Horseshoe crabs live in Williamsburg now? At least the other guys won't eat 'em.

Excellent article, thanks subby!

Hear that Dopey? You are a figment of my imagination. Who knew that comically oversized strawberries had pscyhedelic properties? Oh well, if it ain't broke don't fix it, right Dopey? Let's go make a gigantic fruit salad trip balls and go make fun of Chaka by putting up these posters I had made up. RAWR!I'll take that as a HELLZ YEAH! my imaginary friend!

There is nothing like pulling up a crabbing line, expecting a tasty blue Crab at the end of it and seeing this Lovecraftian looking mother farker staring you in the face instead:


and while they are admittedly harmless, YOU try telling your reptillian brain that something that looks like this is harmless:

brap: [i253.photobucket.com image 152x115]Hear that Dopey? You are a figment of my imagination. Who knew that comically oversized strawberries had pscyhedelic properties? Oh well, if it ain't broke don't fix it, right Dopey? Let's go make a gigantic fruit salad trip balls and go make fun of Chaka by putting up these posters I had made up. [i253.photobucket.com image 320x240]RAWR!I'll take that as a HELLZ YEAH! my imaginary friend!

[snort, chuckle, guffaw]

Don't forget sharks and gators. Two more examples of animals that have barely changed in the last 65+ million years.

Hipster coelacanth didnt yield much, but...

I'm shocked nobody has mentioned crocs, alligators, or sharks. COME ON.

brap: [i253.photobucket.com image 152x115]Hear that Dopey? You are a figment of my imagination. Who knew that comically oversized strawberries had pscyhedelic properties? Oh well, if it ain't broke don't fix it, right Dopey? Let's go make a gigantic fruit salad trip balls and go make fun of Chaka by putting up these posters I had made up. [i253.photobucket.com image 320x240]RAWR!I'll take that as a HELLZ YEAH! my imaginary friend!

Don't mock Holly.

Ed Grubermann: brap: [i253.photobucket.com image 152x115]Hear that Dopey? You are a figment of my imagination. Who knew that comically oversized strawberries had pscyhedelic properties? Oh well, if it ain't broke don't fix it, right Dopey? Let's go make a gigantic fruit salad trip balls and go make fun of Chaka by putting up these posters I had made up. [i253.photobucket.com image 320x240]RAWR!I'll take that as a HELLZ YEAH! my imaginary friend!

Don't mock Holly.


I'm not.  It's an homage.

Warrener: Don't crocodiles and alligators also count as living fossils since they are largely unchanged for a few million years?

The point of the article is that the species that get called "living fossils" are not actually unchanged. The species that are alive in the present are recognizably different from their ancient ancestors. They have simply retained plesiomorphic traits that were present in other species in the past. Calling archosaurs "living fossils" is equivalent to calling me a 19th century Hungarian because I have the same last name as my grandfather.

In the past, archosaurs were a much more diverse group than they are today, and some of them resembled modern crocodiles, alligators and caimans. But the archosaurs of today are also different in many ways from their ancestors. So it's sort of misleading to call them "living fossils."

Technically speaking, a fossil is any trace of life from a prior geological age. The most recent prior geological age was the Pleistocene, which ended about 10,000 years ago. So in order for something to be a "living fossil," it would have to be a living organism that is more than 10,000 years old. The oldest living individual organisms are less than half that, as far as I know.

(Note: there are a few clonal organisms that have persisted for longer, but that kind of blurs the notion of "individual.")

Ed Grubermann: Don't mock Holly.

Also, don't hock Molly.

FloydA: Warrener: Don't crocodiles and alligators also count as living fossils since they are largely unchanged for a few million years?

The point of the article is that the species that get called "living fossils" are not actually unchanged. The species that are alive in the present are recognizably different from their ancient ancestors. They have simply retained plesiomorphic traits that were present in other species in the past. Calling archosaurs "living fossils" is equivalent to calling me a 19th century Hungarian because I have the same last name as my grandfather.

In the past, archosaurs were a much more diverse group than they are today, and some of them resembled modern crocodiles, alligators and caimans. But the archosaurs of today are also different in many ways from their ancestors. So it's sort of misleading to call them "living fossils."

Technically speaking, a fossil is any trace of life from a prior geological age. The most recent prior geological age was the Pleistocene, which ended about 10,000 years ago. So in order for something to be a "living fossil," it would have to be a living organism that is more than 10,000 years old. The oldest living individual organisms are less than half that, as far as I know.

(Note: there are a few clonal organisms that have persisted for longer, but that kind of blurs the notion of "individual.")

Can never trust them 19th century Hungarians!

redmid17:

Can never trust them 19th century Hungarians!

I admit I've got the "Carpathian wild man" eyebrows. Whenever I go to a movie, they get there a couple minutes ahead of me and save me a seat.

cthellis:

Why must you always make me want to hump your leg? (I'd buy her a beer afterward.)

You should be a teacher or something.


That's the most romantic thing anyone has said to me in months!


_{...which is kind of sad, now that I think about it. ;-)}

Warrener: Don't crocodiles and alligators also count as living fossils since they are largely unchanged for a few million years?

1) As others have noted, the article DOES mention crocodilians. :D

2) For those who are not paleogeeks (professional or otherwise) or who did not RTFA--modern surviving crocodilians are actually surprisingly derived little guys; the "ur-crocodilians" actually looked like upright-running small critters, and diversified into everything from dedicated dinosaur-hunters to deep-sea predators (the aforementioned Dakosaurus) to shoreline hunters (the modern niche for crocodilians).

Probably the earliest of the "modern crocs" would be Isisfordia which is one of the first fossils of something living a "modern croc" lifestyle--and which actually looks rather caiman-esque. It's also still only about 90 million years old...the group of crocodyliforms that includes critters that actually lived like modern crocs and had similar body plans (the Neosuchia) is roughly on par with how long birds have been around, something like 140 mya. Much like in the case of dinosaurs where all that survived the K-T were the insectivorous-bat-analogues (modern birds), the only crocodylomorphs that survived were the odd little "sea lion" analogues (modern crocs).

Interestingly, the neosuchians also include the really derived "seal and orca analogue" metriorhynchoid crocodylomorphs, of which the aforementioned Dakosaurus is one--much like how some of the more derived "sea-faring" early birds didn't make it across the K-T, the same seems to have happened with the really derived crocs.

3) Not mentioned in the article, but something to note--some of the traits of modern crocodilians thought to be "primitive" may actually be adaptations for a shore-hunting lifestyle. Among other things, the evidence points to early crocodilians actually being homeothermic (like modern dinosaurs, aka birds) and ectothermy in modern crocodilians being an adaptive trait to conserve oxygen whilst underwater. (Secondary ectothermy isn't all that unknown; crocodilians split from the rest of the Archosauria after homeothermy showed up in that clade so "warm blooded ur-crocs" are likely, and naked mole rats are an example of mammals that are secondarily ectothermic (and for very similar reasons as modern crocs--more on naked mole rat thermoregulation here.) Modern crocodilian gait is also known to be a specific adaptation for shore hunting.

This is especially true if we go above "eusuchid crocs" into crocodylomorphs, including the "ur-croc" spenosuchids which can be best described as "archosaurian greyhound-analogues"--a general lifestyle and body build that practically requires homeothermy. (And frankly, I find some of those spenosuchids cute. Then again, I also find baby modern crocodilians cute; it never ceases to amuse me how little baby scalybutts can quack like chicks. And momma crocodilians can be nearly as broody when they hear those little quacks...)

And to continue the "crocs actually tend to be derived" bit--a neat critter in the "I wish it hadn't been eaten to extinction 1600 years ago" department was Mekosuchus--six-foot-long true crocs that went back to the "old body plan" of completely upright land-dwellers. Interestingly, some species were heterodont--with specialised teeth in the back of their skulls for cracking open shells of molluscs and crabs :D

Darren Naish has a really neat article on all of this if folks care to check it out--extinct crocs (and living ones) and croc-cousins are pretty darn neat IMHO :D

Great Porn Dragon: And to continue the "crocs actually tend to be derived" bit--a neat critter in the "I wish it hadn't been eaten to extinction 1600 years ago" department was Mekosuchus--six-foot-long true crocs that went back to the "old body plan" of completely upright land-dwellers. Interestingly, some species were heterodont--with specialised teeth in the back of their skulls for cracking open shells of molluscs and crabs :D

Darren Naish has a really neat article on all of this if folks care to check it out--extinct crocs (and living ones) and croc-cousins are pretty darn neat IMHO :D


you see that guy and the fact he ws hunted to extinction by primitive man and it makes you wonder if the Jungian archetype of Beowulf/Sigfried/St George might not have been an aboriginal with a stone-tipped spear

Oldiron_79: "Living fossils" are generally members of a genus that just has one or a small handful of living species and the rest of them are long since extinct.


Yes, exactly! As the article noted:


What a "living fossil" that is the last surviving twig on a once luxuriant branch might look like.

Magorn: Great Porn Dragon: And to continue the "crocs actually tend to be derived" bit--a neat critter in the "I wish it hadn't been eaten to extinction 1600 years ago" department was Mekosuchus--six-foot-long true crocs that went back to the "old body plan" of completely upright land-dwellers. Interestingly, some species were heterodont--with specialised teeth in the back of their skulls for cracking open shells of molluscs and crabs :D

Darren Naish has a really neat article on all of this if folks care to check it out--extinct crocs (and living ones) and croc-cousins are pretty darn neat IMHO :D


you see that guy and the fact he ws hunted to extinction by primitive man and it makes you wonder if the Jungian archetype of Beowulf/Sigfried/St George might not have been an aboriginal with a stone-tipped spear

I've actually wondered that myself, especially considering that there were giant goannas in Australia around the time that the traditional owners of country settled that death-continent :D (Reportedly there are traditional stories and Dreaming-lines that involve them, much as there are with mihirungs.)

FloydA: Oldiron_79: "Living fossils" are generally members of a genus that just has one or a small handful of living species and the rest of them are long since extinct.


Yes, exactly! As the article noted:

[i105.photobucket.com image 400x300]
What a "living fossil" that is the last surviving twig on a once luxuriant branch might look like.

This--as it is, not only are we one of four surviving hominin apes on what was once a far more diverse tree (even up until 40,000 BCE we could have had as many as three sister species) but we're the sole survivor of the "bipedal savannah ape" lineage coming from Ardipithecus et al.

/almost is a pity that Sasquatch probably doesn't exist--I imagine if it did, it would be a surviving pithecanthropid and the closest thing we have to a brother species

ArcadianRefugee: PonceAlyosha: ArcadianRefugee: I hate the phrase "living fossil." The term should be eradicated from the vocabulary of science writers, and anyone who employs it should be promptly encased in Carbonite.

and that's where I stopped reading.

You missed the dakosaurus then.

[files.myopera.com image 850x574]

That picture farks with my head. I keep wanting to put a head on the tail and see it's back fins as 'arms'.

Damnit, i would punch you in the arm for that.

But i cant, so heres the fedex arrow.



And you just lost the game.

While reading the article I couldn't help by think of an old Gould essay "The Streak of Streaks" where he writes about DiMaggio'shiatting streak. Worth a read if you have a chance (as are most of Gould's essays).

If you were to give all species an equal chance of going extinct over a give period of time (say, 50% over 1 Myr) then about half of them would go extinct after 1 million years. But of the half that didn't, another half would likely last the next million years, and so on. Essentially, the species survivorship would look like a half life curve. If you had a large enough starting pool of species, there's a good chance some of them would make it far, far longer than you'd expect given their starting odds, and that's just when playing strictly by the odds. But some of those species are probably just really well suited to surviving, and that tilts the odds in their favor. Given that there are probably between 5 and 100 million species living today, and that at least 99% of all species are extinct that's a massive starting pool of species. The odds are good that at least some of them have beat the odds repeatedly. And so, we have coelacanths and horseshoe crabs and the monotremes, who happened to be good players with good luck.

But I like what he said in the article too.