Temporal range: Palaeogene–present
|3 genera, 53 species|
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 similar species, such as those of the families Liphistiidae, Barychelidae, and Cyrtaucheniidae, and some species in the Idiopidae and Nemesiidae. In 2018, the family Halonoproctidae was split off from the Ctenizidae, leaving only three genera; later, the genus Stasimopus was removed. The family now consists of only two genera and five species.
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. Since the advent of molecular phylogenetics and its application to spiders, the family has been progressively dismantled; the World Spider Catalog lists over 100 genera formerly placed in Ctenizidae but now transferred to other families. 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 then left in the Ctenizidae are shaded in yellow):
Stasimopus was later transferred to its own family, the Stasimopidae, leaving only two extant genera in Ctenizidae and a total of five species.
- Extinct genera
- †Baltocteniza Eskov & Zonstein, 2000 Early Eocene Baltic amber
- †Electrocteniza Eskov & Zonstein, 2000 Early Eocene Baltic amber
Ecology and behaviour
The trapdoor is difficult to see when it is closed because the plant and soil materials effectively camouflage it. The trapdoor is hinged on one side with silk. The spiders, which are usually nocturnal, typically wait for prey while holding on to the underside of the door with the claws on their tarsi. Prey is captured when insects, other arthropods, or small vertebrates disturb the "trip" lines the spider lays out around its trapdoor, alerting the spider to a meal within reach. The spider detects the prey by vibrations and, when it comes close enough, leaps out of its burrow to make the capture.
A hungry individual waits halfway outside its burrow for a meal. Male trapdoor spiders can overcome the female's aggressive reactions to their approach, but how is not known. Females never travel far from their burrows, especially if they have an egg sac. During this time, the female captures food and regurgitates it to feed her spiderlings. Predators of the trapdoor spider include certain pompilids (spider wasps), which seek out the burrows and manage to gain entrance. They sting the owner and lay their eggs (usually one per spider) on its body. When the egg hatches, the larva devours the spider alive.
Unlike other mygalomorph spiders, the Ctenizidae have a rastellum on their chelicerae. Resembling "teeth" or "barbs" on each fang, this modification is used to dig and gather soil while constructing a burrow. They use their pedipalps and first legs to hold the trapdoor closed when disturbed.
Distribution and habitat
Genera of Ctenizidae are found in Europe, Asia, and South Africa. They may be more common than thought because of their cryptic habits. They do tend to be localized in distribution, so may be subject to extinction because of local habitat destruction. Most species live in burrows rather than webs. They make silk-hinged doors that blend with their habitat. Not all members of the family use trapdoors.
- "Currently valid spider genera and species", World Spider Catalog, Natural History Museum Bern, retrieved 2018-05-16
- "Family Ctenizidae Thorell, 1887", World Spider Catalog, Natural History Museum Bern, retrieved 2018-05-24
- Godwin, Rebecca L.; Opatova, Vera; Garrison, Nicole L.; Hamilton, Chris A. & Bond, Jason E. (2018-09-01), "Phylogeny of a cosmopolitan family of morphologically conserved trapdoor spiders (Mygalomorphae, Ctenizidae) using Anchored Hybrid Enrichment, with a description of the family, Halonoproctidae Pocock 1901", Molecular Phylogenetics and Evolution, 126: 303–313, doi:10.1016/j.ympev.2018.04.008, PMID 29656103
- Eskov, K. Y.; Zonstein, S. L. (2000). "The First Ctenizoid Mygalomorph Spiders from Eocene Baltic Amber (Araneida: Mygalomorphae: Ctenizidae)". Paleontological Journal. 34 (suppl. 3): S268–S274. Part 1; Part 2 (PDF).
- Holm, Erik, Dippenaar-Schoeman, Ansie; Goggo Guide; LAPA publishers (URL: WWW.LAPA.co.za). 2010
- Tso et al. 2003
- Evans H.E. 1972 The Tribe Ctenoceratini in Australia Aust. J. Entomol. 11(3) 244-252
- Raven, R.J. 1985 The spider Infraorder Mygalomorphae (Araneae): cladistics and systematics. Bulletin of the American Museum of Natural History 182: 1-180.
- Murphy, Frances & Murphy, John (2000): An Introduction to the Spiders of South East Asia. Malaysian Nature Society, Kuala Lumpur.
- Tso, I.; Haupt, J. & Zhu, M. (2003): The trapdoor spider family Ctenizidae (Arachnida: Araneae) from Taiwan. The Raffles Bulletin of Zoology 51(1): 25-33. PDF (Ummidia and Latouchia)
- Hendrixson, B.E. & Bond, J.E. (2004): A new species of Stasimopus from the Eastern Cape Province of South Africa (Araneae, Mygalomorphae, Ctenizidae), with notes on its natural history. Zootaxa 619: 1-14. PDF
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