Corinnidae is a family of araneomorph spiders commonly referred to as corinnid sac spiders. The family is placed within the superfamily Corinnioidea and comprises a diverse group of ground-dwelling and foliage-dwelling species found worldwide, with a higher concentration in tropical and subtropical regions.
Taxonomy
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Arachnida
- Order: Araneae
- Suborder: Opisthothelae
- Infraorder: Araneomorphae
- Superfamily: Corinnioidea
- Family: Corinnidae
The family was first described by Eugène Simon in 1897. Over time, taxonomic revisions have altered its composition; several genera previously assigned to Corinnidae have been transferred to other families, and vice versa. As of the latest consensus, the family contains more than 800 described species distributed among roughly 70 genera.
Morphology
Members of Corinnidae typically have a compact body shape with a relatively flat cephalothorax and abdomen. Their coloration ranges from uniform dark shades to patterned markings, often providing camouflage in leaf litter or on vegetation. The eyes are arranged in two rows, and many species possess robust chelicerae. Unlike some other spider families, corinnids do not build webs for prey capture; instead, they are active hunters or ambush predators.
Behavior and Ecology
Corinnid spiders are primarily nocturnal hunters. They pursue or pounce on prey such as insects and other small arthropods. Some species construct silken retreats or sacs for daytime shelter and for protecting egg sacs, which gives rise to the common name “sac spiders.” The family exhibits a variety of reproductive strategies, and sexual dimorphism is present in several genera, with males often being smaller and more slender than females.
Distribution
Corinnidae has a cosmopolitan distribution, with representatives recorded on all continents except Antarctica. The highest species richness occurs in the Neotropical, Afrotropical, and Indo‑Australian regions. Several genera are endemic to specific biogeographic zones, reflecting the family’s adaptability to diverse habitats ranging from forest floors to grasslands and shrublands.
Economic and Human Relevance
Corinnid spiders are generally not considered medically significant to humans; their bites are rarely reported and typically cause only mild local reactions. Their role as predators of insects can contribute to natural pest control in various ecosystems.
Research and Conservation
The taxonomy and phylogeny of Corinnidae continue to be subjects of arachnological research, especially with the increasing use of molecular techniques to resolve relationships within the family and with related groups. Habitat loss and environmental changes pose potential threats to some localized species, though comprehensive conservation assessments are lacking for many members of the family.