A species of giant millipede, last documented in the late 1800s, has been found by a team of scientists in the mountainous rainforests of Makira Natural Park in Madagascar.
A further 20 species 'lost' to science were rediscovered during the expedition, including three iridescent species of fish and several species of ant-like flower beetles.
The expedition was part of Re:wild’s Search for Lost Species project, a global quest to find plants, animals and fungi that have been lost to science (though likely not to local communities) for at least 10 years – and sometimes hundreds of years.
Lost species expedition
In September 2023, a team of more than 30 researchers from Re:wild, Antananarivo University, American Bird Conservancy, The Peregrine Fund, Wildlife Conservation Society and Biodiversity Inventory for Conservation (BINCO), as well as local guides, set out into Makira's forests to find mammals, fish, birds, reptiles, amphibians and invertebrates that have not been documented for 10 years or more (and not assessed as extinct by the IUCN Red List of Threatened Species).
Christina Biggs, lost species officer for Re:wild, explains that the Makira expedition was different to previous research trips.
“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 in a decade or more,” says Biggs.
“Madagascar is a biodiversity hotspot and Makira is an under-explored area within the country, so we decided to pilot a new model for lost species searches there. We convened a group of scientists to search for as many species as possible, and it proved successful.”
Fishy finds
Over the course of several weeks, and with the help of local guides and fishers, the team found three species of lost fish: the Makira rainbow fish (Bedotia alveyi), lost since 2003, Rheocles sp., lost since 2006, and Ptychochromis makira, lost since 2003.
But it wasn't easy, admits Tsilavina Ravelomanana, a fish biologist at Antananarivo University.
“When we didn’t find anything during the first five days of the expedition it was very frustrating,” says Ravelomanana.
“We sampled a small tributary of the Antainambalana River, then the main river, then upstream and 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.”
After several days, local guides Melixon and Edmé eventually found a Makira rainbow fish (a common fish to local communities) several days' hike from the expedition’s base camp along the Antainambalana River. A few days later they also found Rheocles sp., a small, iridescent fish with red highlights running down its body, and Ptychoromis makira, which biologists think may only live in one small area near the community of Andaparaty.
Big bugs
Prior to the expedition, the team had a list of 30 species they were hoping to find in the forests of Makira, including several insects and bugs. But they found many more than this.
They discovered two species of ant-like flower beetles, lost to science since 1958, a variety of spider species, including five lost jumping spiders and 17 spiders that are new to science.
The team were particularly surprised to find a new species of zebra spider, an animal not thought to live in the rainforests of Madagascar. The spider was spotted in the entrance of a small cave by team member Brogan Pett, director of the SpiDiverse working group at BINCO and doctoral candidate at the University of Exeter.
"I crawled a short way inside the cave and saw a few adult spiders guarding egg sacs—they were quite large spiders and it was remarkable that they had gone unrecognised for so long.”
“I immediately recognised them as something special,” says Pett. “Pendulous egg sacs is one of the characteristics of the family of zebra spiders this new species belongs to. I crawled a short way inside the cave and saw a few adult spiders guarding egg sacs—they were quite large spiders and it was remarkable that they had gone unrecognised for so long.”
However, the most unexpected rediscovered species was a giant millipede: Spirostreptus sculptus.
“I personally was most surprised and pleased by the fact that the giant millipede Spirostreptus sculptus, not uncommon in Makira Forest, appeared to be another lost species known only from the type specimen described in 1897,” says Dmitry Telnov, an entomologist with BINCO on the expedition team.
“The longest specimen of this species we observed in Makira was a really gigantic female measuring 27.5 centimetres (10.8 inches) long.”
Since returning from the expedition, the team has confirmed 21 rediscovered species:
- Spirostreptus sculptus, (millipede) lost since 1897
- Tomocyrba decollata Simon, (jumping spider) lost since 1900
- Echinussa vibrabunda, (spider) lost since 1901
- Tetragonoderus tomasinae, (beetle) lost since 1931
- Omophron amandae, (beetle) lost since 1948
- Sapintus acuminatus, (ant-like flower beetle) lost since 1958
- Spaintus mediodilatatus, (ant-like flower beetle) lost since 1958
- Pandisus sp. (spider) lost since 1968
- Myrmarachne eumenes, (jumping spider) lost since 1978
- Pandisus parvulus Wanless, (jumping spider) lost since 1980
- Nethinius longipennis, (beetle) lost since 1980
- Goleba punctata, (jumping spider)lost since 1980
- Makira rainbow fish (Bedotia alveyi), lost since 2003
- Ptychochromis makira, (fish) lost since 2003
- Rheocles sp., (fish) lost since 2006
- Kaliella crandalli, (snail) lost since 2010
- Oxypristis conspicuous, (leaf-footed bug) lost since 1996
- Hypaspistes bouvieri, (ant-like flower beetle)
- Zetophloeus pugionatus, (straight-snouted weevil) lost since 2010
- Cenoscelis cistelina, (darkling beetle) lost since 2011
- Tamatasida tuberculosa tuberculosa, (darkling beetle) lost since 1949
Animals not found
Despite documenting lost 21 species, the expedition was unable to find a number of animals on their wish list, including the Masoala fork-marked lemur, a large chameleon known as Calumma vatososa, and the dusky tetraka – an Old World warbler.
“The Makira Forest has the potential for two rare bird species, the dusky tetraka and the Madagascar serpent eagle, but we were not able to find them this time,” says Lily Arison Rene de Roland, Madagascar program director for the Peregrine Fund.
“I was surprised by the abundance of white-browed owl. In general this species is very localised and not very abundant, but it was very common in Makira.”
The rediscovery of so many species in Makira was deemed a success by the Re:wild team, but they point out that the forest is still facing pressure from agriculture, and species in the underexplored forest could face steep population declines before scientists have an opportunity to study them.
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