Daily Archives: November 18, 2012

A Remarkable Convergence of Species: The Deadliest Sea Snake

ResearchBlogging.orgSea snakes are true snakes that look a little like eels because of their horizontally flattened rudder-like tails, and they spend a lot of time…for most species, their entire lives…in the ocean. Only one species seems to be able to move on land at all. They seem to all be venomous, some extremely so. They are all tropical or near-tropical, and there are numerous species distributed among about 15 genera.

One species is Enhyrina schistosa, known as the Beaked Sea Snake, or the Hook-Nosed Sea Snake. It lives in the waters near Indonesia and Australia. This is known to be the most venomous of all of the sea snakes, and a certain number of people are bitten by them. In fact, most people who die of sea snake bites were bitten by Enhyrina schistosa. How many people get bitten by them? Hard to say. In Australia, between 1942 and 1950, 56 people died from sea snake bites. What is the meaning of that number? Hard to say; it is just one of those esoteric bits of information one finds in Wikipedia. These snakes probably don’t bite very many people, but when they do, you have a problem.

The Beaked Sea Snake feeds mainly on spiny catfish and blow fish, and as such benefits from have a large gape. Selection for the large gape has altered the morphology of this snake in a way that probably contributes to it’s beaked nose and a couple of other features that are used to distinguish it from other sea snakes and thus identify it to species. The problem is, this selection pressure seems to have caused two distinctly different groups of snakes (actually, three … see below) to converge on a single morphology. So, what we have been calling Enhyrina schistosa, the beaked sea snake, is clearly two distinct species that look enough alike to have been confused as one. This is destine to be a classic example of evolutionary convergence.

This is all being reported in a paper due out soon in Molecular Phylogenetics & Evolution by Kanishka D.B. Ukuwela, Anslem de Silva, Mumpuni, Bryan G. Fry, Michael S.Y. Lee and Kate L. Sanders. Caroline Bird of the University of Queensland Communications Office provided some background and the great snake picture.

From the abstract of the paper:

We present a striking case of phenotypic convergence within the speciose and taxonomically unstable Hydrophis group of viviparous sea snakes. Enhydrina schistosa, the ‘beaked sea snake’, is abundant in coastal and inshore habitats throughout the Asian and Australian regions … Analyses of five independent mitochondrial and nuclear loci for populations spanning Australia, Indonesia and Sri Lanka indicate that this ‘species’ actually consists of two distinct lineages in Asia and Australia that are not closest relatives. As a result, Australian ‘‘E. schistosa’’ are elevated to species status and provisionally referred to Enhydrina zweifeli. … Our findings have important implications for snake bite management in light of the medical importance of beaked sea snakes and the fact that the only sea snake anti-venom available is raised against Malaysian E. schistosa.

Have a look at this diagram:

Fig. 4. Bayesian multi-locus coalescent species tree. Asian and Australian Enhydrina schistosa lineages form separate and distantly-related clades (each with affinities to geographically proximate taxa). Nodes with Bayesian posterior probability >0.9 are indicated. Outgroup Hemiaspis damelii is not shown. (Scale bar = substitutions per site).

You can see the two populations, from Australia (top) and Southeast Asia (bottom), separated by numerous other species that look very different. And, if you look at just the Southeast Asian group, they cluster into two subgroups as well. Apparently this genetic divergence and grouping was not noticed by prior researcher dividing the snakes up into species and genera on the basis of morphology. Having said that, it is also true that the sea snakes are a bit dicy in their overall phylogeny, and are understudied. This, apparently, is being rectified.

There are other potential explanations for this pattern that should be considered, involving the genetics. It is possible to come up with a genetic tree that inaccurately represents the actual phylogeny of the species at hand. This study, however, used multiple methods and multiple DNA sites, involving both mitochondrial and nucleic DNA, so the species tree you see here is probably reasonably close to accurate, and the conclusion that Enhydrina schistosa consists of two groups that are not monophyletic is strong.

“This mixup could have been medically catastrophic, since the CSL sea snake antivenom is made using the venom from the Asian snake based on the assumption that it was the same species,” noted Bryan Fry, one of the study’s authors. “Luckily, the antivenom is not only very effective against the Australian new species but actually against all sea snakes since they all share a very stream-lined fish-specific venom.”

Wear a wet suit!

Ukuwela, K., de Silva, A., Mumpuni, ., Fry, B., Lee, M., & Sanders, K. (2012). Molecular evidence that the deadliest sea snake Enhydrina schistosa (Elapidae: Hydrophiinae) consists of two convergent species Molecular Phylogenetics and Evolution DOI: 10.1016/j.ympev.2012.09.031

Get the latest news about Sungudogo, the science fiction adventure story set in the Congo, which serves as a new Origin Story for the modern Skeptics Movement, HERE.

How To Cook A Turkey

First, consider cooking something other than a turkey

Cooking turkey is actually kind of a dumb idea. Most people don’t ever cook turkey. Turkey is like chicken … it’s a domestic bird that is familiar to all Americans … but it is very difficult to cook in a way that does not ruin it. So once a year, you cook this huge bird and try not to ruin it, and invite everybody that is important to you over to see if it worked.

As a result of this the truth is that many people have never had good turkey. They’ve only had ruined turkey. And for each of these people, what they think turkey tastes like is unique to the particular way their family’s turkey cooker learned to ruin the turkey every year.

How to cook a turkey

… you might as well try doing it the most difficult way possible. But before considering that, try this idea on for size: Cook more than one a year and use different methods to see how it turns out! (Jeesh, you’d think this would be obvious.)

This isn’t the only way, but it is a good way. It is also the hardest way that I’ve done it.

My daughter, Julia, is named after two people. One of them is Julia Child. I happen to think Julia Child has had more influence on American society than most other people, by helping to make varied and interesting cuisine part of American culture.

One day when Julia was a very young child (my Julia, not Julia Child), I was out walking her in her carriage. I turned the corner around the Van Serg Building on the Harvard Campus and practically ran into Julia Child, who was walking in the other direction on her daily constitutional.

“Oh, what a cute child,” she said. (And she was a cute child, I assure you.) “What’s her name.”

Well, that was an interesting conversation…..

Anyway, I want to suggest that you use a recipe invented by Julia Child for cooking your Thanksgiving Turkey this year. It is called “Laid Back Turkey.” It is, in my view, the best possible way to cook a turkey.

But it is not for the faint of heart….

Laid Back Turkey a la Julia Child

You can find more specific instructions in The Way to Cook by Julia Child. Julia made this on her show once, so somewhere out there is a video of this process. Here, I’ll just give you the basic idea. If you are the kind of person to even try this, the you are also surely willing to experiment and take some chances. All you should really need is the basic theory. If you are the kind of cook who prefers specific instructions and actually follows recipes, then hang up now…

The first thing you need to do is to remove all but a few of the bones from the bird.

Lay the uncooked turkey on it’s front. Slice down to the bone along the spine. Use this slit as the starting point to expose the entire skeleton, working your way around the rib cage, etc., all of which you will remove except for the wing bones and the distal leg bones. Cut through the wing and leg joints at this point in order to free the “outer” part of the bird from the main skeleton.

Caution: As you work your way around to the front … to the breastbone … your chances of cutting through the skin increases. Don’t do this.

When you’ve got the skeleton out of the turkey, lay the deboned bird on it’s front, exposed flesh facing up, and brush the livid tissue with an appropriate oil based marinade. I recommend half grape seed oil and half olive oil with lots of thyme, some black pepper, and a little salt.

In the meantime, make a huge pile of stuffing. Put this pile on a flat pan with very low sides big enough to hold the turkey. You are going to lay the turkey on this pile later. If possible, put the stuffing on a cookie sheet that, in turn, fits into a large low-sided baking pan. You can even fashion the pan from aluminum foil or from those disposable pans you get in the spice and cooking supply aisle of your basic grocery store. You’ll see later why this method … the cookie sheet set into a crushable aluminum foil pan … is useful.

Now, back to the turkey. You’ve got the exposed flesh facing up, and you’ve put it on some kind of a pan, temporarily. Fire up the broiler and slide the bird in there. Watch it closely. You want to brown the exposed flesh and hopefully get it cooked a quarter to a half inch deep. The more cooking at this stage, without burning, the better.

Now, take the large, floppy bird that is now covered with hot oil (so be careful!) and lay it flesh side down over the big pile of stuffing. Manipulate the corpse to make it look like nothing’s happened, like it is supposed to be this way. Brush the skin, which is now facing up, with your favorite substance for these purposes. I recommend coating the skin with oil and sprinkling copious amounts of dried green spice (thyme and basil … avoid oregano) for this purpose.

Put this in the oven and cook until done. It will take a fraction of the time that a “normal” turkey will take. It is also a good idea to make sure the stuffing is not cold … in fact, it could be heated up in advance .. when you put the turkey on there. You want to avoid partly cooking bird-meat, cooling it down, then cooking it again. Makes it a bit rubbery.

Now, here comes the fun part.

When the bird is done, wrangle it onto a huge cutting board, big enough to hold this laid back bird. This is where the cookie sheet inside the big pan is helpful. You could poke a hole in the pan and drain it into a bowl sitting in the sink, then cut away one side of the pan, and then use this fenestration to slide the bird-bearing cookie sheet out of what is now a scrap aluminum mess. To cut the turkey properly, slide it off the cookie sheet onto a huge cutting board. Have a mop handy. Might be good to wear rubber boots with a good tread, as the floor tends to get slippery at this stage.

Get a whopping big knife, which you have sharpened, the biggest spatula you have (maybe two) and possibly something large and flat and metal like a cookie sheet cut in half down the long axis. Maybe a flattened hubcap. Whatever you’ve got that is big and flat and thin.

Having an assistant help you with this step is a good idea, if it is someone you work well with.

Get the plates ready … the plates you will be serving dinner on.

Cut the laid back turkey right down the middle, the long way, in half. Using large flat devices, separate the two halves by a couple of inches.

Now, cut a slice about a third of an inch from this freshly exposed cut … so you are cutting a saggital section from near the midline of the bird. Use your flat devices to keep this slice from falling apart, angle it onto the flat surface, and move it over to one of the plates. Now, carefully slide this big slice onto a plate. You will probably have to curve the ends in to make it fit on the plate.

Now, look at what you’ve done. You have a slice of white meat and a slice of dark meat, nestled along side a slice of stuffing, all in one glorious unit. Because both forms of meat will cook much more nicely with this method than the usual ways of cooking turkey, your guests will enjoy both even if they’ve come to the table with preconceptions about their preference for dark vs. light meat.

Repeat this slicing operation, working from both halves of the turkey. As you work your way laterally, make the slices a bit thicker if you want all of the servings to be similar in total mass.

If the slicing procedure does not work well, don’t worry. Just cut the bird up and serve as normal. The flavor will be far superior to any other method you’ve ever tried, and the meat will be moister and tastier.

An interesting variation of Laid Back Turkey is Laid Back Flock. Here, you get a few birds, like a few of Cornish game hens, two big chickens, and a medium sized turkey. You totally fillet the smaller birds (cut off the wings and the distal legs and get rid of the skin) and arrange them over the giant pile of stuffing, and cover them all with the turkey. This can produce astounding results.

The frame of the turkey can be used for stock. Also, don’t forget to make some excellent gravy to go on this dish.

The Wreck of the Essex and the Aftermath

Do you now the story of the Essex? It is a ship that went down to the sea in the 19th century, and the first mate survived to chronicle the story (The Wreck of the Whaleship Essex). There are a lot of reasons that this story is interesting and important. For me, there is a special level of interest because I was involved in the excavation of the shipyard where the Essex was built.

My friend Romeo Vitelli is writing a multi-part blog post on the Essex Disaster, which begins thusly:

When the whaleship Essex left Nantucket on August 12, 1819, the twenty-one men on board had no idea that they would soon become part of one of the most harrowing survival tales of the 19th century. Not to mention inspiring a great literary classic.

Though sailing under a new captain, George Pollard, the Essex was a reliable three-master that successfully completed decades of whaling voyages. Throughout the 18th and 19th centuries, Nantucket was the centre of the world’s whaling industry and whaling products were the mainstay of the island’s economy. Many of the Essex’s crewmembers belonged to old whaling families that had been hunting whales for generations. …

This is going to be interesting. Go check it out!