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Marine vertebrate paleontology in Half Moon Bay

Paleontology along California's coastline

Paleontology along California's coastline. A) Fieldwork on the coast often involves climbing up ledges to get access to just one more meter of outcrop. B) A fossil tooth of the great white shark, Carcharodon carcharias. C) A freshly collected tympanic bulla of an extinct porpoise (Phocoenidae).

This week, we welcome guest blogger Robert Boessenecker. Bobby has been interested in paleontology since he was a kid. He grew up in the Bay Area; when he found Miocene shark teeth in the Santa Cruz Mountains, he was hooked.  He first got involved with the UCMP when he was a high school freshman — he visited the museum with his dad, to interview UCMP Assistant Director Mark Goodwin for a school project. Bobby is now getting a Masters' degree at Montana State University. He studies the taphonomy and preservation of marine vertebrate fossils in the Mio-Pliocene Purisima Formation of Central California.

After the completion of my first year of college, I was relaxing during my family's annual vacation at Lake Tahoe. While at the beach I received a phone call from my uncle; a surfing buddy of his had discovered a bunch of fossil bones somewhere near Half Moon Bay. I was excited, primarily because few discoveries of fossil vertebrates had been made along the San Mateo County coastline. I knew that much of the county's shoreline was made of the Purisima Formation, a rock unit I was familiar with from collecting fossils in the Santa Cruz area.

The Purisima Formation is late Miocene and Pliocene in age (7-2.5 Mya). In the Santa Cruz area, fossils of sharks, rays, skates, bony fish, sea birds, walruses, fur seals, dolphins, belugas, baleen whales, and sea cows had been discovered. With such a diverse fossil assemblage, I knew there was serious potential for discovery at this new spot in Half Moon Bay.

A day or two after we returned from Tahoe, my friend Tim Palladino and I followed directions to the locality, and sure enough, it was all Purisima Formation. When we arrived, the exact spot the surfer pointed out was up along a two foot wide ledge overhanging a thirty foot drop to the beach; neither of us were crazy enough to try climbing up there, and we decided to explore elsewhere. Shortly thereafter, we discovered several bonebeds with abundant bones and invertebrate shells preserved. Because the locality was on government-owned land, collecting without a permit was illegal.

After returning to Montana for my second year of college, I applied for (and eventually received) a permit, so that I could return to the locality and establish a collection. In summer 2005, I returned, and discovered a fossil skull of a baleen whale. The excavation took four days and half a dozen volunteers, but eventually the skull was excavated and wrapped in a plaster jacket for safe transport back to Montana. After the plaster jacket was removed that fall, I found that the skull was also encased in a concretion — the sandstone closer to the middle of the skull had been cemented with calcium carbonate, the same mineral in limestone. Needless to say, preparation took four and a half years, and was only finished in March 2010.

In 2006 I returned to the locality. We made two major finds that summer: the nearly complete skull of a fossil porpoise, and a complete lower jaw of the "'dwarf"' baleen whale Herpetocetus. In addition to these finds, by the end of 2006 I had collected several shark teeth (including those of great white sharks, basking sharks, angel sharks, a mako shark, and even a sawshark), fish bones, the humerus of an extinct flightless auk (Mancalla diegensis), bones and teeth of a walrus and a fur seal, and multiple ear bones of porpoises and several baleen whales (Herpetocetus, a right whale, and a rorqual whale). All of this fossil material is currently under curation for UCMP collections. UCMP has more fossil material from the Purisima Formation than any other repository, and now it is the recipient of an entirely new fossil assemblage from the Purisima. All in all, the collection includes several hundred specimens that represent 22 different species of marine vertebrates.

To learn more about Bobby's research, check out his blog, The Coastal Paleontologist.
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Special exhibit: Fossil eggshell

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This week, we've launched a new online special exhibit — Fossil eggshell: Fragments from the past. This is the best online source of information about fossil eggshell — you can't find this info anywhere else!  This special exhibit was created in collaboration with Laura E. Wilson, Karen Chin and Emily S. Bray, from the University of Colorado, Boulder, and Frankie D. Jackson from Montana State University.

We can learn a lot from fossil eggshell. Using scanning electron microscopy, we can examine the details of the shell morphology and structure. This provides clues as to the identity of the egg-layer; different groups of animals have very different types of shells. Fossil eggshell can also tell us about the ecology and behavior of the egg-layers — and their babies.

This online special exhibit features a case study of the Willow Creek Anticline in the Two Medicine Formation, Montana, where paleontologist Jack Horner and colleagues found numerous dinosaur eggs and eggshell fragments. Read about the discovery of the fossils, and what Jack and his colleagues learned about the egg-layers — dinosaurs Maisasaura and Troodon — through their detailed analyses of the fossil eggshell.

Much of the material in the online exhibit comes from the Hirsch Eggshell Collection at the University of Colorado Museum of Natural History. The collection was donated by eggshell enthusiast Karl Hirsch who made significant contributions to the field of fossil eggshell research. Learn about his legacy in the special exhibit section Karl Hirsch and the Hirsch Eggshell Collection.

Visit the UCMP on Cal Day!

Cal Day 2009Join us at the UCMP on Cal Day, Saturday April 17!  Events run from 9am to 4pm; check the schedule for a full listing of activities. Here are just a few of the Cal Day events at the UCMP:

~ Take a tour of the collections with a museum scientist. The collections are open to the public just one day a year, so this is your chance! Tours are held throughout the day, but tickets are first-come, first- served, and they go fast — come early to pick up your free tickets in advance.

~ Visit the special mini-exhibit, If You Build It They Will Come: New Construction Means New Fossils. See the bones of a short-faced bear found while digging the Alameda Tube. Check out a ground sloth discovered while building the Oakland Coliseum. Look at mammoth teeth found right here in Berkeley while excavating for the Downtown Berkeley BART station. And learn what might be uncovered in upcoming construction projects, like the fourth bore of the Caldecott Tunnel and the construction of California's high-speed rail line. To learn more about fossils found during construction, see the recent blog post Fossils found fortuitously.

~ Search for fossils in the hands-on Fun with Fossils activity. You’ll find real fossilized fish scales and maybe even a dino tooth!

~ Enjoy a talk by a UCMP scientist.

  • Evolution's Big Bang: Explaining the Cambrian Explosion of Animals, with Charles Marshall, 11am.
  • The Sierra Nevada: Old or New? Higher or Lower? What Fossil Plants Tell Us, with Lenny Kouwenberg, 1pm.
  • The Life and Times of Triceratops, with Mark Goodwin, 2pm.

~  Think you've found a fossil? Bring it to the Biodiversity Road Show and expert paleontologists will help you identify it. Experts from botany, zoology, and entomology will be there too, so bring in any specimens you're curious about.

To get a taste of what's in store, check out this audio slide show, Cal Day at the UCMP, which shows highlights from Cal Day 2009.

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UPDATE!

Thank you for joining us for Cal Day 2010! To look at some photos from the day, check out Cal Day at the UCMP.

Highlights from Understanding Evolution

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Map and photos: Tom Devitt

Ring species are often touted as examples of speciation in action — and the Ensatina salamander, which forms a ring around California's Central Valley, is a classic example. Biologists discovered this ring species back in the 1950s, and investigations of Ensatina continue today. Learn more about Ensatina in this research profile of biologist Tom Devitt, on the UCMP's Understanding Evolution website. Tom is a graduate student in Integrative Biology here at UC Berkeley. The profile follows him from the field to the lab, from studying the morphology to investigating the molecules. Tom even does some exciting experiments on Ensatina mating behavior — be sure to check out this research profile!

Creatures from the black lagoon

Lake Merritt

Lake Merritt, Oakland, California.

Very little was known about wetland ecology back in 1869, when Samuel Merritt dammed a former tidal slough and began developing its surrounding wetland as his "Jewel of Oakland." By restricting the flow of waters in and out of the newly created tidal lagoon, a.k.a. Lake Merritt, silt and algae were allowed to accumulate and within a few years the lake had become a bit of an environmental disaster. Nevertheless, part of it was designated by Teddy Roosevelt as our nation's first wildlife refuge, protecting more than 90 species of migrating waterfowl. Lake Merritt serves as a drainage basin for the regional flood control system, receiving urban runoff from a 4,650-acre watershed through 60 storm drain outfalls. Four creeks drain into this 145-acre lagoon from the east, while tidegates regulate flow to the south through a narrow channel that connects it with Oakland Inner Harbor and San Francisco Bay. The lagoon is also polluted by illegal dumping of substances such as paints, solvents, and oil, which are highly toxic to marine life. In addition to mechanical harvesting of its widgeon grass, 1,000 to 7,000 pounds of trash are removed from the lagoon every month. Merritt’s short-lived dream as a spectacular swimming hole in downtown Oakland is, in reality, more accurately described as a very large recreational sewer.

Despite all of its tarnish, the Jewel of Oakland has been a haven for some organisms that thrive on an abundant supply of bacteria and algae and tolerate the tidal, seasonal, and anthropogenic changes of this stressed environment. Among them are a few species of microscopic foraminifera (think of sand-sized shelled amoebas) that are being monitored by Ken Finger, Jere Lipps, and Dawn Peterson. Recent studies have shown that foraminifera might be useful environmental indicators of pollution. Lake Merritt presents an opportunity to study how they will respond to the remediation measures planned by the City of Oakland. Currently, only the shoreline of the lake supports living populations of foraminifera, while the deeper lake bottom is a dead zone of black mud stinking of methane. Why is that, you ask? Well, all of the algae, widgeon grass, bird droppings, and other organic waste that escapes harvest sinks to the bottom, and the process of their bacterial decomposition depletes the dissolved oxygen in the stagnant water just above. In contrast, wind-driven circulation keeps the surface waters and shallow margins circulating and aerated, enabling fish, invertebrates, plants, and foraminifera to survive.

But the foraminifera have a higher coincidence of malformed shells in Lake Merritt than in San Francisco Bay, which could be related to their stressed environment, where temperature, salinity, and oxygen levels change regularly. Studies elsewhere suggest that these micro-mutants result from high levels of contaminants, heavy metals, industrial pollution, and domestic sewage. In 2002, Oakland passed a bond measure that will clean up and improve the health of the lake by increasing tidal flow and installing aeration units. With these changes, will the shell deformities become less severe or more infrequent? Will living foraminifera begin to colonize the deeper parts of the lake? We hope to answer these and other intriguing questions as we continue to collect and analyze these minute “creatures from the black lagoon.”

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Fossils found fortuitously

Whale Excavation INot all fossils are discovered by paleontologists combing the earth on special expeditions. Many fossils are found by accident — particularly during construction projects. Impressive fossils, like whales, mammoths, and sloths, have been found while digging foundations for buildings, leveling land for highways, and excavating subway tunnels. This spring, the UCMP blog will take you on a tour of Bay Area construction sites, past and present, to show you some of the fossils underfoot in the region.

This week, Dave Haasl, a former Museum Scientist at the UCMP, tells us about his work with PaleoResource Consultants, a consulting firm that performs what is known as mitigation paleontology. If fossils are found on public lands during construction, the law requires that they be preserved. The fossils need to be excavated quickly, so that construction can carry on. And, the fossils need to be excavated by trained paleontologists, so they are properly preserved for future scientific study. This is a job for mitigation paleontologists! As Dave explains, "we need to mitigate the impact [of construction] to scientifically important resources. This includes fossils, as well as archaeological specimens."

There are two parts to mitigation paleontology. First, the paleontologists do pre-construction field surveys. "We look at the stratigraphy of the area, and plot the potential fossil localities," says Dave. Then, when those areas are dug up, workers know to be on the lookout for fossils. The second part of paleo mitigation is monitoring, which occurs throughout a construction project. Construction workers may not recognize fossils when they come across them, so it's important to have a trained paleontologist on site. If fossils are found, the monitors halt construction and quickly excavate the fossils. They call in a network of paleontologists, and typically they are able to excavate the fossils within a few days.

Recently, two marine mammal skeletons, a whale and a dolphin, were found during the construction of a sea wall along the California coastline. Santa Cruz County is building a sea wall between Santa Cruz and Capitola, to protect the cliffs and buildings from large waves. However, the sea wall will block access to that section of the coastline, preventing any future paleontological exploration of the area. Paleontologists were asked to survey the area before the wall was built, to see if any fossils were present.

An amateur paleontologist had seen vertebrae protruding from the sandstone — these vertebrae belonged to a small whale that lived in the late Miocene, about 5 million years ago. PaleoResource Consultants excavated the specimen, wrapped it in plaster to protect it during transport, and brought it back to their offices in Auburn, California, where it is now being prepared.

A second skeleton, a dolphin, was found by Robert Boessenecker, a graduate student at Montana State University studying marine vertebrate fossils in California. The dolphin, now extinct, is also from the late Miocene, and is related to the Chinese river dolphin. "Marine mammals were much more diverse at that time," says Dave.

While Dave's career path as a paleo mitigation consultant may seem unusual, there is a real need for trained paleontologists in this field. "There is more paleo work in the West than paleontologists who can do it," he says. "Often, archaeologists do the work, because paleontologists are not available." And this work is important. As a result of big construction projects, fossil material is collected that otherwise would still be in the ground. These specimens are then used in scientific research. Says Dave, "This is our historic heritage. If it's destroyed or sealed off, we're losing something of potential scientific value. Yeah, we need roads, we need power plants. But we're going to try to preserve as much of our past as we can."

Learn more about fossils found during construction projects in upcoming blogs!

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Fish in the UCMP

Salmonid FossilIt is pretty unusual to see fish in the UCMP. It’s not that we don’t have any fish specimens — we have over a million fossilized fish fragments. It’s just that none of our museum scientists focus on fish, and so the museum’s fish parts tend to stay in the cabinets. But this past summer, Ralph Stearley of Calvin College visited the UCMP, and he did a little fishing.

Ralph pulled some spectacular specimens from the murky depths of the cabinets. The two specimens shown here are exceptional — nearly all the bones are in place, and one of the specimens even has imprints of scales! It is really rare for fish to fossilize like this — most of the time, fish break apart into individual bones and tiny scales.

These two specimens are salmonids. They are related to salmon, char, and trout — their closest living relative is probably the Dolly Varden. They lived 15-10 million years ago, in the ancient lakes that back then dotted Western Nevada. They were collected by UCMP curator Howard Hutchison in 1975, in an area called Stewart Valley. This site contains fossilized vertebrate, insect, fish, and plant material — it is rare to find so much taxonomic diversity in one place. Hutchison and his colleagues really got a sense of the entire fauna that once inhabited the area.

Ralph was excited to find these salmonid specimens in our collection — he and his collaborator, Gerald Smith of the University of Michigan, study the biogeographic history of salmonid fish. These specimens provide evidence that salmonids once lived in Western Nevada. For Ralph and Gerald, these fish are definitely keepers.

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Predicting the future of San Francisco Bay: Learning from history

Short Course 2010

Speakers at the University of California Museum of Paleontology's 2010 Short Course, Predicting the future of San Francisco Bay: Learning from history. From left to right: Andrew Cohen, Will Travis, Jere Lipps, and Doris Sloan. Not present: Robin Grossinger.

Hundreds of thousands of people cross San Francisco Bay each day. But as commuters zip through the BART tunnel or drive over the bridges, they probably don't think about what the Bay looked like in the past — or what it will look like in the future. On Saturday, February 6, over 150 people attended the UCMP's annual Short Course, Predicting the future of San Francisco Bay: Learning from history. Throughout the course's five talks, they saw a very different view of San Francisco Bay.

A theme that emerged from the course was that San Francisco Bay is constantly changing. Doris Sloan, Adjunct Professor in Earth and Planetary Science at Berkeley and Curatorial Associate at the UCMP, spoke about the geologic processes that shape the Bay. For example, sea levels have fluctuated dramatically throughout the Bay's history. In the past, sea levels were low enough to make the Bay a dry river valley — and were high enough to make San Francisco an island. UCMP Faculty Curator Jere Lipps talked about the Bay's geology, too. He emphasized tectonic processes that are happening in the present day — and he brought his earthquake bucket. (If you live in a tectonically active area, please see below for more info on earthquake buckets!) The next speaker, Robin Grossinger of the San Francisco Estuary Institute, showed that geologic processes aren't the only things that shape the bay. He compared fascinating old maps to recent aerial photos to show that humans are responsible for numerous changes to the shoreline over the past 200 years. Andrew Cohen, Director of the Center for Research on Aquatic Bioinvasions (CRAB), talked about the ecological history of the bay. It is important to know which organisms (and how many of them) lived in the Bay, as we make plans to restore it. And Will Travis, Executive Director of the San Francisco Bay Conservation and Development Commission (BCDC), talked about strategies for adapting to changes in the Bay that will occur in the future. Throughout the short course, it became clear that that San Francisco Bay has been changing since it first formed — and it will continue to change. At this point, we know a lot about the Bay — and we can use this knowledge as we plan for the future.

To learn more about the speakers, look at the agenda for the Short Course. The PowerPoint presentations will soon be available. And in a few weeks, videos of the presentations will be available on UC Berkeley's YouTube channel, iTunes U, and webcast.berkeley.edu. Check back for the links!

** In the event of an earthquake, Jere won't share the contents of his bucket with you – you need to put together your own earthquake preparedness kit! The website 72hours.org has a list of things you should include in your bucket. In addition to the items on the list, Jere suggests including a few other things that might just save your life: a wind-up radio/flashlight, a small one-burner propane stove, pillows, and gloves and kneepads for crawling around on broken glass and debris. If Haiti's recent earthquake is any indication, it could be several days before emergency services are able to reach everyone; Jere recommends including a supply of food and water to last at least 7 days.

How many mammoths?

Jake Enk cuts off a piece of a mammoth toothA few weeks ago, the UCMP welcomed visitor Jake Enk, a graduate student from McMaster University in Hamilton, Ontario. Jake visited the UCMP to saw off chunks of fossil mammoth teeth. Yes, you read that right. He took a small saw, sterilized the blade with bleach, and sliced off a small piece of tooth. Even after tens of thousands of years, mammoth teeth still contain DNA. Jake will put a little piece of the tooth in a test tube, and use a series of chemicals to purify the mammoth DNA. He does this work at the McMaster Ancient DNA Centre. The DNA from the mammoths' teeth can tell us about mammoth population structure.

Here at the UCMP, Jake took samples from 35-40 mammoth teeth in our collections — including one of Lupé's teeth! The UCMP is just one stop on his museum tour — Jake visited the Illinois State Museum, the University of Nebraska State Museum, the Denver Museum of Nature and Science, and the Santa Barbara Museum of Natural History. Over the course of his trip, Jake collected samples from a total of about 175 animals. The mammoth teeth were collected all over the country — from Florida to Washington, and many localities in between. And, the animals lived at different times, over a period of about 200,000 years. By looking at the genetic diversity of the mammoths, through space and time, Jake will learn about variation in the size of the mammoth breeding population. This information can then be used to help answer ecological questions about mammoths.

Jake Enk's visit to the UCMP was funded in part by the Welles Fund. To learn how you can support research at the UCMP, click here.

Cutting off a piece of mammoth tooth Examining mammoth tooth sample

Collaborating, with the help of the collections

Triassic research group A few weeks ago, we blogged about the discovery of a new species of dinosaur, Tawa hallae. Two UCMP alums, Sterling Nesbitt and Randy Irmis, described this new dino in the journal Science. A few weeks ago, Sterling, Randy, and two of their Tawa co-authors, Nate Smith and Alan Turner, visited the UCMP. They've come from Texas, Utah, Illinois, and New York, to work together and delve into the UCMP's collections. Along with UCMP Faculty Curator Kevin Padian and graduate student Sarah Werning, they are looking at the fossils in old collections — dinosaurs and crocodile relatives that lived around the same time as Tawa, in what is now Arizona and New Mexico.

"We're looking at the old fossils in the context of new ones," says Randy. Many of the fossils were collected by Charles Camp in the 1930s — others were collected even before that. Quite a few were never identified and have not yet been entered in the UCMP’s database. For those specimens that were identified, says Sarah, "we're potentially re-identifying them." There are many new species that were not known when the fossils were last studied. In looking through these old collections, the team could find additional specimens of Tawa, or specimens that represent species that have not yet been described.

Their work in the collections will likely influence their field work plans this summer.  They're returning to the Hayden Quarry, in New Mexico, for their 5th full season. They'll also visit nearby areas where fossils from the old collections were found, years ago. "Some of the big discoveries in paleontology have happened when you re-identify fossils that have already been collected, and then you go back to a particular area to look for more," says Nate.  For example, Tiktaalik, an important fossil that represents an intermediate form between fish and amphibians, was found when paleontologists re-visited a field site in Nunavut, Canada.

The scientific community will reap some benefits as a result of this week's work. As experts in the field of Triassic dinosaurs, "we play a mini-curatorial role," says Nate. They straighten out the identities of the fossils, and they add the specimens to the database, so other researchers can access this information.

When they're not looking through the collections, the team clusters around their laptops in the Padian lab, drinking coffee and Diet Coke and bouncing ideas off each other. It's great to be all in one place, they say. Online communication is "good for getting things started and wrapping things up," says Alan, "but for the meaty part in the middle it's best to be in one place."

This research was made possible in part by the Welles Fund. To learn how you can support research at the UCMP, click here.