Mauritius Libythid Butterfly

Known from only one specimen

Only a single specimen of the Mauritius libythid butterfly or snout butterfly is known, collected in 1865 on the Mascarene island of Mauritius in the Moka District. A certain Mr. Colville Barclay discovered the snout butterfly and gave it to the British-South African naturalist Roland Trimen, saying that this butterfly species was very rare on Mauritius.

Trimen described the Mauritius libythid butterfly a year later in Notes on the Butterflies of Mauritius as the new species Libythea cinyras. In doing so, he referred to a specimen of a butterfly in the South African Museum, collected by one E. L. Layard on the island of Madagascar, more than 1,000 kilometers away, which he said did not differ from the animal on Mauritius. According to Dawn Larsen, head of the museum collection, however, a review of the butterflies in the South African Museum resembling the Mauritius libythid butterfly shows that they are most likely African snout butterflies (Libythea labdaca).

In his original description of 1866, Trimen also stated that a butterfly similar to the Mauritius libythid butterfly had also been collected at the mouth of the Shire River in Mozambique, a country in southeastern Africa. Later, in On some hitherto undescribed butterflies inhabiting southern Africa (1879), Trimen found that this too was not the same snout butterfly as on Mauritius, but rather Libythea laius, which in turn resembles L. labdaca.

Because of the great visual similarity between the snout butterfly species, scientists suggested that ancestors of the Mauritius libythid butterfly flew from Madagascar or Africa to Mauritius. In this way, a new species could have evolved over time.

Mauritius libythid butterfly – fact sheet

alternative name	Mauritius snout butterfly
scientific names	Libythea cinyras, Libythea labdaca cinyras
original range	Mauritius (Indian Ocean)
time of extinction	unclear, 1865 at the earliest
causes of extinction	unclear
IUCN status	extinct

Snout butterflies: at rest they resemble a withered leaf

Snout butterflies (Libytheinae) are a small subfamily of brush-footed butterflies (Nymphalidae) consisting of only two genera with 15 species and numerous subspecies. These day-flying butterflies are mostly brown and, unlike other butterfly species, possess especially long and scaled palps, four times the length of the head, which look like a snout.

In 2013, the Japanese-American entomologist Akito Y. Kawahara revised the extant and fossil genera and species of the snout butterflies. In the process, he synonymized 41 species names. In Systematic Revision and Review of the extant and fossil Snout Butterflies, Kawahara confirms the species status of the Mauritius libythid butterfly.

Mauritius libythid butterfly: causes of extinction unknown

The IUCN has listed the Mauritius snout butterfly in its Red List as Extinct since 1986. The conservation organization gives no information about possible causes of the butterfly’s extinction.

Only with the settlement of Mauritius by humans at the beginning of the 17th century did land-dwelling mammals such as rats, mice or mongooses reach the island at all. Before that, bats were the only mammals living there. The small Mauritian flying fox went extinct between 1864 and 1873 due to hunting and the destruction of its natural habitat.

The more than 100 native bird species living on Mauritius were and still are threatened by introduced mammals and changes to their habitat. At least eleven endemic bird species went extinct on Mauritius between 1690 and 1837, such as the dodo or the red rail (Aphanapteryx bonasia).

Introduced animals also became a threat to the island’s reptiles. For example, the Mauritian giant skink died out in the mid-17th century, and two species of giant tortoise had already been exterminated by Dutch settlers by around 1700.

Changes to its habitat and vegetation, or perhaps even the displacement of its caterpillars’ main food plant, may also have proved fatal to the Mauritius libythid butterfly. The butterfly species Morant’s Blue, once native to South Africa, probably also died out around 1879 due to habitat loss.

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