The mostly tropical mygalomorph spider family Ctenizidae (trapdoor spiders) includes 128 described species (Platnick 2013), 14 or 15 of them occurring in North America north of Mexico: Ummidia is found throughout the United States (10 or 11 described U.S. species but many undescribed species as well), Cyclocosmia in the southeastern U.S. (two U.S. species), and Bothriocyrtum and Hebestatis in California (one U.S. species each) (Bond and Hendrixson 2005; Bradley 2013; Platnick 2013). Ctenizids, the best known of the trapdoor-building spiders, have eight eyes, like most spiders. Analyses by Bond et al. (2012) suggest that Ctenizidae may not be a monophyletic group as currently composed.
All known North American ctenizids live in silk-lined terrestrial burrows, with burrow linings consisting of a heavy layer of parchment-like silk and packed soil. Burrows are constructed with a trapdoor (often well disguised) that is used in prey capture. The spider waits beneath a slightly ajar trapdoor and when it detects potential prey passing by, itlunges out of the burrow, bites its prey, and returns with the prey to the bottom of the burrow to feed. In the United States, ctenizid habitat ranges from the more mesic climates of the southeast to the xeric climates of California deserts. Taxonomic investigations of North American ctenizids are limited, with the exception of the revision of Cyclocosmia by Gertsch and Platnick (1975). Numerous undescribed Ummidia species are known even from the United States. (Bond and Hendrixson 2005)
Ctenizidae is a small family of mygalomorph spiders that construct burrows with a cork-like trapdoor made of soil, vegetation, and silk. They may be called trapdoor spiders, as are other, similar species, such as those of the families Liphistiidae, Barychelidae, and Cyrtaucheniidae, and some species in the Idiopidae and Nemesiidae. The name comes from the distinctive behavior of the spiders to construct trapdoors, and ambush prey from beneath them.[2]
In 2018, the family Halonoproctidae was split off from the Ctenizidae.[3] A further genus, Stasimopus, was split off into its own family, Stasimopidae, in 2020.[3][4] The family currently consists of two genera and five species.[1]
The name derives from Greek κτενὶζειν ktenizein, meaning "combing" or "cleaning", referring to their behaviour of cleaning continuously, and the suffix "-idae", which designates belonging to a family.
The family Ctenizidae was first described by Thorell in 1887, being based on the genus Cteniza.[3] Since the advent of molecular phylogenetics and its application to spiders, the family has been progressively dismantled;[5] the World Spider Catalog lists over 100 genera formerly placed in Ctenizidae but now transferred to other families.[3] The Halonoproctidae were split off in 2018, leaving only three genera. Even so, the family was not monophyletic, since Stasimopus is not in the same clade as the other two genera, according to a 2018 study (the three genera left in the Ctenizidae at that time are shaded in yellow):[5]
Heteromigas (Migidae)
Idiops (Idiopidae)
Myrmekiaphila (Euctenizidae)
In 2020, a large scale molecular phylogenetic study confirmed the placement of Stasimopus outside the clade consisting of Cteniza and Cyrtocarenum, and transferred it to its own family, Stasimopidae.[4] This placement is accepted by the World Spider Catalog as of February 2022.[3]
As of February 2022, the World Spider Catalog accepted only two extant genera:[3]
The two genera of Ctenizidae are found in Europe and Turkey, particularly in France and Italy.[3] Like many other mygalomorphs, Cteniza have highly localized distributions. This results in clumps of spider burrows a short distance from their maternal burrows, resulting in a dense cluster of spiders surrounding a large female.[7]
Ctenizidae is a small family of mygalomorph spiders that construct burrows with a cork-like trapdoor made of soil, vegetation, and silk. They may be called trapdoor spiders, as are other, similar species, such as those of the families Liphistiidae, Barychelidae, and Cyrtaucheniidae, and some species in the Idiopidae and Nemesiidae. The name comes from the distinctive behavior of the spiders to construct trapdoors, and ambush prey from beneath them.
In 2018, the family Halonoproctidae was split off from the Ctenizidae. A further genus, Stasimopus, was split off into its own family, Stasimopidae, in 2020. The family currently consists of two genera and five species.
