Episinus

Walckenaer, 1809

Square-ended Cobweb Spiders

Episinus is a of -footed in the Theridiidae, first described by Walckenaer in 1809. The genus includes approximately 64 described distributed across Asia, Africa, and the Americas, with 16 species recorded from China. These small spiders are known for their highly reduced, H- or Y-shaped webs constructed near ground level in low vegetation. Several species have significance, including the Tree H-weaver (Episinus maculipes) which is Red Data Book listed in the UK.

Episinus by (c) Steve Kerr, some rights reserved (CC BY), uploaded by Steve Kerr. Used under a CC-BY license.

Episinus amoenus by (c) skitterbug, some rights reserved (CC BY), uploaded by skitterbug. Used under a CC-BY license.

Pronunciation

How to pronounce Episinus: //ˈɛpɪˌsaɪnəs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Theridiidae by the combination of: highly reduced H- or Y-shaped webs; with distinct and often horn-like projections between ; with humps and ; circular arrangement on tubercles with median eyes smallest; and characteristic resting posture with first two pairs of legs extended forward and last two pairs stretched backward. The low, flat, anteriorly projecting and specific (1423 or 4123) further separate Episinus from similar .

Images

Habitat

Found at ground level between low vegetation, in evergreen shrubs, or in leaf litter in forest areas. Webs constructed very close to ground level.

Distribution

Worldwide distribution with recorded from Asia, Africa, and the Americas. In China, 16 described species occur mainly in southern provinces (Yunnan, Guizhou, Guangxi, Hunan, Hubei, Jiangxi, Sichuan, Taiwan, Zhejiang) with two species in northern China (Gansu, Shaanxi). Additional records from Israel, South Africa, Angola, and Europe (Denmark, Norway).

Seasonality

Courtship has been observed in summer. No other seasonal activity patterns documented.

Behavior

Constructs highly simplified webs consisting of only two or three threads forming H- or Y-shaped structures near ground level. When resting, extends first two pairs of legs forward and stretches last two pairs backward. Body coloration with black, and spots provides against substrate.

Human Relevance

Episinus maculipes (Tree H-weaver) is Red Data Book listed in the UK and has been a of efforts, including successful campaigns to protect its at Radford Quarry in Plymouth from development. The has contributed to public discourse on protection and the moral responsibility to prevent extinction.

Similar Taxa

TheridionBoth are Theridiidae with -footed , but Episinus has highly reduced H- or Y-shaped webs versus more extensive cobwebs, and distinctive horn-like projections and tuberculate not typical of Theridion
ArgyrodesBoth Theridiidae with small body size, but Argyrodes are often kleptoparasitic in other ' webs and lack the characteristic reduced web structure and specific / of Episinus

More Details

Species diversity

As of 2025, the includes 64 described with five proposed species groups for Chinese Episinus based on morphological characteristics. Recent taxonomic work has described new species from Jiangxi, Yunnan, and Shaanxi Provinces.

Conservation significance

The protection of Radford Quarry for Episinus maculipes and the critically endangered Nothophantes horridus (Horrid ground-weaver) represents a notable case where concerns successfully halted development, with the planning inspector upholding the decision primarily on biodiversity grounds.