Species species of the Week week #4 OR Hiphopopotamus

Hippopus hippopus

(The Horse's Hoof Clam OR 

The Strawberry Clam OR 

The Bear Paw Clam)

Figure 1. What a wacky looking clam!!
Photo Credit: Mehmet Atatur

Figure 2.  Yup, wacky from this angle too!

Right, so the radness of the shell alone (Figs 1 & 2) is pretty much enough coolness for this tautonym to stand on, but there is so much more to Hippopus hippopus (Disambiguation: Did you mean "Hiphopopotamus"?) that makes it cool. And for that we need to see a picture of it in situ, up close:

Figure 3. Open live H. hippopus, looking even wackier

Go closer...

Figure 4.  Siphon and wacky mantle tissue.
Photo Credit: Artesub.com

Closer still...

Figure 5. Extreme Close-up. Reflective proteins in mantle tissue of Tridacna
Micrograph Credit: Griffiths et al. 1992

Too close, a little too close!

Figure 6. Dinoflagellates (non-algae algae) of the genus Symbiodinium.
They live in giant clam flesh!

There!  Living right in the mantle tissues of these Giant Clams are dinoflagellates (1),  phytoplankton of the genus Symbiodinium.  The genus name kind of says it all.  These  wiggly bulbous photophiles have a symbiotic relationship with the clams whereby they use sunlight to produce carbohydrates, which the clam then eats, and in return, they get a stable habitat in which to live and drink up the sun.  Free-living dinoflagellates, like all plankton, are at the mercy of the tides and currents and can get forced down to a depth beyond which they can obtain sufficient light to photosynthesize (= bitty dinoflagellates, wasting away).  By paying a bit of rent in the form of sugar to the clam, symbiotic dinoflagellates are assured that they will not be sucked into the deep.

Ok, so that's cool enough, but not unique.  This is roughly the same symbiosis as corals and our own local Anthopleura anemones (see really, really ... really cool research at Western on climate change and symbiosis).  

But!  What I learned just this week at a talk by Alison Sweeney (2) was that not only do the clams have algae all up in their skin, but they apparently also modify their own mantle tissue feed more dinoflagellates, and thereby get more sugar.  They're farmers! The iridescence you see in the mantle (Figure 4) is generated by iridocytes, cells with organized proteins all stacked up (Figure 5).  What are the iridocytes for?  There are a number of ideas that have been considered, including protecting the dinoflagellates from exposure to too much sun, which can cause chemical stress on both dinos and clams.  

However, modelling and experiments done by Dr. Sweeney and friends indicate that proteins in iridocytes forward scatter wavelengths of light that are useful in photosynthesis, deeper into the clam than it would otherwise go.  This is good news for the dinoflagellates and the clam (more light -> more photosynthesis for more dinoflagellates -> more candy for the clams!).  However, the iridocytes backscatter  the other wavelengths (like green), so we see green iridescence. So, it's possible that the clam uses iridocytes to improve their dinoflagellate husbandry.

Dang, clam, you pretty and smart!

References and miscellany:

(1) Pedantic note about pronunciation of this word: Neigh on a decade ago, it was STRONGLY emphasized to me by Greg Teegarden who learned it from his Academic forefathers/mothers that "Dinoflagellates" is pronounced "DEE-no" NOT "DYE-no".  The former is derived from Greek meaning "rotation", referring to the transverse flagellum that causes these guys to spin, while the latter signifies the Greek word "deinos", meaning "terrible" - like Dinosaur = "terrible lizard".   It seems to me that these are spinning, but not terrible, flagellates.  

(2) Most official website I could find for Dr. Sweeney, this is from Duke where she did her Ph.D. Currently at UCSB Institute for Collaborative Biotechnologies, headed to Penn Physics this fall. She has also done lots of work on coloring and iridesence and optic stuff in cephalopods. 

Species species of the Week week #3 OR Foaming with rage and bruised all over the chest

Grapsus grapsus

(The Sally Lightfoot Crab)

Dang, Sally, you pretty!
The whimsically named and colored Grapsus grapsus.

John Steinbeck will undoubtedly provide a much more interesting perspective on this whimsically named (in both Latin and common) Grapsus grapsus than I ever could.  So, I leave it to him to describe this tropical member of the Grapsid family:

Many people have spoken at length of the Sally Lightfoots. In fact, everyone who has seen them has been delighted with them. The very name they are called by reflects the delight of the name. These little crabs, with brilliant cloisonné carapaces, walk on their tiptoes, They have remarkable eyes and an extremely fast reaction time. In spite of the fact that they swarm on the rocks at the Cape, and to a less degree inside the Gulf, they are exceedingly hard to catch. They seem to be able to run in any of four directions; but more than this, perhaps because of their rapid reaction time, they appear to read the mind of their hunter. They escape the long-handled net, anticipating from what direction it is coming. If you walk slowly, they move slowly ahead of you in droves. If you hurry, they hurry. When you plunge at them, they seem to disappear in a puff of blue smoke—at any rate, they disappear. It is impossible to creep up on them. They are very beautiful, with clear brilliant colors, red and blues and warm browns.

…

Man reacts peculiarly but consistently in his relationship with Sally Lightfoot. His tendency eventually is to scream curses, to hurl himself at them, and to come up foaming with rage and bruised all over his chest. Thus, Tiny, leaping forward, slipped and fell and hurt his arm. He never forgot nor forgave his enemy. From then on he attacked Lightfoots by every foul means he could contrive and a training in Monterey street fighting has equipped him well for this kind of battle. He hurled rocks at them; he smashed at them with boards; and he even considered poisoning them. Eventually we did catch a few Sallys, but we think they were the halt and the blind, the simpletons of their species. With reasonably well-balanced and non-neurotic Lightfoots we stood no chance.

-The Log from the Sea of Cortez (1951)(1)

Hit Parade:

• Grapsus grapsus have been reported to remove the ticks from marine iguanas - how thoughtful, AND delicious!(2)
• Here is an educational video in Portuguese, complete with whimsical music. I certainly do not speak this language, but it's pretty footage and I do think I recognized the phrase "voracious predator".  If anyone wants to offer a translation of the narration...
• Our most common local Grapsids are Hemigrapsus oregonensis and Hemigrapsus nudus, which can be found on almost any salty beach around town, scuttling away from overturned rocks. My dog Jay used to think they were little chicken nuggets with legs.

References and miscellany:

(1) A highly, highly, recommended read. I enjoyed being reminded that I missed the golden days of ocean exploration and could still pretend I was doing reading for "work" by learning about beasties along distant coasts.

(2) Beebe, W. (1924).  Galapagos: World's End. New York: G.P. Putnam's Sons.

Species species of the Week week #2 OR Emily's FAVORITE Tautonym

Gemma gemma

(The Amethyst Gem Clam)

As it's at least supposed to be a molluscan marine blog it seemed worthy to start (1) with a redundant local marine mollusk.  Unfortunately, it turns out that very few, if any, tautonomical invertebrates are native to the Pacific Northwest (2).  So why not a non-native? It turns out this one is also my very, very favorite tautonym.

Figure 1. Peterson (of field guide fame) refers to G. gemma as, "a handsome ... clam, easily overlooked because of its small size".  Just so, sir.  Just so.

Photo Credit: Fisheries and Oceans Canada. Melissa Wong.

In addition to being the name of my wireless network, Gemma gemma (3) is the diminutive Amethyst Gem clam (Disambiguation).  These tiny bivalves are native to the east and Gulf coasts of North America, from Nova Scotia to Texas. They were introduced along the west coast of the US around 1960, but have only recently become very abundant in San Francisco Bay - but hey, what hasn't these days?! Am I right, folks?! (<---- NOTE: That was an excellent/horrible invasive species joke.  Insert rim shot here ... plz.)  

But seriously...

Ted Grosholz (UC Davis) tried to figure out why the gem clam population didn't really take off until decades after it was actually introduced (4).  It looks like the gem clam populations used to be held in check by competition (Figure 2) with native clams of the genus Nutricola (which I'm pretty sure are referred to as "Nut" clams).  

Figure 2. Schematic depicting San Francisco Bay pre-Green Crab Invasion (5).  Native Nutricola spp. (Pink, Yellow, and White individuals) originally kept non-native Gemma gemma (Green individual) at low abundances by eating up all of the food (phytoplankton represented by dinoflagellates, chain-forming and pennate diatoms and coccolithophores) leaving only scraps for poor G. gemma. 

Gem clams were kept at such low abundances that they were not, apparently, worthy of much notice or concern.  That is, until the arrival of the [non-whimsically named] European green crab, Carcinus maenas, which came to SF bay as a stow-away in the late 1980's.  The invasive crab, embracing the gastronomic culture of its host country, prefers to eat the biggest thing is can get its little green claws on, which in SF bay is the native Nutricola spp. The tiny gem clams get overlooked - lucky Gemma gemma devils!  That means no more selfish native clams hogging all the delicious phytoplankton (Figure 3)! Time for tiny gem clams to make tiny gem babies! 

Figure 3. My, how the tables have turned!  Schematic representing San Francisco Bay post-Green crab invasion.  Crabs (lower left) preferentially consume native Nutricola spp. (lonely yellow individual), freeing up more food for non-native gem clams (prolific green individuals) to make gem babies! 

Cool, huh?!  In many cases like this one, non-native species are present at low abundances for years after they are introduced, leading people to be all like, "ohhhhhhh....whateverrrr...it's no big deallll...I mean, who cares about some dumb clam anyway..."  And then something changes.  Maybe the non-native population develops a key adaptation that enables it to make more babies than before, or something else in the environment frees up resources (*cough, cough* I'm looking at you C. maenas), and the population of the non-native explodes and messes things up for EVERYONE.  And people are all like, "whaaa!? But how could we have known!?"  And I'm all like, "because it happens every time!"  Well, not every time, but surprisingly often. 


So called "lag times" are a pretty common property of biological invasions, and one extremely good reason that, notwithstanding any aesthetic arguments(6) for the moral equivalence of human and non-human invasions, all introductions of non-native species deserve to be treated with caution. 

References and miscellany:
(1) Yes "start" more than a month later, this is the first second species species of the week week. I did warn the one of you that reads this that these would be irregular and unlikley to actually appear on a weekly basis.
(2) I'm tempted do some arm waving here about how this probably has something to do with the idea that the tautonym species are so-named because they were the first of the genus to be described, and most of the marine genera in the PNW were first described in Europe or the east coast of North America.  But that arm waving will only appear in small print in the foot notes.
(3) On the pronunciation of Gemma gemma: "gemma" comes from Latin for "jewel". I assume it SHOULD be a hard G if you're being true to Latin pronunciation, but I have only ever heard it pronounced with a soft G, presumably in honor of the common name - which also pretty much comes from Latin for "jewel" but has since been bastardized.
(4) Grosholz, E., (2005) PNAS. 102(4): 1088. 
(5) If you have to look this game up, and don't have age as an excuse, your childhood was misspent.
(6) Drew Christie is a great Seattle animator and illustrator whose work I actually really like, but this piece got under my skin (really really far under my skin), for making a tenuous aesthetic (but it's cute!) and moral (humans are invasive too, who are we to point the finger?!) argument that manipulates feelings about a legitimate conservation issue.

Species species of the Week week #1 OR The Whimsey of Nomenclature

I have been told, and I shall not say by whom, that the scientific name (1) for the green sea urchin is the longest currently assigned.  Weighing in at 32 letters, I present:

Strongylocentrotus droebachiensis

Ta-da! Oh, to bear the weight of so many syllables! (credit: enature.com)

Now I don’t know if this claim is merely intertidal boosterism, but I do know that is a long name and it’s not immediately clear how one would know the pronunciation without initiation into a secret society (hint: "STRON-JUH-LO-SEN-TRO-TUS DRO-BAK-EE-EN-SUS"). 

In addition to being a marine nerd, I’m also a word nerd, and I dig on the etymology of how organisms are named and described by their scientific name, in part because it’s both lyrical and logical.  Just removed enough from common usage to make you feel like you are gaining insight into the natural world just by knowing the “true” name.  Scientists avoid using common names because,  Buff thighed puffley notwithstanding, these names are often vague, and are either shared by several species, or are only one of a list of names for a single species. 


However, the Genus species approach, AKA binomial nomenclature, though, perhaps, more precise, still only gives you a false sense of security that you know the true identity of an organism.  Scientific names are more dynamic that you would expect, as scientists move species into new genera believed to more accurately reflect their evolutionary history.  One of the snails I study is Ocinebrina inornata, but has variously been known as Tritonalia japonica, Ocinebrellus inornatus and is still identified by the Washington Dept. of Fish and Wildlife as Ceratostoma inornatum  (2).  

Names are also logical - mostly.  True, some are named after people, those who discovered them, those who were/are influential in the field, or those who were important to the scientist in a more personal way.  But, more typically, the name tells a story about the organism, what it looks like, where it lives, or what it does.  Take the cumbersome sea urchin moniker.  According to a similarly word nerdy blogger: Strongylo = round, centrotus = spiky, droebach = Drobak, Norway, where the organism was first described.

Now for the Whimsey...

One of the types of names I am especially tickled by is double genus species names, where the name of the species is the same as the genus.  The poster child of double names, of course, is Gorilla gorilla.  Come on, say it out loud.  It’s a little bit whimsical, isn’t it?!  Imagine applying that to people names.  My last name is Grason and my parents joked about naming their firstborn son, my older brother, Grayson, so he would be Grayson Grason (same pronunciation).  What would you do if you met Grayson Grason?  Then again, maybe you already know folks that do have double names. 

This is not at all to make light of someone who might have the same first and last name.  In fact, I think of these organisms and people as the “type” specimen, the realized Platonic ideal of its kind, by comparison to which the entire group is defined.  Grayson Grason is the Grason-iest Grason.  Is Gorilla gorilla the gorilla-est member of the genus Gorilla. Is that really how you spell “Gorilla”? I’ve now been staring at it too long to tell.  Incidentally, according to Wikipedia (I know, my sources are unimpeachable), the name “gorilla” was derived from Greek meaning “tribe of hairy women” – lovely.

"Tribe of hairy women"? You decide.

So, what’s the deal? Did these folks run out of steam?  Well if a new species being named (3) is the only member of a genus, you could imagine it might end up with the same species as genus name.  But this isn’t always the case.  There are two species in the genus Gorilla for instance, so I would guess that G. gorilla came first.  I fully admit, I’m more interested in the names themselves than in speculating about, or spending much time doing research on, the origin of this naming trend. 

And so, here, with Gorilla gorilla, I mark the official launch of a [mostly irregular] series called 


Species species of the Week week


in which you can look forward to a highlight of some double named organism that has caught my fancy.  Certainly it won’t be weekly, and they won’t all be marine, but they will be cool.  I’d also love to hear what other people’s favorites are. 

Yup, footnotes.  I'm the David Foster Wallace of the Marine Ecology Blogosphere

1. You will perhaps recall from 9^th grade biology, the scientific name consists of the two most (commonly used) specific taxonomic levels of classification - genus and species name for that organism, written as: Genus species. Just remember that King Phillip Came Over For Good Spaghetti.
2. This makes it extremely difficult to find previous research on organisms because you’re never quite certain that there isn’t another synonym that you don’t know about.
3. There are a lot of rules for this sort of thing these days, no more naming things after yourself.