The Integrative Paleontologists

A Dinosaur’s Unexpected Appearance

By Andrew Farke
Posted: May 13, 2013

Sometimes your research shows up in the places where you least expect it.

Seniors at Armour High School–my alma mater square in the middle of Armour, South Dakota (population 699)–have a fun and quirky tradition at graduation. When called across the stage, each graduate trades some small object with the school board president in exchange for a diploma. One year it was hard-boiled eggs. The year that I graduated, we traded pirate figurines.

My mom is the current president of the Armour public school board, and consequently at the receiving end of the tradition. This year it was plastic alphabet letters. One for each senior, all 10 members of the graduating class. And what did those letters spell?

Dahalokely spelled out in plastic alphabet letters

Photo courtesy of Joanne Farke.

That’s right…the seniors spelled out “Dahalokely“–the name of the dinosaur from Madagascar that I named a few weeks ago in PLOS ONE. All 10 letters, handed over to the mom of the senior author on the paper.

This epitomizes everything I love about my small town. People are connected in a way that you don’t always see elsewhere, maintaining those connections and memories for years. So, to the AHS class of 2013, I say: Congratulations! Good luck! From what I know of you, you are a cool, creative, and hard-working bunch. No matter where life takes you, be proud of your roots. The lessons I learned in Armour–of community, connection, and work ethic–have served me well. May you take these qualities with you, whatever your destination!

Category: Dinosaurs, Miscellaneous, Navel Gazing, Paleontology | Leave a comment

All Creatures Great and Small: Small Mammals and Conservation Paleobiology

By Shaena Montanari
Posted: April 26, 2013

Small mammals, at times, don’t seem very interesting or informative (like when there is a rat in your apartment and you just want it out.) A lot of paleontologists are keen on studying enormous carnivorous beasts like dinosaurs and sabre-toothed cats and are not often thinking about small, adorable (at least I think so) rodents. Fortunately for us, some people love all creatures, great and small. Ancient and modern small mammal communities are probably the best indicators of how climate change will affect diversity, extinction, and speciation of vertebrates as a whole. They are often the base of food webs and vital to the survival of ecosystems. We were recently discussing how paleontology is relevant, and I would say these fossils are some of the most important resources we have as paleontologists interested in researching the future of global biodiversity in the face of warming temperatures.

A paper I read recently by Prost et al. 2013 in Global Change Biology serves as an excellent reminder of the dangers facing small mammal communities in a warming world. They utilized both ancient and modern data to help understand the future of both the narrow-skulled vole and collared lemmings. Polar regions are particularly interesting to study because they exceed tropical and temperate regions in warming. They used both ancient DNA and ecological niche modeling to look at changes in populations and biogeography since the Last Glacial Maximum, and then used this information to project into the future potential issue these vital species may have.

A friendly vole (Wikimedia Commons)

Interestingly, while both are small mammals that superficially occupy similar niches, they responded differently after the Last Glacial Maximum. The collared-lemming had a distinct range decrease, while the narrow-skulled voles were only minimally impacted. Also fascinating is that there is a strong correlation between extent of suitable habitat for narrow-skulled voles and their ancient genetic diversity. These animals are at the bottom of the food chain, and their survival can be integral to the entire artic and boreal forest ecosystem.

Population sizes in the two species (collared lemming in green, narrow-skulled vole in purple, oxygen isotope values of ice core on the bottom) reacted differently after last glacial maximum. Collared lemmings clearly had a more severe population decrease than narrow-skulled voles. (Figure 2, Prost et al. 2013).

Another researcher who does stellar work on climate change and small mammal communities is Rebecca Terry. I greatly admire the importance and interdisciplinary nature of her modern and paleo-ecological work. The bulk of her work to this point has been analyzing small mammal bones in caves form the Great Basin region of the western United States. In a 2011 paper, Terry et al. analyze cave data from the last 7500 years to see how this rodent community responded to past climate change. The skeletal remains in these caves are predator-derived, meaning they are mostly owl and raptor regurgitate (pellets). These preserve the hard parts from prey and represent a solid composite signal of long term demographic trends.

Owl pellets contain bone and hair from prey (Wikimedia Commons)

The results clearly indicate a rather unexpected trend. Rodents with diets adapted to plant fodder had a marked decline during dry periods, while rodents that primarily ate seeds dominated the faunal assemblage. Climate models show the Great Basin will warm considerably over the coming decades, so this sort of detailed information obtained from paleocommunities can help us conserve populations that are apparently vulnerable to these climate shifts.

I think these types of studies are so important to point out because they illustrate that our fossil record can be robust and useful for conservation- this has brought about the relatively new subfield ‘conservation paleobiology’ where we use paleo-information to inform modern conservation. Most of these studies are also quite interdisciplinary, using ancient DNA, niche modeling, stable isotope sampling, etc. Robust, all-inclusive sampling is needed to best understand the information locked in these fossils. Although big dinosaur fossils are cool, those finds are often sparse, and can’t tell us the useful, nitty-gritty details of community response to climate change.

Let this be a lesson to you future paleontologists, don’t ignore the little guys!

References:

Prost, S., Guralnick, R. P., Waltari, E., Fedorov, V. B., Kuzmina, E., Smirnov, N., van Kolfschoten, T., Hofreiter, M. and Vrieling, K. (2013), Losing ground: past history and future fate of Arctic small mammals in a changing climate. Global Change Biology. doi: 10.1111/gcb.12157

Terry, R. C., Li, C. and Hadly, E. A. (2011), Predicting small-mammal responses to climatic warming: autecology, geographic range, and the Holocene fossil record. Global Change Biology, 17: 3019–3034. doi: 10.1111/j.1365-2486.2011.02438.x

Category: Paleontology | Tagged climate change, ecology, paleoecology | Leave a comment

A Dinosaur’s Journey to Publication

By Andrew Farke
Posted: April 19, 2013

With yesterday’s publication of the paper describing and naming the dinosaur Dahalokely, one stage of a loooong research journey has reached its end. The details on the animal itself have been covered elsewhere, so this post focuses on the path of Dahalokely towards publication.

The fossils were first found in August 2007, and we presented a poster on the preliminary results at the 2009 Society of Vertebrate Paleontology meeting in Bristol, England. I wrote an initial outline of the paper in October 2009, and started penning the preliminary text that same month. More bones were recovered in 2010, and by the summer of 2011, those fossils were completely prepared. The first solid draft of the manuscript was finished in September 2011, and co-author Joe Sertich and I sporadically bounced it back and forth for the next few months.

One of the vertebrae from Dahalokely, modified from Farke & Sertich 2013. CC-BY.

From the start, we knew that Dahalokely was something of fairly broad importance. Yes, it was a new dinosaur, but far more interesting was that it came from a poorly known time and place. Our initial phylogeny–based on all of the data available at the time–suggested that it was probably ancestral to later animals on Madagascar and India, a relationship never documented for any dinosaur before! As a consequence, we wanted to go for something of higher-than-average visibility.

Joe and I talked a fair bit about where to send the manuscript. One thing I was quite firm on was that, immediately or after a short delay, the paper had to be open access in some fashion; that is, freely available online at the journal website*. Our dinosaur was found in Madagascar, and I wanted people in Madagascar to be able to read it**. Also, we couldn’t afford to pay thousands of dollars to make the paper open access, as some journals require. This ruled out Nature*** as well as (sadly) some society journals that I really like otherwise. We thought the paper had a good shot at a place like Proceedings B (which opens its archives after a year), a journal with a broad readership and good reputation in the community. So, we formatted our manuscript accordingly and sent it off.

We submitted on April 12, 2012, and got the decision back on April 19. Our paper wasn’t of sufficient appeal for the journal’s general readership. We were a little surprised, because we thought we had fairly clearly laid out our case for broad interest in our cover letter and manuscript. But, this game is a bit of a lottery sometimes, so we went to the next journal.

Next, we then turned to PNAS (Proceedings of the National Academy of Sciences of the United States of America). The formatting requirements were almost identical, so it didn’t take long to turn around the manuscript. We sent it in on May 15, 2012, and got a decision back on May 23. Unsurprisingly by this point, it too was rejected without review, for similar reasons of not being of broad enough interest.

At this point, we were a little frustrated, and were done with playing the “potential impact” game. So, Joe and I elected to reformat for PLOS ONE, where the scientific soundness of the research alone matters, not its potential citability. This had an additional benefit of being able to move a bunch of supplementary information back into the main text where it belonged. Among other things, we pulled over the gorgeous photographic plates that Joe had assembled, as well as a bunch of the discussion on geology. Although the original manuscript plus supplementary information collectively formed a complete description, it is far better to be able to have all the good stuff in a single document.

Then, something annoying happened. Our phylogenetic analyses up to that point had unequivocally placed Dahalokely as a member of Abelisauridae, and even more importantly as the earliest member of a group including only animals from India and Madagascar. This very, very nicely supported the hypothesis that Dahalokely was ancestral to later animals from both places.

Our original hypothesis of the relationships of <i>Dahalokely</i>, showing it more closely related to other dinosaurs from India and Madagascar than those from anywhere else.

Our original hypothesis of the evolutionary relationships of Dahalokely, showing it more closely related to other dinosaurs from India and Madagascar than those from anywhere else.

While we were bouncing around other journals, our colleagues Diego Pol and Oliver Rauhut published a new animal called Eoabelisaurus. As the name (which means “dawn Abelisaurus“) implied, those authors hypothesized that the critter was the oldest known member of Abelisauridae by more than 40 million years. If we wanted our own paper to be complete, we had to throw Eoabelisaurus into our data matrix for phylogenetic analysis. How much harm could it do to our neat little hypothesis, right?

The results were annoying to the extreme. Thanks to the effects of Eoabelisaurus, Dahalokely was kicked out of the India-Madagascar abelisaurids, and placed at a most unsatisfactory position as a noasaurid. This poorly resolved group includes animals from all over the place (South America, India, and Madagascar), and now our poor fossils weren’t nearly as relevant for Madagascar itself.

The published phylogeny of Dahalokely, showing its path from abelisaurid to noasaurid. Modified from the original figure in Farke and Sertich 2013. CC-BY.

As consolation, it was actually quite easy to place Dahalokely back as an Indo-Malagasy abelisaurid (one extra step, to use the technical lingo). We also could have fiddled with characters (i.e., adding features of dubious validity to the matrix) that would help move Dahalokely back where we “wanted” to see it. But, this would be a pretty weak way of doing things, and not exactly good science. We were stuck. The picture was now less clear, so we had to rewrite parts of the introduction and discussion, and reframe the description slightly to include broader anatomical comparisons. As something of more major interest, our new phylogeny showed fairly convincingly that Eoabelisaurus was probably not an abelisaurid. But, that is only tangential to our overall story.

Between the major reworking of the paper, a field season for both Joe and me, teaching obligations in the fall, and the arrival of a baby in my household, it took a few months to get our manuscript into shape for resubmission. We submitted to PLOS ONE on January 3, 2013, and got our initial decision (revise) on February 20.

The comments from the reviewers (Oliver Rauhut and Fernando Novas) were quite reasonable, and very helpful. Both Oliver and Fernando are unequivocal experts in abelisaurid dinosaurs and their close relatives, and have worked with a huge number of specimens, including some Joe and I haven’t seen in person. The reviewers pointed out a few features we originally thought were unique to Dahalokely that were actually found in some other theropods, so we revised our diagnosis and description accordingly. Another great suggestion was to move the geology section towards the front of the paper (rather than after the description), which we happily did. Finally, we added some extra labeling to the photographic plates, pointing out features that weren’t necessarily clear to a reader. We chose not to incorporate only a handful of minor suggestions (either because we had a different interpretation of a feature than the reviewer and consequently beefed up our text to explain things better, or because the suggestion seemed a little outside the scope of our paper). Overall, our manuscript was measurably improved by the peer review process.

It took us a few weeks to get everything into order, and we resubmitted the revised version on March 11. The notice of acceptance arrived on March 19–I definitely danced a little happy dance upon seeing that email. Later that day we got a request to fix a few little issues in the text prior to publication, which we did immediately. These final changes were accepted just a short two days after. The paper went live on the PLOS ONE website on April 18, less than a month after acceptance.

It was about a year from initial submission of the manuscript at one journal to publication at another. Most of the time wasn’t spent in review, but rather revision. In hindsight, the minor delay at the outset was actually a good thing, because it allowed us to incorporate important new data. Although PLOS ONE perhaps isn’t as fast as it was several years ago (higher volume of papers and all that), it was still only three and a half months from submission to publication, including a thorough review process. The editor (Richard Butler) and reviewers were pretty speedy, a major factor in this quick turnaround.

All told, I’m pretty proud of this paper. We have presented a fairly comprehensive description of an important new taxon, with detailed figures and measurements of every single known element. It’s a satisfying feeling.

*Yes, I know there is some hand-wringing about the definition of open access, and many (for good reason) say that open access under any model other than immediate CC-BY or BOAI is not really open access. Although I see some merits to this, particularly relating to text mining, I also think it distracts from the more immediate problem of just being able to read the darned literature. Personally, I don’t care what flavor of open access it is–I just want to be able to read it freely when and where I want.

**At least those with Internet access. This is an issue in its own right, unfortunately overshadowed by even bigger political, environmental, and social issues of more immediate concern. In any case, the university professors and students who would be most likely to have access to the article theoretically have better computer availability than your average Malagasy citizen.

***The snarkier side of me notes that the lack of feathers preserved with Dahalokely would hinder its chances at some journals to be left unnamed.

Citation
Farke, A. A., and J. J. W. Sertich. 2013. An abelisauroid theropod dinosaur from the Turonian of Madagascar. PLOS ONE 8(4): e62047. doi:10.1371/journal.pone.0062047

Full disclosure: Although I am a volunteer editor for PLOS ONE and a blogger at PLOS Blogs, I had no role in the editorial process related to my paper.

Category: Dinosaurs, Navel Gazing, Nuts and Bolts, Open Access, Paleontology, PLOS ONE | 13 Comments

Madagascar’s Lonely Little Thief

By Andrew Farke
Posted: April 18, 2013

When we think of Madagascar, its unique wildlife immediately springs to mind. Around 95 percent of the terrestrial animals on this island are endemic, meaning that they are found nowhere else on earth. This unusual situation is a product of Madagascar’s isolation, because it is separated from eastern Africa by 250 miles of inhospitable saltwater. That makes it pretty tough for animals to get from point A to point B, and is why you don’t see lions Madagascar or lemurs in Mozambique. For decades, scientists have been working to understand how Madagascar’s unique fauna developed and changed over time. Detailed analyses of modern organisms have certainly been important, but my personal interest is in what the fossil record can tell us. Today, fellow paleontologist Joe Sertich and I published a new addition to this fossil record–a “little” carnivorous dinosaur that predates the next youngest named dinosaurs of Madagascar by around 20 million years.

The lonely island of Madagascar – map by Addicted04, CC-BY.

Madagascar has been isolated for the past 88 million years; for a good stretch of time before that, its only direct connection was to India. The two landmasses formed a single big island in the middle of the Indian Ocean, after they split from Antarctica around 100 million years ago. Somewhat counter-intuitively, it’s been at least 130 million years since Africa and Madagascar last touched! Thanks to a series of stunning discoveries in northwestern Madagascar, we now have an excellent record of life on the island around 70 million years ago. These fossils, unsurprisingly, show close relationships between the dinosaurs of Madagascar and India, with a somewhat more distant link to the dinosaurs of South America (explained by the connection of all of these and Africa via Antarctica, when the continents were closer together).

Despite the excellent 70 million year old fossils, we knew almost nothing about dinosaurs in Madagascar between that time and 165 million years ago. Some fragmentary bones offered a little information, but there wasn’t anything published that could be identified at the species level. This massive gap makes it difficult to document the evolution of Madagascar’s dinosaurs. So, I set out in 2007 to try and change this.

My target was some Cretaceous-aged rocks (from the time period between 145 and 66 million years ago) in northernmost Madagascar. Geological maps and publications indicated that sedimentary rocks from terrestrial environments were exposed in the area, and none of them had been explored for dinosaurs. I used Google Earth to narrow the search region (excluding forested areas and farm fields), scrounged up some grant money, and piggybacked on an expedition from Stony Brook University (my graduate institution) that was already headed to another part of Madagascar. With a small team, I headed up to the area around Antsiranana (Diego-Suarez), a city at the very tip-top of the island. The weather was quite nice thanks to a beautiful ocean breeze, but much of the land was covered in secondary growth following recent deforestation. Virtually every plant was thorny, spiky, pokey, or generally unpleasant; my favorite field hat and a t-shirt or two were ripped to pieces. We searched in vain for days, a discouraging pursuit if there ever was one.

Joe Sertich in the area where Dahalokely was found. Judging by this scene of beaches and ocean, it's the worst place on Earth to do fieldwork, right? Photo by AAF.

Joe Sertich in the general area where Dahalokely was found. Judging by the beaches and coral reefs in the background, it’s the worst place on Earth to do fieldwork, right? Photo by AAF.

Finally, just a few days before we planned to depart the area, Joe Sertich found some bone poking out of a cliff. It looked to be a vertebra of some sort…and a little digging revealed more bones! The hollow spaces the bones inside made it clear they were some sort of dinosaur. This was a pretty happy moment, because we knew that dinosaur vertebrae can be exceptionally useful for identifying species. We collected all that we could, and Joe returned with our colleague Liva Ratsimbaholison to collect the rest in 2010. Preparators at Stony Brook University carefully removed the rock from the bones, and before we knew it they were ready for study.

We had seven vertebrae and a few ribs. This may not seem like much, but it was more than enough to nail down the type of dinosaur. The arches, hollows, and spines on the vertebrae marked the animal as an abelisauroid–a type of carnivorous dinosaur common to the southern continents during the Cretaceous. Additional comparison revealed many features that were unique to the animal, allowing us to name a new genus and species. Careful examination of the local geology allowed us to estimate the age of the animal with some precision; this was absolutely critical to place it into a broader context.

Outline of Dahalokely (based on related animals), showing the bones that were found in white. The human silhouette is to scale. CC-BY 3.0.

Dahalokely tokana lived about 90 million years ago, and was around 10 or 12 feet in total body length. At this juncture in time, Madagascar and India were still conjoined. This is interesting, because Dahalokely shares features with later abelisauroids known in both Madagascar and India. It could potentially be ancestral to animals from these areas–something I strongly suspect, but which couldn’t be definitively supported in our evolutionary analysis. More bones are needed to nail this down for sure. Regardless, Dahalokely is the first dinosaur to be described from a critical interval in Madagascar’s history, and will undoubtedly figure in future work in this area. It also shortens the “barren” zone of Madagascar’s named dinosaur record by about 20 million years.

So, what’s with the unusual name? As is common for new animals named from Madagascar, we chose to work from the Malagasy language rather than the “traditional” (and Euro-centric) Greek or Latin. A “dahalo” is a thief–most often a cattle rustler. We chose this part because our dinosaur was almost certainly a predator (at least from what we know of its close relatives). “Kely” means “little”, because the dinosaur was certainly on the small end of things, even for an abelisauroid. Finally, “tokana” means lonely–and this dinosaur would indeed have been lonely, way out there in the middle of the Indian Ocean with no way to get off the island!

Dahalokely appears in today’s batch of PLOS ONE articles, where we comprehensively describe, illustrate, and compare the animal. After 90 million years, Dahalokely walks the earth again!

Citation
Farke, A. A., and J. J. W. Sertich. 2013. An abelisauroid theropod dinosaur from the Turonian of Madagascar. PLOS ONE 8(4). doi:10.1371/journal.pone.0062047

Full disclosure: Although I am a volunteer editor for PLOS ONE and a blogger at PLOS Blogs, I had no role in the editorial process related to my paper.

Category: Dinosaurs, Paleontology, PLOS ONE | 9 Comments

Rooted in History. . .Remembering Wann Langston, Jr.

By Andrew Farke
Posted: April 12, 2013

Perhaps it’s because we are a historical science. Maybe it’s a direct result of our small numbers. No matter what the cause, vertebrate paleontology has a rich oral history. Stories are passed down, from advisor to student, from colleague to colleague, over campfires and over beers. It keeps connects us to those who came before. If we are truly lucky, we encounter the greats in our field, face-to-face.

When I was an undergraduate, I was granted some external funding to travel to the major collections of horned dinosaurs in North America. One of these trips took me to Austin, Texas, where the remains of an animal called Agujaceratops mariscalensis (then Chasmosaurus) were housed at the Texas Memorial Museum. I had just gotten my bearings in the basement collections, surrounded by dusty specimens excavated in the 1930s, when an old paleontologist stopped by to say hello. It was none other than Wann Langston, Jr.

The name might not mean much to those of you outside the fold, but Wann Langston is one of the big names in vertebrate paleontology, with a publication record spanning seven decades. He helped name the “fin-backed” meat-eating dinosaur Acrocanthosaurus, and dug up some of the best examples of the horned dinosaurs Pentaceratops and Pachyrhinosaurus. Additionally, Wann was closely tied to the discovery and study of the largest known flying animal, Quetzalcoatlus, as well as the best specimens of the iconic (and giant) alligatoroid Deinosuchus, among many other research interests.

Quetzalcoatlus northropi, one of the Cretaceous critters studied by Wann Langston. Image by Mark Witton (from Witton and Naish 2009), CC-BY 3.0.

Growing up as a young dinosaur fan, I had read all about Langston’s work. I knew every discovery, from every angle. As I delved into the primary literature, I grew to appreciate his contributions even more. His papers–and his students’ papers–provided erudite observations on a variety of North America’s ancient inhabitants. Actually meeting the man in person was a big moment for me!

Wann invited me to lunch, and when noon rolled around I piled into the passenger seat in his car and we drove to a local restaurant. We talked about all things horned dinosaur–he actually treated me like a colleague, and not the greenhorn student that I was. The best moments, though, were when he casually wandered into the history of the field. Struck by the anecdote, I later jotted some of Wann’s recollections into my notebook.

“[Charlie Sternberg] was a prince of a guy, but a terrible bore. He could beat a dead horse!”

Wann was talking about Charles M. Sternberg–a legend of North American paleontology, and a son of Charles H. Sternberg, one of the world’s most productive and famous fossil collectors. At that moment, I realized I was only one handshake away from Charles M. and two handshakes away from Charles H. As someone steeped in paleontological history, this was a huge geek-out moment. I felt honored and enriched to be imparted with this kind of oral tradition. At that instant, I wasn’t just sharing a meal with Wann Langston. He had invited the Sternbergs along, too.

Wann Langston, Jr., passed away on Sunday, April 7, 2013. Our field lost an influential figure, whose research is used by many and who launched the careers of numerous paleontologists today. He wasn’t perfect–many of us wished he hadn’t left some specimens unpublished for as long as he did–but he was certainly a great scientist and a kind person to me and many others. Just as critically, Wann recognized the importance of grounding ourselves in the lore of our field.

As the older generations depart, we lose these opportunities to connect with history. So, here’s my advice to students of all ages. Talk to our predecessors. Learn about their own history as students. Read their papers, to get the context for their work and your own. Take a few moments to introduce yourself to a luminary of the field. If invited out for lunch, by all means do it! You will be better for the experience.

[Matt Wedel has a touching tribute to Wann over at SV-POW!, and Tim Rowe wrote a fitting memorial for UT Austin]

Category: Navel Gazing, Paleontology | 1 Comment

How species are like pornography: Species concepts and the fossil record

By Sarah Werning
Posted: April 1, 2013

Recently I helped name a new species, an animal we think is the oldest dinosaur found to date—if not, it’s the closest cousin to dinosaurs we know of (Nesbitt et al. 2013). It was the first time I’ve named a new species of anything, though given my profession, it’s likely I’ll get to name others in the future. Our new species (Nyasasaurus parringtoni) was described based on two partial specimens, which together comprise just twelve bones: a humerus (upper arm bone) and a bunch of vertebrae (back bones). You can see and download photos of all the bones of Nyasasaurus here, for free. Now, we don’t have a lot of bones to go on, and we don’t think Nyasasaurus was a one-armed, ridiculously short-backed dinosaur with no head. And two of my co-authors have shown there are other, closely-related animals found in the same rock formation (Nesbitt et al. 2010). So how did we know we were looking at a new species?

Nyasasaurus parringtoni: If not the grandmother of all dinosaurs, certainly a cousin close enough to bring on an extended vacation.
Image (c) 2012 Natural History Museum, London and Mark Witton, and available here.

For that matter, how does any paleontologist know they are looking at a new species? And what do we mean by the word “species”, anyway? Unfortunately, my answer to that is: it depends on who you talk to.

One common definition of “species” goes something like this: “a group of organisms that can interbreed in nature and produce fertile offspring, but that can’t mate with other groups and produce fertile offspring”. This way of defining species is called the biological species concept, and it centers around the observation that species tend to be isolated from other species, reproductively-speaking, even when they live in the same area.

Applying the biological species concept to fossil animals is problematic because it’s difficult to prove whether or not they were reproductively isolated from each other. Finding fossil vertebrates that died in the act of mating is pretty rare (though check out these lascivious turtles), but even when you find them, that tells you more about mate choice than mating isolation. In the fossil record, the best evidence for reproductive isolation is when organisms are separated by many millions of years, but even that doesn’t rule out a really long-lived species.

So, vertebrate paleontologists tend to think about fossil species using definitions other than the biological species concept (which, if you think about it, is also not so helpful for organisms that don’t have sex, or ones that hybridize easily, like plants). One common definition we use is called the morphological species concept, which more or less means “a group of organisms that shares anatomical characteristics within the group, which are not shared with other groups of organisms”. Basically, organisms that look similar to each other and different from everything else.

Go away, Larry. I’m trying to stay reproductively isolated from you.
Image (c) 2007 José Nestor Cardoso, and available here on a CC BY-SA 3.0

Another common way we think about fossil species is the phylogenetic species concept, which requires an analysis of evolutionary relationships. Under this definition, species are the smallest groups of organisms that both share a common ancestor and are evolutionarily distinct from all the other groups on the tree. Anatomical characteristics are the data we use to reconstruct evolutionary relationships for fossil species, so in reality, most fossil vertebrate species are described using a hybrid method that takes into account both anatomy and evolutionary relationships. In the Nyasasaurus example above, the combination of anatomical features we see in those twelve bones are unique, and they fall out in a novel position on the dinosaur family tree.

It may be surprising that different scientists define species in different ways. A lot of this depends on what type of organism that person does their research on, because many definitions work really well for a particular group of organisms, but are completely inapplicable to other groups of organisms. If you’re a paleontologist, you won’t have much use for a definition that requires showing genetic isolation or genetic similarity, because it will be difficult to apply to most fossil organisms. Similarly, a bacteriologist might not find the morphological species concept too helpful when trying to sort out thousands of species that look identical under the microscope.

Interestingly, the idea that experts should determine which characteristics and species definition are most biologically relevant to the organisms they work on and define species that way is its own species concept: the taxonomic species concept. Though I feel that this is probably the most practical species concept (it’s basically what goes on now), it does have that unsatisfying “I know it when I see it” quality. Who would have guessed that species and pornography could be identified using the same, Supreme Court-sanctioned method?

New species or turtle porn? I know it when I see it.
Image from Joyce et al. (2012), available here.

The difficulty of finding and agreeing on a universal definition for “species” has led some biologists to doubt whether species are biologically real entities at all (Mishler 2010). Rather, they argue that species are arbitrary constructs that biologists impose on the natural world. I think that this viewpoint is a bit extreme; when organisms pass on their DNA in fundamentally different ways (sex vs. no sex, for example), why should we expect a one-size-fits-all definition of species to work?

However, if you use the taxonomic species concept, you have to acknowledge that all species are not exactly biologically equivalent to each other, because we use different methods to parse out what a species in each group. And our opinion of what a species is might be very different from the organisms’ opinion. With genetic data cheaper than ever to obtain, we’re just starting to discover how many species we’ve been lumping together because they look so similar. Despite anatomical similarity, these species have clearly been genetically isolated for many years. We call these groups “cryptic species”, and some types of organisms are much more likely to have cryptic species than other (see Bickford et al. 2007 for a review).

We already know that the fossil record is incomplete; even as good as it is, not every species will be preserved. Right off the bat, any estimate of past species diversity based on fossils is an underestimate. But even among the species we know about and have described, we’re going to miss all the cryptic species. Genetic studies of fossils are still technologically impossible for taxa that have been extinct for hundreds of millions of years, and the skeleton (or a small part of it, in the case of Nyasasaurus) is often all we have to go on. So what we call a fossil “species” might actually have involved several genetically distinct, reproductively isolated groups back in the day.

Now that we’re on the same page regarding how paleontologists think about fossil species, I’ll cover more of the nuts and bolts of how we figure out something is new to science next time. For more on species concepts, go here for the basics, here for a longer list, and here for a very thorough explanation.

References

Bickford D, et al. 2007. Cryptic species as a window on diversity and conservation. TRENDS in Ecology and Evolution 22: 148-155.

Joyce WG, et al. 2012. Caught in the act: the first record of copulating fossil vertebrates. Biology Letters 8: 846-848.

Mishler BD. 2010. Species are not uniquely real biological entities. pp 110-122 in: Ayala FJ and R Arp, Eds. Contemporary Debates in Philosophy of Biology. Wiley-Blackwell, Singapore. 440pp.

Nesbitt SJ, et al. 2010. Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira. Nature 464: 95-98.

Nesbitt SJ, et al. 2013. The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania. Biology Letters 9: 3pp.

Category: Background, Paleontology, Zoology | Tagged fossils, species, species concepts | 5 Comments

Fossil Egg-cellence

By Shaena Montanari
Posted: March 26, 2013

I’m usually thinking about eggs. Not chocolate eggs (well, maybe this time of year), but fossil eggs. I am really interested in fossil eggs and what they tell us about behavior, but also the environments they were laid in. I have written before about stable isotopes, which can be used in egg and eggshell studies, but I will begin more generally about fossilized eggs and why so many paleontologists are keen to crack their mysteries (see what I did there?)

Reptile and bird eggs are composed in a similar basic fashion. The egg consists of yolk, surrounded by albumen, which is contained in an organic shell membrane all held in by a crystalline shell on the outside. The shell is made of calcite crystals in differing arrangements. I will mostly talk about rigid bird and dinosaur eggs because that is what fossilizes the best, but soft, leathery reptile eggs have been known to fossilize too (Hou et al. 2010). Bird eggshells (and fossilized non-avian dinosaur eggshells) are composed of columnar calcite crystals with an organic matrix of collagen fibers. The inner surface of the calcite shell has radiating cones (called mammillae) that are anchored at their tip to a thin organic membrane that encases the yolk and albumen.

General egg and eggshell microstructure diagram. (Photo credit: Shaena Montanari)

Eggshell pores are present along calcite crystal boundaries that provide a mechanism for gas exchange while the eggs are incubating. The sizes of these pores can help us understand paleoenvironments and behavior. For example, a 2008 study of fossil egg porosity by Jackson et al. indicates sauropods did not fully bury their eggs, which gives us a behavioral inference we never would have known before.

Fossilized bird and non-avian dinosaur eggs come in all shapes and sizes, from big round soccer ball-like sauropod eggs, to elongated ornamented oviraptorid eggs, to tiny fossil bird eggs that are like robin’s eggs. Most of the time you will find eggshell fragments in areas where fossilized eggs can be found, but if you are lucky you can find whole eggs, or even whole clutches. Most famously a specimen of Citipati osmoslkae was found brooding atop a nest of eggs in Ukhaa Tolgod, Mongolia, which helped us learn how dinosaur parents cared for their nests (Varricchio et al. 2008).

Nest with brooding Citipati at the American Museum of Natural History (Photo Credit: Wikipedia)

Since eggshells fossilize well and are made of calcite, they can be used for geochemical analyses and paleoenvironmental reconstruction in the same way fossilized tooth enamel can be. Fossil ratite bird eggshells have proved most useful for these sorts of analysis due to the fact they are robust and are present in the fossil record from at least the Neogene to present. Both δ18O and δ13C of extinct elephant bird Aepyornis indicate it ate primarily C3 vegetation in the Holocene landscape of Madagascar, and also had a δ18O less influenced by evaporation than modern ostriches (Clarke et al. 2006). This allows us to better understand potential environmental mechanisms that could have caused the extinction of this species.

Aepyornis egg, with skeleton for size comparison. Big egg! (Photo credit: Wikipedia)

Aepyornis egg, with skeleton for size comparison. Big egg for a big bird! (Photo credit: Wikipedia)

Carbon isotopic composition of Adélie penguin (Pygocelis adeliae) eggshells illustrated a recent shift to lower trophic level prey in the last 200 years when compared with the previous 38,000 years (Emslie and Patterson 2007). For a small plug of some of my own dissertation work, dinosaur eggshells from Late Cretaceous Gobi Desert localities indicate clear variation in the paleoenvironments within one region during the same time slice (Montanari et al. 2013). These are just a few examples of how geochemistry can be used to understand ancient environments in great detail using just fossilized eggshell as a proxy, and there are many more excellent studies in the literature.

This is just a small seasonal introduction on something near and dear to me, so I hope you’ve enjoyed it and decided to forgo the Cadbury mini eggs this season for a solid chocolate Citipati one (can someone make me one of those actually?)

References

Clarke, SJ, GH Miller, ML Fogel, AR Chivas, CV Murray-Wallace. 2006. The amino acid and stable isotope biogeochemistry of elephant bird (Aepyornis) eggshells from Southern Madagascar. Quaternary Science Reviews 25 (17-18): 2343-2356.

Emslie, SD, WP Patterson. 2007. Abrupt recent shift in δ13C and δ15N values in Adélie penguin eggshell in Antarctica. Proceedings of the National Academy of Sciences 104 (28): 11666.

Hou, LH, PP Li, DT Ksepka, KQ Gao, MA Norell. 2010. Implications of flexible-shelled eggs in a cretaceous choristoderan reptile. Proceedings of the Royal Society B: Biological Sciences 277 (1685): 1235-1239.

Jackson, FD, DJ Varricchio, RA Jackson, B Vila, LM Chiappe 2008. Comparison of water vapor conductance in a titanosaur egg from the Upper Cretaceous of Argentina and a Megaloolithus siruguei egg from Spain. Paleobiology, 34(2), 229-246.

Montanari, S, P Higgins, MA Norell 2013. Dinosaur eggshell and tooth enamel geochemistry as an indicator of Mongolian Late Cretaceous paleoenvironments. Palaeogeography, Palaeoclimatology, Palaeoecology. 370, 158-166.

Varricchio, DJ, Moore, JR, Erickson, GM, Norell, MA, Jackson, FD, Borkowski, JJ 2008. Avian paternal care had dinosaur origin. Science 322(5909), 1826-1828.

Category: Paleontology, Review | 3 Comments

Who’s to blame (or credit) for fast peer review?

By Andrew Farke
Posted: March 21, 2013

Peer reviewers, too, are an important part of unlocking the literature.

Lately around the blogosphere and Twitterverse, I’ve been seeing an increasing number of folks complimenting open access journals on their quick turnaround for peer review–or blaming open access journals for slow review. Fast turnaround is an excellent thing, no doubt, and slow turnaround is a bad thing. However, the implication of some of these statements is that open access publishers are doing things quicker (or more slowly) than non-open journals, simply by the virtue of being open access (or being PLOS or PeerJ or choose your favorite publisher). I’m not convinced of this, and here’s why.

Peer review is done by peers. Not by journals, not by content management systems, not by the paid editorial staff at the journals, not by the numerous volunteer editors. Based on my experiences as a volunteer editor at two different open access journals (full disclosure: PLOS ONE and PeerJ), author on papers submitted for numerous other journals, and conversations with colleagues, at least 80% of a speedy turnaround rests with the reviewers.

If a reviewer finishes his or her review in a timely fashion, you’re probably going to get your paper back in a timely fashion. If the reviewer drags his or her feet for six weeks, you’re going to have a slow time of it. Now, the journals and editors can help things along, by nagging tardy reviewers (I’m getting better at this with more experience). Journals can also set short but reasonable deadlines (perhaps 2 weeks rather than 4 weeks, for instance). But at the end of the day, it’s up to the reviewer to be on time.

Our implicit standard for what makes a “good” reviewer rests on their fairness, expertise, thoroughness, and timeliness. Timeliness in turn is dependent on a few other factors–personal schedules and manuscript length in particular. It’s not terribly reasonable to expect a reviewer to submit their review in 10 days if those days span Christmas and New Year’s. Neither would I expect a 10 day turn-around for a 150 page manuscript (some reviewers have surprised me, though!). On the other hand, if a reviewer accepts an invitation, they should be willing to do the work on deadline (or pretty darned close to it). It all comes down to the “Golden Rule.” I’m annoyed when my paper sits in reviewer limbo for three months; why should I subject someone else to these sorts of delays, if I can help it?

So, are open access journals any better or worse than non-open journals? This is an inherently testable claim (particularly when journals post relevant data), but for now I’m going to speculate. For one, I think it depends a lot on the paper itself (particularly length). For another, reviewers may be more excited about reviewing particular papers or for particular journals. Maybe some reviewers are quicker for open access journals. Note that in all cases the responsibility is largely with the reviewer! Journals can help this along, though, by selecting reviewers known to do a good job in minimal time, and avoiding reviewers who chronically delay things (note that we all have our slow times, though!). But, the reviewers rule in this system. Timeliness depends on them. Let’s not forget it.*

*Some might argue that this is a strike against pre-publication peer review. I’ll freely admit that slow reviewers are a problem, but I’m on record elsewhere in favor of pre-publication peer review, coupled with liberal use of preprint servers, is a good thing. I trust my own work more after it’s been reviewed, and hold others to the same standard.

Category: Open Access | Tagged open access, peer review | 12 Comments

Fishing Without a Fossil (Part 2)

By Andrew Farke
Posted: February 28, 2013

Our thrilling conclusion to a 70 million year old mystery in Madagascar. . .if you haven’t already, make sure to read Part 1 for more detailed information!

Lungfish are cool critters. . .they’re hardy fish that are well-adapted to harsh environments and have massive tooth plates that fossilize readily. We know from these abundant fossils that lungfish lived in Madagascar perhaps around 85 million years ago, but there’s no sign of any tooth plates or bones by 70 million years ago, even though the environment was seemingly perfect.

Let me correct that statement. . .there’s no sign of lungfish bones or teeth, but there are traces of lungfish. This highlights an important distinction from the last post–body fossils (such as bones) and trace fossils (tracks, burrows, and other leavings). Body fossils are great for precise identifications, but trace fossils often only allow the most general of identifications. It turns out, though, that lungfish are a merciful exception to this generality–their burrows are pretty darned distinct!

Setting the stage for all of this, joint expeditions in Madagascar with my alma mater Stony Brook University and the University of Antananarivo have uncovered a rich trove of fossils from the end of the Age of Dinosaurs. Paleontologists there have focused on abundant bones of dinosaurs, birds, crocodiles, frogs, and more. But, these body fossils are only part of the story. In order to reconstruct ancient Madagascar in the most thorough detail, geologists also had to get involved.

Enter Ray Rogers, head geologist for the Mahajanga Basin Project and professor at Macalaster College. Ray is a master scientist, perhaps best known in paleontological circles for his work interpreting how dinosaur bones accumulate in drought and other harsh conditions. He is the sort of person who can “read” the sandstones and mudstones housing fossils, assembling the subtle clues that flesh out a past environment. Ray is also a master educator. Some of my fondest memories in Madagascar are those days I have tagged along with Ray, soaking in his lessons on how fluids and sediments interact to produce intricate layers of rocks. His excitement is infectious (and it’s coupled with a ridiculous sense of humor…any work with Ray is guaranteed to be accompanied by good-natured ribbing)! As part of the educational process, Ray engages many undergraduate students from Macalaster in fieldwork. These students are more than just field assistants, but really are given the lead (and take the lead) in research.

Back in 2010, then-undergraduate Madeline Marshall (now a graduate student at University of Chicago) arrived in Madagascar with a mission: to figure out an odd outcrop of rocks that Ray and colleagues had noticed on a previous expedition. They had suspicions about the nature of these rocks, of course, but needed to do some careful documentation and sampling. If all went well, the project would form the core of Madeline’s senior thesis project.

Madeline Marshall and Ray Rogers, at the field station in Madagascar. In this photo, Madeline works diligently on updating field notes while Ray. . .doesn’t. Photo by A. Farke; CC-BY.

The rocks in question were within a big, lumpy outcrop of sandstone. At first glance, it wasn’t anything remarkable. . .just rocks that had been eroded in the subtropical elements. But, there were some interesting features. In particular, scores of circular and dumbbell-shaped markings dotted the surface. These were interesting to look at, but could they possibly just be odd weathering structures? The subtropical rains can do funny things to rocks, creating all sorts of surface patterns. Being good geologists, Madeline and Ray dug deeper. Thanks to fairly soft sandstone, they were able to quarry out a face of rock showing cross-sections through the surface markings (photo below). This showed, beyond a doubt, that they were genuine features, and not just weathering.

Green arrows mark odd structures in sandstones of the Maevarano Formation. Note in particular the one in the middle – you can follow it from the surface to a few feet below. The event that formed the structure cut across several layers of rock, deforming them in the process. The inset at lower left shows a close-up. Photo by A. Farke; CC-BY.

Madeline identified over 70 of these structures spread across 100 square meters of outcrop–so, they weren’t just a random fluke. Many things can deform soft sediments before they turn to rock (and even after). Dinosaur feet are one option, but the shape of the structures in question just weren’t right. Plant roots were also out of the question, because they leave distinctive branching patterns. Dewatering structures–produced when water is squished out of sand as it is compacted–also weren’t a great match. Based on the way the sandstone layers were curved and deformed, the best explanation was an animal burrow–a type of trace fossil. But what kind of animal?

Several possibilities existed, based on the overall size and shape of the burrows. Crayfish, lungfish, clams, and amphibians were all candidates. But, based on comparisons with modern and fossil burrows for all of these, the field was narrowed down. The burrows were too big for clams, and the wrong shape and size for crayfish or amphibians (and the margins of the burrows were too smooth for the latter two). Beyond process of elimination, pretty much every feature of the burrows and their encasing rock screamed “lungfish trace fossil”…the tubes that turned into dumbbell cross-sections, the size, the spacing, the occurrence in a harshly seasonal prehistoric environment. Lungfish were a logical fit all around.

A lungfish cozily curled up in its burrow (highlighted in blue), with selected cross-sections at right. CC-BY. Original illustration by A. Farke, patterned after a figure in Marshall and Rogers, 2012.

When times get tough, lungfish estivate. That is, they squirm down into the mud or sand, surround themselves with a nasty mesh of mucus (to slow drying out), and (more or less) go to sleep. The rivers or ponds that they lived in might dry up, but the lungfish happily snoozes until the waters return. Then, they wriggle back out of the burrows and return to doing whatever it is that lungfish do in their spare time. The process of squirming in and out of the sediment produces the distinctive trace fossil that is the signature of lungfish.

The burrows in Madagascar are cool for several reasons. Importantly, they’re the first evidence of lungfish from the latest Cretaceous of that island. This is a fantastic example where trace fossils provide information that isn’t preserved in the bony fossil record! Previously, we simply didn’t envision lungfish in the 70 million year old landscape of Madagascar. Now we can also predict, if there are burrows, that lungfish body fossils will be found at some point…maybe even in the bottom of a burrow. Worldwide, Mesozoic lungfish burrows are scarcely reported (most are from the older Paleozoic, prior to the age of dinosaurs). . .and never before from the southern continents. This is truly an important new occurrence. Finally, lungfish burrows are associated with harshly seasonal environments–this is one more piece of evidence, among many others, for how rough it was in northwestern Madagascar 70 million years ago.

To many people, a lungfish burrow may not be as riveting as a dinosaur skull or crocodile skeleton. But, these squirms and scratches capture the moments in time when a long-gone fish wriggled its way in and out of a drying landscape. Ironically, the supposedly more durable bones and teeth haven’t survived the test of time. Only the sands remain to tell the lungfish’s story.

Citation
Marshall, M. S., and R. R. Rogers. 2012. Lungfish burrows from the Upper Cretaceous Maevarano Formation, Mahajanga Basin, northwestern Madagascar. PALAIOS 27:857–866. DOI: 10.2110/palo.2012.p12-018r [paywalled, unfortunately]

Learn more. . .there’s a great video interview with Madeline at the Macalaster College website.

Category: Paleontology | Leave a comment

Why Paleontology Is Relevant

By Sarah Werning
Posted: February 19, 2013

In these times of budget cuts and belt-tightening, you might wonder why our government, universities, and museums should fund paleontological research. After all, there are bridges to repair, children to educate, and fires to put out. Few would disagree the latter problems all deserve our attention and our tax dollars. But what about paleontology?

When trimming budgetary fat, why isn’t paleontology something that falls clearly in the “non-essential” column? Is it even relevant to today’s world? Does it provide value to other scientific fields? Professional paleontologists understand why our field is relevant and can articulate that to an academic audience, but I don’t know how well we communicate its value to the public. These are the five “public-friendly” justifications I hear most often:

“Paleontologists teach anatomy at many medical schools.”
“Fossils play an important role in oil discovery.”
“Paleontology is a good ‘gateway drug’ to the other sciences.”
“Paleontology is a good way to teach critical thinking skills.”
“Paleontology is inherently interesting; it doesn’t need further justification.”

These responses are pretty abysmal, in my opinion. Yes, they’re all true, but I personally wouldn’t blame the government, university, or natural history museum who instantly defunded paleontological science based on any of them.

I didn't go to medical school to be called MISTER T, buddy.

I pity the fool who didn’t learn anatomy from a paleontologist.
Image accessed here.

I think there is a better way to articulate the importance of paleontology, one that focuses on its scientific necessity and directly links our field to today’s world:

Paleontology is the study of the history of life. Because that history is written in the fossil and geological record, paleontology allows us to place living organisms in both evolutionary (life-historical) and geological (earth-historical) context. It is this contextual background that allows us to interpret the significance of characteristics of living organisms, and the significance of biological events occurring today.

The benefits of having such context are not limited to:

Determining the evolutionary identity of living and past organisms
Determining cause-and-effect relationships (How do things actually change under x, y, z conditions? )
Gaining predictive power with regards to rare events that have been experienced in the past, and may be experienced again in the future
Understanding the relative magnitude of changes happening in today’s world

These are above and beyond any of the fringe benefits that paleontology also facilitates (“gateway science”, critical thinking skills, anatomy instructors, it’s inherently cool, etc.).

And tonight Mr. Kite is topping the bill

You *might* think my feathers originally evolved to enable flight, if all my non-flying dino-ancestors didn’t have them too.
Image (c) 2006 Thomas Kraft CC BY-SA 2.5; accessed on Wikipedia.

Now, I’m not arguing that you can’t figure out some of these things without paleontology. We use many lines of evidence in addition to the fossil record of anatomy to determine the evolutionary identity and relationships of organisms, including DNA and developmental sequences, which often aren’t preserved in fossils (but sometimes are!). You can infer the evolutionary history of some body parts or characteristics when you the understand relationships among organisms, and you can often test function of individual body parts directly. But in all these cases, your data are improved by observing the direct record of change through time that only the fossil record provides.

The fossil record is the only source of natural (as opposed to experimental or theoretical) examples of what happens to living organisms under conditions the Earth is not experiencing today. For example, let’s say you want to know what happens to animals when the Earth gets much hotter – maybe five or seven degrees warmer than today’s average annual temperature. The last time this happened was during the Miocene (~14.8 million years ago), but it’s been that hot several times in Earth’s history. The fossil record shows that temperature increases have similar effects every time they happen. For example, warm-adapted animals expand their range north- and southward from tropical regions, so animals like crocodylians and monitor lizards live happily in places like Canada and Europe (Böhme 2003). Ectotherms get much, much bigger (think 42-foot snakes; Head et al. 2009).

Because these changes happen when temperatures go up and the reverse happens when temps go down, we can infer a cause-and-effect relationship between global temperature and various aspects of animal biology based on actual evidence. It happened before. It will happen again, if conditions are right. This is why paleontology is critical for predicting the effects of climate change at several scales.

An expat from the Miocene.
Image accessed here.

In cases where you want to understand the magnitude of current change, the fossil record is again your only source of context. For example, many vertebrate species have gone extinct in the last 500 years. Some of these extinctions resulted from habitat loss (e.g., the dodo) or overhunting (the dodo and the moa), some indirectly from climate change, and some from disease (chytrid fungus in amphibians, or white-nose fungus in bats). Many, many more species are threatened with extinction (“critically endangered” means they’re not likely to last long, folks). If all of these species do go extinct in the next century, how bad would that be? Are we experiencing normal levels of extinction, or are we experiencing a mass extinction? The answer requires knowing what the normal rates are, and how mass extinctions are different. That understanding can only come from the fossil record.

To answer the above question, in 2011, Anthony Barnosky and colleagues published a study in Nature that compared the modern rates of extinction to those during the “Big Five” mass extinctions (times where 75% of the world’s species went extinct in a short amount of time). They determined that if only the species we consider critically-endangered go extinct over the next 100 years, at that rate would mean it would take 890-2270 years to reach 75% extinction (mass extinction levels). If, however, all the species we consider “threatened” also go extinct, we’ll hit that point within 540 years. Both of these are blinks of an eye in geological terms (faster than the end-Cretaceous extinction that wiped out the non-bird dinosaurs), but over two hundred years or two millenia we might be able to reverse some of these trends. They also showed the duration required to get to 75% is longer than the duration of some (though not all) of the “Big Five” extinctions. Some good news: we’re not experiencing mass-extinction level rates right now.

Extinction rates for different types of animals. White numbers: % of species in each group that went extinct in the last 500 years. Black numbers: % of threatened species, plus those that have gone extinct in the wild. Asterisks indicate groups with data for only a few species.
Image from: Barnosky et al. (2011), Nature.

I think if we were asked why studying American history or world history is important, we could make all of these same arguments and come up with a similar list of benefits. In fact, The American Historical Association did just that. This parallel between the relevance of life’s history and the relevance of our cultural history is a good one. When paleontology is reduced to cataloging the weird things that once were, it instantly becomes as irrelevant to our own time as cultural or political history would be, if it were reduced to a list of things that once happened.

References:

Barnosky AD, et al. 2011. Nature 471: 51-57.

Böhme M. 2003. Palaeogeography, Palaeoclimatology, Palaeoecology 195: 389-401.

Head JJ, et al. 2009. Nature 457: 715-717.

Category: Background, Miscellaneous, Paleontology, Zoology | Tagged climate change, Paleontology | 14 Comments