''Tasmanoplectron isolatum'' is a rare

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

species of

cave cricket The orthopteran family Rhaphidophoridae of the suborder Ensifera has a worldwide distribution. Common names for these insects include cave crickets, camel crickets, spider crickets (sometimes shortened to "criders" or "sprickets"), and sand trea ...

, and is the only species represented in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Tasmanoplectron'', belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Rhaphidophoridae The orthopteran family Rhaphidophoridae of the suborder Ensifera has a worldwide distribution. Common names for these insects include cave crickets, camel crickets, spider crickets (sometimes shortened to "criders" or "sprickets"), and sand trea ...

. In 1971, Aola M. Richards was first to describe this species in

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, where its geographical distribution is restricted to.Bryant, S. L. and Shaw, J. (Editors) (2006). "Tasman Island: 2005 flora and fauna survey". ''Hamish Saunders Memorial Trust, New Zealand and Biodiversity Conservation Branch, DPIW, Hobart, Nature Conservation Report Series 06/01.'' The genus is thought to have affinities with

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

due to its marked differences from the other Australian Rhaphidophoridae.

Distribution and habitat

''Tasmanoplectron isolatum'' is

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 ...

Tasman Island The Tasman Island, part of the Tasman Island Group, is an oval island with an area of , lying close to the south-eastern coast of Tasmania, Australia. The island is located in the Tasman Sea, situated off the Tasman Peninsula and is contained ...

off the southeast coast of

. This small long-legged insect seeks refuge among rocks, forming small artificial cavities, or in bird burrows. On Tasman Island, the species has been collected from Allocasuarinas (she-oak) forest and from old drains in buildings.

Morphology

''Tasmanoplectron isolatum'' is predominantly brown-coloured, except for the

ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typica ...

being light reddish brown, and it is fully thickly covered by

setae In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae ...

. The body size of ''T. isolatum'' ranges from 18 to 21 millimetres, and males are usually slightly larger than females. It possesses long

filiform Filiform, thread or filament like, can refer to: * Filiform, a common term used in botany to describe a thread-like shape *Filiform, or filiform catheter, a medical device whose component parts or segments are all cylindrical and more or less un ...

antennae as well as long slender legs. Fore and middle legs are of the same length, and are 2.5 times longer than the body, whereas

hind A hind is a female deer, especially a red deer. Places * Hind (Sasanian province) (262-484) * Al-Hind, a Persian and Arabic name for the Indian subcontinent * Islamic State – Hind Province, claimed province of the IS in India * Hind (cra ...

legs are 3.8 times longer than the body.

Taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

''Tasmanoplectron isolatum'' is believed to be more closely related to at least nine

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

existing in New Zealand and

subantarctic islands The sub-Antarctic zone is a physiographic region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region inc ...

(e.g. '' Insulanoplectron'') than those existing in Australia, due to similarities in leg spination and external

genitalia A sex organ, also known as a reproductive organ, is a part of an organism that is involved in sexual reproduction. Sex organs constitute the primary sex characteristics of an organism. Sex organs are responsible for producing and transporting ...

. However, ''T. isolatum'' possesses four unique characteristics which explain why it is the sole member of the genus ''Tasmanoplectron'': * the second segment of hind tarsus has either reduced or no apical spines, * the

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

valves of ovipositor distally have a row of spines, * pseudo

sternite The sternum (: sterna) is the ventral portion of a segment of an arthropod thorax or abdomen. In insects, the sterna are usually single, large sclerites, and external. However, they can sometimes be divided in two or more, in which case the su ...

of males is elongated, and *

abdominal The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

br>styli
are located at the ventral and distal portion of the genital plate of males.

References

Rhaphidophoridae Insects described in 1971 Orthoptera of Australia Vulnerable fauna of Australia Taxonomy articles created by Polbot Monotypic Orthoptera genera Ensifera genera {{rhaphidophoridae-stub