I believe that P. phrygianus is nowadays considered to be a Palearctic species. Kaston (Spiders of Conn., 1981 rev.) used P. phrygianus (C.L. Koch), but noted that Chamberlin & Ivie (1943) restored Hentz's name, costatus, for the Nearctic species, which they considered distinct from the European one.

So, perhaps this guide page is redundant and should be merged with P. costatus? You don't say whether the determination was made from specimen or from image, but in any event, a subadult male would likely not have been sufficient to make such a distinction (I am assuming -- I've not looked at Ivie & Chamberlin). Perhaps he/she was merely using the original name from Kaston?

-Kevin

It would be helpful when submitting images of species potentially new to BugGuide to include identification characteristics and info on how to distinguish the species and/or genus from similar ones. For example, what diagnostic field marks are visible in this photo? Also, if someone other than yourself identifies a specimen, please provide the name of that person along with their credentials.
These kinds of info could help BugGuide visitors identify their own photos (or future submissions by others) and assist editors in filling out Guide pages.
Lastly, "penultimate" normally means next-to-last but I'm wondering whether it means something else in this instance. Can you expand on what a "penultimate male" is?
Thanks for your help.

Guide page created. Wonderful image!