Fresh Manatees

Fitting in as a fine addition to the previous post, the fine gentlemen at Zooborns have provided us with footage from the Singapore Zoo of a recently-born manatee.  Enjoy!

HARK! A SIRENIAN

I have been requested to do a post on sirenians by my friend Nicole.  Out of all the marine mammals, sirenians (manatees and dugongs) seem to get the least media time:

West Indian manatee gesturing for emphasis.

-whales show up because they're charismatic megafauna and people still hunt them, contravening the moratorium on whaling 

-pinnipeds (seals, walrus & co.) get airtime for the same reason, see "clubbing baby harp seals" for details. 

-dolphins (which are a subset of whales) have recently gotten attention due to The Cove and the movement for dolphin-safe tuna that I remember being a semi-big deal as a child during the early 90s.  As an addendum to this, I suggest reading this post at Southern Fried Science.  Dolphins have been popular in the public consciousness as long as I've been alive, possibly thanks to Flipper (the first movie came out in 1963) and Sea World.

-some types of otters are also considered marine mammals, though I think they don't seem so in most people's minds because they don't live in the open ocean.

-Wikipedia (always the most scholarly source) claims that polar bears can be considered marine mammals because they live on sea ice; WE REPORT YOU DECIDE

Just a dugong munching.

Sozzani, R. (Photographer). (2005). The Dugong, or sea cow [Web]. Retrieved from http://www.greenpeace.org/international/photosvideos/photos/the-dugong-or-sea-cow-2

But yeah, pretty much the only attention sirenians get in the media is when they're getting hit by boats and personal watercraft in Florida.  However, there is more to these creatures!  To conclude that manatees only exist as obstacles to watercraft is equivalent to dismissing my local raccoon population as simply obstacles to automobiles, which is what you would probably conclude if you lived here (we saw 10-11 dead raccoons on the road on an 11-12 mile stretch recently).

Do sirenians only consist of manatees and dugongs?

Yes.  There are three species of manatee (West Indian manatees, Amazonian manatees and African manatees) and a single species of dugong.  Up until 1768, there was a third type of sirenian, the massive Steller's sea cow, which was hunted to extinction within 27 years of its discovery, though other factors were involved in its demise.

Steller's sea cow?

Steller's sea cow was discovered on the Commander Islands east of Russia's Kamchatka Peninsula in the Bering Sea in 1741.  Manatees (~4 m) and dugongs (~2.7 m) are much smaller than Steller's sea cow was; these animals clocked in at around 8 m (26 ft).

Self-Sullivan, C. (2009, August 1). Call of the siren - manatee & dugong research, education and conservation. 

Retrieved from http://www.sirenian.org/caryn.html 

It's suggested that the population at the Commander Islands was a remnant group, having been hunted to extinction elsewhere.  It's not terribly surprising, given that they are large, slow, defenseless herbivores (they ate kelp) who lived near to the shore.  As a result, they were hunted for their meat (according to anecdotes in Callum's An Unnatural History of the Sea, sailors claimed it was delicious), skin and blubber, which could be refined into an oil that burned smokelessly, which is incidentally a property of whale oil.  Reports by Steller (the naturalist on the Bering expedition that found them) indicated an initial population of 1,500-2,000 animals.  Clearly this did not last long after information about the population

It's been suggested by some (Anderson, 1995) that hunting was entirely directly responsible for their extinction; Anderson argues that reduction of the sea otter population (which lives on both the Commander Islands and Kamchatka) resulted in an explosion in the growth of sea urchins.  Sea urchins eat kelp, which was incidentally the main (only?) food consumed by the sea cows.  Thus, Anderson claims that part of this extinction event can be attributed to Steller's sea cows losing their source of food.

And that's pretty much it for Steller's sea cows.  It's a small consolation, but as a result of being hunted, there are skeletons on display in museums, such as this one at the Muséum national d'histoire naturelle, in Paris.

Alright, so let's talk about manatees and dugongs.  How are they different?

Size: Manatees are overall larger animals than dugongs.

Tails: Manatees have very wonderful paddle-shaped tails; dugongs' are split and fluked like a dolphin's.

Flippers: Manatees have vestigial nails on their flippers (scroll down); dugongs do not.

Heads: Manatees and dugongs differ in their dentition: how their teeth grow, what kind of teeth they have, etc.  Manatees also tend to have a shorter snout than dugongs.  It's more complicated than that, but this is one of those cases where if you're interested in the nitty-gritty of comparative sirenian cranial anatomy, you'll have to look elsewhere.

HERE HAVE A HELPFUL CHART:

sirenian. (2009). In Encyclopædia Britannica. Retrieved November 28, 2009, from Encyclopædia Britannica Online: http://www.britannica.com/EBchecked/topic/546552/sirenian 

These things are weird looking.  What're their phylogenic relationships with other species?

As you may have noticed from the image of the manatee's toenails and references to snouts, modern sirenians somewhat resemble fusiform aquatic elephants; elephants are their closest living relatives (as far as common ancestors go), along with hyraxes.  Yes, these little fat snuffly things:

Shang, N., and Carrick, G. (2006, July). Africa. 

Retrieved from http://www.hennessea.com/Africa.htm 

I like Wikipedia's description of the hyrax: "From a distance, a hyrax could be mistaken for a very well-fed rabbit or guinea pig."

However, a more accurate description of hyraxes are that they are the remaining examples of a group of animals that look like rodents (but aren't) that used to be much more widespread.  They belong to the Afrotheria clade, which along with sirenians and elephants includes elephant shrews (which are not actually shrews but that's okay because they are still precious), tenrecs, aardvarks and others.

Hmmm, that doesn't actually help much, does it.  Perhaps the most interesting features of hyraxes are that they display a number of early mammalian features, including:

-they have poorly developed internal temperature regulation (which they deal with by huddling together for warmth, and by basking in the sun like reptiles).

-Unlike other browsing and grazing animals, they do not use the incisors at the front of the jaw for slicing off leaves and grass.  Instead, they use molar teeth at the side of the jaw.

-Unlike the even-toed ungulates (deer, antelope, pigs, giraffes, etc.) and some of the macropods (kangaroos, wallabies, etc.), hyraxes do not chew cud to help extract nutrients from coarse, low-grade leaves and grasses.

They do, however, have complex, multi-chambered stomachs that allow symbiotic bacteria to break down tough plant materials, and their overall ability to digest fiber is similar to that of the ungulates.  (Thanks Wikipedia!)

Hyrax tower!

Duke, D. (2008, January 1). The Chaircat's blog. 

Retrieved from http://animalorphanagekenya.org/blog/page/2/

Hyraxes inhabit the Middle East and various parts of Africa.  They have been doing this for a very long time, on the order of 40 million years.  40 mya places hyrax development in the Eocene epoch (55.8 ± 0.2 to 33.9 ± 0.1), known as the time in which modern mammals emerged (go here for more details about the Eocene).

Due to living the Middle East, there are a number of biblical references to hyraxes; however, they were generally translated as "rabbit" or "hare" because the European translators had no idea what hyrax was.  This is disappointing because hyraxes are cooler than lagomorphs.  Here is Rocky the Hyrax producing lovely vocalizations:

Moving away from hyraxes in particular though, the Eocene marks the appearance of the earliest sirenians, including such august figures as Prorastomus and Protosiren.  Check this illustration of Prorastomus, plus some collectible figures.

Honestly though, to explain sirenian evolutionary relationships, I think this chart does it most succinctly.  For reference, Trichechus refers to manatees, Hydrodamalis is Steller's sea cow and Dugong is self-referential.  This chart even has a handy-dandy geologic time scale built in for your convenience!

That was a long tangent.

Yeah, pretty much.

So what do sirenians do?

Well...they eat a lot of sea grass?  According to Gerstein (1994), manatees are capable of understanding discrimination tasks; Dierauf & Gulland (2001) state that their abilities in discrimination and task-learning behaviors are similar to that of dolphins and seals in acoustic and visual studies.

They're basically very chill animals, eating their delicious sea grass and swimming around in warm shallow water (about 3-7 ft./1-2m deep). However, manatees have problems, many due to humans. The main causes of manatee mortality include: watercraft collisions (40% for West Indian manatees), cold stress, hurricanes, red tide (harmful algal blooms), entanglement/swallowing fishing equipment, getting crushed in water control mechanisms, etc. If you'd like to read more, Stith, Slone and Reid (2006) have written a review and synthesis of manatee data in Everglades National Park detailing much about manatee mortality.

Photo by J. Marino at Crystal River Manatee Tours

Those of you who were around in the 80s will remember the media attention given to manatee casualties and gruesome injuries due to watercraft collisions. As a response to this, the U.S. Geological Survey has launched the Sirenia Project, which monitors the West Indian manatee and supporting their recovery.

In a more popular measure, in 1981, musician Jimmy Buffett and former U.S. Senator Bob Graham formed the renowned Save the Manatee Club, where you can adopt a Florida manatee.

While hunted in the past for their meat, skin and bones, by and large manatee and dugong populations are protected by laws in most countries. However, poaching does occur, specifically mentioned in the West Indian and African manatee populations. Dugongs are legally hunted by aboriginals in Australia for subsistence purposes; they are poached elsewhere due to a demand for dugong products. For more information on this, please consult Sirenian International.

Well, that was depressing.

Here's some information that's a bit more light-hearted:

Have you ever wanted to hear an angry manatee? Frightened? Normal manatee burbling? You've got it!

This video shows yawning manatees and provides a closer look at their mouth anatomy, which is kind of weird.

Munching dugong!

-The oldest manatee in captivity is Snooty, who was born in captivity and resides at the South Florida Museum.  Snooty was born in 1948, making him 61 years old on his last birthday.

-There are locations in the United States where it is legal to swim with manatees.  However, if you're going to do so, don't be this guy.  Manatees are easily stressed, they do not need people harassing them.

References

Anderson, P.K. (1995). Competition, predation, and the evolution and extinction of steller's sea cow, hydrodamalis gigas. Marine Mammal Science, 11(3), 391 - 394.

Myers, P. 2002. "Dugongidae" (On-line), Animal Diversity Web. Accessed 

November 21, 2009 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Dugongidae.html.

Antarctic Echinoderms

Sweet time-lapse video of starfish, urchins and worms crawling around the Antarctic sea floor.  Now with seal corpse dissolving action!

Thanks to Vera for the link!  Buy her comics!

Lil' living fossils

Behold the first footage of a juvenile coelacanth:

Big ups to Charlette for this one.

UPDATE 11/19/09 00:42 - Here's a news release, courtesy Casey.

Echinoderms!

I love "how to tell these things apart"/"what are the differences" posts and Chrism of the Echinoblog has a fine post on how to tell asteroids and ophiuroids apart.

Choriaster granulatus, an example of my favorite type of starfish (CHUNKY)

Messersmith, J. (2009, March 31). Underwater variety pack [Web log message]. 

Retrieved from http://www.messersmith.name/wordpress/2009/03/31/underwater-variety-pack/ 

BRIEF EXPLANATION: Both asteroids and ophiuroids are echinoderms, the group that includes sea stars (starfish), sea urchins, sea cucumbers, sand dollars, crinoids and all those cool invertebrate cats.   HOWEVER, not all starfish are equal! What the general public calls "starfish" can be categorized as asteroids ("sea stars") or ophiuroids ("brittle stars").  I will let Chrism tell you the rest.  Enjoy and consider this an appetizer to a series I'm planning on doing about invertebrates, because people absolutely do not care enough about invertebrates.

Because people do not care enough, here is a link to Circus of the Spineless, a blog carnival starring some of the folks I regularly follow that is devoted to invertebrates both terrestrial and other.

A victory for lungfish, turtles and Queenslanders!

 Seen here is the largest specimen of Murray (Mary River) Cod.

Tibbetts, T.A. (2003, January 6). Pictures from the snowy mountains. 

Retrieved from http://www.uisgebeatha.org/snowymountainspictures_dec2002jan2003.html

Remember when I was hating on folks for the idea of damming the Mary River, home of Australian lungfish, the Mary River Turtle and Mary River cod?  Almost certainly not, but as a result of that entry I joined the SAVE THE MARY RIVER!!!! group, whose e-mails have kept me abreast of the situation. As of yesterday, I am pleased to announce that it looks like the Mary River is safe from damming!  Australian conservationists are a-twitter (probably literally); I need to check Australian news sources for more info.  Look at these guys:

DPI researcher with a lungfish caught in Splitters Creek. (ABC: Jodie van de Wetering)

van de Wetering, J. (2009, February 10). Learn about lungfish. 

Retrieved from http://www.abc.net.au/local/stories/2009/02/10/2487576.htm

 

Mary River Turtle, sporting awesome headgear.

Perhaps the second-largest specimen of Mary River cod?

Scott, B. (2007, July 20). A Snail's eye view. Retrieved from http://snailseyeview.blogspot.com/2007_07_01_archive.html 

Good job, everyone!

Aquarium Gets Hits by a Car

Apparently a woman in Florida who was driving with a 6-year-old in her lap drove her vehicle into an aquarium exhibit at the Tampa Airport, killing nearly all of the fish; survivors (for the moment) were gathered in a bucket.  

Species mentioned in the article were saltwater tropical fish, including such crowd-friendly species as "clownfish, angelfish and blue tang"; there were around 30-40 fish in the tank.  No mention was made about how the invertebrates in the tank fared, though one article mentioned people searching for hermit crabs, but I can't imagine well.  I would imagine there were also plants and whatnot.

This wigs me out because I repeatedly have dreams about aquariums being damaged and fish spilling out that can't be saved, so I have to stand there in horror and helplessly watch them suffocate.  This sounds like a nightmarish scene.

Not surprised.

Oceana's blog announced the winner of the 2009 Freaky Fish contest; unsurprisingly, the winner was the anglerfish.  I personally think that anglerfish should be retired from these kinds of contests or just get honorable mention because they're going to win every time by virtue of being, well, anglerfish.  More on freaky fish at a later date, though.

I found a review for Callum Roberts' The Unnatural History of the Sea over at Conservation Maven and recently acquired a copy from the library.  If I end up having anything worth saying after I read it, I'll post it.  

The thought that came to mind when I read the synopsis was a comment from I read in one of my social studies textbooks that said something to the effect that European explorers in the 15th century described the abundance of sea life at the Grand Banks as so great that you could scoop up cod in a basket.  For some reason, that image has captured my imagination, even more so given the dire state of the long-famed New England fisheries.

Photo by Dieter Craasmann, taken from Blue Ocean Notes

The Atlantic cod, long a backbone of the New England fishing industry.  Its tastiness has led to it becoming a case study in the wages of overfishing and an unsustainable industry.

Things in the pipeline: Freaky fish update, a special post by request about sirenians and possibly the letter "B" in my Alphabet of Fish.

Freaky fish? That is not a freaky fish, THIS is a freaky fish!

Oceana (a PAC concerned with oceanic affairs) apparently has an annual "freakiest fish" contest on their blog, the Beacon.  I viewed this year's candidates and am by and large unimpressed; the only fish that I think legitimately belong on that list are the wolf-fish, hairy angler, hagfish and maybe the crown-of-thorns starfish.

Why are coelacanths on there?  Yeah, they're not conventionally attractive, but they're hardly freaky; if anything, their behavior is kind of dull.  And leafy seadragons?  All they do is look pretty!

Past winners of the Freaky Fish voting include:

2008 - Fanfin seadevil.  This is not surprising, as anglerfish ALWAYS excel in this kind of contest.  Seriously, look at that thing.

ANGLERFISH PROTIP: As terrifying as they look, they tend to be pretty small, less than a foot (~30 cm) long; and that's the big females, males tend to be very small and essentially are free-swimming gonads before becoming just plain gonads.  I'll elaborate on this later.

2006 - Blobfish, fangtooth, monkfish.  Blobfish are Internet famous due to an e-mail meme claiming that they're an example of deep sea creatures washed up during a tsunami.  Fangtooth?  Well, they can live in the abyssopelagic zone, which pretty much implies that they're going to be freaky looking.

ABYSSOWHAT?

Abyssopelagic!  TIME TO TALK ABOUT LAYERS (or ZONES) OF THE OCEAN 

"Abysso-" - the abyss.  I'm reasonably sure that everyone reading this knows what "abyss" means/implies.  For our purposes, let's say that it means "stupid deep".  The average person will have no interaction with the abyssopelagic zone due to the pressure/temperature/general conditions down there; for a general idea, here's a demonstration of what happens to styrofoam cups.  The current record for human free-diving is around 530 feet (161.5 m); so, as you can see, without a submersible, even the most enthusiastic human diver will never plunge below the euphotic/epipelagic zone. 

"-pelagic" - if a fish is described as "pelagic", it means it lives in open water, not near/on the bottom of a body of water (those organisms are called "demersal") or in reefs.  There are further subdivisions within these categories, but this definition of "pelagic" will suffice for the time being.

 

It kind of reminds me of the internal structure of the earth:

 

Earth's polar diameter is 7,899.80 miles (12,713.5 km); the average thickness of the continental crust is 21-43.5 miles (35-70 km), while oceanic crust is only 3-6 miles (5-10 km) thick; bear in mind that humans have never even dug to the mantle.  We interact with very little of earth's interior, similarly to how little of the ocean most of us personally access.

Brief tangents into geology aside, the ocean is typically divided into about five layers; only the two uppermost layers receive any light from the sun.  Generally speaking, we're most familiar/comfortable with forms of life that ultimately depend on sunlight to survive, either directly or by consuming organisms that directly use sunlight for life (i.e. plants).  Note I certainly do recognize that abyssopelagic scavengers depend on the sun indirectly, by eating things like dead whales that sink to the ocean floor.  Things that live in places with no sunlight (such as the aphotic zone and deep caves) tend to seem a little freaky to us.

Continuing on though, we have monkfish.  I first encountered monkfish in this context, familiar to readers from the Pacific Northwest:

That is at Seattle's famous Pike Place Fish Market, where fish are tossed daily for your pleasure!  Every time I've visited, they've also had at least one monkfish amid the salmon, with his happy monkfish sign.  If you look closely at them, you'll figure out why they're ugly - monkfish are anglerfish!  

Though I've never had them myself, they've been called "the poor man's lobster" and are evidently tasty enough to have led to an overfishing problem.  They're also known as "headfish" or "goosefish"; monkfish liver used in sushi is called "ankimo".  Research also reveals that their flesh is known to be marketed as a substitute for scallop, so if you're trying to make ethical seafood choices, please read your labels carefully to avoid consuming monkfish.

Okay, I'll admit - the illustration of the John Dory doesn't do this fish justice.  In its blurb, they also neglected to mention that it has protusible jaws, which ups the freak factor considerably.  

Additionally, my research on John Dories allows me to provide you a source for frozen John Dory halves and monkfish!, straight from the marine processors of China!  If that's not enough, how about these tasteful John Dory plates, yours for the princely sum of £29.95 (~$49 US)?

OTHER NOMINEES I OBJECT TO:

The upside-down jellyfish.  Jellyfish have a pretty high base level of "weird"; this one is by and large pretty normal looking, aside from the upside down business, but does that actually surprise anyone?  I personally nominate the granrojo jellyfish (Tiburonia granrojo), Nature's very own Metroid:

 

They're about 2-3 feet wide (60-90 cm), have gross fleshy arms and live 650 to 1500 meters (2000 to 4800 feet) down.  They're not much to say about them, because we don't know much about them.  However, one interesting feature is that their number of arms of variable between individuals.  George Matsumoto, an MBARI (Monterey Bay Aquarium Research Institute) biologist who was lead author on the paper in which granrojo was first described, has this to say about it:

The feature that researchers find most intriguing is a collection of short stumps protruding from Big Red's surface—so- called "oral arms" that might be used for feeding. What mystifies Matsumoto is why some of these jellies have four arms, whereas others have six or seven.

"It is like finding one human with four arms, another with three, and another with two," says Matsumoto. 

 (2003, May 5). Mbari news - big red jelly surprises scientists. Retrieved from http://www.mbari.org/news/news_releases/2003/nr03-matsumoto.html

They're huge, freaky and AWESOME.  The MBARI press release also has links to more images of granrojo, which I strongly recommend you look at.

My final objection is the crown-of-thorns starfish.  Yes, I changed my mind from earlier.  While yes, their appearance is can be kind of concerning, starfish (more appropriately called "sea stars" because they are echinoderms, not fish, but I call cuttlefish "cuttlefish" so I clearly don't care all that much) are by and large a pretty freaky group.

Starfish are popular with children because of their familiar shape.  However, their familiar shape is kind of inherently freaky because they exhibit radial symmetry.  Humans and most animals exhibit bilateral symmetry; that is, we have a left and right side that would more or less match up if we were folded in half along a vertical axis.  Organisms with radial symmetry only have a top or bottom, no right or left.  Think about that for a second and recognize how utterly alien that would be to the human experience, to have no right or left.  The evolutionary biology of starfish

Other organisms that exhibit radial symmetry include jellyfish, some types of sea anemones, sea urchins (bearers of custardy gonads, considered a delicacy in many cultures), sea lilies and many plants. 

Then there's the way that starfish eat.  To put it bluntly, they have two stomach, one which they evert (basically, push out of their bodies) to engulf/digest food, one to further digest food.  Some are able to force their everted stomachs inside the protective shells of soft-bodied mollusks (e.g. clams) to devour them within their own homes.

But as far as plain freaky visual appearance goes, the crown-of-thorns starfish is a non-entity compared to say, the basket star:

Tanenbaum, J. (2006, June 15). Jacob tanenbaum: teacher at sea: 06/01/2006-07/01/2006. Retrieved from http://jacobtanenbaum.com/~tasblog/2006_06_01_archive.html 

I know I am not the only one getting a Lovecraftian vibe from this thing.  Look at the arms!  The mouth!  The everything!  Also, they're pretty large, with the central disk growing up to 5.5 inches (15 cm) across.  JUST THE DISK.  Did I mention they don't have blood?  And look like dendritic structures inside the brain, except they're mobile, huge and have regenerative limbs?

Here's a video to help drive home how...special...they are:

In case you didn't find that unsettling, let's also meet their cousins, the brittle stars!

And a final video, in honor of Halloween.  One of the defense/stress mechanisms of sea cucumbers (another echinoderm; while many cultures eat them, they are NOT sea vegetables, they are mobile organisms) is to violently expel parts of its respiratory organ out of its anus.  It is things like this that make me happy to be a human, for while I may cope with stress poorly, my reactions do not include violently crapping out my lungs. 

When they do this (called "evisceration" for obvious reasons), they may expel a nasty chemical soup that will hopefully take care of the predator...however, if you're keeping sea cucumbers in a tank, it may also kill all the other inhabitants in a charming process called "cuke nuke".  GAME OVER, PLEASE INSERT COIN AND TRY AGAIN.  They do grow these organs back, but depending on the violence of the evisceration, the cucumber may be injured in the process.

So, for your pleasure, here are some divers molesting a sea cucumber to get it to demonstrate this marvelous ability.  While I personally think molesting sea cucumbers is rather rude, evisceration evidently pretty normal for them.

Hope you enjoyed, have a Happy Halloween! 

A is for ammonite

I may have mentioned to some of you that the other day I woke up with a single sentence on my lips: "A is for Anomalocaris", my Cambrian super-predator BFF.  This thought launched a brilliant/horrible idea: A blog series/potential children's book on aquatic creatures from A-Z!  Fabulous!  So, starting today, I present you with A, which is not in fact for anomalocaris, but AMMONITE.





A IS FOR AMMONITE
What's an ammonite?


Ammonites are extinct cephalopods, related to celebrated extant creatures such as octopus, squid, cuttlefish and the relative who they most superficially resemble, the nautilus.  Sadly for us, the ammonite has been extinct for quite a while; they got iced along with the dinosaurs during the Cretaceous–Tertiary extinction event, which happens to be the most recent mass extinction event in the history of Earth.  And when I say "most recent", I am implying that there have been more, because, well, there have been more.

Anyway, despite becoming extinct, ammonites had a pretty sweet run of it.  Let's consult our handy-dandy Chart of Geologic Time:




I have colored the right vertical section of the chart in tasteful hot pink to show the 435 million year run of the ammonites.  As you can see, dinosaurs of any real sort were only around for roughly half of that. 

Also, if you've ever wondered what period of geologic time we're currently in, we're in the Cenozoic Era, Quaternary Period, Holocene Epoch; it's that very thin sliver of time topping the rest of the history.  Cephalopods have owned the earth for far longer than any of us hairless primates have been trundling around, and it's likely that they will continue to do so after we're gone.

Cryptic quasi-apocalyptic suppositions aside, ammonites, like their descendants, were numerous.  Currently, the worldwide biomass of squid exceeds the worldwide biomass of humans; that is, there is more living squid matter than living human matter.  Bear in mind this is just for squid, this isn't even counting all the other cephalopods. 

Ammonite fossils are distributed worldwide and make very useful index fossils, special fossils that can be used to date different strata of rock because they are specific to a particular time period.  Given the long reign of the ammonite, in this case specific species of ammonite are used as the rock-clocks.

So what's great about them?

#1) They are named after the Egyptian god Amun/Ammon, who was often depicted with ram's horns.  People thought that ammonite fossils resembled coiled ram's horns, thus they are called ammonites.

#2) They were ridiculously diverse in terms of shape and size.  Along with the traditional nautilus-shell-looking ammonites, there were crazy variations.  This gallery depicts a large variety, and this thread from good ol' TONMO (The Octopus News Magazine Online; if you have more than a passing interest in cephalopods, you need to join this site NOW) has a number of images of the nipponites, the squiggliest of ammonites.




Illustration based on nipponite fossils
#3) They are the source of ammolite, a rare and lovely gemstone.




Gem-quality ammolite is found in some ammonite fossils deposited in a region once covered in a shallow inland sea that stretched from  "...Alberta to Saskatchewan in Canada and south to Montana in the USA.", according to Wikipedia other ammolite resources.  It is iridescent like an opal and is the official gemstone of the Canadian province of Alberta.

Personally, ammolite (and opals, natch) is one of my favorite gemstones and there is no shortage of websites out there with examples of their ammolite jewelry.  I think it looks better in fossil format, personally; patterns and colors can be viewed here at the Gem Society's page on ammolite, which provides much more comprehensive mineralogical information than I am providing here. 

BONUS LINK: Here's a Russian site with all sorts of colorful ammonite fossils, including some with pyrite (fool's gold).

#4) They are a natural example of the spira mirabilis.




The spira mirabilis, the "miraculous spiral", is known by approximately 8 billion different names.  These names include "logarithmic spiral", "equiangular spiral", "growth spiral" and others.  For the specific mathematic properties of this curve, I suggest consulting Wolfram MathWorld's page on the topic.  This site is messier, but has interesting examples of the curve in nature.

#5) They range widely in size!

Ammonites can be tiny...




....or very large.



And numerous!





I leave you with a few ammonite links:

-Site about large chalk ammonite fossils viewable at Peacehaven, in the UK.  There are other interesting fossilized creatures there, too.

-Beautiful gallery that shows the diversity of ammonite shapes and shells from all over the world/time.  At the bottom, there's a gorgeous iridescent blue shell that's not to be missed.

-This website can direct you if you're interested in purchasing ammonite fossils, or samples of ammolite.  They are not cheap.  More are available here.

-FAQ on Fossil Cephalopods from the venerable Cephalopod Page, presented by Dr. James B. Wood

-Article on nautiloids by Phil Eyden from TONMO.

It's that time of year again~!

It's that time of year again: The Social Media Challenge results in Seed Media Group, the maintainers of the ScienceBlogs blogging network (home to such luminaries as Zooillogix and other fine blogs), running a DonorsChoose.org donation drive.  

DonorsChoose.org allows you to contribute funds to a teacher/school in need; you select the project.  This year I am supporting the GeoBloggers' projects, which are listed here.  The project I chose to support involves teaching meteorology to ESL students at a Title I school .  The only way this project could be more up my alley is if it involved cats, weather, Gnosticism and Sumerian.

Any number/types of blogs are participating, a list can be found here, though I am biased towards supporting ScienceBlogs and encourage you to do so as well.  I know some gamers are reading this; looks like Gawker Media (maintainers of Kotaku) is also participating.  Basically, there's something for everyone here.  If you have the means, I strongly encourage you to donate.

SOON TO COME: A SECRET PROJECT THAT I CONCEIVED OF THIS MORNING

RIP, little dudes.

So not okay.

I Love Ancient Fish EPISODE I: Bowfin

Image by Solomon David, curator of the fabulous PrimitiveFishes.com. Also, possessor of the most Torah-iffic name I've ever heard.

This week I visited my hometown of Sulphur, Louisiana, and couldn't help but notice the word "choupique". Choupique Bayou, some kind of Cajun sausage hut involving the word "choupique"...the word seemed familiar but wouldn't quite come to me, so I looked it up when I got home. "Choupique" is the name used for the bowfin, Amia calva, in South Louisiana.
Like so many other fish, the choupique goes by a wide variety of confusing names, such as "mudfish", "speckled cat" (probably because they have barbels; they are NOT catfish), "grindle", "cypress trout" (they are not trout), "lawyer" and "dogfish". Personally, I think "dogfish" is the worst of these because "dogfish" conjures images of small sharks, not these guys. I suppose it could be worse, there's the good ol' mahi-mahi/dolphin name issue that alarmed me as a very young fish dork.

In addition to the fish, "Choupique" is also the name of a Louisiana band depicted here in what appears to be gay Klan attire, bless their hearts (no seriously, that's just a joke guys, no allegations of racism here)
.
The bowfin, like its excellent brethren the gar, bichir, coelacanth and others, is considered a living fossil. Bowfin flourished during the Jurassic and Cretaceous periods of the Mesozoic, making them contemporaries of superstar dinosaurs Allosaurus and Brachiosaurus. This is not a recent fish. Like several other types of "living fossil" (e.g. Nautilidae, the nautiluses, who are spiffy and deserve their own entry), the bowfin is the only remaining member of its family (Amiidae).

PRO-TIP: Here's a handy tour of events through geologic time, courtesy the San Diego Natural History Museum. The good folks at the Geological Society of America have even made up a colorful PDF chart of geologic time that you can print up and tape to your wall/give to your loved ones so you never have to look too far to see when the PLIENSBACHIAN AGE was.

*~BOWFIN Q&A HOUR~*

So why are they called bowfin?
Bowfin are distinguished by their very long dorsal fin.

QUICK EXTERNAL FISH ANATOMY PRIMER WITH OUR FRIEND THE LARGEMOUTH BASS! THIS WILL BE USEFUL IN THE FUTURE, TRUST ME.

Courtesy KentuckyLake.com

The dorsal fin is the fin(s) running along the length of the fish's back. Most fish have fairly short dorsal fin(s); the bowfin is not most fish.
What kind of sweet prehistoric features do they have?
Bowfin have a couple: in particular, the gular plate and their kind-of lung. The gular plate is a large bony plate located in their mouths. Gular plates are not unique to bowfins, they're also found in Elopidae (ladyfishes, skip-jacks), Megalopidae (tarpon) and Albulidae (bonefishes); other types of gular plate are found in living fossil-mates the coelacanth and the bichir. For photographic details, here's a drawing from The Dictionary of Ichthyology. Other owners of gular plates include the bowfin's evil twin, the snakehead. Notice that snakeheads have long anal and dorsal fins.
I hate to give any species bad press, so I need to say that snakeheads are not evil in their appropriate context. However, as an invasive species they can wreak havoc on ecosystems.
Regarding their lung, while bowfin do not have lungs in the same manner as lungfish, their swim bladder can function as a primitive lung and they may take oxygen by breathing air. This behavior is also exhibited by those perennial aquarium darlings, the betta and the gourami, though they possess a different type of lung-like organ (called the labyrinth organ; will be visited later). Being able to obtain oxygen through a method other than gills is very helpful when you live in low-oxygen environments, which are incidentally the habitats in which both bowfins and bettas are found.
Also, here is a picture of a bowfin skull:

Image by Udo M. Savalli

As you can see, they feature the armored head that I love so dearly in old-school fish.
Do I want to a catch a bowfin?
Maybe. Bowfin are renowned for their enthusiastic fighting and penchant for biting, much like my cat. With these fish, the fight continues after they've been removed from the water, so come prepared with leather gloves. To quote The Bowfin Anglers' Group, possibly the people on the Internet who are most excited by bowfin, "Bowfin fight like cat[fish]s or carp on speed" and "The bowfin has sharp teeth that will make hamburger of a careless thumb".
Do I want to eat a bowfin?
Depends who you ask. The good folks down at the Bowfin Anglers' Group seem to think so and provide recipes for your perusal. Folks at other message boards give opinions ranging from "tastes like fish jello", "the cats wouldn't eat it" to "if you cook it quickly after it's killed it's okay". In my neck of the woods people definitely eat bowfin, but my people are also from the swamp and eat pretty much anything, so take that with a pinch of file.
Can I keep one in an aquarium?
Not with other fish if you're not using them as feeders. Bowfin pretty much eat anything, including each other. If you're feeling saucy, I hear they're fans of crawfish.
Anything else I should know?
Male bowfin are very protective of their young, to the point that they will display aggressive behavior (i.e. take a chunk out of you) if you happen to be wandering around their habitat and they feel you have come too close their fry.
References/Recommended Reading:
Brent Courchene on bowfin
FishBase's entry on bowfin
The Bowfin Anglers' Group
Alan Richmond of the University of Massachusetts on bowfin