Oedothorax trilobatus
(Banks, 1896)
Tricorn Dwarf Weaver
Oedothorax trilobatus is a of dwarf spider in the Linyphiidae, Erigoninae. It is a tiny spider, measuring approximately 2 mm in total body length. The species is notable for the distinctive cephalic swellings present in mature males, which give the species its name. It has been recorded from the United States, Canada, and Russia.
Pronunciation
How to pronounce Oedothorax trilobatus: /ˌiːdəˈθɔːræks ˌtraɪloʊˈbeɪtəs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Males are readily identified by the trilobed or tumor-like swellings on the , a feature unique to this among similar dwarf spiders. Females lack these structures and may require examination of genitalia for definitive identification. The small size (approximately 2 mm) and placement in the Erigoninae help distinguish it from larger linyphiids in other subfamilies.
Appearance
A minute spider with a total body length of approximately 2 mm. Mature males possess distinctive tumor-like swellings on the , which are the source of the epithet 'trilobatus.' These cephalic modifications are a key diagnostic feature. The overall body form is typical of the Erigoninae, with relatively compact proportions.
Distribution
United States, Canada, and Russia (including Kamchatka). Specific Canadian provincial records include Alberta, British Columbia, and Manitoba.
Similar Taxa
- Walckenaeria communisAnother erigonine dwarf spider with approximately 2 mm body length; males of this possess a horn-like cephalic extension rather than the tumor-like swellings of O. trilobatus.
More Details
Taxonomic Note
The was first described by Nathan Banks in 1896. It belongs to the diverse Erigoninae, commonly known as 'dwarf spiders,' which contains numerous species with bizarre male cephalic modifications used in species identification.