Madagascar: Expedition Rediscovers 21 Lost Species in the Makira Forest

A scientific expedition to the Makira Forest, the largest and best-preserved forest area in Madagascar, has rediscovered 21 species long lost to science. Among the rediscovered species are three iridescent, nearly transparent fish species and a millipede last documented 126 years ago.

The expedition was part of the Search for Lost Species initiative by Re:wild and was conducted in collaboration with teams from the University of Antananarivo, the American Bird Conservancy, the Peregrine Fund, the Wildlife Conservation Society, and the Biodiversity Inventory for Conservation (BINCO). It was the first multi-taxa expedition of this initiative.

Specialists searched the Makira Forest for mammals, fish, birds, reptiles, amphibians, and invertebrates that had not been documented for at least a decade but were not listed as “extinct” by the IUCN Red List. The search spanned several weeks in September 2023, with the subsequent analysis of the results taking several months.

As many species as possible

While previous expeditions of the Search for Lost Species initiative primarily focused on finding just one or two lost species, the team aimed to rediscover 30 lost species this time. These included three mammals, three fish, seven reptiles, twelve insects, and five spiders. Globally, around 4,300 species have been missing for over a decade.

“Madagascar is a biodiversity hotspot and Makira is an underexplored area within the country, so we decided to pilot a new model for lost species searches there,” explained Christina Biggs, the Lost Species Program Manager at Re:wild. “We convened a group of scientists to search for as many species as possible, and it proved successful,” Biggs added.

Missing fish and insect species

Tsilavina Ravelomanana, a fish biologist at the University of Antananarivo, reported on the difficulties in searching for the fish. “When we didn’t find anything during the first five days of the expedition it was very frustrating,” he said. It was only through the support of local guides and fishermen and a changed strategy that the researchers were able to find the three missing fish species: the Makira rainbow fish (Bedotia alveyi), last collected in 2003, a yet-to-be-described species of the genus Rheocles, which was last seen in 2006 and is characterized by iridescent scales and red markings on its fins, and the cichlid Ptychochromis makira, which was last documented in 2003 and had significantly declined due to overfishing and habitat loss.

Entomologists also discovered several missing insect species, including two ant-like flower beetle species, Hypaspistes bouvieri and Sapintus mediodilatatus, which had not been documented since 1958. Particularly astonishing was the rediscovery of the giant, dark brown millipede Spirostreptus sculptus, which had only been known from the type specimen since 1897 and does not appear to be so rare in the Makira Forest. The longest specimen found by the expedition team was a female measuring 27.5 centimeters in length.

New and rediscovered spider species

Numerous spider species were discovered in the Makira Forest, including five lost jumping spider species and 17 new species. Particularly unexpected was the discovery of a new, relatively large species from the family of zebra spiders. Their hanging egg sacs were found in a small cave. This find was remarkable, as no one had previously suspected that zebra spiders inhabit the rainforests of Madagascar.

The longest missing spider species was the jumping spider Tomocyrba decollata, which had not been documented since its first description in 1900. Another rediscovered jumping spider species, Echinussa vibrabunda, was last recorded in 1901.

Species not found

Despite the successful rediscoveries, the team was unable to find some of the species they were searching for. These included the Masoala fork-marked lemur (Phaner furcifer), a lemur last documented in 2004, and the chameleon Calumma vatososa, last seen in 2006.

The dusky tetraka (Xanthomixis tenebrosa), rediscovered last year in Andapa and Masoala, was also not found during this expedition in the Makira Forest. Additionally, the team could not locate the Madagascar serpent eagle (Eutriorchis astur). The bird was considered missing and extinct since 1930 until it was rediscovered in 1990. The researchers were surprised by the frequent presence of the usually rare white-browed owl (Athene superciliaris) in the Makira Forest.

Despite its size, the Makira Forest remains under pressure from agricultural activities. The expedition team fears that the populations of the newly discovered and rediscovered species could decline significantly before they can be adequately studied. The researchers emphasize the need to enhance the protection and study of this unique ecosystem to prevent further species extinctions.