Research Publication Title of the Week – The Virtue of Modesty

Comparison of the five extant species of rhinoceros - Wikimedia Commons

ANALYSIS OF COMPLETE MITOCHONDRIAL GENOMES FROM EXTINCT AND EXTANT RHINOCEROSES REVEALS LACK OF PHYLOGENETIC RESOLUTION - Eske Willerslev, Marcus Gilbert, Jonas Binladen, Simon Ho, Paula Campos, Aakrosh Ratan, Lynn Tomsho, Rute da Fonseca, Andrei Sher, Tatanya Kuznetsova, Malgosia Nowak-Kemp, Terri Roth, Webb Miller  and Stephan Schuster

BMC Evolutionary Biology 2009, 9:95

doi:10.1186/1471-2148-9-95

From our irregular series, oh, nevermind.

Amidst the recent outcry over phylogenetic hype, it is nice to see some truth in advertising.  Sure one might quibble over whether the lack of a pattern is something that can be “revealed” but microecos never quibbles over semantics…

Semantics aside, what is tremendously cool about this paper is the recovery of mitochondrial genes from preserved soft tissues of the extinct woolly rhino, Coelodonta antiquitatis. Despite the overall lack of resolution among the clade, Willerslev and company recover strongly supported sister relationships between the two African rhinos (the white rhino, Ceratotherium simum and the black rhino, Diceros bicornis) and between the congeneric Javan and Indian rhinos (Rhinoceros sondaicus, R. unicornis).

Charles Knight's iconic, heroic woolly rhino

While neither of these relationships are surprising, the authors also found support for a sister relationship between the woolly rhino and the ridiculously adorable, critically endangered Sumatran rhino (Dicerorhinus sumatrensis).  This relationship has been postulated before, at least partly based on the fact that Dicerorhinus is unique among living rhinos in sporting luscious, auburn locks that put agent Scully to shame.  However, this hypothesis has been controversial and this new paper certainly leaves the door open for considerable improvement in our understanding of the evolutionary history of living rhinos.

One of the problems here is that today we are left with only a tattered remnant of the great perissodactyl radiation that produced some of the most impressive, perplexing and yes (ahem) EXTREME mammals that have ever existed.  Aside from the four rhino genera, a handful of tapirs (all in genus Tapirus) and a rather more respectable smattering of zebras, asses and kiangs (in the familiar, but rather lumpy genus Equus) are all that remains of this once diverse order.  In the recent analysis, relationships amongst the rhino couplets changed dramatically depending on whether tapirs or horses were used as the out-group, perhaps indicating a geologically explosive radiation of rhinos from their perissodactyl ancestors at some point in the Cenzoic.

Living rhinos on the brink - from Intl Rhino Foundation

Sadly, we stand to lose even more of this evolutionary majesty if the poaching and deforestation that imperil all living rhinos isn’t checked.  While the recovery of genetic material from the extinct woolly rhino is a remarkable achievement, it would be terribly tragic if scraps of keratin are all that future studies of rhino evolution have to go on.

But I hate to leave you on such a bitter note, so behold, the otherworldly wonder that is a baby Sumatran rhino:

Baby Rhino!

Monophyly FAIL

Unless you have been living under a slab of oil shale, you will have already heard, read and seen quite a lot about the Eocene primate Darwinius masillae recently described in the online open-access journal PLOSone.  The blogosphere has been, ahem, a-twitter over the “hype” surrounding this important fossil–to the extent that some have even begun to decry the anti-hype hype–and it has provided fodder for some excellent satire.  Even the Old Gray Lady has weighed in.

In my forthcoming (‘cough) book on the late 20th/early 21st C. social history of fossils (tentatively entitled Paleontology After Modernism) I discuss the role of flash-powered websites in the promotion of important fossil discoveries (see: Tiktaalik’s or Puijila’s).  Given that Darwinius already has its own book and not one, but two television specials, one of which is narrated by Sir David Attenborough, it comes as no surprise that it has its own flashy website too.

Unfortunately, it appears that the website creators did not bother to read the freely available publication they are trying to summarize, and instead chose to present a woefully outdated picture of primate evolution.  I’m sure Brian Switek will take them to tasks for trotting out the old “march of progress” canard,  and perhaps we can forgive the pervasive “Homo sapians” typo.

However, suggesting that primates “diversified into two key groups: the anthropoids and the prosimians” (see image at top of post) is misleading at best and, at worst, directly contradicts the argument laid out in the new paper.  “Prosimian” is term used to refer to various primates perceived to be um, primitive in their anatomy including lemurs, lorises and tarsiers.  However it has been well known for quite some time that this is not a natural group that can be split from the “anthropoid” monkeys and apes, but rather a paraphyletic group of animals including the direct ancestors of anthropoids, as well as animals only distantly related to anthropoids.

Exactly which “prosimians” are more closely related to anthropoids is a matter of debate, and one that this fossil may shed new light on, though, see Brian’s detailed critique of  the new paper.  It is certainly understandable that the LINK website designers would not want to go into the finer details of this debate, however there is no excuse for falling back on a “simplified” but outdated and erroneous picture of primate evolution.

I’m wholeheartedly in favor of trying to get the public excited about important scientific discoveries, even when it involves some minor exaggeration, disseminating misinformation on the other hand is simply inexcusable.

And don’t get me started on this….

Why is a protarded boa constrictor like a writing desk, I mean, thermometer?

“In a word, the form of the tooth entails the form of the condyle; the forms of the shoulder blade and the claws, just like the equation of a curve, entail all their properties. Just as in taking each property seperately as the basis for a particular equation, one would find both the ordinary equation and all the other properties of any kind, so likewise the claw, the shoulder blade, the condyle, the femur, and all the other bones taken seperately, determine the teeth, and each other reciprocally. Beginning with each of them in isolation, he who possesses rationally the laws of organic economy would be able to reconstruct the whole animal.” — Cuvier 1812, trans. Martin Rudwick.

From our irregular series, "Bloggers half-assedly opining about peer-reviewed papers when, really no one asked them in the first place anyway."

Baron Georges Léopold Chrétien Frédéric Dagobert Cuvier was a man of strong opinion and bold statement. In the most dramatic articulation of his “Principle of the Correlation of Parts” Cuvier argued that anatomy, like God, bows to math. Given a single isolated bone, he claimed, one might be able to infer what the entire animal looked like, at least in principle. In following paragraphs Cuvier hedges his bold assertion just a bit, but this is the idea for which Cuvier is remembered, and misremembered, the most.

Creationsists love to bring this up, “scientists find a few scraps of bone and make up a dinosaur.”  Ironically, it was Cuvier’s own vision of “intelligent design” and “irreducible complexity” that informed his view. On the opposite side of the spectrum, Thomas Henry Huxley took Cuvier’s claim to task in his lecture “On Natural History, as Knowledge, Discipline, and Power” (see also Hugh Falconer’s rebuttal). In a later, and tremendously entertaining essay, “On the Method of Zadig” Huxley argues that Cuvier’s principle can be of some use, as long as it is conducted cautiously and in an explicitly evolutionary context.

These days most paleontologists would claim that they aren’t so bold as Cuvier, and that they wouldn’t seriously attempt to reconstruct an animal based upon a single bone (though they certainly might do so for a laugh). I would argue, however, that we’ve actually gone far beyond Cuvier’s wildest dreams. Correlation and exrapolation are largely the name of the game. This is how we sex the brooding theropod, draw out the fetal leviathan, and diagnose the dueling dinosaur.

The much publicized recent discovery of Titanoboa is significant not only because it’s a freaking huge-ass snake, though admittedly it is one ginormous, redonkulus, totally protarded animal. Even more amazing than the snake is what Jason Head and coauthors* do with the fossils. Given a handful of vertebrae from several individuals, they first extrapolate the body size of the animal based on the anatomical proportions found in the largest living snakes, python and anaconda. Then, and this is the really amazing part, they use the size of the snake to calculate paleo temperature based on the relationship between geographic distribution, temperature and body size among living reptiles. In fact, the authors even propose a pole to equator temperature gradient–based on the size and shape of the backbone of an extinct snake!!

If the scientists were simply saying “big snake = tropical weather,” as most news outlets are basically reporting it, that wouldn’t be very noteworthy. But this may be the first time that a fossil vertebrate has been used to calculate a numerical paleotemperature estimate. At last year’s Society of Vertebrate Paleontology Conference I saw one of the authors, David Polly, give a pretty amazing lecture using ankle bone shape to estimate paleoenvironment and paleoclimate.

Taking the temperature of the tropics with a snake – Head et al. 2009

This kind of claim is certain to draw criticism and skepticism within the paleontological community and, probably especially, from neontologists and paleoclimatologists. That’s not neccesarily a bad thing, radical new ideas in science need to be tested. I’m certainly not totally convinced. Still, for a science as old and dusty as comparative anatomy, it’s pretty exciting to see this kind of novel and creative work. It gives me hope that there are plenty of new surprises out there still waiting to be discovered. Cuvier would be proud I think.

For more huge-ass snakes see: Snake Handlin’

* – full disclosure, I’m friends with one of the authors and have worked with him in the field.

I Support Scientific Triassicism

If 2008 is remembered for anything, surely it will come to be known as the year Triassic broke.

When you were a kid, the Triassic was an impossibly dreary place peppered with some generic economy-model dinosaurs.  Oh sure there were also some stupid looking synapids, a bunch of “thecodonts” and “eosuchians” or whatever, a mess of footprints, maybe a mass extinction event or two…but honestly, who gave a Morganucodon’s ass?

I mean, check out the short shrift the Triassic gets in Zallinger’s famous Age of Reptiles mural. “Dude, is that a Plateosaurus?  No way…sick!”

click to buy the t-shirt!

While Triassic dinosaur faunae may not be as a charismatic as those of the later Mesozoic, there are still plenty of reasons to be interested in what was going on on our planet between ~250 and ~200 million years ago.  Emerging from wake of the largest mass extinction event of all time, perhaps uncoincidentally, the Triassic was a time of dramatic evolutionary change.  A great wealth of new clades appeared in the Triassic–including the first “true” mammals, crocodilians, frogs, turtles, squamates, dinosaurs, pterosaurs, ichthyosaurs, sauropterygians, scleractinian corals, modern sharks, coccolithophores, several important insect groups, I could go on and on–this evolutionary overdrive is so pronounced that some even speak of a “Triassic explosion.” The end of the Triassic was marked by another pronounced extinction event, which although pale in comparision to the Permo-Triassic event may have paved the way for the rise of the dinosaurs although others maintain it was the rise of dinosaurs themselves that drove the extinction.

All of which makes this classic Onion article even more hilariously poingnant.  In fact, we “secular Triassicists” are witnessing something of a golden era.  Nick Fraser’s spectacular Dawn of the Dinosaurs, published in 2006 is a great resource for those interested in delving into the Triassic world, as visualized by the exceptionally talented Douglas Henderson.  However the pace of discovery and the renewed scientific interest in the Triassic is so pronounced that a revised edition is already needed.

In the mean time, here is my list of the top 5 Triassic news stories of 2008:

click to buy the t-shirt!

5) The Aeto-Contra scandal – The confusion and controversy surrounding the naming of a new species of the unusual armored hellasaurs known as aetosaurs exploded across the internets in early 2008 and blossomed into a full fledged “-gate” with its own website and everything.  While in the end, the “resolution” of the conflict left plenty to be desired, if it’s true that there is no such thing as bad publicity then perhaps the silver-lining to the scandal is a somewhat higher profile for those wacky Aetosaurs.

4) Kryostega the Crocomander and Gerrothorax the, uh, Toiletmander? – While large, freakazoid “amphibians” (i.e. non-amniote tetrapods) were diverse and widespread in the Paleozoic they gradually trickled out during the Mesozoic leaving only the extant lissamphibians.  However during the Triassic a number of impressive “amphibians” were still around kicking ass and taking names.  The antarctic Kryostega a 4.5 meter aquatic predator was in the news this year, as was the rather smaller Gerrothroax whose unusual head-lifting bite inspired some choice wordsmithing by headline writers across the globe.  Don’t miss Matt Celeskey’s awesome interactive Gerrothorax animation at the Hairy Museum of Natural History. (Speaking of Antarctica, the oldest known tetrapod burrows, sweet.)

3) Longisquama Lets its Freak Flags Fly – Even among the surreal host of Triassic creatures, Longisquama stands out as a weirdo.  Recent work on the bizarre skin appendages of Longisquama add to our understanding of this strange animal but still leave much room for future discovery…more on this later, maybe.

2) The Triassic (Blog) Explosion – No fewer than three, that’s right three Triassic themed blogs launched this year all of which are required reading for Triassophiles:

Life of the Madygen – triassiccritters.blogspot.com – Written by a paleontologist based in Germany, this blog highlights the important Triassic fossils of Central Asia, including the aforementioned Longisquama.  The outcrop photos are geo-porn at its finest.

Chinleana – chinleana.blogspot.com – The Chinle Formation is the most famous and arguably most important source of terrestrial Triassic fossils in North America.  Recent discoveries in the Chinle have shed light on the origin of dinosaurs, transformed our understanding of late Triassic stratigraphy and revealed a host of interesting hellasaurs all of which (and more) are fodder for Chinle expert Bill Parker.

Paleoerrata – paleoerrata.blogspot.com – Yet another expert on North American Triassic terrestrial vertebrates, Jeff Martz’s blog thus far has covered not just the evolutionary history of the Triassic but is also a font of wisdom for aspiring young bucks and does, er, un- or underemployed paleontologists.

1) Triassic Turtle Mania – Odontochelys and Chinlechelys: a one-two punch in the ongoing turtle evolution cage-match.  Confusingly each fossil is seen as a TKO by the respective rival camps, on the plus side both paint a picture of Triassic turtles as being more morphologically and ecologically diverse than ever imagined.  Both fossils sent ripples across the blogosphere as usual, the Hairy Museum of Natural History is an excellent place to start.

Coming in 2009 – The Return of the Enigmatic Hellasaur (including Thalattosaurs…I swear!).  See you next year!

Left Behind

Much of the chatter around the Latimeria tank at the newly revamped California Academy of Sciences concerned the health of the specimen, as in, “is that thing alive?” Of course, the putative “living fossil” was, in fact very dead–although a certain fish expert I know with quite a bit of aquarium experience predicts live, captive coelacanths the near future.

Vitality deduced, many passers-by voiced familiarity with “the greatest fish story ever told.” In fact, a few even recalled recent news about the discovery¹ of a second living species of coelacanth in an Indonesian fish market.  Now, perhaps the San Francisco museum-going crowd is more hip to these things than most, but it’s impossible to deny that Latimeria has become something of a pop-culture icon , making cameo apperances in commercials, video games, and swan-songs of American primitivists.

Wordless Wednesday 2

Words to follow.

Virtually, my favorite museum

Visit the 3D museum.  Pan.  Rotate.  Zoom.  Enjoy.  If you are interested in donating your own 3D fossil scans to the collection drop me a line.