An expedition to Madagascar largest and most intact forest found 21 species that were considered lost to science. A team studying the Makira forest found three iridescent, almost translucent fish species and the first documented sighting of an approximately 10-inch long millipede in 126 years. The dark brown centipede was probably never considered lost by the local communities.
The September 2023 expedition lasted several weeks and was part of the Searching for lost speciesa long-term project of the environmental organization Re:Wild. Local guides and teams from Antananarivo University, American Bird Conservancy, The Peregrine Fund, Wildlife Conservation Society and Biodiversity Inventory for Conservation (BINCO) also participated in the search. Several specialized teams searched the forest for various invertebrates, amphibians, reptiles, birdsfish and mammals that have not been documented in the past 10 years or more but are not yet considered extinct by the World Health Organization. IUCN Red List of Threatened SpeciesThe entire team spent several months analyzing their data
(Related: Why small, scary and ‘non-charismatic’ lost species are harder to rediscover.)
“In the past, the Search for Lost Species has primarily looked for one or two species on each expedition, but there are now 4,300 species that we know of around the world that have not been documented for a decade or more,” Christina Biggs, Re:wild’s lost species officer and biologist, said in a statement. “Madagascar is a biodiversity hotspot and Makira is an unexplored area of the country, so we decided to test a new model for lost species. We got a group of scientists together to look for as many species as possible, and it worked.”
A large brown beetle
Makira was home to several lost species of insects. Some of the insects were not even on the original list of lost species for the area and were found by chance. The team’s entomologists found two different species of ant-like flower beetles which had been lost to science since 1958. The most unexpectedly rediscovered lost species was a large, dark brown centipede.
“Personally, I was most surprised and pleased by the fact that the giant centipede Spirostreptus sculpture“not uncommon in the Makira forest, turned out to be another lost species known only from the type specimen described in 1897,” BINCO entomologist Dmitry Telnov said in a statement. “The longest specimen of this species we saw in Makira was a truly gigantic female measuring 27.5 centimeters (10.8 inches) in length.”
They also found a variety of spider species, including five jumping spiders which were considered lost to science because they were not documented, but not necessarily to the local population. Seventeen of the spider species found on the trek are considered new to science. The jumping spider Tomocyrba decollata holds the record for the longest lost spider. It had not been documented since 1900, when it was first described by outside researchers.
(Related: Discover the strange new species discovered near Chile – with the help of a deep-diving marine robot.)
A new species zebra spider was the most unexpected buggy discovery. Previously, scientists did not think that zebra spiders lived in the rainforests of Madagascar. However, one of the team members saw a hanging egg sac in the entrance of a small cave.
“I immediately recognised them as something special,” Brogan Pett, director of the SpiDiverse working group at BINCO and a PhD candidate at the University of Exeter, said in a statement. “Hanging egg sacs are one of the hallmarks of the zebra spider family to which this new species belongs. I crawled a short distance into the cave and saw a couple of adult spiders guarding egg sacs. They were quite large spiders and it was remarkable that they had gone unnoticed for so long.”
Three Lost Fish
Initially, the team had a list of over 30 lost species that they hoped to find in Makira. This included three mammals, three fish, seven reptiles, 12 insects and five spiders. They found all three fish species with the help of local fishermen and guides. The Makira rainbowfish (Bedotia alveyi) And Ptychochromis makira which had been lost since 2003 and Rheocles sp–lost since 2006. Finding these fish was much more difficult than the team expected.
“When we didn’t find anything during the first five days of the expedition, it was very frustrating,” Tsilavina Ravelomanana, a fish biologist at Antananarivo University, said in a statement. “We took samples from a small tributary of the Antainambalana River, then from the main river, then upstream, then downstream, but we still didn’t find any fish. We changed our strategy and sent our local guides on a two- to three-day hike away from our base camp to interview local fishermen.”
Two local expedition guides – Melixon and Edmé – hiked around a steep waterfall and over mountains to villages from the expedition base camp along the Antainambalana River. The guides found the Makira rainbowfish – a common fish in local communities – after a few days. 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 the Rheocles sp. This fish is only a few centimetres long and has iridescent scales and red highlights on its body at the tips of its fins. Melixon and Edmé found it in collaboration with local fishermen.
(Related: ‘Lost Bird’ Not Seen in 20 Years Photographed for First Time.)
“We already had two species, but we had to find one more,” Fetra Andriambelomanana, a fish biologist at Antananarivo University, said in a statement. “The guides told us they thought the best place to find it would be an area on our walk back out of the forest. They left before us and we made plans to meet them as we left Makira.”
They also found a fish named Ptychoromis makiraBiologists believe that this species lives only in a small area near Andaparaty and that it is a rare species, even for local communities.
Among the species the team could not find were the Masoala maki with fork mark–not documented since 2004–and a large chameleon named Calumma vatososa–not documented since 2006.
