Wednesday, April 15, 2015

Paleofest 2015 report

For the first time in my life, I was able to attend Paleofest on the weekend of March 14. Paleofest is an annual celebration and gathering of paleontology fans and experts at the Burpee Museum in Rockford, Illinois. Paleontologists gather from all over the world to give talks, while children engage in interactive, educational play with museum docents and visiting scientists. I had been aware of this event for three years and especially wanted to go to last year’s event on the Cenozoic. This year it was all about the Triassic, a period of reptile diversity and evolution, and the emergence of the first mammals and dinosaurs as the ecosystems of the world revived from the Permian extinction.

The talks took place downstairs, in the main classroom of the museum below all the other exhibits. There was a substantial crowd, and I wasn’t the only representative from the Field Museum’s volunteers to attend. Only visitors wearing the event badges were allowed in, and I paid $85 for the full weekend.  The talks were attended by people of all ages, and both genders were well-represented. It was genuinely inspiring to see how diverse the appeal of paleontology is.

The first talk was by Antoine Bercovici, currently of the Smithsonian Institution in Washington DC. He talked about his specialty, plant diversity and evolution, and the transition between the Permian and the Triassic 251 million years ago. I learned that there is no clear boundary in the rock in many cases, unlike other era transitions. Only in specific formations like the Karoo of South Africa is the transition recorded geology. The extinction hit mostly spore-bearing plants like ferns and horsetails, but they bounced back, albeit with more competition from the opportunistic seed-bearing plants. The Triassic was drier than previous periods, but still wet and very warm, averaging about 104 degrees farenheit in the equator according to mineral chemistry.  The world was split into vast interior deserts and coastal wetlands. This talk was not particularly interesting due to the plant focus, but very informative and did well in setting the stage.

The second talk was by Nicholas Fraser, currently of the National Museum of Scotland in Edinburgh. His talk was very insightful-connecting reptile and mammal evolution to insect evolution. After the Permian extinction, many modern insect orders evolved-cockroaches became more sophisticated, dragonflies replaced griffonflies as the aerial predators, flies and bugs appeared and quickly became successful, beetles diversified into huge suborders, scorpion flies, sawflies, mothflies, mosquitoes and other modern freshwater lineages began their ascent.  All these insects, he convincingly argued, promoted reptile and synapsid evolution. The first dinosaurlike reptiles, flying pterosaurs, and mammals were all insectivores, and their unique adaptations first evolved to prey on these sophisticated, abundant flying insects. This revelation is a brilliant one, and perfectly logical in my mind.

Next up was Susan Evans of University College, London. She’s a specialist in lissamphibians (basically surviving amphibians today) and lepidosaurs (represented today by lizards and snakes), both lineages that are rare in the fossil record but especially rare in the Triassic.  So far the only fossil frog of the Triassic was Triadobatrachus from Madagascar. However, in 1998, Evans, her counterpart Magdalena Borsuk-Białynicka and a team of students and teachers from the Jagiellonian university, Krakow tried their luck at an old fossil site from where very little was previously found. Their hunch paid off-they found a cave at the Czatkowice limestone quarry that contained small but significant fossils.  On their first trip they found what Evans was looking for-the earliest fossil frog: Czatkobatrachus! Evans and her Polish comrades found more species over the past 17 years-Sophineta, the earliest lizard and possible ancestor of all lizards, the earliest gliding reptile Pamelina, a slender, long necked reptile Czatkowiella, and Osmolskina, a small, agile basal archosaur.  The environment was a pond, a desert oasis with a self-contained ecosystem of amphibians and reptiles.  My family comes from a village less than 90 miles from the site, so these new species are especially fascinating.

The next talk was less interesting, unfortunately. Andrew Heckert of Appalachian State University in North Carolina talked about the microfossils so often ignored by other scientists. He made an almost-convincing case-they’re certainly important and should be studied as well as possible. He showcased bizarre tooth taxa (animals from which only teeth have been found) like Colognathus, Crosbysaurus and Uatchitodon. His emphasis was on the teeth establishing different fauna on each side of North America, even greater differences between each side of the equator, and the unfortunate lack of Gondwanan microfossils. The problem is that microfossils don’t preserve very well, and that teeth tell more about ecology than phyoogeny, so that many tooth taxa are still mysterious. He did a good job establishing the strengths and weaknesses of microfossils -"Triassic archosaurian ghosts require busting".

The next talk was my least favorite-Paul Olsen just seemed too vehement and insistent on very specific scenarios, with little room for ambiguity. On the plus side, he explained the most likely cause of the Triassic-Jurassic extinction as volcanic activity from the Central Atlantic Magmatic Province, a geological region that expanded, split Pangaea, and created the Atlantic Ocean.  The volcanism, supported by CO2 deposits in the period, would have created alternating baking heat and freezing cold. Another good point was that observation that prosauropods, the most successful animals during the extinction, lived in colder, drier climates. Finally, there was the point that dinosaurs and other reptiles excreted uric acid in semi-solid state rather than water-consuming urine of amphibians and synapsids (including today’s mammals).  However, he made many mistakes in my opinion-first was the assertion that the cold spells were deadlier than the heat. He insisted that the French Revolution was the result of the Laki Eruption of 1783, despite the same horrible winters of 1779 and 1772, as well as many more throughout the Little Ice Age of the 14th to 19th centuries.  He insisted that feathers or featherlike integument are basal to dinosaurs, despite dinosaur skin showing that while many dinosaurs did have quills, feathers, and fuzz, others, including his prosauropods, had scaly skin.  All in all, it was frustrating and unconvincing.

Much better was the talk by Ryosuke Motani of the University of California at Davis. He talks about the marine reptiles that first emerged in the Triassic, and created new ecological roles that still exist today. The Triassic reptile radiation included many marine and amphibious forms: seal-like eosauropterygians and thalattosaurs, shell-eating placodonts, fully aquatic icthyosaurs, the bizarre hupesuchians and protorosaurs.  Adapting to the water means evolving to breathe, see, hear, smell, and move differently, not to mention finding a way to keep a constant body temperature. The Triassic was very warm, promoting reptiles to invade the sea.  Motani went on to talk about the main ecological roles of marine tetrapopds today and their prehistoric equivalents. First was top predators-instead of orcas, there were big icthyosaurs like Thalattoarchon. Second was the “whale pump”, or animals releasing carbon and nitrogen, at the surface of the ocean, as fish do not need to surface to breath out or excrete waste.  He went on to describe various Chinese marine animals he studied with Dayong Jiang, Hailu You, Cheng Ji, Xiao-hong Chen, -they found specimens of the primitive icthyosaur Chaohusaurus at Lake Chao, Hupesuchus at Mt. Hubei, the giant ichthyosaur Guanlingsaurus from Guanling and Qianicthyosaurus from Nimaigu. All in all, a great talk.

Another great talk was Robin Whatley from Columbia College in Chicago. She talked about the strange but sophisticated herbivores, Rhynchosaurs. Like their synapsids counterparts, the dicynodonts, they evolved beaks. However, unlike the dicynodonts, they kept their teeth to grind down the chopped foliage.. While the trilophosaurs, silesaurs, and prosauropods probably used gastroliths to process food, the rhynchosaurs joined the tritylodont cynodonts and the dicynodonts in crushing and grinding plants in their mouths.  What appears to have happened was that with dicynodont numbers hit hard by the Permian extinction, the rhychosaurs exploited the vaccum and took over the low-level browsing niche.  Whately, David Hone and Mike Benton have written a lot of interesting material on them. I hope to write about these stranger herbivores soon in the future.

Another Triassic herbivore group is more familiar, and the subject covered by Tyler Lyson, currently of the Denver Museum-turtles. His study was on turtle evolution, especially the shell. By the end of the Triassic, recognizably turtle-like turtles like Chinlechelys and Proganochelys appear in the fossil record. What’s more difficult is their evolution. The weird thing about turtles is that their shoulder girdles are within the rib cage, and that their shells seem to be made of both scute and rib.  The mystery was partially solved by the recent find of Odontochelys,  which had teeth and no osteoderms (bone plates) but did have a full plastron (underpart of the shell).  Odontochelys settled a debate-did the shell form from the ribs and backbones of a turtle, or from osteoderms? With the lack of osteoderms but wide, thick ribs, Odontochelys demonstrated that the ribs evolved first.  What Lyson did was find the ancestor of Odontochelys-he settled on a squat Permian reptile with wide thick ribs, Eunotosaurus. Eunotosaurus fits the bill as the ancestor of turtles.

Michelle Stocker of Virginia Tech talked about Phytosaurs, archosaurs that were crocodiles while crocodiles were still small and terrestrial.  Her talk was about Rutiodon, a species I will feature eventually. Rutiodon, due to being found in North Carolina, is the most famous phytosaurs and used as a wastebasket taxon. Wastebasket taxa are names that are used for many, many different animals. For example, for decades Megalosaurus, the first theropod named, was used for every large theropod discovered, eventually creating a genus that ranged from the early Jurassic to the late Cretaceous!  In this case, phytosaur remains are referred to Rutiodon despite slight morphological and huge geographic differences.  Other phytosaurs like Paleorhinus and Belodon may also be made of different genera, as well. Suffice to say, phytosaurs are fascinating in how they presaged crocodiles in so many ways.

Speaking of crocodiles, the next talk was James Clark’s on crocodile jaw evolution. Simply put, crocodile jaws evolved to not only empower the jaw’s abductor muscles but strengthen the bones to comfortably absorb massive forces. Crocodiles have a stronger bite than any other animal today –a saltwater crocodile’s bite force was measured to be 3,700 pounds per square inch.  How did it all get started? Clark first looks to the Welsh fissures, where the early crocodile Terrestrisuchus was found. It’s a lithe, weedy animal with long legs, typical of the early crocodile group called the Spenosuchians. Meanwhile, the Nugget Sandstone of Utah has produced another, new crocodilian, but it’s still scanty and quite tiny. In Glen Canyon’s Kayenta formation, Kayentasuchus is promising, but the specimen was damaged during transport. Better preserved is Junngarsuchus from the Middle Jurassic of China, with a fixed quadrate bone, and the more modern Almadasuchus from Late Jurassic Patagonia. The famous Morrison formation has both the primitive Fruitachampsa (affinity still debated) and the very advanced Amphicotylus. These, however, are still late and divergent from the modern crocodile line-there’s already a split after the Triassic extinction-Kayentasuchus was probable prey for the more derived Calsoyasuchus. Instead, the Protosuchians seem to hold the key-Protosuchus lived just before Calsoyasuchus and may have been an ancestor. The earliest species so far, Hemiprotosuchus of the Los Colorados formation, is poorly preserved.  It seems that Protosuchus seems to hold the key, but more specimens are needed to establish a clear line.

From Museo Friulano di Storia Naturale came the next paper and guest, Fabio Dalla Vecchia. His talk was on known Triassic pterosaurs-a diverse but mysterious group in terms of evolutionary relationships. The vast majority of Triassic pterosaurs are found in the Eastern Alps, specifically around the Carnic alps on the Austro-Italian border. Dalla Vecchia explains this is because the region was a gulf in the past, similar to today’s Adriatic Sea, although he compared its clime to the Persian gulf.  Like the other scientists, he lamented the lack of material. The existing fossils are fascinating, though; they indicate that pterosaurs evolved very quickly in the middle Triassic and quickly diversified into multiple predatory niches. The small pterosaurs; Caviruma, Eudimorphodon, Peteinosaurus, Austriadactylus, Preonodactylus, are not as spectacular as their Cretaceous successors, but still quite intriguing in terms of pterosaur evolution.

Christian Sidor of the Burke museum finished the first day with a talk on paleoecology, a favorite subject of mine. He used Facebook and other social networks as an analogy-a site or ecosystem is like a group of friends, with each friend having their own networks and connections.  Some people, or rather species, are part of many groups and have many friends, while others share very few friends in general.  Some reptile families are unique to a region, and others are widespread. Biogeography, another favorite subject of mine, is the key concept of the lecture; different organisms have different ranges, due to evolution, environment, or both.  He took a survey of known fossil ecosystems across the Permian and Triassic borders, and found an interesting pattern. In the Late Permian, there’s a lot more common species and families between sites; it was very cosmopolitan.  In the early and Middle Triassic, however, there’s a lot of endemic species and families, with some groups only represented in one or two areas. The paleontological refrain is repeated: we need more evidence! In any case, this is my favorite lecture of the day.

The first talk of the second day was Matthrew Bonnan of Stockton University on posture and locomotion-what advantages do erect limbs confer?  In both cases of dinosaurs and mammals, the hindlimbs are erect first, and for a long time the back limbs are still sprawled. Using footage taken of lizards and rats pacing on a treadmill (the footage itself failed to load on the projector during the presentation, unfortunately). Bonnan came to the conclusion that the splaying stance grants stability, especially when static, while erect stance grants dynamic stability, pushing the center of mass higher to handle maneuvers better. So while a car is much more stable at lower speeds, a motorcycle can make far sharper turns at high speed. This indicates that the animals evolved with erect posture were moving faster as a rule. Back to the front limbs, Bonnan also noticed that while the radius and ulna of moving mammals cross, they are locked in place for reptiles, indicating that they were moving very different while in the same posture. Unfortunately, he was in the middle of figuring how a dinosaur would move before Paleofest, so there is still much work to be done. I can’t wait to learn what he finds out!

The main guest of honor for this Paleofest was vertebrate paleontologist Hans Sues of the Smithsonian Institution. For his talk, Sues talked about the Erfurt formation of the Lower Keuper beds.  In addition to a wide variety of strange reptiles, the area had two top predators. One was the giant predator amphibian Mastodonsaurus, the other was the armored archosaur Batrachotomus. Remember my post on Teratosaurus? Batrachotomus is possibly an ancestor. The archosaur ruled the land and the amphibian metoposaur ruled the water. Most fascinating was the presence of bite marks on specimens of both genera-Batrachotomus marks on Mastodonsaurus bones, and Mastodonsaurus marks on Batrachotomus bones! This doesn’t prove they were killing each other, but they were certainly eating each other!  Dramatic epic battles between these big (each was about 10-15 feet long) predators would make for great documentary setpieces or striking paleoart, and I hope to find some in the future.

Adam Pritchard of Stony Brook University gave a more generalized talk about the strange diapsid reptiles of the Triassic. He first highlighted several bizarre groups-the long necked Tanystropheids and other small-headed protorosaurs, the arboreal, claw-tailed Drepanosaurs, and the enigmatic Longisquama, a long-scaled reptile that could have flown or glided. He placed them at the base of the split between the lizards and tuataras and their kin (Lepidosauromorphs) and the dinosaurs, birds, crocodiles and their kin (Archosauromorphs). He suggested that this diapsid diversity was already beginning in the late Permian and was only accelerated by the Permian extinction rather than these reptiles being part of a huge radiation occurring just after the extinction.

The famous Paul Sereno of the University of Chicago gave the next talk, which was not about organisms themselves, although he helpfully gave a recapsulation of his Triassic discoveries in Argentina in the 1990s. His point, however, was on methodology. Today’s study of evolution and classification relies on cladistics, using morphological differences to separate groups into nodes and branches. The problem, Sereno points out, is that there’s no standardization for what constitutes a defining characteristic. Different scientists have different qualifications for classification, and don’t consult each other on their decisions. Sereno’s talk was not a lecture, but an argument and call to action for paleontologists and biologists to share notes, compare classification schemes, and standardize phylogeny.

The next talk was back to the Archosaurs, as Richard Butler of Birmingham University encapsulated Archosauromorph evolution on a grand scale. The emphasis was on the radiation of Archosauromorphs, which he identifies happened in three different times. The first growth of archosauromorphs was in the Permian, alongside the great Synapsid empire. Animals like Eorasaurus, Protorosaurus and Archosaurus were the start of the Triassic lineages, animals that survived the Permian extinction to diversify further in the Triassic. The second radiation was during the early Triassic-Archosaurus began a short-lived but successful group called the Proterosuchids. Noteosuchus started the herbivores family of Rhynchosaurs, the Proterosaurs burst, and Archosauromorphs began to take roles previously exclusive to the synapsids.  Finally, the Middle Triassic saw the Rhynchosaurs and Protorosaurs expand into dominant groups, the Erythrosuchids and their successors the Rauisuchids take over as top predators, and Euparkeria and its kin began the lineage of true Archosaurs. Butler demonstrated that like most other groups, Archosaurs went through several boom-bust cycles starting from the late Permian and continuing even today in terms of bird and crocodilian groups.

One of the scientists I’d hope would present would be Ken Angielczyk from the Field Museum, a scientist I once met who has participated in several expeditions to Tanzania. Luckily, his research partner Sterling Nesbitt of Virginia Tech covered the Manda beds that they had prospected over the past years. He covered the Manda and the North American equivalent, the Moenkopi formation. The Moenkopi has temnospondyl amphibians, shuvosaur archosaurs, and the big sailbacked archosaur predator Arizonasaurus. The Manda is more diverse, and Nesbitt and his teammates have discovered remains of a great number of species: the rauisuchid predator Nundasuchus and its sketchy relatives Stagonosuchus, Mandasuchus and Pallisteria, the dicynodonts Kannemeyeria and Angonisaurus, the big, mysterious basal suchian Parringtonia and the equally mysterious archosaur Asperoris, the cynodont Scalendon, the Rhynchosaur Stenaulorhynchus, the strange dinosaur-like archosaur Nyasaurus and the more familiar Silesaur Asilisaurus.  Talking to members of their team at the Field Museum has brought my interest in the Manda site, and I eagerly wait what they find next.

Stephen Brusatte of  the University of Ediburgh gave a briefing of new sites in Poland and Portugal. In Krasiejow, new metoposaur remains have been found. More significant was material of the dinosaur-like archosaur Silesaurus, counterpart to the Nunda’s Asilisaurus and the Chinle’s Eucoelophysis. At Stryczowice, the dinosauriform ichnotaxon (classified by footprints alone) Prorotodactylus gives a fascinating glimpse at archosaur evolution from the Early Triassic. Finally, a side near Poreba showed remains of silesaurs and very early dinosaurs resembling Coelophysis and Herrerasaurus.  Moving on the Portugal, the sites of Faro Algarve and Penina reveal a motherlode of temnospondyl mastodonsaurs and metoposaurs and phytosaurs.  All these are faint traces, but promise that further investigation will lead to some very interesting finds.

Randy Irmis of the University of Utah went back crocodile evolution.  Some interesting revelations from this talk include the fact that crocodiles are not living fossils in the conventional sense as they are distinct from their prehistoric ancestors, that the Spenosuchians included such forms as the herbivorous Phyllodontosuchus and the big predator Redondaventator, North Carolina and Arizona each had their own genus of Sphnosuchian, and that new species of Sphenosuchian had been found in both the Chinle and Newark formations.  It appears that the high point of Sphenosuchian diversity was the Triassic-Jurassic transition, and were only displaced over the Jurassic Period by Eucrocodilians.

One of my favorite talks for the second day was William Parker of the National Park Service talking about his park, the Petrified Forest, and the sheer amount of material from the Chinle Formation.  As a point of comparison, in 1983 the park featured a mural depicting all 8 species of animal-Placerias, Trilophosaurus, a Metoposaur, Coelophysis, Desmatosuchus, Typothorax, and a phytosaur. By 1986 Paratypothorax and Postosuchus joined. In 1987 three more species were found. At this moment, more than 50 species of land animal have been found in amazing quality in this site, qualifying it as a Lagerstätte, or paleontological site of exceptional richness.  Amusingly, an artist of a recent mural drew pterosaurs and a drepanosaur on the mural. No sooner did Parker complain about their scientific dubiousness, than evidence for the said drepanosaur and pterosaur were discovered! Ironically, there have been no cynodonts found, so the BBC’s Walking With Dinosaurs series featured a currently-fictional species based on strange, undiagnostic teeth.

To continue the topic, Anna Behrensmeyer of the Smithsonian Institution gave an account of her own experience in the Petrified Forest. On Parker’s advice, she and her team investigated one of the younger, upper members of the Chinle, a streambed site far off from the main sites. Called the Black Forest Bed, part of the Owl Rock Member, this site had a different fauna from the others. Unfortunately, most of what was there was teeth and osteoderms. However, a significant discoveries was still made, namely, the aforementioned pterosaur material. It’s still relatively undiagnostic, just a jaw and some teeth, but Behrensmeyer and her team found material of the earliest known American pterosaur. This small but significant find may be the start of a new species, and hopefully more material will be found.

The next talk was a jump into the Jurassic and south to Antarctica-namely the Hanson formation of Mt. Kirkpatrick. The speaker was Nathan Smith of Howard University, who traveled with a team including William Hammer of Augustiana college (more on that institute in a later post) and Peter Makovicky of the Field Museum (where many of the specimens are kept) to discover dinosaurs of the early Jurassic.  Working in the frigid slopes of the mountain, the teams uncovered large tritylodonts (herbivorous cynodonts, mammal ancestors) dimorphodonts (primitive pterosaurs), the crested predator Crylophosaurus (found by Hammer in 1991) and prosauropod (early sauropodomorph) Glacialosaurus.. In 2010 two more distinct prosauropods were found-one related to the contemporary Leonerasaurus from Argentina (a species closer to derived sauropods), and one related to Ignavusaurus from South Africa and Sarahsaurus from North America. Glacialosaurus, on the other hand, is related to Massospondylus from South Africa and Yunnanosaurus and Lufengosaurus from China. It appears that Antarctica had a similar fauna to other early Jurassic formations, indicating a similar environment where sauropodomorph diversity was sustained across the continents. This is the only talk featuring dinosaurs and the Jurassic, so it’s a fascinating change of pace.

The last talk of the symposium was an overview of Ethiopia in the Mesozoic by Mark Goodwin of University of California Berkley. It was an overview simply because Ethiopia, like Portugal and Poland, have not been extensively prospected for fossils. Goodwin made an excellent case for Ethiopia’s Mesozoic value as well as its classic late Cenozoic locations. He focused on the Northwest Plateau of the country, as it looked more promising, had more universities nearby, and was further away from the chaos of Eritrea and Somalia. At Adigrat, he and other paleontologists discovered Abiadisaurus, a capitosaur (giant temnospondyls like Mastodonsaurus) amphibian.  At Gohatison, a middle Jurassic site, crocodilians of unknown species are seen. Mugher is a late Jurassic Marine site. Fish include lungfish, the ubiquitous gar relative Lepidostes, the equally ubiquitous shark Hybodus, and guitarfish. There’s a wide variety of freshwater turtles-sidenecks including ancestors of modern African sidenecks, and the extinct paracryptodires and plesiochelyds are all represented.  Archosaurs are represented by material of crocodilians, carnosaurs akin to Allosaurus, “hypsilophodonts” similar to Othnielosaurus, and even mammaliforms. Of course, all of these are scraps or teeth, so further expeditions must be made. Even so, this is exciting news and hopefully Ethiopian and foreign scientists will discover more material from this ancient, geologically rich country.

I consider the high price and long commute totally worth it. Paleofest is an amazing gathering of paleontologists in a fine museum where new and fascinating finds are discussed. It is a great place for social networking among the paleontological community, and the specific focus on the Triassic provided new light on a previously obscure and often neglected but critical period of biological history.  I recommend this event for not only professionals, but also amateurs, paleoartists, and fans like myself.  Paleofest is one event in the year that’s not to be missed, and I can’t wait to see what’s next.

1 comment:

  1. Fossils and signs from history are stored in the rocks of the Earth so its imperative to understand how the Earth came about and understand that the world is dynamic and fluid. The world has undergone change constantly, for there wasn’t always seven continents.