The wafer trapdoor spiders, family Cyrtaucheniidae, are a widespread family of

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

s that lack the thorn-like spines on tarsi and metatarsi I and II (the two outermost leg segments) found in true trapdoor spiders ( Ctenizidae).

Etymology

The scientific family name derives from the Greek κυρταύχην, ''kyrtaúchēn'', which in turn is derived from Greek κυρτός ''kyrtós'', meaning "curved", "arched" or "bent", αὐχήν ''auchen'', meaning the cervix or neck, and the suffix -''idae'', which designates belonging to a family.

Biology

Many, but not all, make wafer-like doors to their burrows, while others build the cork-like doors found commonly in the true trapdoor spiders. The biology of nearly all the species is poorly known. The monotypic ''Angka hexops'' has only six eyes, with the posterior median eyes missing. It is up to 15 mm long in both sexes.Murphy, Frances & Murphy, John (2000). ''An Introduction to the Spiders of South East Asia''. Kuala Lumpur: Malaysian Nature Society.

Distribution

The family is well represented

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

, and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

. A currently undescribed genus in the western United States may hold an altitude record for the family, being found up to over . The genus ''Anemesia'' is found only in

Central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...

, and ''Cyrtauchenius'' reaches from Algeria north to Italy, with one species found in the USA. ''Angka'' is endemic to the cloud forest of

Doi Inthanon Doi Inthanon ( th, ดอยอินทนนท์, ) is the highest mountain in Thailand. It is in Chom Thong District, Chiang Mai Province. This mountain is an ultra prominent peak, known in the past as ''Doi Luang'' ('big mountain') or '' ...

, Thailand.

Genera

The former subfamily Euctenizinae from the US and Mexico were promoted to family rank as

Euctenizidae The Euctenizidae (formerly Cyrtaucheniidae subfamily Euctenizinae) are a family of mygalomorph spiders. They are now considered to be more closely related to Idiopidae. Etymology The name comes from the Greek prefix (''eu-''), meaning "valua ...

in 2012, and are now considered more closely related to

Idiopidae Idiopidae, also known as armored trapdoor spiders, is a family of mygalomorph spiders first described by Eugène Simon in 1889. They have a large body similar to tarantulas. Description In some species the males have a spur on their legs, whic ...

. Further changes to the

circumscription Circumscription may refer to: *Circumscribed circle * Circumscription (logic) *Circumscription (taxonomy) *Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthrop ...

of the family were made in 2020. , the

World Spider Catalog The World Spider Catalog (WSC) is an online searchable database concerned with spider taxonomy. It aims to list all accepted families, genera and species, as well as provide access to the related taxonomic literature. The WSC began as a series of ...

accepted the following genera: *'' Acontius'' Karsch, 1879 — Africa, Argentina *'' Ancylotrypa'' Simon, 1889 — Africa *'' Anemesia'' Pocock, 1895 — Asia *'' Bolostromoides'' Schiapelli & Gerschman, 1945 — Venezuela *'' Bolostromus'' Ausserer, 1875 — South America, Caribbean, Panama, Uganda *'' Cyrtauchenius'' Thorell, 1869 — Algeria, United States *'' Fufius'' Simon, 1888 — South America, Trinidad *'' Rhytidicolus'' Simon, 1889 — Venezuela Genera formerly placed in the family include: *'' Amblyocarenum'' Simon, 1892 →

Nemesiidae Nemesiidae, also known as funnel-web trapdoor spiders, is a family of mygalomorph spiders first described by Eugène Simon in 1889, and raised to family status in 1985. Before becoming its own family, it was considered part of "Dipluridae". Desc ...

*'' Angka'' Raven & Schwendinger, 1995 → Microstigmatidae *'' Homostola'' Simon, 1892 → Bemmeridae

Footnotes

References