Dragonflies are cool, but their babies are even cooler

 

I just read this story over at Wired and I have to say that it is, quite possibly, the greatest thing I have ever read in my entire life.  Better even than "Go the F*ck to Sleep" or "Everyone Poops".  It goes into detail about dragonflies which, in my estimation, are some of the coolest critters around.  There are videos of nymphs catching prey with their offensively quick and extremely protrusible lower jaws.  There are pictures of nymphs molting, nymphs lounging and nymphs that appear to be smiling.  There are also several little facts about dragonflies and nymphs that will, should you be of delicate disposition, make you feel slightly queasy and possibly faint.  A brief selection of said facts is below.

• Dragonflies are thought to be the first winged insects to evolve.  This happened about 300 million years ago.  This is roughly 50 million years after amphibians began crawling around on land and about 50 million years before dinosaurs began their rule.
• Some dragonfly adults can fly at up to 35 miles an hour.
• Nymphs have jet powered butts!  They suck up water into their anuses and squeeze it out when they want to evade predators or, in my experience, zip away from an interested entomology student who is just trying to finish up his collection and would really rather that the nymph in question STAY STILL for just one more sec...
• They can shoot out their labrum (translation:  lower lip) to catch prey almost an entire body length away.  It is a good thing these critters are small.  How much would it stink to be caught and eaten by one of these things?  It would probably ruin your day.
• Those jet powered butts are also the main respiratory surface for the little critters.  That's right, folks.  They breathe through their butts.  I once new a guy who could suck air into his butt so he could break wind on command, but now that I am thinking about it that isn't really the same thing.  Sorry I brought it up.

 

Giant Megalapteryx Foot! An exercise in Critical Thinking.

Since I am a teacher and the internet is a thing, I often get students showing me pictures and videos that they found on "this one website" which is totally credible because it is run by "this one dude who probably has a Ph.D. in science or something.  Astrology or something?" Anyway, this reared its head today, probably because it was found on the IFLS  Facebook feed. I like to use these things to help the students sharpen their critical thinking skills.         

The caption for this picture is technically correct, which, as we all know, is the best kind of correct.  However it does require a bit of description before it becomes correct in a way that is more than technical.  Allow me to explain.  

First, the foot in the picture is, indeed, from a Megalapteryx.  So far, so good.  Megalypteryx is sometimes better known as the Moa, a giant flightless bird from New Zealand.  Think Kevin from "Up", only not nearly as colorful.  They went extinct in around 1500 A.D.

Second, the Moa is, indeed, a dinosaur.  All birds are, and not just in the technical, "we classified them so they are dinosaurs" kind of way.  As mentioned in a different post, taxonomists now classify them as "Avian Dinosaurs" due to the number of structural and physiological similarities between living birds and extinct dinosaurs.  So technically, Megalapteryx is a dinosaur.  

Third, the flesh on it is well preserved.  So if we put all those things together, technically the foot in the picture is the possibly the best preserved dinosaur tissue to date.  None of those things are wrong, but the way it is presented isn't that great.  You are supposed to see that picture and think, "Holy cow!  They discovered a dinosaur foot and it totally still has skin on it!  How cool is that?!?"  However, you are also probably supposed to think that the dinosaur foot in question is 65 million years old or more which, I am sorry to say, it is not.  

Don't fret though.  The fact that something like this existed only about 600 years ago is fairly amazing, and just look at that foot!  Could it be any more dinosaur-like?  Yet another easy to see clue that shows that birds evolved from dinosaurs.        

    

Giant Bird Ancestor

As it turns out I am still a 9 year old kid.  I love dinosaurs and until today my favorite was the always classic Tyrannosaurus rex, mostly for its size and ferocity, but also because I am a bit afraid that if it is not my favorite one will spontaneously appear in my backyard and eat me.  Apparently I am a 9 year old boy in more ways than one.  I say “until today” because as of now, T. rex is no longer the king.  The recently discovered bones of Siats meekerorum dethroned T. rex due to the fact that it is, as one of my students put it, offensively large.  Preliminary estimates put this thing at about 4 tons and stretching to the length of a school bus.  Next time you have a chance, go stand next to a school bus and tell me that a walking, breathing, roaring creature of that stature wouldn’t make you want to curl up in a ball and call for your mommy.  You might notice that in the picture below the critter has feathers covering its body.  Since it was a theropod dinosaur, like modern birds, it most likely had feathers.  Personally I think the feathers make it slightly adorable.

Siats meekerorum.  Because I didn't have enough trouble sleeping.

Chickenosaurus

I am going to go out on a limb here and state, unequivocally, that I like the Earth.  Except for a few notable occasions in the past involving what can only be described as biblical amounts of rain-water entering my basement, it has been nice and hospitable to me and my family.  I am rarely struck by a meteor when I leave the house, and, thanks to the fact that there is ample oxygen in the atmosphere, I can breathe normally as long as I am not in the midst of an asthma attack.

The planet wasn't always this enticing to life.  At various times over the previous 4.6ish billion years the planet has seemed downright antagonistic to the squishy things that keep evolving on it.  You are probably aware of the fact that despite their long reign as kings and queens of the planet, there are no dinosaurs tromping about the place anymore. This, I should point out, is probably for the best.  It is one thing to be amazed by the sheer size and majesty of a 75 foot long Apatosaurus skeleton in your local museum of Natural History, but quite another to actually encounter an office building sized animal on your way to your car in the morning.  I would, in all likelihood, pee myself should such an event transpire.   

Despite the overall looseness of my bladder and the fact that we have all seen “Jurassic Park,” a group of scientists led by Jack Horner are in the process of building a dinosaur using the DNA of a chicken as their model.  This may seem silly given that a dinosaur of any size is an imposing reptile while a chicken is, well, a chicken.  How can they plan to resurrect dinosaurs by using chicken DNA?  

It turns out that chickens, and indeed all birds, are direct descendants of dinosaurs.  In fact, some taxonomists have decided that birds are not only related to dinosaurs they have begun splitting dinosaurs into two different groups:  Avian dinosaurs (birds) and Non-Avian dinosaurs (all the other ones).  

From the massive Cassowary to the tiny hummingbird, all birds are dinosaurs, and this is most evident from their DNA.  Horner and others have discovered atavisms, or hidden traits, in birds that can be activated by tinkering with their DNA.  Mess with the DNA that controls beak formation and you get a beak with teeth.  Mess with the DNA that controls tail formation and you can produce a reptilian bony tail.  Tweak the DNA associated with wing formation and you can get a wing with claws.  Change all of this DNA in a single bird and you can get a chicken with teeth, a bony tail, and claw wings.  Still not exactly a T. Rex but significantly more dinosaur like than the current model of chicken.  

For more information on the chickenosaurus take a look at the video below.  I am also including YouTube links to an amazing BBC documentary on the dissection of a Cassowary for any that are interested.     

TED Talk - Jack Horner:  How to build a dinosaur from a chicken

Inside Nature's Giants (Cassowary Dissection) Part 1

Inside Nature's Giants (Cassowary Dissection) Part 2

Inside Nature's Giants (Cassowary Dissection) Part 3

Inside Nature's Giants (Cassowary Dissection) Part 4

Happy Thanksgiving

We'd like to give thanks to a new blog and wish everyone a Happy Thanksgiving.

and speaking of Turkeys....

Interested about Evolution? Check out our Evolution Chapter from our zoology text.