Calymmaria
Chamberlin & Ivie, 1937
basket-web weavers
Species Guides
7Calymmaria is a of small North American spiders known for their distinctive inverted cone-shaped webs. These araneomorph spiders were first described in 1937 and contain 31 , with most distributed along the Pacific coast of the United States and Canada. They are primarily and construct unique 'basket' webs under bark, rocks, and other sheltered substrates.
Pronunciation
How to pronounce Calymmaria: /kəˌlɪməˈmaɪriə/
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Identification
Distinguished from similar by their unique web architecture—an inverted cone with a thin sheet platform—rather than morphological features visible to casual observation. -level identification requires microscopic examination of genitalia, particularly in males. Calymmaria bifurcata and C. emertoni are essentially identical in external appearance, differing only in subtle genital characteristics.
Images
Habitat
Microhabitats under loose bark, in bark furrows, beneath moss on rocks or logs, among rocks by streams, under cliff overhangs, cave entrances, and on human structures. Requires sheltered, often moist environments with substrates suitable for web attachment.
Distribution
North America: predominantly Pacific coast of USA and Canada, east to Cascade Mountains and Sierra Nevada; two restricted to Appalachian Mountains; two species in Mexico (C. rosario, C. tecate).
Seasonality
Active year-round in mild climates; have been observed during winter months in Pacific Northwest.
Diet
Small insects, particularly flies.
Behavior
; spiders emerge at night to hang beneath the sheet portion of the web, sometimes venturing onto the exterior of the cone. Prey capture involves biting and retreating, possibly multiple times, before hauling the victim to the platform web for feeding.
Ecological Role
of small flying insects in sheltered microhabitats.
Human Relevance
Occasionally found on buildings; no documented medical or economic significance.
Similar Taxa
- TegenariaSimilar body size and general appearance; Calymmaria was historically classified in Agelenidae and some placed in Tegenaria
- Agelenidae (funnel-web weavers)Similar web-building and overall ; distinguished by Calymmaria's unique inverted cone web architecture
More Details
Taxonomic history
Calymmaria was originally classified in Hahniidae; recent phylogenetic studies place it in Cybaeidae. The was revised comprehensively by Heiss & Draney in 2004.
Web architecture
The 'basket-web' structure is unique among North American spiders: an inverted cone anchored above and below, with a thin sheet platform from which the spider hunts.