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Field work during a mass extinction

Imagine that a “time machine” allowed you to go back in time — back exactly 64,999,995 years ago, just five years before the crash of the meteor that marked the end of the Age of the Dinosaurs. You have just enough time to do your field work, analyze your data, and write your Ph.D. dissertation. Your field work starts in the closest emerged land to the Chicxulub impact site. In no time at all you begin discovering new species of dinosaurs that are unknown from the fossil record, and you diligently test dozens of hypotheses about the behavior and physiology of these Mesozoic giants.

Mauna Kea vegetationFor three years you have that chance to explore a completely different world to the one where you grew up. Australia is still connected to a temperate Antarctica and India is on its way to cross the equatorial line. Continental seas cover extensive regions of North America, Europe, Asia and in South America, east of the rising Andes.

During your last year of field work, a series of small meteorites begin to impact the Earth. These events become more and more frequent and some of them have local effects similar to the volcanic explosion of the island of Krakatau in 1883. Your advisor and dissertation committee recommend that you come back, but you refuse to do so. You still want to do field work for your last chapter concerning the ecology of Titanosaurus in South America. It is literally the last chance to study these sauropods before they become extinct. However, communications with your family and friends make you change your mind. After carefully packing up all your samples, including Ornithuromorpha feathers, Nymphaeaceae flowers and pollinator insects, you come back to the present. The Cretaceous world is not a safe place anymore ….

Our reality today is in some ways not too far from this fictional story. Based in Laupāhoehoe on the Big Island of Hawai’i this past January, I took part in field work on the slopes of Mauna Kea and witnessed how the environment is changing in a precipitous way. I had the chance to do an altitudinal transect with climate change researchers from the University of Hawai’i, Mānoa. Starting at 1,116 meters we were surrounded by an amazingly beautiful native forest. Huge o’hia and koa trees dominated the canopy, while the understory was full of a variety of endemic plants, including the hapu’u fern, ‘ōlapa tree, ‘ōhelo berries and more than 15 other endemic species. Flying and singing amongst the vegetation, different species of native birds, (i’iwi, apapane, ‘oma’o, ‘amakihi) accompanied us. The bark and leaves of the trees hosted an abundant community of terrestrial invertebrates. Dozens of species of Drosophila, giant Leptogryllus crickets, colorful Tetragnatha spiders and, of course, the curious Hawaiian happy face spider, were part of this unique world.

However, as we descended, the increase of invasive species, like strawberry guava, clidemia and Kāhili ginger, became obvious. At 934 meters, most of the strawberry guavas were juvenile — they were the advancing front of an invasion. By 800 meters, the strawberry guava trees were older and the diversity of endemic plants had declined dramatically. Toward the end of the transect, we were in a pure strawberry guava forest. Most of the native plants were gone and many of the animals appeared to be absent as well. It became obvious to me that I was witnessing the potential future for the higher elevation areas.

Today, the disappearance of "critically endangered," "endangered" and "vulnerable" species could lead us further down a path toward what might be the planet's sixth mass extinction. Indeed, it is likely that many more organisms will go extinct in our lifetime. The clock is ticking for many species worldwide and we have a limited time to discover and document our existing biological diversity. Unlike the K/T extinction, we can use our knowledge of contemporary species distribution and abundance to prevent these extinctions. However, for this to occur, human society must undergo fundamental yet attainable changes. If we fail to learn the lessons from the past, there might not be a future from which to escape once the Earth ceases to be a safe place ….

Acknowledgement: I want to thank Scott Laursen for suggestions for the text and for letting me join the research team to visit Laupāhoehoe.

Relicts of the Bug-men

What are bug-men and how did their existence benefit UCMP? Watch and listen to this slideshow about an obscure link recently discovered by UCMP micropaleontologist Ken Finger.

Click cover page below to download the full article.

 

Student Spotlight: Jenna Judge travels to Japan in search of deep sea snails

Congratulation to UCMP's Jenna Judge who was awarded a spot in the NSF East Asia and Pacific Summer Institutes (EAPSI) last spring. NSF EAPSI provides funding for a graduate student to spend a summer in an East Asian or Pacific country to conduct scientific research as well as engage in societal and cultural practices. Jenna spent her summer in Japan, studying  the evolutionary history and ecology of a group of limpets that live in a variety of habitats in the deep sea! Check out her adventures on her personal blog - the eclectic limpet.

One fossil locality, eight days, 513 rocks, 757 photographs and thousands of plant fossils

Figure 1: Bolzano covers the floor of intersecting alpine valleys defined by stunning dolomite peaks (upper left). Check out the local GAP for the latest in dirndl fashion (lower left). Cin and Ivo inspect a big slab with Late Permian conifer branches (right).

This summer we headed to the Italian Alps to work on fossils from a newly discovered Late Permian plant locality in the incredibly scenic Bletterbach gorge. This research is part of a larger project, which tries to quantify the hits that the terrestrial ecosystem took during the end-Permian world-wide biotic crisis. Back in those days Europe and North America were connected and part of one and the same floral realm, not surprisingly called Euramerica. Euramerica was tropical and semi-arid, and its floras were characterized by conifers and seedferns. Floral remains from this area and time interval are few and far between and notoriously incomprehensive, and thus also is our understanding of the floras. The discovery in the north Italian Dolomites of a specimen (as well as taxon-rich macrofossil flora some years ago) therefore means a big leap forward. Last year a multidisciplinary team was assembled to make an inventory and study the various plant groups and reptilian ichnofossils collected at the site. We were there to study and photograph the conifer remains and sample them for preserved leaf cuticles.

Truckloads of fossiliferous material had already been collected by volunteers over the last few years and were ready to be worked on. As a result, the field part of our expedition was reduced to sampling cuticle bearing sediment layers - sitting right on top of the Butterloch waterfall in Geoparc Bletterbach. The remaining time was spent digging the museum collection.

The collection is housed in the natural history gem Naturmuseum Südtirol in Bolzano - or Bozen as the German speaking South Tyroleans call it. The museum in turn is housed in a beautiful respectfully converted historic building from the latest 1400s in the “Bozner Altstadt”. So - just like last year - we spent the hottest part of the European summer up on the attic of yet another natural history museum.

Our counterpart, curator Dr. Evelyn Kustatcher, turned out to be a fabulous cook as well as a wonderful host. That, together with daily macchiatos and apiretivos on café terraces, and the stunning natural beauty of the area made Bolzano a particularly difficult place to leave.

We will be back...

Figure 2: Sampling the cuticle-rich layer close to the waterfall (upper left). Our host Evelyn Kustatcher (red shirt) explains geo-tourist spectators what we are doing (lower left). A look into the Butterloch-Bletterbach Gorge from above (right).

Student Spotlight: Joey Pakes 2010 Diving Expedition for Remipedes in the Yucatan

Imagine what it would be like: swimming in the dark, deep underwater, in an enclosed space, “armed” with only a flashlight and a tank of air. For UCMP graduate student Joey Pakes, that is a typical day of research in the subterranean caves in Mexico. Check out her video which describes her 2010 expedition to the Yucatan Peninsula as part of her ongoing investigations into underwater cave systems. Meet some of the people and animals that make her research so special.

Student Spotlight: Emily Lindsey and the late Pleistocene megafauna in South America

This post's text is also available in Spanish.

Emily Lindsey fossil hunting at her site in Ecuador.

Congratulations to graduate student Emily Lindsey, this year's recipient of the George D. Louderback Award! Emily has been hard at work the past few years investigating the timing, dynamics, and key players behind the late Pleistocene extinction of megafauna in South America.

Like the famous La Brea Tar Pits in Los Angeles, California, Emily's excavation site on the Santa Elena Peninsula in Ecuador is an asphalt seep preserving the remains of a wide array of organisms. However, unlike the Tar Pits in California, the Ecuador site doesn't appear to be a tableau depicting the tragic demise of animals stuck in tar. Instead, it is likely the final resting place of remains transported by running water and then covered by nearby asphalt.

A. Setting up camp at Emily's site on the Santa Elena Peninsula. B. Close up of one of the excavated walls. C. Panoramic view of the entire site during the fossil dig.

So what mysterious late Pleistocene megafauna did she uncover in the seep? Mainly giant ground sloths (Eremotherium laurillardi) ranging from juveniles to adults, along with gomphotheres (elephant-like relatives of mastodons), giant armadillos and prehistoric horse. In general, Emily’s site had rather reduced biodiversity compared to other notable tar seeps. In fact only herbivores were found, unlike La Brea, which included the infamous and carnivorous sabertoothed cat and dire wolf.

All photos demonstrate the excavation process in the field by Emily's many international collaborators. B. Close up of bones being exposed.

Emily couldn’t do all this work without some help. For the excavation, she brought together a slew of collaborators from across continents to uncover (zing!) and understand the mysteries surrounding the late Pleistocene megafaunal extinctions. The Universidad Estatal Peninsula de Santa Elena (UPSE) sponsored the excavation and kept the fossil finds at the Museo Paleontologico Megaterio (MPM). Members of the Page Museum in California also flew down to Ecuador, bringing their expertise on the La Brea Tar Pits and asphalt seeps. And, several U.C. Berkeley students and alumni have volunteered their time on the dig. Several international articles were written about Emily’s exciting work, including one from the Natural History Museum in Los Angeles and the Universidad Nacional de Piura (UNP).

A. An area of deposited bones after they've been excavated. B. and C. The exposed fossils are plastered to protect them for transport to the museum.

Emily’s collaboration with UNP members in Peru was part of her goal to compare asphalt seeps from different locales. “I think the Talara tar seeps in Peru are pretty similar to La Brea, geologically & taxonomically, just my site in Ecuador is distinct from them,” says Emily. “This isn’t necessarily true of other asphalt sites here on the Santa Elena Peninsula, which may represent more traditional “tar pit” scenarios.”  Emily presented her results in a lecture at UNP last year.

Another large focus of Emily's work has been to tease apart the roles of climate change and habitat degradation from the arrival of humans on the disappearance of large mammals.  Several of the fossils uncovered at her site in Ecuador were found with cut marks. Though this might suggest that humans played a hand in overharvesting and subsequently pushing these mammals to extinction, there is no further evidence of human activity at her site. “It is also possible that the marks are ‘taphonomic’ features, caused when the bones were swept down a river or rubbed against other bones and rocks in the tar pit,” says Emily. Likely both climate change and human activities led to the downfall of these South American megafauna. The question is, how much did each factor contribute.

Other important tasks to do at the site include A. mapping out the location of the bones, B. measuring the stratigraphic layers, and C. sifting for microfauna.

With a much deserved award under her belt, we look forward to hearing more about Emily’s discoveries in the future!

A display of a giant ground sloth at the Museo Paleontologico Megaterio (MPM).

En Español:

Felicitaciones a la estudiante de doctorado Emily Lindsey, ganadora este año del Premio George D. Lauderback. Emily ha estado trabajando los últimos años investigando la cronología, los patrones y los actores principales en la extinción de la megafauna sudamericana al fin del Pleistoceno.

Tal como el famoso sitio Rancho La Brea en Los Ángeles, California, USA, el sitio que Emily está excavando en la Península de Santa Elena en Ecuador es un charco de asfalto que preserva los restos de una gran variedad de organismos. Sin embargo, a diferencia de los charcos de brea en Los Ángeles, el sitio en Ecuador no parece que fue una trampa donde varios animales murieron atrapados en brea, sino la ultima morada de restos trasladados por agua corriente y luego enterrados en el asfalto.

¿Y cual megafauna misteriosa ha encontrado Emily en los charcos de Santa Elena? Principalmente perezosos gigantes (Eremotherium laurillardi), desde críos hasta adultos, junto con gonfoterios (un pariente de los mastodontes parecidos a elefantes), armadillos gigantes, y caballos prehistóricos. En total, el sitio tiene menos biodiversidad en comparación con otros conocidos fosilíferos charcos de brea. De hecho, hasta ahora solo han encontrado herbívoros, a diferencia de Rancho La Brea, donde los fósiles más encontrados incluyen los famosos – y carnívoros – tigres dientes de sable y Canis dirus.

¡Emily no podría hacer todo este trabajo sin ayuda! Para las excavaciones, unió a un grupo de colaboradores de distintos continentes a des-cubrir (:)) y entender los misterios sobre la extinción de la megafauna Pleistocena sudamericana. La Universidad Estatal Península de Santa Elena (UPSE) apoyó la excavación y guardó los fósiles excavados en el Museo Paleontológico Megaterio (MPM). Personal del Museo de Historia Natural en Los Ángeles, California, también vino a ayudar con las excavaciones, contribuyendo con su alta experiencia y conocimiento sobre los charcos de brea. Además, varios alumnos y exalumnos de la Universidad de California en Berkeley han llegado como voluntarios a ayudar con los excavaciones. Algunos artículos internacionales han sido escritos sobre el trabajo emocionante de Emily, incluyendo uno del Museo de Historia Natural en Los Ángeles, y otro del Universidad Nacional de Piura (UNP) en Perú.

La colaboración de Emily con el personal del UNP fue en conexión con su proyecto de comparar charcos de brea de distintos lugares. "Yo creo que los charcos de brea en Talara, Peru son bien parecidos, geológicamente y taxonómicamente, con los de Rancho La Brea en Los Ángeles; solo el sitio que yo tengo es distinto," dijo Emily. "Esto no necesariamente es el caso con los otros sitios de asfalto que encontramos aquí en la Península de Santa Elena, los cuales podrían representar escenarios mas tradicionales de "trampas de brea."

Otro gran enfoque del trabajo de Emily ha sido diferenciar las contribuciones de cambios climáticos y degradación de hábitats y la llegada de los primeros humanos a Sudamérica, como causantes de la desaparición de mamíferos gigantes del continente. Algunos de los fósiles descubiertos en su sitio en Ecuador fueron encontrados con marcas parecidos a las hechas con cuchillos. Aunque esto podría sugerir que los humanos tenían un papel en la sobrecaza de estos animales y su eventual extinción, no hay mas evidencia de acciones humanos en el sitio. "También es posible que las marcas sean características 'tafonómicas,' producidas cuando los huesos fueron arrastrado por un río o cuando se frotaban unos contra otros o contra piedras en el charco de brea," dice Emily. Probablemente, ambos procesos – cambios climáticos y acciones de humanos – contribuyeron a la extinción de la megafauna Sudamericana. La pregunta es, ¿cuánto contribuyó cada factor?

Ya con un premio bien merecido, ¡esperaremos escuchar mas sobre los descubrimientos de Emily en el futuro!

Molly Wright's Trip to the Smithsonian Collection

National Museum of Natural History

DAY 1 (5/17/2011): I work with Professor Roy Caldwell to study the evolution of the behaviors and morphology of mantis shrimps – pugnacious crustaceans that are distant cousins to lobsters, true shrimps, and crabs. Mantis shrimps use fearsome raptorial appendages to smash or spear their prey. Even more surprisingly, some mantis shrimps live in male-female pairs in sandy burrows, with both sexes caring for the young and sharing food. Social monogamy, when a single male and female live as a pair for an extended period of time, is very rare among crustaceans, so I’m naturally interested in how it arose.

Molly Wright and her husband, Tim Dulac, at the airport.

In particular,  I’m really curious to find out whether lifestyle traits, such as living in sandy burrows or ambush hunting, may have opened the door for the evolution of social monogamy.  To try to answer my questions, I will be looking at some of the thousands of mantis shrimp specimens housed at the Museum of Natural History and the Smithsonian Museum Support Center. By looking at the morphologies and behaviors of different mantis shrimp species and considering their evolutionary histories, I hope to figure out whether the evolution of morphological traits like the relative size and shape of eyes, raptorial appendages, and body shape, is correlated with the evolution of social monogamy, ambush hunting, and burrow-living.

I’ll be updating this blog while I am in Washington D.C. with more about my research and lots of tasty tidbits about mantis shrimp biology.  So stay tuned!

 

 

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Just a few of the many mantis shrimp specimens at the National Museum of Natural History.

DAY 2 (5/19/2011): My first day in Washington D.C. started off with a 6am wakeup call, followed by a rushed morning of picking up a rental car at Dulles International Airport, driving to the nearest metro station to take a train into Washington D.C., and literally running to the Smithsonian Museum of Natural History to make my 9:30am appointment to obtain a visitors badge. Then, before I could even catch my breath, I was on the Smithsonian Employee shuttle and off to the Museum Support Center (MSC) in Maryland.

The MSC houses all of the invertebrate collections that are stored in ethanol, as well as many of the Invertebrate Zoology research labs. Museum Specialist Karen Reed met me at the entrance of the building. Karen led me through the labyrinth of hallways in the MSC, set me up at a work bench with all the tools I needed, and oriented me to the Crustacean collections, helping me select some specimens to get started on. The Crustacean collections take up two large rooms in the MSC. Walking through shelves containing thousands of specimens, I was continuously distracted by amazing creatures - giant American lobsters, spiny lobsters, giant isopods, and king crabs, all stored in jars of slightly yellowed ethanol. This place is great!

By the time I collected my specimens, it was time to eat lunch. The entire Invertebrate Zoology staff eats together everyday, which is great for visiting scientists like me because it gives us a chance to get to know everyone. After lunch, I set up my camera and started taking pictures. In half a day, I got through most of the Nannosquilla (a genus of small mantis shrimps) and started up on the Lysiosquillina (a genus of HUGE mantis shrimps), taking more than 100 pictures of animals ranging from 10mm to 30cm!

 

A. Molly is photographing mantis shrimps at the National Museum of Natural History to better understand how their morphology and behaviors have evolved. B. Lysiosquillina maculata specimens collected from French Polynesia. C. A nannosquilloid mantis shrimp. Nannosquilloids are among the smallest mantis shrimps, while the lysiosquilloid mantis shrimps are among the largest.

After a long, but fruitful, day at the MSC, I finally got to head to the apartment that my husband and I are renting for the next week and a half. It felt great to collapse on the couch and put my feet up. After a quick nap, my husband and I went out for a quick dinner – of course, I had to order the crab cake and shrimp dish because there’s nothing quite like eating the animals you study!

Molly's dinner on her first night in Washington D.C. She enjoyed two different crustaceans, blue crabs and shrimps, as well as some delicious scallops.

 

 

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A giant mantis shrimp, also known as a zebra mantis shrimp.

DAY 3 (5/20/2011): Today I examined several specimens of the giant mantis shrimp (Lysiosquillina maculata), so named because it can grow more than 30 cm in length. This species is often called the zebra mantis shrimp because of it’s striking black stripes. Although color usually fades when crustaceans are preserved in ethanol, many specimens that I looked at this afternoon still had vibrant yellow bodies with dark stripes.

 

Giant mantis shrimps and other members of the Lysiosquillina genus have fascinating behaviors.  They are socially monogamous. Heterosexual pairs dig long, U-shaped burrows in the sand. Males in this genus usually do the hunting, waiting at the opening of the burrow for a fish to swim by then grabbing it from the water column with their long, sharp raptorial appendages. Then they share the food they catch with their mate. We have been observing one male Lysiosquillina maculata in our lab in Berkeley for many years.  He always provisions his mate first, coming back a few minutes later for more fish.

Lysiosquillina maculata is also sexually dimorphic – that is, males and females have slightly different body shapes. Males have larger eyes and longer raptorial appendages. We suspect that this might be because they spend more time at the burrow opening, catching food and defending themselves and their mates.

A. The largest giant mantis shrimp in the Smithsonian collection, over a foot long! B. A zebra mantis shrimp with it's raptorial appendages displayed.

 

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Molly is preparing to take a picture of a large California mantis shrimp (Hermisquilla californiensis).

DAY 4 (5/23/2011): Starting my first full week at the Smithsonian this morning, I was excited to take a look at some other socially monogamous mantis shrimps in the Lysiosqulloidea clade.

After waking myself up with a big cup of coffee, I proceeded up to the large crustacean storage room in Pod 5 of the Museum Support Center with Museum Specialist Karen Reed  . I was curious to see Pod 5 for more than just it’s scientific significance because it was prominently featured as the site of the protagonist’s lab in Dan Brown’s novel The Lost Symbol. Unlike its description in the novel, it is filled with jar after jar of specimens preserved in ethanol. Karen helped me navigate through the collections, returning the specimens that I looked at last week and choosing new specimens to examine. Everything is organized with an accession number, much like in a library, otherwise if a specimen were misplaced, it might not be found again for decades or even centuries!

I pulled more than 40 specimens to examine over the next few days from several families of mantis shrimps in the Lysiosquilloidea clade – the Nannosquillidae, the Coronididae, and the Tetrasquillidae. I’m particularly interested in looking at the Nannosquillidae family because it contains both promiscuous and socially monogamous species. I hope that by looking at morphological traits that occur in socially monogamous species but not in promiscuous species, I can better understand howsocial monogamy evolved.

 

A. One of the larger American lobsters in the Smithsonian's wet collection. B. A giant isopod from the Smithsonian's wet collection. C. A few of the many mantis shrimp specimens that Molly looked at during her trip.

 

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Molly's prep and picture station at the Smithsonian.

DAY 5 (5/25/2011): Today is a rather special day for me – my birthday! And what better way to spend it than at the MSC, looking at mantis shrimps?

In the past two days, I’ve photographed and measured 48 mantis shrimps – not bad, considering it takes me about 20 minutes to process each specimen! First I look up the accession number in the Smithsonian’s online database, which provides  information on when and where it was collected, as well as any notes from collection and later curation. After adding this information to an excel spreadsheet, I use calipers to measure the mantis shrimp’s eyes, antennal scales, legs, and total length. I then mount the specimen in a dissection dish with pins, getting it in just the right position to photograph. I take several shots of each animal from different view points to make sure that I am getting all of the morphological information I need, remounting it each time. I always include a small ruler in the photo so that I have an idea of the size of the animal.

This morning, I searched the wet collections for some of the rarer genera of Lysiosquilloidea. Once I measure and photograph the 13 specimens that I pulled this morning, I will have completed my survey of the Lysiosquilloidea. Of course, I couldn’t look at every lysiosquilloid mantis shrimp in the Smithsonian collection – the museum has over 400 mantis shrimps just in this super-family – but I did manage to examine at least a few examples of each genus!

Tonight my husband and I are going to celebrate both my birthday and my success thus far in the Smithsonian collections with a delicious Italian dinner!

A. The specimens, like this giant mantis shrimp, are kept in large jars with a fixative for preservation. B. Molly's stomatopod of interest, the giant mantis shrimp. C. The antennal scale, antennae, and eyes of a giant mantis shrimp. D. A close up of the giant mantis shrimp, also known as a zebra mantis shrimp.

 

 

 

"Field Notes": Devonian liverworts and Permian conifers

Susan Tremblay (left) and paleobotanist Carol Hotton (right) talking liverworts

Susan Tremblay (left) and paleobotanist Carol Hotton (right) talking liverworts

On a cold Berkeley morning late in March paleobotanist Cindy Looy and grad student Susan Tremblay hopped on a plane to Washington DC. Their goal was not to enjoy the gorgeous spring weather and peaking cherry blossoms, but instead to search for clues to the early evolution of plants in the collections of the National Museum of Natural History (NMNH). Devonian liverworts and Permian conifers were on the menu.

Pallaviciniites devonicus, described by Francis Hueber in 1961, is one of the oldest known fossil liverworts. The shale from which the fossils originated, a locality in Eastern New York, has been completely quarried and used for road repairs. Until recently the taxon was thought to exist only in the form of six type slides. However, on a previous visit to the NMNH, Devonian specialist Carol Hotton pointed Cindy to several cabinets with the original shales collected by Hueber. One of our goals was to re-examine the material.

Cindy Looy taking notes on Early Permian conifer branches

Cindy Looy taking notes on Early Permian conifer branches

At first glance the shales don’t seem to contain any fossils at all. But when looked at with a stereo microscope using polarized light a variety of plant fossils, including liverwort thalli, become clearly visible. A selection of this material was shipped to the UCMP, where preparations are being made to free the fossils by dissolving the matrix. P. devonicus and other Paleozoic liverwort taxa have dark cells scattered across their surfaces. These are hypothesized to be homologous to the scattered, oil body containing-cells of some extant liverworts. Susan will use morphometrics and biogeochemical information to test possible homology. This might elucidate the evolution and possible function of these mysterious organelles found only in liverworts, the sister group to the rest of the land plants.

Cin’s quest to reconstruct the early history of the Paleozoic conifers also continued. The earliest conifers are small trees with a growth habit similar to that of extant Norfolk Island Pine. They played a prominent role in the composition of plant communities in the equatorial Euramerican floral realm during the Late Carboniferous and Early Permian. Conifers generally fossilize as leaves or isolated shoots, or fragments thereof. The specimens studied were collected by Cindy and NMNH colleagues and originate from an Early Permian seed-plant-dominated flora from Texas. The presence of complete branch systems provides valuable information about the life history of the plants that produced them. New finds from New Mexico were loaned for further study at the Looylab.

Museum nomads

For many paleobiologists summer is that part of the year during which data is gathered in its purest form: fossils. Such summers may take you in diametrically opposite directions, though. Some bring broadly boasted outdoor adventures of fieldwork. Others, however, take you deeper and deeper into the collection labyrinths in the dark bowls of natural history museums around the globe. Despite what others may let you believe - and don’t tell anyone we told you - fieldwork is often boring, tedious work, the outcome of which - if any - is generally unknown. Sometimes long after you have made it back to the lab - as is the case for most palynological expeditions - you still have no clue if the trip was successful or not.

Digging deep in museum collections, on the other hand, can be surprisingly exciting. It is like treasure hunting with the guarantee of success. Now when you tour the big museums in the world, you’re bound to run into fellow hunters. Wherever you may go, you always run in to other members of our tiny community. They are like snowbirds that tour the same limited number of Arizonian RV parks in winter. This year we realized: we’ve joined this small herd of museum nomads. Our trip this summer to the Museum für Naturkunde in former East Berlin was no exception. On the first day of our visit Harvard’s Andy Knoll gave a talk, and we saw Scotsman and paleontologist Allistair McG striding the hallways, a sight we had seen before during our stay at the Smithsonian’s NMNH.

The species that brought us to Berlin is Pleuromeia sternbergii - a 250 million year old quillwort. P. sternbergii is one of the few plant species that actually thrived during the aftermath of the end-Permian crisis, the largest mass extinction ever recorded. From the moment we heard of the plant, we were intrigued by the incredible success of this paleobotanical oddball. Word has it that the first Pleuromeiawas discovered in the 1830s when - during a repair - a sandstone block fell from the Cathedral of Magdeburg and broke into pieces on the pavement (Mägdefrau, 1968). The accident revealed a piece of fossil Pleuromeia stem; nine years later first described by count Georg zu Münster as a Sigillaria species. Fortunately for us, the quarry that produced the stones that built the cathedral was known to be close to the nearby town of Bernburg. Many more important specimens have been found in the same quarry since, and that’s exactly what we were after in Berlin.

Typical Pleuromeia fossils look like a small baseball bat, often with a spirally arranged pattern of dimples on it. These are almost always sandstone casts (infillings) of decayed Pleuromeia stems. Since the decay of these lycopsid stems occurs in distinct phases - starting from the inside-outward, depending on the resilience of concentric tissue layers – virtually all remains are casts of inner stem tissues layers. Now among the many published papers on Pleuromeia sternbergii - the first ones starting in the late 1800s - there was one of by Mägdefrau (1931) that figured a rare feature: the detailed leaf scars on the outside of a Pleuromeia stem. This is crucial information for a new reconstruction we plan to make of P. sternbergii. However, for most of the 20th century this important specimen was considered lost, until someone recently rediscovered it in Berlin. So we had to see it.

While walking through the hallways of the 121 year old museum building, we stared in the face of a Brachiosaurus brancai, the largest mounted dinosaur skeleton (really, it's in the Guinness book of records), walked past a wooden closet decorated with Paleozoic sea lilies and fossil horsetails in wood carvings, and saw many nice old paleo reconstructions. A stone staircase led the way to the attic of the museum; that’s where the Mesozoic paleobotany collections are housed. The collections space is not air conditioned, and it was around 100 degrees Fahrenheit outside. Up on the attic it was quite a bit warmer, so we had to take care not to spill little streams of sweat on the fossils. Luckily, a small table fan was already performing its duty. We sat down and started browsing though three cabinets with Buntsandstein collections.

Mesozoic plant curator Barbara Mohr very modestly apologized that the collection was not very extensive, but we couldn’t believe our eyes. They turned out to have a huge number of specimens, most of which were collected in the 19th century. Many of the specimens showed important features that have never been published on. Beside the unique specimen with detailed features of the outside of the stem, we found three more specimens. There was a lot of reproductive material in the collection as well - terminal cones, isolated sporophyls and dime to quarter-sized sporangia. Moreover, a short stack of drawers contained hundreds leaf fragments. Now leaves have hardly been figured in Pleuromeia publications, so that was something we knew very little about. For two days, we felt like two little kids in a candy store, photographing as much as possible.

Ceci n’est pas une Pleuromeia
Overseeing this enormous collection, we realized how far off we were with our earlier whole-plant reconstruction of Pleuromeia (see fig.). Now we need to get started on a new one a.s.a.p. Of course, each illustrated reconstruction of an extinct organism or landscape is a hypothesis, and should be treated as such. However, such graphic hypotheses seem almost immune to the natural selection of other memes such as more conceptual, verbal hypotheses. That is because most ‘users’ are not so much interested in the intellectual merit of the hypothesis, but are looking for a pretty picture of an old dead thing. Therefore, falsified but pretty reconstructions have a very slow decay rate, or may even grow in importance. Thus, falsifiability - the one thing that sets scientific claims apart from most non-scientific ones - is continuously threatened by esthetics... The fact that in most reconstructions it is impossible to see the degree of accuracy of the various depicted components adds to the problem. In an ideal world all reconstructions come with an integrated disclaimer or are all just really ugly. Until then, we’d better make sure that each new reconstruction looks better than the predecessor it replaces.

Karl Mägdefrau 1934. Zur Morphologie und phylogenetischen Bedeutung der fossilen Pflanzengattung Pleuromeia. Beih. Bot. Centralbl. 48: 119-140.

Karl Mägdefrau 1968. Paläobiologie der Pflanzen. 4th edition, Fischer, Stuttgart, 549 pp.

Even a mantis shrimp is what it eats

Neogonodactlyus wounds

Neogonodactlyus bredini with damage on its predatory appendage from another mantis shrimp's strikes! Photo by Roy Caldwell.

Ask most anyone what butterflies use their wings for or what fish do with their fins and you will undoubtedly hear an answer like, "Wings are used for flying and fins are used for swimming!" Some body parts just seem so well-adapted to perform certain functions; this is why there is a paradigm in biology that "specialized" body parts correspond to specific ways in which animals go about their daily business. In other words, specialization in morphology corresponds to specialization in ecology. A classic example of this concept is variation in the beaks of the Galapagos finches. Some finches have beaks adapted to crush hard seeds, while others have beaks specialized for eating insects.

However, not all animals seem to exhibit this pattern. The marine crustacean known as the mantis shrimp has legs, called predatory or raptorial appendages, which can produce one of the fastest movements in the animal kingdom. These raptorial appendages come in many shapes ranging from sharp spear-like appendages to hammer-like appendages. Mantis shrimp use their fast-moving appendages to crush open snails and other hard-shelled marine organisms, so they can eat the soft bodies inside. However, mantis shrimp also appear to eat other foods, like fish, which probably do not need to be smashed to bits before they are consumed. Even though they have specialized legs well adapted to smashing or spearing prey, some species may not use their raptorial appendages for this purpose. The goal of my research is to determine if mantis shrimp have diverse diets. Then if so, I will see how diet diversity correlates with raptorial appendage morphology across the mantis shrimp family.

First, a little background about mantis shrimp. Mantis shrimp are closely related to decapods, such as lobsters, crabs, and true shrimp. Even though mantis shrimp look like decapods, they actually branched off and became their own group 400 million years ago. Mantis shrimp have the most complex visual system ever reported in the animal kingdom. They are also one of the fastest swimmers in the sea, swimming at speeds of up to 30 body lengths per second — comparable to speeds measured in squid, which previously held the record.

But my favorite characteristic of mantis shrimp is of course their lightning fast raptorial appendages. Researchers in the Patek Lab at the University of Massachusetts and Caldwell Lab at Berkeley have found that a mantis shrimp’s predatory strike can move 23 meters per second (50 miles per hour) and produces accelerations that are comparable to a flying bullet! So it would be surprising if some mantis shrimp species were capable of this rapid movement, but didn't use it to catch prey. Hence, my study of mantis shrimp diets! I am using two techniques, stable isotopes and behavioral studies, to figure out which food items mantis shrimp eat.

Before I could study their diets, I first had to collect several different species of mantis shrimp and their possible prey. Most mantis shrimp live in the tropics, so I have traveled to Lizard Island, Australia and Mo’orea, French Polynesia to collect the animals. However, my main field site is in Colon, Panama where I collect at the Smithsonian Tropical Research Institute’s Galeta Marine Laboratory. After collecting, I transport all of the specimens back to the UC Berkeley Center for Stable Isotope Biogeochemistry, where I analyze the carbon and nitrogen stable isotopes of mantis shrimp and their prey.

What is a stable isotope? Let's go back to high school chemistry for a moment! A normal atom has the same number of neutrons and protons in the nucleus, but a stable isotope has more neutrons than protons in the nucleus. For example, a normal carbon atom has 12 neutrons in the nucleus, but its stable isotope has 13 neutrons. These isotopes are stable, because they do not exhibit radioactive decay over time — they won't lose that extra neutron — which means that the isotope will always have 13 neutrons in the nucleus. Researchers look at the ratio of normal atoms to stable isotopes to track diet, because the ratio of normal atoms to stable isotopes in the body of a predator can reflect the type of prey it has eaten. For example, if the mantis shrimp has a ratio of 10 carbon-13 atoms to carbon-12 atoms and the crab that you think the mantis shrimp eats has a ratio of 8, then there is a good chance that the mantis shrimp eats this species of crab. The reason why the mantis shrimp’s ratio is not exactly 8 is that there is an expected change in the predator’s ratio that occurs when the predator metabolizes the prey. You are what you eat (plus a little bit!), and stable isotopes allow us to track this pretty accurately.

Back In the laboratory, my assistants and I identify all of the prey items and stomatopods that we collected. We then take muscle tissue samples from the mantis shrimp and from the prey. We use a mass spectrometer to analyze the carbon and nitrogen stable isotopes in both the mantis shrimp and prey tissue. Finally, we compare the isotope ratios of the mantis shrimp and prey to determine who ate what. Since the mantis shrimp is what it eats, all prey items that have isotope ratios similar to the mantis shrimp’s ratios are likely a part of the mantis shrimp diet.

To confirm the accuracy of the stable isotope analyses, I also conduct behavior experiments that help me to determine which animals mantis shrimp are physically capable of eating. To do this, I stock aquaria with mantis shrimp and potential prey, and I wait to see which prey the mantis shrimp eat. So far, I have performed this experiment on only one species, but eventually I will look at many species of mantis shrimp, with different appendage morphologies, to see if mantis shrimp with different appendage shapes have different diets. Together with the isotope analyses, these experiments will give me a good picture of mantis shrimp diet and ultimately lead to an in-depth understanding of the relationship between raptorial appendage morphology and diet across the mantis shrimp family. This fall, I’ll return to Panama to complete my field experiments, so stay tuned for updates in future blog posts!

To learn more about Maya's research, watch the Paleo Video Field notes: Collecting stomatopods on the Great  Barrier Reef.

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