Because Brachiopods-that's why! 5 Things to know about Brachiopods!

Image by Open Up!

What are Brachiopods?  
Brachiopods are actually a PHYLUM of animals. That's right a whole GROUP of animals that most folks have probably never heard of!

image by Herman Giethoom

Brachiopods are a very old, old group of invertebrates with a relatively rich fossil record.  They have two shells (and are superficially similar to bivalves, e.g; clams and mussels) but are better known in several other ways...

Brachiopods are one of the few groups of marine animals which live ONLY in the Ocean! (Echinoderms being one of the others...)


Some places you learn about some new mammal, but HERE at the Echinoblog? you learn about a whole PHYLUM of animals in five easy steps!

1. What does the name mean? 
Brachiopoda, when you break it down:  "brachio"= arm and "poda"= foot. Wha?  The Arm foot?


The name refers to a structure known as the pedicle. That's the purple stalk bit that is anchoring the animal down to the substrate. This is how the pedicle looks
in the group informally known as the "articulate" brachiopods. Arm refers to the muscular arm-like aspect and "foot" to its use (or disuse) in attatching to the bottoms.

The pedicle manifests in two different ways relative to which of the two major groups of brachiopods you are looking at!

One group has been referred to as the "Articulate" brachiopods. And yes; they are very well spoken thank you. ha ha.you have now caught up with the jokes:

The "articulate" part refers to how the two shells have teeth that articulate with one another.. Here are some hinges on various brachiopod valves.. (images below by Open Up! fr. this awesome photoset fr. the University of Tartu-go take a look at some AWESOME photos! )
 


In the "inarticulate" brachiopods the pedicle is this much more developed tail-like feature. the animal is almost kind of a worm. These live in burrows. People eat these! (see below)

Lingula adamsi Dall by Changhua Coast Conservation Action

2. So these look like clams? What's the diff? 
Relative to the animal inside, brachiopod shells are oriented top-bottom vs. those in bivalves, which are oriented left-right

This image from Kristie Bradford's Historical Geology web page!

Yes. I know the symmetry seems strange and can be oddly difficult to "get" the first time around. Here are some brachiopods...

image by mpjones_007

Image by Alexander Semenov

and here's some clam for comparison (positioned for convenience!)

Image by Royston Vasey

3. What/How do they eat?
Brachiopods have a feathery feeding structure called a lophophore! Brachiopods are basicaly suspension feeders. Water flows in and over the lophophore and tiny finger-like bits called cilia pick the food up!

Here's some reality from the very talented Arthur Anker showing the lophophore with the animal's valves open!

A further GREAT pic of the lophophore can be found here..

And here is the diagrammatic approach that gives you a general idea of what you're looking at.... The animal below has been turned upside down to show parallel orientation with the pic above...

4. In the Paleozoic (roughly 250-500 million years ago), brachiopods were once THE happening invertebrate! 

image by David Cartier

Earliest known fossils date back to the Cambrian (600 million years ago-but probably more), but the time of the brachiopod was in the Paleozoic!  (bear in mind how vast a time period 250 million years is.. that's MUCH older than humanity..).  They dominated in diversity and abundance. This was their "time"...   Sadly, most brachiopods underwent a huge extinction at the end of the Paleozoic...

According to the World Brachiopod Database only about 385 species occur today from the ~30,000 described (mostly fossil) ones!!

Many of these species live in out of the way and isolated places...

Here is a gorgeous pic of Coptothyris adamsia from the Sea of Japan

Image by Alexander Semenov

Here is Laqueus californica from Monterey Bay in some pretty amazingly high densities...

and more from Alexander Semenov: Hemithyris psittacea (Rhynchonella psittacea)

5. Geology! Fossil Brachiopod Shells are sometimes replaced by Pyrite! (aka Fool's Gold)
In the fossil record, the "shells" (called valves) of brachiopods sometimes undergo a process in which they are replaced with pyrite aka fool's gold!

This makes them golden and sparkly!

Image by jsj1771

Image by E. Sese

Image by JS1771

5a! More Geology Fun! Brachiopod valves are often found in cross sections of rock! 
Geologists know the value of a good cross section! Brachiopods are VERY abundant in Paleozoic rock. And if you cut through the shells of one you get some pretty distinctive impressions in the rock..

Image by Maitri

Sometimes there are minerals such as agate!

Image by Captain Tenneal

Brachiopod shells can be pretty dense and sometimes you see a lot of them! 

Sometimes you see some neat rare stuff.. like this soft-part preservation of a lophophore!

Image by Dietmar Down Under

FUN FACT!  People EAT brachiopods!
I wrote about this earlier... but yes, apparently some curry and/or garlic is appropriate....

Image by Peter Roopnarine

5 Unusual Invertebrates that People Eat! (it takes an Invert Zoo Class to know what some of them are!)

Okay you invertebrate zoologists out there!! How many phyla can YOU recognize on the plates above???   By the end of this blog you WILL know! (and maybe, you will hate me for telling you)

Everyone seems to have a "Weirdest foods" list out there-but here at Echinoblog we offer you only the STRANGEST sampling of bizarre marine invertebrates cuisine! forget insects, snails or shrimp!

Some of the edible (?) metazoans below are usually only noticed by marine biologists, zoologists and the well-studied biologist!

What better application of knowing the strangest of marine invertebrate phyla can there be than to recognize it on your plate? Its scientific name disguised by colorful cultural argot  or perhaps in a different language?

1. SEA SQUIRTS! (Halocynthia sp. possibly H. roretzi). The Korean name for sea squirts as food is: meongge (although there are several more)
Sea squirts are a kind of tunicate, which are in turn members of the phylum Chordata (the group humans and other vertebrates belong to) and when alive they look like this:

As it turns out, sea squirts are eaten all over the world, including Japan (called hoya and maboya) and Korea (meongge, and in a stew called agujim). They also eat sea squirts in France, Italy, Greece, and Chile .
Images of sea squirts eaten in Korea. Image by scbrianchan

image by scbrianchan

A video showing preparation. Sea squirts are filter feeders and processing water through their body is a primary function. Thus, drainage seems to be an important feature...

when cooked and prepared it looks like this

image by seoxcookie

or this..

Image by toughkidcst

sometimes served with oysters...

Image by Food Fetishist

UPDATE February, 2014. I've actually tried hoya in Tokyo! The raw stuff! Its got a very...sour, almost soapy taste. Not for everyone.. but I'm told that its an acquired taste. Folks who grew up with it, LOVE it...

 

2. ECHIURAN WORMS! aka "fat inkeeper worm" aka "penis fish" aka gaebul (genus Urechis)
Most people have never heard of this phylum of worms. Commonly known as "spoon worms"

One of the best studied examples is Urechis caupo, occurring on the North pacific coast -living in muddy burrows which serve as homes for many other commensals, including tiny shrimps and fishes.

Image by Peter_r

But in Korea, a related species, Urechis unicintus is collected and eaten!

Apparently it is cut up into segments and served while twitching....

In other cuisines, it is cooked and stir fired..

the picture above? gaebul and mongae aka Echiuran and Sea squirt!!

and uh yeah, there's a belief that eating these imbues men with more virility. That seems unlikely....

3. INARTICULATE BRACHIOPOD  (Lingula sp.)
Brachiopods are one of the oldest animals observed in the geological record, going as far back as 500 million years. In some cases-they appear relatively unchanged appearing very much as they do as fossils.

and now we eat them.

This gives you an idea of what they look like alive..living in a muddy habitat

Image by Changhua Coast Conservation Action

There are two shells that fit over the animal on the top and bottom. Bivalves and other clams are fundamentally different in that their shells are oriented on the body left-right. 

In one group, known as the "inarticulate" brachiopods, there is a big fleshy structure called the "peduncle" which emerges from the shell

Biologist Richard Fortey noted that they tasted like "straw' (quote is here).

Here is an image of brachiopods as sold in a food market in Makassar.

Image by Arthur Anker

Here is another from a Thai market.

Image by Peter Roopnarine

In Indonesia this dish is called Probolinggo TEBALAN. The blog linked here suggests that Lingula  tastes "sweet and spicy" whereas others I've seen suggest that it is served with a tasty curry.

Huh. Brachiopod curry. NOT something I was expecting to write today!

4. STALKED BARNACLES! Barnacles. Those well-known shelled crustaceans that live on docks and use their "legs" to filter feed out of the water like this:

These of course are what's known as "goose" or "goose-necked" barnacles because of the long, prominent stalk attached to the body sitting on top.

Yes. People eat them! I've seen them in Paris and Belgium.

Imge by RobertoGrego

In some places, barnacles are quite expensive...

Image by erikamussen

Other "unstalked" barnacles are also eaten! 

Image by charclam

In the Azores and Portugal, these are called cracas!  Basically, these are boiled "acorn" barnacles. 

Image by Bellyglad

5. SEA STARS! (family Asteriidae- species: Asterias amurensis)
So, first let me distinguish between the "starfish for show" pictures that one sees around like this versus apparently real accounts of people who eat the gonads of starfish as seen in the video below..

Image by Robin G. Ewsing

Honestly, eating sea stars baffles me. And I  recommend against it (as here) and here but obviously, people really eat these.  On the plus side, Asterias amurensis (the species shown below) is a problematic invasive in Australia (as I wrote here)

so maybe there is a silver lining to this?