Expedition To Madagascar: in Search of Lost Species

Local guides help scientists find long-lost species of living creatures in Madagascar's Makira Forest. An expedition to Madagascar's largest and most pristine forest has discovered 21 species thought lost to science.

However, the dark brown millipede was likely never considered lost to the local population. The expedition, which took place in September 2023, took place over several weeks as part of the long-term "Search for Lost Species" project run by the environmental non-profit organization Re:Wild.

Local guides and teams from the University of Antananarivo, American Bird Conservation Society, Peregrine Fund, Wildlife Conservation Society and Biodiversity Inventory for Conservation (BINCO) also participated in the search.

Various specialized teams surveyed the forest in search of various invertebrates, amphibians, reptiles, birds, fish and mammals that have not been seen for 10 years or more but are not considered extinct on the IUCN Red List of Threatened Species. The full team spent several months analyzing the data.

In the past, the Search for Lost Species Project has mostly looked for one or two species per expedition, "but now there are 4,300 species worldwide that have not been documented for a decade or more," lost species specialist and Re:wild biologist Christina Biggs said in a statement. "Madagascar is a biodiversity hotspot and Makira is a little-explored area of the country, so we decided to test a new model for finding lost species on it. We assembled a team of researchers to find as many species as possible, and it was successful."

Makira was home to several extinct insect species. Some of them were not even on the original list of lost species for the area and were found by chance. Entomologists discovered two different species of ant-like flower beetles that had been lost to science since 1958. The most unexpected of the newly discovered lost species was a large dark brown millipede.

"I was personally very surprised and pleased that the giant millipede Spirostreptus sculptus, often found in Makira forest, turned out to be another lost species known only from a type specimen described in 1897," BINCO entomologist Dmitri Telnov said in a statement. "The longest individual of this species we observed in Makira was a giant female 27.5 centimeters long."

They also found many species of spiders, including five jumping spiders (jumping spiders) that were considered lost to science because they had not been documented, but not necessarily to the locals. Seventeen species of spiders found during the hike are considered new to science. The jumping spider Tomocyrba decollata holds the record for the longest-lost spider. It has not been documented since 1900, when it was first described by researchers.

A new species of argiope (zebra spider) has become the most unexpected discovery in the field of insects. Scientists had not previously thought that zebra spiders lived in the rainforests of Madagascar. However, one of the team members saw a hanging egg sac at the entrance to a small cave.

"I immediately recognized something special about them," says Brogan Pett, director of the SpiDiverse working group at BINCO and a doctoral student at the University of Exeter. "Pendulous egg sacs are one of the characteristics of the zebra spider family to which this new species belongs. I crawled a little way inside the cave and saw several adult spiders guarding the egg sacs - they were quite large spiders, and it's amazing that they went unrecognized for so long."

The team originally had a list of more than 30 endangered species they hoped to find in Makira. It included three mammals, three fish, seven reptiles, 12 insects and five spiders. With the help of local fishermen and guides, they found all three species of fish. They are the Makira rainbow fish (Bedotia alveyi) and Ptychochromis makira, which had been lost since 2003, and Rheocles sp - lost since 2006. Finding these fish proved to be much more difficult than the team had anticipated.

"When we didn't find anything during the first five days of the expedition, it really upset us," Cilavina Ravelomanana, a fish biologist at Antananarivo University, said in a statement. "We took samples in a small tributary of the Antainambalana River, then in the main river, then upstream, then downstream, but we never found any fish. We changed strategy and sent our local guides on a two- to three-day trek outside our base camp to interview local fishermen."

The expedition's two local guides - Melickson and Edme - hiked around a steep waterfall and through the mountains to villages from the expedition's base camp along the Antainambalana River. After a few days, the guides found a rainbow makira fish, a common fish for the locals. They brought it back to base camp in a bucket of water.

A few days later, they returned to the same villages with photos of Rheocles sp. This fish is only a few centimeters long and has iridescent scales and red highlights on its body at the tips of its fins. Working with local fishermen, Melikson and Edme found it.

"We already had two species, but we needed to find another," said fish biologist at the University of Antananarivo, Fetra Andriambelomanana. "The Heads told us that they thought the best place to look for it was an area on the way back from the forest. They left before we did, and we agreed to meet up with them when we left Makira."

Species the team failed to find include a forked lemur from Masuala, not seen since 2004, and a large chameleon named Calumma vatososa, not seen since 2006.