Ctenizidae

Ctenizidae: The Trapdoor Spiders

Ctenizidae is a small family of mygalomorph spiders distinguished by their remarkable construction of burrows sealed with a unique trapdoor. This door, crafted from a mixture of soil, vegetation, and silk, serves as an effective ambush point for unsuspecting prey. The family name itself, Ctenizidae, originates from the Greek word 'ktenizein,' meaning "combing" or "cleaning," a direct reference to the spiders' diligent and continuous maintenance of their subterranean homes.

Geographic Distribution and Habitat

The extant members of the Ctenizidae family are found in Europe and Turkey, with notable populations in France and Italy. These spiders often exhibit highly localized distributions, leading to dense clusters of burrows in specific areas. This pattern can result in a concentration of spiders surrounding a larger, maternal burrow.

Taxonomy and Classification

First described by Thorell in 1887, the Ctenizidae family has undergone significant taxonomic revisions, particularly with the advent of molecular phylogenetics. Historically, it encompassed a larger number of genera, but several have since been reclassified into new families, such as Halonoproctidae and Stasimopidae. As of October 2025, the family officially includes two genera: Cteniza (found in Italy and France) and Cyrtocarenum (found in Turkey and Greece). Extinct genera, such as Baltocteniza and Electrocteniza, have also been identified from Baltic amber deposits.

Hunting and Behavior

Ctenizidae spiders are primarily ambush predators. They lie in wait beneath their expertly constructed trapdoors, with only the slightest vibration signaling the approach of prey. Their diet consists of insects and other small invertebrates that wander too close to their concealed burrows. The continuous cleaning and maintenance of their burrows are defining behavioral traits of this family.