Lychas Braueri
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''Afrolychas braueri'', commonly known as the Seychelles forest scorpion, is a species of
scorpion Scorpions are predatory arachnids of the Order (biology), order Scorpiones. They have eight legs and are easily recognized by a pair of Chela (organ), grasping pincers and a narrow, segmented tail, often carried in a characteristic forward cur ...
in the family
Buthidae The Buthidae are the largest family of scorpions, containing about 100 genera and 1339 species as of 2022. A few very large genera ('' Ananteris'', '' Centruroides'', '' Compsobuthus'', or '' Tityus'') are known, but a high number of species-poor ...
. It is currently thought to survive only on
Silhouette Island Silhouette Island lies northwest of Mahé, Seychelles, Mahé in the Seychelles. It is the third largest Granitic Seychelles, granitic island in the Seychelles. It has an area of 20.1 km2 and has a population of 200, mostly workers on the ...
,
Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...
, although the species was historically found on two additional Seychellois islands. This scorpion lives in leaf litter in forests that are largely unaffected by invasive plant species. It is a small yellowish-brown scorpion with three prominent keels on the dorsal surface of its
mesosoma The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings. Wasps, bees and a ...
, which distinguishes it from other scorpions. While not much is known about the Seychelles forest scorpion's ecology due to the paucity of sightings, it is known to rely solely on its venom to capture its prey and defend its young. Its venom is not dangerous to humans. The Seychelles forest scorpion has only been observed a handful of times and as such is believed to live in very low population densities. It is listed as a
critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
species by the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
and is one of the most endangered scorpion species in the world. It is thought to be primarily threatened by invasive plant species, particularly ''
Cinnamomum verum ''Cinnamomum verum'' ( synonym ''Cinnamomum zeylanicum'', also called true cinnamon tree or Ceylon cinnamon tree) is a small evergreen tree belonging to the family Lauraceae, native to Sri Lanka. The inner bark of the tree is historically regard ...
'', degrading its habitat. Its entire known range is protected by Silhouette National Park, and recent conservation efforts on the island include vegetation restoration and the removal of cinnamon.


Taxonomy

The Seychelles forest scorpion was originally described in 1896 by
Karl Kraepelin Karl Matthias Friedrich Magnus Kraepelin (; ; 14 December 1848 – 28 June 1915) was a German naturalist who specialised in the study of scorpions, centipedes, spiders and solfugids, and was noted for his monograph ''Scorpiones und Pedipalpi'' (B ...
as ''Archisometrus braueri''. In 1913, it was moved to the genus ''
Lychas ''Lychas'' is a genus of scorpions belonging to the family Buthidae. It is one of the most widespread genus of the scorpions, where the species are found throughout in Africa and Seychelles, and in the Oriental region from India to Melanesia. De ...
'' by Arthur Stanley Hirst. ''Lychas'', a primarily Asian genus, was largely regarded as
polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...
and it was long suspected that this scorpion may belong to a different genus. In 2019, the species was split into the new genus ''Afrolychas'' along with '' Afrolychas burdoi'', a mainland African species believed to be its closest relative, by František Kovařík. The genus name ''Afrolychas'' is a reference to the African range of its species and to the fact that the two species used to be members of the genus ''Lychas''. The
specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...
''braueri'' is in honor of
August Brauer August Bernhard Brauer (3 April 186310 September 1917) was a German zoologist. Brauer was born in Oldenburg. He studied natural sciences at the Universities of Bonn, Berlin and Freiburg, obtaining his doctorate in 1895 with a thesis on the cilia ...
, a German zoologist who conducted scientific surveys in the Seychelles and who collected the initial specimens. The
type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...
was collected from
Praslin Island Praslin () is the second largest island (38.5 km2) of the Inner Seychelles, lying northeast of Mahé, Seychelles, Mahé. Praslin has a population of around 7,533 people and comprises two administrative districts: Baie Sainte Anne and Grand ...
by August Brauer in 1894 and is held at the Zoological Institute and Museum of the
University of Hamburg The University of Hamburg (, also referred to as UHH) is a public university, public research university in Hamburg, Germany. It was founded on 28 March 1919 by combining the previous General Lecture System ('':de:Allgemeines Vorlesungswesen, ...
. The species was next found in "high jungle" on Mahé and on Silhouette in 1905 by the
Percy Sladen Walter Percy Sladen (30 June 1849 – 11 June 1900) was an English biologist who specialised in starfish. The son of a wealthy leather merchant, Sladen was born near Halifax, Yorkshire on 30 June 1849. He was educated at Hipperholme Grammar Sch ...
Memorial Expedition. After these initial collections, it was not seen again until being rediscovered in 1990 in Silhouette's Jardin Marron.


Description

The Seychelles forest scorpion is a small, yellowish-brown scorpion measuring in length. It is best distinguished from similar scorpions by having three conspicuous keels on its
mesosoma The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings. Wasps, bees and a ...
's dorsal surface. Additionally, on both the movable and fixed fingers of the scorpion's
pedipalps Pedipalps (commonly shortened to palps or palpi) are the secondary pair of forward appendages among Chelicerata, chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to ...
, or pincers, the sixth cutting edge lacks external and internal granules. Overall this scorpion is a blotched yellowish-brown in coloration with a smooth and glossy fifth
metasoma The metasoma is the posterior part of the body, or tagma (biology), tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the mesosoma. In insects, it contains most of the digestive tract, respiratory sy ...
l segment and a notably long
telson The telson () is the hindmost division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment (biology), segment of the arthropod body, or an additional division that is not a true segm ...
, or stinger. Its pectens have 14–18 pectinal teeth. Adults are not noticeably
sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
. Its sting is not considered dangerous for humans.


Distribution and habitat

''Afrolychas braueri'' is currently only known from a wooded portion of
Silhouette Island Silhouette Island lies northwest of Mahé, Seychelles, Mahé in the Seychelles. It is the third largest Granitic Seychelles, granitic island in the Seychelles. It has an area of 20.1 km2 and has a population of 200, mostly workers on the ...
in the Seychelles. It is one of only three species of scorpion found in the Seychelles. It is only found in the higher elevations of this island between . Historically this scorpion was
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to the broader Seychelles, and was found on Mahé before invasive plants drove it to local extinction. The Seychelles forest scorpion is found at very low population densities. The Seychelles forest scorpion lives in the leaf litter of forests that are largely unaffected by invasive plant species and therefore maintain their natural flora, such as '' Dillenia ferruginea''. They shelter under stones and logs.


Ecology and behavior

The invasive ant species ''
Technomyrmex albipes ''Technomyrmex albipes'', commonly known as the white-footed ant, is a species of ant first described in 1861 from Sulawesi, Indonesia by the British entomologist Frederick Smith (entomologist), Frederick Smith. Invasive pest ants in Florida, pre ...
'' is known to have killed Seychelles forest scorpions. Like all buthid scorpions, the Seychelles forest scorpion relies solely on its venom to capture its prey. In June 2009, a female was discovered carrying seven young scorpions on her back, which she, like other scorpions, would care for until they were able to survive on their own.


Conservation

The Seychelles forest scorpion was assessed as a
critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
species by the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
in 2012. It is currently known only from a small area of woodland on Silhouette Island that is being degraded by invasive plant species, notably ''
Cinnamomum verum ''Cinnamomum verum'' ( synonym ''Cinnamomum zeylanicum'', also called true cinnamon tree or Ceylon cinnamon tree) is a small evergreen tree belonging to the family Lauraceae, native to Sri Lanka. The inner bark of the tree is historically regard ...
''. It is thought that this scorpion went extinct on the islands of Mahé and Praslin after 1909 due to invasive plants taking over its habitat. It may also be threatened by an invasive ant species. As of 2009, since 1909, the species has only been observed three times, in 1990, 2006, and 2009, all on Silhouette Island. Its limited range is evident as several surveys have failed to locate the arachnid. While the entire known population of the species is protected within Silhouette National Park, as of 2012 the park was not being managed to protect the scorpion. However, since then the
Island Conservation Society The Island Conservation Society (ICS) was registered as an NGO in Seychelles on 25 March 2001. The Head Office, known as The Island Conservation Centre, is situated at Pointe Larue, Mahé. ICS focuses on the protection and rehabilitation of the sma ...
's Silhouette Island Conservation Centre has begun to implement conservation projects on the island, including vegetation restoration and the removal of cinnamon.


References

{{Taxonbar, from=Q3268351 Buthidae Scorpions of Africa Arthropods of Africa Endemic fauna of Seychelles Animals described in 1896