Wolf Spider
Harker Heights, Texas 04-15-07

Photographs by Bryan H.

Bryan wrote:

I have found numerous instances of these in my new home (Harker Heights, TX) and want to verify that it is in fact a Wolf Spider.  The pictures I attached are of the most recent and largest find (approx 1-2in. in total dia.).  The others were about half the size and were all found inside the house on the vinyl floors near or in each of the bathrooms.  Next time I find one, I will attempt to photograph the underbody as well.  I have not yet been bitten (nor do I intend to).  If you can help verify that this is a Wolf Spider and not something else, it would be much appreciated!  Thank you!

Wolf spiders (of the family Lycosidae) are not as unique as I used to think.  Once I believed that any spider, with the general features evident in this specimen, was a Lycosid.  But, several families of spiders fit this profile, at least from a distance.  The Pisauridae family, or nursery-web spiders, are so similar that only a careful examination of the eyes sets them apart.  Pisaurid eyes are positioned like those of the Lycosids, but (1) each eye is about the same diameter, (2) the anterior row (AER) is curved upward, and (3) the four eyes in the posterior row are close enough together to appear to form a single row; while (a) the Lycosid PME (the two eyes in the second row) are dramatically larger than the rest, (b) the anterior row is either not curved, or is only slightly so, and (c) the distance from each PME and PLE is such that the PME appear to form a median row, while the PLE form a third row. Since for this specimen the PME are quite large compared to the AER, the AER form a remarkably straight row, and the PME and PLE are spaced far apart, this is not a Pisaurid.

Let's assume, then, that it is a Lycosid.  We cannot be absolutely sure, because the resolution of the images is not sufficient to enable a positive identification based on an examination of minute anatomical features.  We can, however, rule out the chance that this is a harmful spider. Only two spiders (the brown recluse and the black widow) are found in Texas that are known to harm man, and this is, without any doubt, neither of those.

Within the Lycosidae 13 separate genera are presently recognized.  Markings on the carapace are definitive for many genera, particularly the Trochosa, Pirata, and Trebacosa, each of which exhibits a unique pattern of markings. In this particular case, however, carapace markings are somewhat nondescript, and the angle of the photo does not show off the markings well, so identification to genera isn't possible using that strategem.

The genera Sosippus, Pirata, and Tarentula can be ruled out due to location, as none of their species range into Texas, or at least into the region around Harker Heights. The genus Geolycosa, the burrowing wolf spiders, cannot be ruled out, as G. missouriensis, and Arctosa littoralis extend their range into Texas. The genus Pardosa (Thin-legged Wolf Spiders) cannot be ruled out because the tibia and patella of the hindmost leg (leg IV) together may be longer than the carapace, which is a distinguishing feature of this genus.  Due to the angle of the photo, an accurate comparison of those features is problematical. Pardosa lapidicina is found in Texas, has markings similar to those of this specimen, and often has yellow spots on the abdomen (the presence of such spots cannot be ruled out for this specimen, as spots of some kind do appear to exist). The genus Schizocosa can be ruled out because conspicuous brushes on the anterior legs, characteristic of the genus, are lacking.  Finally, the genus Lycosa cannot be dismissed, as many of its numerous species are found in Texas, and many exhibit the gross features shown here. 

Note the way the right PME booms in like a headlamp, reflecting the flash used to take these photos.

Many thanks to Bryan and his fellow soldiers at Fort Hood for their service to our country.