PhD candidates Unggul Prasetyo Wibowo, Indra Sutisna and Meagan Powley are part of a team investigating ancient island life from the Pleistocene. Their work involves excavating and researching fossils from Flores, Indonesia–an area that offers fascinating insight into an entirely unique ecosystem and its evolutionary pressures.
Flores itself, despite fluctuations in sea level over time, has been separated from larger land bodies through today. This has implications for the type of creatures that could access the island and sustain life upon it. Consider North American Pleistocene megafauna–mastodons and mammoths, for example–who had enormous expanses of land in which to roam and graze. Their size could be supported on a continent of resources. An island, in contrast, has only so much space, only so many resources.
“Island rule” refers to the evolutionary pressure that eventually dwarfs creatures in comparison to their larger mainland sizes. Smaller creatures in smaller spaces are more sustainable over the long term. So Flores is home to Homo floresiensis, a 3-foot hominin, and Stegodon florensis insular, a tinier version of an ancient elephantid.
To date, no fossil mammalian carnivores have been discovered there. Unlike North American felids like Smilodon, with terrifying claws and nightmarish fangs, Flores was the domain of reptiles: crocodiles and Komodo dragons.
Meagan, Indra, Unggul and their team are interested in understanding whether ancient hominins hunted Stegodon. During the Middle Pleistocene, Stegodon hadn’t yet dwarfed, so it was still the size of today’s elephant and thus would have been a potentially important source of nutrition. The team worked at Mata Menge, the site of numerous fossils, including a handful of Homo floresiensis and an entire bonebed of Stegodon florensis–a middle- to large-sized Stegodon. If evidence of butchering was to be found, this location was a great place to start.
In a paper published in the December 2021 edition of Quaternary, the three aforementioned colleagues, Katarina Mikac and Gerrit van den Bergh detail their observations of the bonebed, a collection of fossils that contains remnants of Stegodon, hominins, crocodiles, giant rats, birds and Komodo dragons. They chose to focus on Stegodon limb bones, as this would offer the best insight into possible hominin butchery. And while they did notice a number of traces on the Stegodon fossils, they determined that these were a result of possible trampling before becoming submerged and the processes a bone undergoes when traveling through a river.
I asked Meagan, lead author of the paper, if this was a disappointment. “I cannot say I was disappointed,” she wrote back in an email, “because I have come to really appreciate the research methodology, the examination of the material and identifying the taphonomic processing that likely occurred to modify the bones in the bonebed. This is really interesting as it uncovers what may have happened here before the final burial of the bones. When you do this type of research I think it is more about uncovering the story behind the material and what I reported on was one part of the whole story.”
She was, however, surprised by the overall findings, as “there are clearly two types of material at this site: the first was only transported short distances from the death sites, while the other highly fragmented material was very rounded and this is likely from long periods of transportation in water. Much of the material had experienced multiple taphonomic processing events, and some chronologically later modifications may have obscured modifications made at or close to the death of the animal. This finding is very interesting because it does leave open the possibility of identifying evidence for hominin modification in other material.”
“The exciting thing is that there is still much more material available to analyse and so with this preliminary study, and the research methodology I developed and tested, it would be possible to roll this out over a much larger scale, once we can return after COVID restrictions.”
Co-authors Unggul and Indra are geologists at the Geological Museum Bandung, where all of these fossils are housed.
“We work at the Geological Museum under the Geological Agency of Indonesia,” they explained in an email. “Our Geological Agency has been researching the island of Flores since the 90s. In 2009 until now there has been a collaboration between the Geological Agency (Indonesia) and the University of Wollongong (Australia) to study the paleontology of the island of Flores, since 2012 we have been actively involved as a research team.”
“[A]part from Flores Island,” they wrote, “we are also working on Stegodon fossils from [other] islands in Indonesia such as Java, Sulawesi, Sumba and Timor.”
This project was a group effort: it involved not only the scientists studying these fossils, but people from the local community.
“Our excavation project involved local tribes at least from three villages in Soa Basin,” Unggul and Indra stated. “They are people who [follow] the traditions that have been carried out since their ancestors. During our activities, we always follow local manners and we are happy for that.”
Among those listed in the acknowledgements in the paper are a number of people from Indonesia and Australia. Indra and Unggul explained:
- “Ruly Setiawan is our office colleague, he is a geologist who specializes in dating and geochemist.
- Dida Yurnaldi is our office colleague, he is a geologist who specializes in paleomagnetism.
- Erick Setiyabudi is our office colleague, he is a paleontologist who specializes in reptiles
- Ifan Yoga Pratama is our office colleague, he is a geologist
- Susan Hayes, she is a face reconstruction expert from Australia
- Fransiskus Bani is the owner of the house that we rent for our base camp in the Flores field. He always helps us if we need assistance especially in dealing with local residents.”
Meagan, who is based in Australia and studies at the University of Wollongong, wrote, “I spent nearly 3 months in Indonesia in total, during two visits. The first was to the museum in Bandung, where I worked with the museum staff looking at suitable material for this research and where I performed all the analysis. This was a great opportunity to have discussions about the material with some of team that had been on the excavations. Being immersed in the museum everyday certainly helped to keep up motivation over the long visit.”
“My second visit was to the excavation site Mata Menge on Flores. This was an amazing experience living and working in the village. We had 46 local men on our team at the excavation site as well as a team from the museum and the researchers from Australia. A long history of successful excavations here between the museum team, the researchers and the locals allowed for a great partnership. The house we stayed in was approximately 50 minutes’ walk from the site, through the village and local farmland. I enjoyed this walk as it gave me an opportunity to see the homes and people and say hello.”
“The research team from the University of Wollongong and other Australian universities have been excavating in association with the team from the Bandung Geological Museum and the locals regularly for more than 20 years,” Meagan wrote. “Many of the locals on our team had relatives also present and some were the children of the first team members. Each village in the area has representative members on the excavation team and this is coordinated at a local level using the local leaders. The long association between the museum, university and the locals has led to many friendships and contact is continued throughout the year. Some of the scientific team from the museum have also been students at the University of Wollongong.”
“Indonesia’s position which is between mainland Asia and Australia makes Indonesia have an important role in the study of migration of living things, both animals and humans in the past,” Indra and Unggul pointed out. “In the study of paleontology, islands in Indonesia also have an important role in testing scientific theories, especially in the field of evolution such as the island rule theory about the phenomenon of dwarfism in living things on an island and also endemicity phenomenon.”
I cannot express how grateful I am to Indra Sutisna, Unggul Prasetyo Wibowo and Meagan Powley–all of whom were incredibly busy (Indra and Unggul took time to write to me from the field!) and all of whom made time to answer my numerous questions. THANK YOU ALL!! It was great fun and a great honor connecting with you! I look forward to reading about your future discoveries!
- Louys et al. (2016), Direct dating of Pleistocene stegodon from Timor Island, East Nusa Tenggara. PeerJ 4:e1788; DOI 10.7717/peerj.1788
- Powley,M.J.;Sutisna,I.; Mikac, K.M.; Wibowo, U.P.; van den Bergh, G.D. The Stegodon Bonebed of the Middle Pleistocene Archaeological Site Mata Menge (Flores, Indonesia): Taphonomic Agents in Site Formation. Quaternary 2021,4,31. https://doi.org/ 10.3390/quat4040031
- Van den Bergh, GD; de Vos, J; Aziz, F; Morwood, MJ. Elephantoidea in the Indonesian region: new Stegodon findings from Flores. Conference: The World of Elephants, International Congress, Rome 2001. Volume: The world of elephants. Proceedings of the 1st International Congress, Rome