Heptathelidae is a

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 ...

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

s. It has been sunk within the family

Liphistiidae The spider family Liphistiidae was first recognized by Tamerlan Thorell in 1869. When narrowly circumscribed, it comprises a single genus '' Liphistius'', native to Southeast Asia; , this was the circumscription accepted by the World Spider Cata ...

as the subfamily Heptathelinae, but was accepted by 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 ...

. It is placed in suborder

Mesothelae The Mesothelae are a suborder of spiders (order Araneae). , two extant families were accepted by the World Spider Catalog, Liphistiidae and Heptathelidae. Alternatively, the Heptathelidae can be treated as a subfamily of a more broadly circum ...

, which contains the most basal living spiders.

Taxonomy

The group was first proposed by

Kyukichi Kishida was a Japanese zoologist, who published in arachnology, mammalogy, and herpetology. He described several spider Genus, genera and species including : * ''Heptathela'' ** ''Heptathela kimurai'' (Kimura-gumo) * ''Pireneitega'' References * ...

in 1923, when he described a new genus, '' Heptathela'', and suggested creating two tribes within the family Liphistiidae, with ''Heptathela'' placed in Heptatheleae. In 1939,

Alexander Petrunkevitch Alexander Ivanovitch Petrunkevitch (; December 22, 1875 – March 9, 1964) was a Russian arachnologist. From 1910 to 1939, he described over 130 spider species. One of his most famous essays was "The Spider and the Wasp." In it he uses effective ...

raised the tribe Heptatheleae to a separate family, Heptathelidae. In 1985,

Robert Raven Robert John Raven is an Australian arachnologist, being the Head of Terrestrial Biodiversity and the Senior Curator (Arachnida) at the Queensland Museum. Dr Raven has described over 450 species of spider in Australia and elsewhere, and is spider ...

reunited the two families, a view supported by Breitling in 2022. Other authors have maintained two separate families, a position accepted by the

Phylogeny

Molecular phylogenetic studies have repeatedly shown that the family is

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. One possible relationship between the genera is shown in the following Bayesian cladogram (numbers in parentheses give the number of units in the study):

Genera

, the World Spider Catalog accepted seven genera: *'' Ganthela'' Xu & Kuntner, 2015 *'' Heptathela'' Kishida, 1923 *'' Luthela'' Xu & Li, 2022 *'' Qiongthela'' Xu & Kuntner, 2015 *'' Ryuthela'' Haupt, 1983 *'' Songthela'' Ono, 2000 *'' Vinathela'' Ono, 2000 The genus '' Sinothela'' is considered a (dubious name). File:Heptathela.kimurai.yanbaruensis.burrow.-.tanikawa.jpg, Burrow of '' Heptathela kimurai'' File:Ryuthela.sasakii.female.-.takinawa.jpg, '' Ryuthela sasakii''

Description

Members of the Heptathelidae share features with the other Mesothelae family, Liphistiidae. They are medium to large spiders. They have downward pointing, daggerlike

chelicerae The chelicerae () are the arthropod mouthparts, mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated ...

. Like other members of the suborder Mesothelae, and unlike all other extant spiders, they have a segmented series of plates ( tergites) on the upper surface of all segments of the abdomen and their

spinneret A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and ar ...

s are placed in the middle of the underside of the abdomen, rather than at the end. Their sternum (a plate on the underside of the

cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...

) is narrow, and there is another smaller ventral plate (the sternite) between the fourth pair of legs. They respire by means of two pairs of

book lung A book lung is a type of respiration organ used for atmospheric gas-exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open, ventral-abdominal, air-filled cavity (atrium) and co ...

s. Unlike members of the Liphistiidae, the palp of the male lacks a tibial apophysis. They live in burrows closed by trapdoors. Unlike members of the Liphistiidae, heptathelids do not construct signal lines radiating from the burrow.

References

{{Taxonbar, from1=Q112260927 Spider families