|'Giant Kangaroos & Wombats' by Charles R. Knight|
Field Museum of Natural History
03 July 2014
15 June 2014
Courtesy International Panorama Council
- Historically interesting - The Laysan Cyclorama really got its start in 1902, when UIMNH director Charles Nutting visited the island. He was enchanted by the nesting birds he saw there and in 1911 he sent taxidermist Homer Dill on an expedition to Laysan (an expedition that was, delightfully, funded in part by proceeds from a skit put on by the football team). When the specimens collected in 1911 were put on display three years later, the cyclorama became the first exhibit in the museum to depict an entire ecosystem. This may not sound terribly remarkable, but given that Carl Akeley had only just introduced the concept of creating dioramas that represented ecological snapshots rather than simply displaying individual animals in glass cases, the Laysan Cyclorama was, in fact, part of the leading edge of a major change in the way natural history exhibits were designed.
- Scientifically important - When the UIMNH expedition visited Laysan in 1911, it was already a dying ecosystem. The introduction of rabbits to the island in 1903 wreaked havoc on the native plant, insect, and bird life. Most severely affected were the endemic species that had depended on the vegetation that was decimated by the rabbits. Three species - the Laysan rail, millerbird, and honeycreeper - went extinct and two - the Laysan finch and duck - survived but remain endangered to the present day. Specimens of these species on display in the cyclorama and preserved in the collections of the UIMNH and a handful of other museums are the last remaining evidence of the extinct birds and a source of valuable information about the surviving taxa.
- Educationally effective - The gorgeous, narrow, wood-panelled passageway that leads into the cyclorama leaves little doubt as to the vintage of the exhibit, but the display was ahead of its time in its efforts to teach visitors about the effects of human activity on island ecosystems. Perhaps the most remarkable thing about about the Laysan Cyclorama is that age has made it an even more valuable educational tool. Over the course of the intervening century, the last remaining rabbits have been extirpated from Laysan, some native species have begun to recover, and the island has become a natural laboratory for studying the ecology of island ecosystems. Instead of a window into a lost world, then, the cyclorama represents a look at the beginning of an ecological epic that continues to unfold today. The modern signage in the exhibit does a nice job showing how this story has developed since 1914 and very effectively demonstrates that ecosystems are not static and that time is an important variable in biology (a lesson near and dear to my heart as a paleontologist).
- Aesthetically pleasing - A trend in modern biodiversity exhibits is to develop large, walk-through environments rather than classic "window on the world" dioramas (and lest you all think I'm being characteristically curmudgeonly, I think this is generally a trend for the better). The cyclorama format of the Laysan exhibit anticipates the immersive exhibits of today, but it also retains the artistry and almost obsessive attention to detail that characterize the great dioramas of the early 20th Century. Dill didn't just bring back bird specimens from his expedition: he brought back sand from Laysan's beaches and rocks, which would literally form the groundwork of the exhibit. The authenticity of the cyclorama is augmented by the background mural by Charles Corwin, who was not only a talented painter but also a member of the 1911 expedition. The end product is not only very authentic, but extremely detailed (if you ever have a chance to visit, see if you can pick out the nesting sea turtle) and beautiful to look at. The intent of the exhibit was to make visitors to feel as though they'd been transported to Laysan, and the fact that it conveys that feeling even today is a testament to how well the designers succeeded.
- Unique - Other museums have dioramas depicting Pacific island rookeries (the Denver Museum of Nature & Science has a particularly impressive example), but both the cyclorama format and Laysan setting of the UIMNH exhibit make it unique. Many natural history exhibits are repeated between museums, the best example being the "African watering hole" diorama pioneered by the aforementioned Carl Akeley in Chicago and New York and then repeated ad nauseum by museums across the globe; each iteration is impressive, but the sheer number of them makes each less remarkable than it would otherwise be. The uniqueness of the Laysan Cyclorama makes it truly stand out. Not only is the exhibit groundbreaking, important, and educational, but it's something that can only be seen in Iowa, and if you're ever in the area you should do yourself a favor and pay it a visit.
As mentioned above, everyone with an opinion on such things probably has a slightly different idea of what constitutes a great natural history exhibit, and I welcome peoples' comments on favorite displays and criteria for evaluating them. However, regardless of how you judge exhibits, it's hard to imagine that anyone would find the Laysan Cyclorama to be anything less than remarkable. So, join me in wishing a Happy 100th Birthday to an exhibit that was ahead of its time, that has told generations of Iowans an important ecological parable, and that looks as good today as it did a century ago!
08 May 2014
By Mauricio Antón
04 May 2014
It's May 5th, or, if you prefer to use Spanish, el Cinco de Mayo, which means it's time for perhaps the stupidest of all "holidays" (Mexico has a cultural and historical legacy that we in the US can only dream of and yet, generally speaking, the only time we celebrate our neighbor to the south is by getting drunk on cheap margaritas, bad tequila, or Corona on what is not even a major holiday in the country the day allegedly honors). That said, there are many aspects of Mexico that deserve to be celebrated: the dazzling scientific achievements of the Maya, the monumental architecture and sculpture of the Aztecs, the stunning Baroque design of Spanish colonial buildings, and the powerful modernist art of Diego Rivera, Frida Kahlo, and their contemporaries all spring to mind. However, Mexico has a heritage that predates its oldest archaeological artifacts. I can hardly do justice to the entire Mexican fossil record in one off-the-cuff blog post, but here are some highlights of the country's 200+ million year history of vertebrates :
The oldest vertebrate fossil in Mexico (or at least the oldest that I could find in the Paleobiology Database) is a specimen of the whorl-toothed "shark" Helicoprion. Not only is the age of the specimen noteworthy, but the location from which it was recovered, in the central Mexican state of Puebla, is as far south as this most bizarre of chondrichthyans has ever been found, making it geographically superlative as well.
Puebla is also home to the most spectacularly-preserved fossils in all of Mexico. Tlayúa Quarry near Tepexi de Rodríguez represents a Cretaceous reef and preserves a primarily marine fauna, though a few terrestrial vertebrates have been found there as well. Tlayúa has drawn comparisons to Solnhofen, which is very high praise. While visiting the collections at the Universidad Nacional Autónoma de México a few years ago, I was fortunate enough to be able to be able to view some of the specimens from this site, and I can vouch for the fact that they are nothing short of spectacular. The bulk of the vertebrate fossils from the site are fish, but several reptiles have been uncovered as well. UNAM has a long-standing research program at the site and has established a museum there as well, making this one of the best-studied localities in the country. The icing on the cake of this spectacular site is that many of the new genera and species from Tlayúa have been named in Nahuatl, giving them marvelous names to match their marvelous preservation; my personal favorite is the early iguana relative Huehuecuetzpalli mixtecus.
The best place to find dinosaurs in Mexico is the north, particularly in Baja California and Coahuila. This dinosaur fauna dates to the latest Cretaceous and is dominated by hadrosaurs, some of which grew extremely large. Incidentally, if this post gets you really excited about Mexican fossils but you lack a passport or the money or time to fly south of the border, you can always check out the Fossil Mysteries exhibit at the San Diego Natural History Museum, the Cretaceous section of which focuses on fossils from the Two Californias (Alta and Baja) and features an excellent mural of Mexican dinosaurs by William Stout.
Volcaniclastic sediments throughout Mexico preserve a Miocene fauna of which the most impressive and abundant members are horses. When I travelled to UNAM, it was these fossils that I was visiting, as they were part of my dissertation research on body size evolution in mammals. Interestingly, and counter to any predictions that one would make based on modern mammals, horses in central Mexico and Oaxaca were much more similar in size to those from Oregon than to those from California or Nevada (an observation for which I have - as yet - no good explanation, though it is intriguing that both landscapes are highly volcanic). However, my work is just a small, fairly inconsequential drop in the bucket of Miocene mammal studies in Mexico; the one person who has done more to fill the bucket than anyone else is Ismael Ferrusquía-Villafranca, whose lab is responsible for much, if not most, of what we know about the Mexican Neogene (who, besides being a hugely important figure in the field, also happens to be a really nice guy to whom I am still exceedingly grateful for allowing me to work with the collections he has helped amass).
When the Isthmus of Panama closed, Mexico became part of the land bridge connecting North and South America. Much of the wildlife that migrated north colonized Mexico before the rest of the continent, meaning that South American migrants such as sloths and glyptodonts are well-represented in the Mexican Pleistocene, as are native taxa such as mammoths and saber-toothed cats. This Panamerican fauna forms the bulk of the displays in the UNAM's fantastic Museo de Geología, as magnificent an example of a classic academic museum as you will find anywhere (also the home of most of the important works of José María Velasco, who really should be one of your favorite old-school paleoartists). Mexico's Pleistocene fossil record also overlaps with the country's incomparable archaeological record. To cite just two examples, a mammoth skeleton from Santa Isabel Iztapan shows evidence of butchery by humans, while a camel sacrum from Tequixquiac carved to resemble the head of a wolf or coyote represents one of the earliest works of art in Mesoamerica.
|Helicoprion by Ray Troll|
|Huehuecuetzpalli mixtecus from Reynoso 1998|
|Baja California in the Cretaceous, by William Stout|
|Mexican fossil horses, UNAM Museo de Geología|
|Mexican megafauna mural by Iker Larrauri|
Museo Nacional de Antropología
01 May 2014
|Smilodon Mosaic in the Nebraska State Capitol|
- Nebraska professor Jason Head spoke about a subject very near and dear to my heart: how the fossil record can inform models of future ecological change. Ecological niche models take the climatic conditions in which an organism lives today and use these to predict where the range of that animal might shift as climate warms in the future. However, many studies have shown that these models generally fail (sometimes spectacularly) to predict ranges of species during periods of past climate change. Jason Head's study was interesting because he used fossil occurrence data and paleoclimatic reconstructions for boid snakes to augment ecological niche models, and found that the models that included paleoecological data predicted somewhat wider ranges for rubber and rosy boas in the future than did models based purely on modern data.
- Did you know sloths have an especially high rate of dental anomalies (i.e., they frequently have either fewer or extra teeth)? I didn't until I saw Robert McAfee's talk last week. What's more, not only do living tree sloths often have abnormal numbers of teeth, but so did extinct ground sloths. In fact, McAfee suggested that rates of caniniform tooth loss in Paramylodon from Rancho La Brea were so high that the population may represent the beginning of a speciation event that was nipped in the bud by the Pleistocene megafaunal extinction.
- Joseph Peterson spoke about dinosaur paleopathology, and in particular on the use of 3D reconstructions of a hadrosaur vertebra with tooth marks on it (as well as theropod jaws) to determine the identity of the animal that bit the vertebra. Turns out it was most likely a juvenile Tyrannosaurus.
- My old officemate Jonathan Calede spoke about his dissertation work in the Cabbage Patch Beds of Montana. The Cabbage Patch Fauna (named after a bar, not the creepy dolls, to paraphrase Jonathan) has been uncovered from several sites, which Jonathan found to be broadly similar in terms of geology and quality of preservation, suggesting that any trends observed between these sites represent genuine ecological patterns rather than taphonomic bias.
- Nebraska's Shane Tucker discussed one of the coolest fossil sites of which I've ever heard: the Happy Jack Mine in the central part of the state. The tunnels of the mine intersect infilled rodent burrows from the Miocene, allowing the 3D structures of these burrows to be observed. On balance, the burrows most closely match those of ground squirrels, though gophers may have been responsible for some. Shane and George Corner also presented talks about Miocene faunas from elsewhere in the state, underscoring the absurd richness of the Nebraska fossil record.
- Ross Secord and his student Tom Baldvins both spoke about isotopic records across two important intervals of climate change: the Paleocene-Eocene Thermal Maximum and the glacial-interglacial cycles of the Pleistocene, respectively. I was particularly interested in Baldvins' talk, which showed that C4 grasses were more abundant in the northern Great Plains during interglacial periods. More intriguingly (to me, at least) his analysis of horse body size from the same sites showed a positive correlation with temperature (i.e., horses were larger in warmer climates). Always nice to see another study that shoots holes in Bergmann's Rule, though I'd be curious to see if the trend would persist with a larger sample size and using tooth-based estimates of body size.
- An entire session was devoted to the White River Group and its fossils, which was not only interesting in and of itself, but gave some great ideas for the design of the Sedimentology & Stratigraphy class I'll be teaching next year. Particularly intriguing to me was Kurt Spearing's talk on the first evidence of inner ear bones in nimravids. Ear morphology is hugely important in carnivore phylogeny, and I have high hopes that more nimravid ear ossicles will turn up in the coming years, which could potentially help determine where in the feliform tree these enigmatic animals belong.
- I also spoke at the conference (on the humerus morphology of felids and whether or not it can be used to identify the huge cat that was present in the Late Miocene of western North America), but perhaps more importantly, for the first time I had a student presenting. Laurel Perper discussed some of the early findings of our project comparing the morphology of the bizarre South American marsupial sabertooth Thylacosmilus, the subject of this month's upcoming Fossil Vertebrate of the Month feature.
|Carnivore reconstructions by Mark Marcuson|
08 April 2014
I'll be heading to the Southern Hemisphere twice this (northern) summer, in honor of which my Fossil Vertebrates of the Month between now and August will all be from Gondwana, the former southern continent of which Australia, South America, Antarctica, Africa, India, Madagascar, and New Zealand are the primary remnants. I was going to start this series in May, but this recent publication inspired me to start this month.
The traditional story of vertebrate life on land in the Mesozoic is a relatively simple one, particularly in regards to mammals (small and shrew- or rat-like according to this view), dinosaurs (diverse and dominant), and crocodilians (aquatic ambush predators, then as now). The beauty of nature, of course, is that it is seldom simple, and one of the more exciting accomplishments of paleontology in recent decades has been the elucidation of the glorious complexity of ecosystems from the woefully misnamed "Age of Dinosaurs." Several mammalian paleobiologists, spearheaded by Zhe-Xi Luo, have shown that mammals were much more diverse than had previously been thought (some of them even preying upon dinosaurs). Even crocodiles, long used as the exemplar of a group that found its niche early on and succeeded by staying there, were not all swamp lurkers in the Mesozoic. In fact, one group of Cretaceous crocodilians on the southern continents evolved to inhabit ecological roles generally associated with mammals today. Known as notosuchians (literally 'southern crocodiles'), their most remarkable features can be found in and around the jaws. Much has been made of the complex teeth of mammals and how this allowed them to diversify to take advantage of a wide variety of diets, but notosuchians show that our own class does not have a monopoly on such adaptations. Unlike most reptiles, many notosuchians had heterodont dentition, as do mammals, and the wide ranges of niches into which the group evolved led to some of the strangest animals that have ever lived. Some members of the group were likely predatory, making them at least superficially similar to living crocodilians, but other members of the group have been interpreted as omnivores or even herbivores. Malawisuchus likely processed food through a forward-backward motion of the jaw, Anatosuchus had a duckbill, Yacarerani had huge, procumbent incisors, and the eponymous Notosuchus may have had cheeks and a pig-like snout. Not all bizarre adaptations among notosuchians were related to eating: as its name suggests, Armadillosuchus evolved interlocking, flexible armor that anticipated that evolved by armadillos millions of years later.
|Pakasuchus, among the most mammal-like notosuchians.|
03 March 2014
|Sharks jaws (C. megalodon at right)|
Florida Museum of Natural History