ARACHNIDA > ARANEAE > Tetragnathidae > Tetragnatha and Pachygnatha

The Tetragnathidae family includes 14 species in four genera; Tetragnatha (6), Pachygnatha (3), Metellina (3) and Meta (2).

This page is for the Tetragnatha and Pachygnatha species although, at present, I haven't encountered any of the latter.

The common name of this family suggests that all species are equipped with long jaws, but that isn't actually the case as only the members of the two featured genera are described as having enlarged chelicerae. It's a characteristic feature that applies equally, but with the Tetragnatha being further distinguished by their distinctly elongated abdomen and long legs, whereas the Pachygnatha have a more conventional body shape.

Tetragnatha spiders construct fairly simple webs where they sit waiting for prey but, because there's no built-in retreat, they quickly leave the web if disturbed to stretch out on a grass or reed stem, which often provides them with good camouflage. They are often referred to as 'stretch-spiders'.

The two most likely species to be encountered are Tetragnatha extensa and Tetragnatha montana; the former very much associated with wetlands and the latter more likely to be found a little further away from water. They are very similar in appearance, although the abdominal markings in Tetragnatha montana are typically a bit darker and, if the sternum is visible as in the final two photos, it will be plain dark brown, whereas in Tetragnatha extensa there's a small pale yellow triangular shaped patch towards the front end.

But there are also a further four species in the genera that need to be considered, notably Tetragnatha pinicola and possibly Tetragnatha obtusa, particularly in woodland. There are good 'identification pointers' for each species which, together with other information regarding distribution and habitat, provide sufficient detail in most cases for a 'likely' candidate. For recording purposes though, the species cannot be reliably distinguished without dissection, hence the cf. qualifier in the captions.

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Updated, Nov.23 (v.2)