Synonyms and other taxonomic changes
First described in 1804 by
Pierre André LatreilleExplanation of Names
From Greek tetra (τετρα)- "four" + gnathos (γναθος)- "jaw"
Numbers
15 species and 3 sub-species in Bugguide's range.
Identification
Levi, 1981:
1) The distance between the two lateral and the two median eyes is useful.
2) Some characteristics of the chelicerae vary greatly. The following are the only useful features Levi mentions:
- Male T. dearmata and T. pallescens always lack the first distal, long tooth.
- T. elongata generally has longer chelicerae than T. versicolor.
3) Size is not useful as specimens in the same species can be twice as long. Also smaller individuals tend to have fewer teeth than larger ones in the same species.
From Rod Crawford:
Using eyes to separate T. elongata, laboriosa & versicolor
Yes, the online image is clear enough to show the eye distances well. The lateral eyes (front & back) are the same distance apart as the median eyes. That makes it T. laboriosa. Some laboriosa specimens have the lateral eyes a little closer together, but never as close together as in versicolor or elongata.
Range
Exact distribution within these countries will be added when time permits.
branda - USA
caudata - USA, Canada
dearmata - Holarctic
elongata - USA, Canada
- elongata debilis - USA
- elongata principalis - USA
- elongata undulata - USA
extensa - Holarctic
gracilis (=earmra) - USA
guatemalensis - USA, Canada
laboriosa - USA, Canada
nitens - cosmotropical
pallescens - USA, Canada
shoshone - USA, Canada
straminea - USA, Canada
vermiformis - USA, Canada
versicolor - USA, Canada
viridis - USA, Canada
Habitat
Larger species near water, especially along the shores of rivers and streams. Smaller species in fields and meadows.
Remarks
These spiders spin circular (orb) webs, mostly in the horizontal plane, often just inches above the surface of water where they can intercept emerging insects like midges, mayflies, and stoneflies.
Internet References
Nouveau Dictionnaire d'Histoire Naturelle, v.25, p.135 Latreille's original description of the genus (in French)
