In the 2 October issue of Science, an international and multidisciplinary team co-led by Tim White of the University of California, Berkeley, unveiled the oldest known skeleton of a potential human ancestor as well as information about its living environment. Found in the Middle Awash  in the Afar region in Ethiopia, the 4.4-million-year-old skeleton became known as Ardipithecus ramidus, or Ardi for short. The discovery of the fossils was reported in 1994, but it was 15 years before the team presented its results to the world in 11 research papers .
Some of that work, at the time of the discovery and since, has been done by early-career scientists, which raises some interesting career-related questions: How do you become involved in such important research? What's it like? And how does working on such a project affect your career? To investigate these questions, Science Careers profiles two scientists involved in the Ardi project.
Born in Beirut, Faysal Bibi, 29, traveled extensively as a child. His travels sparked an early interest in "the discovery of cultures, as well as the history and the diverse biological backgrounds" of people, he says. While an anthropology undergraduate at the University of California (UC), Berkeley , Bibi took an interest in the search for the most ancient human origins and the study of human bones, volunteering for archaeological fieldwork in Honduras and learning how to analyze vertebrate fossils in the lab of Anthony Barnosky. When "I got my hands dirty for the first time with fossils, I discovered something that I really enjoyed," he says.
Bibi didn't pursue a Ph.D. immediately. Instead, he continued studying vertebrate fossils with Barnosky and started working with White, whom he knew as his undergrad professor of human osteology classes. As a research assistant in White's lab at Berkeley's Human Evolution Research Center , Bibi searched fossil collections and the scientific literature, and acquired and interpreted remote-sensing imagery to assist the lab's fieldwork.
Read more online  about Science's Breakthrough of the Year.
The opportunity to join the excitement at the Middle Awash digs came in November 2002. There and then, Bibi experienced what White calls the "hominid fever," he says. "You want to be the one who finds an important specimen." He did, eventually: an Ardi premolar.
Earlier that year, while visiting family in the United Arab Emirates, Bibi saw an opportunity to have his own excavation team when he found himself standing at the top of a fossil-rich hill in the island of Shuweihat in the Abu Dhabi emirate. "There were fossils everywhere, and I remember I pretty much lost my head in the excitement," Bibi says. He read a 1999 monograph written by Peter Whybrow and Andrew Hill on the Abu Dhabi fossil site White had loaned him for the journey. The paleontologists who had worked on the site previously had abandoned it, so Bibi then applied for funding from the Abu Dhabi government to start his own dig. As soon as his first field season with White in Ethiopia ended, "I was back in Abu Dhabi with two friends from UC Berkeley to find some fossils from the Abu Dhabi Baynunah sites," he says. "That experience really taught me the value of just taking opportunities, as and when they come, and not self-doubting too much."
Bibi's independent fieldwork proved to be a "giant catapult" into independent research, he says. "I was 22, fresh out of university, and in charge of a paleontological survey team. Of course, our team consisted of just three people, and we were all learning together, but the challenge was there." He says his experience in the Middle Awash "had given me the basics of survey, collection, and fossil conservation and preparation, everything from how to drive in off-road conditions to understanding the way fossils weather out of the ground. We did our best to replicate the meticulousness of the Middle Awash approach in Abu Dhabi, and despite our inexperience at the time, I think we did okay."
Fieldwork, Bibi says, is "the experience of discovery at its rawest." Yet it is also physically and emotionally demanding. In an area like the Middle Awash, for example, "You are constantly in a sort of struggle to deal with the things around you, anything from malaria parasites to ... water-born diseases, to snakes, scorpions, lions, hyenas, wild dogs, and let's not forget people," Bibi says. It "reminds you that you are alive," he says.
Fieldwork isn't just hard; it's also slow. Like the Middle Awash work, the Abu Dabi fieldwork will take a long time to reach the publication stage. Fossils are fragile and fragmented, often "not in any kind of condition that can be studied," Bibi says, which makes digging and documenting a very slow process. Back in the lab, cleaning and reconstructing fossils can take anywhere from months to years, depending on the specimen. Bureaucracy and fieldwork logistics can slow things down even further. Meanwhile, you can have "little to show for your work," Bibi says. Such long delays can hamper publishing and--hence--career advancement. "That's difficult sometimes to justify when you need ... a job."
Bibi's solution: "I conduct more specialized work that permits me to publish more regularly," Bibi says. In 2004, he started a Ph.D. with Elisabeth Vrba at Yale University  on the fossil record and evolution of bovids with a special focus on antelopes. This work uses specimens already available in museums and research labs. "The antelope fossil record is huge. There are more materials than there are people to study them," he says.
Some of these specimens were retrieved from the Middle Awash. Although not a co-author in the Science papers, Bibi contributed  to reconstructing the living environment of Ardi with taxonomic determination and comparative assessment of the common Aramis tragelaphine antelope. For his Ph.D. work, Bibi looked at Middle Awash antelopes dating from the late Miocene to the Pleistocene, including those found in the Ardi sites.
Bibi finished his Ph.D. in May 2009, then took a postdoc at the Institut International de Paléoprimatologie, Paléontologie Humaine: Evolution et Paléoenvironnements 
at the University of Poitiers in France. He sees the institute as a good place to advance his career while continuing his work as a member of various field teams: White's team in the Middle Awash, the Baringo Paleontological Research Project in Kenya with Hill, the Omo Group Research Expedition in southern Ethiopia with Jean-Renaud Boisserie, and his own Baynunah Paleontology Project, which he now co-leads with Hill. "My postdoc here allows me to interact with people who know about the site and for them to know about my work," Bibi says.
Bibi doesn't yet know what he's going to do next. One option is staying in a country like France or the United States with good funding and research opportunities. But he says he is also considering "returning where my roots are, and where my family is, in Lebanon, where the academic infrastructure is much more modest, but the opportunity for making a difference in terms of education is greater."
Jean-Renaud Boisserie registering different localities in the Djourab desert, Chad, in 2004.
Born just 20 kilometers away from the Paleolithic paintings of the Lascaux Cave in southwestern France and forming an early, keen interest in animals and history, Jean-Renaud Boisserie seemed destined for a paleontology career. At age 16, he helped excavate nearby archaeological sites during summer camps.
Boisserie obtained a B.Sc. degree in paleontology and earth sciences from the University of Poitiers 
Hippos "are frequent in the African paleoanthropological sites, ... but very often people don't collect them" because of their bulkiness, Boisserie says. A complete fossil hippo cranium, for example, is from 50 centimeters to 1 meter long and weighs between 30 to 80 kilograms. "It creates a lot of logistics problems."
Back in the lab, "You have to describe in detail the morphology: How are the teeth, how they are inserted on the cranium or a mandible, what is the shape of this mandible?" Boisserie says. Boisserie compared his Chad specimens with fossils found in other places and analyzed the hippos' diet by studying tooth morphology and microwear, and stable isotopes in teeth and bones.
He also reconstructed the distribution of the past hippos in the region. This work provided a bonus: Because hippos live mainly in water, "you get a picture of what was the distribution of rivers and lakes in Africa in the past," Boisserie says. This in turn gives you information about the environmental constraints for other animals, including our ancestors, he says.
Halfway through his Ph.D., Boisserie became an international volunteer at the National Museum of Ethiopia  in Addis Ababa for a year and a half as part of his military service, which was still compulsory in France. There, Boisserie met White as he was retrieving fossils from the Middle Awash; White asked him to join his Middle Awash dig, focusing on hippo fossils. Together, they collected several hundred hippo specimens, and Boisserie studied them as he had done with the ones from Chad. Boisserie helped preserve a chunk of the past Hippopotamidae record and reconstruct the environmental context in which Ar. ramidus lived some 4.4 million years ago, a contribution that made him a co-author of one  of the 11 Ardi papers.
During his time in the Middle Awash, Boisserie learned from White some lessons about fieldwork. White "expects a lot of you when you go to the field," Boisserie says. "He can get a lot of results from his field that many other people cannot get, thanks to his sense of perfection," he says. "I really benefited from that because it gives you a lot of rigor."
After obtaining his Ph.D., in 2002, Boisserie continued his research, both in Chad and the Middle Awash, while postdoc-ing with White at the Human Evolution Research Center . He also started deciphering the relationships between hippos and other mammals, expanding the fossil record showing that hippos are not related to pigs, as many paleontologists believed, but rather to whales, as geneticists had been arguing for some time already.
Boisserie came back to France in 2006 to take a permanent junior researcher position at the French National Center for Scientific Research . There, he has continued his research on hippo fossils in Chad and the Middle Awash and launched his own Omo Group Research Expedition  in the Lower Omo Valley in southwestern Ethiopia. That project focuses largely on sediments dated between 2 million and 3 million years, which corresponds to when "Australopithecus like Lucy ... gave birth to different hominid lineages, including ... our genus," Boisserie says.
This is also when the first stone tools were developed and when important environmental changes occurred, such as a drier climate with more grassland and different animals. "We want to ... understand what is actually the real impact of these environmental changes on our evolution," he says. Last July, at 34, he took a 2-year sabbatical from his institution, the Institut International de Paléoprimatologie, Paléontologie Humaine: Evolution et Paléoenvironnements  in Poitiers, to work at the French Centre of Ethiopian Studies  in Addis Ababa.
The long delay before the publication of the Ardi work was not a problem for Boisserie. "When you want to [present] something with a lot of details, with [a] general analysis of the environment, it takes a lot of time," he says. "When you are part of a project like that, you have your own research you conduct and you can publish other things ... that are faster." Today, his CV lists 36 publications, including descriptions of large mammals in the Ardi sites and of another important hominid called Toumaï Sahelanthropus tchadensis, which was found in Chad. His work also reports the discovery of new hippo species in Chad, the Middle Awash, and other places, and the study of the origins and relationships of Hippopotamidae. "I'm not just relying on these major papers with hominid description to be able to build my CV," he says.
A greater challenge for Boisserie is combining fieldwork with private life. "The people around you ... have to accept that you are going to go for 1 month, 2 months, 3 months every year in a place which is not always easy and where anything can happen," Boisserie says. "You have to be ready to have some pressure from your family about these issues. ... It's a difficult aspect of our job, definitely."
Elisabeth Pain is contributing editor for South Europe.