2012.

So, how did we go about that?  

The first step is to find all of the names that have been given to species in the genus Crepipatella.  This includes the currently recognized species, as well as any other species that have been synonymized with them.  Species are synonymized when two different species are named but are later found to be the same species.  This was not uncommon in the 1800s when access to publications was not as rapid as it is today.  It also happens when different individuals of one species look differen. For example males and females can look different and could have been described as different species.

When two species are synonymized the oldest name is the one that is used, and all of the younger names are considered “junior synonyms”.

When David and I started our search for names in 2009, two names, C. fecunda and C. dilatata, were in use in Chile. But it turned out that 14 species of Crepipatella were described from South America in the 1800s.  We knew the species discovered by David was not the same as C. fecunda or C. dilatata, but we had to check the 12 other species. 

The text and a figure from the original species description of 
Crepipatella nautiloides by Lesson in 1830.

We tracked down the original species descriptions, checked the associated figures, plates or illustrations – these often tell you much more than the short text - to determine if any of them matched our new species.  And finally – if they still exist - we checked the type specimen (the example of the species to which the name is formally attached) or their photos to see if they can tell us something useful. 

Shells of Crepipatella dilatata are on the 
top row, C. occulta in the middle row and 
C. fecunda (now called C. peruviana) on 
the bottom.  From Veliz et al. 2012.
The problem for us was that the old species descriptions are mostly based on shells, but our species show diagnostic genetic and developmental differences from the other two.  Luckily there is also a tendency for the shells to differ:  Crepipatella fecunda tends to have larger, more robust shells that are white on the inside. Crepipatella dilatata tends to have smaller streaky brownish-red shells and our species tends to have glossy chestnut shells.  But there is a lot of variation in each species.

Based on the geographic locations of these old species – some were collected 1000s of miles from the known range of our species – and the shell color, we were able to eliminate all of the previously named species and show that the species discovered by David more than 10 years ago really did need to be named. 

We chose the name occulta – The Latin adjective for hidden.  Since it looks just like the other Crepipatella species and has been hidden in plain sight for 100s of years.

Tuesday, November 20, 2012

New Babies – Peanut Worms!

We have some new babies in the lab this week.

Newly hatched.   And a new kind of invertebrate for us to work with: Sipunculan worms.

These little guys were spawned in a dish last week and we are keeping our eyes on them to see how they grow.   What kind of development they have.  How long before they settle.  At this early stage it’s a bit hard to imagine how they are going to grow.

Sipunculid worms are often relegated to the “The Lesser Phyla” in invertebrate text books.    It’s true they are not well-known or well-studied.  But they hold great potential to answer some very interesting questions about developmental processes and how the body plans of different invertebrate larvae evolve.   Dr. Michael Boyle will be joining the CollinLab early in 2012 so we will all be learning more about these funny looking little worms.