A. oregonensis and A. utahana are phenotypically almost inseparable. It makes sense given the genetic work done in Whitman-Zai, et al. (2015). They are very closely related. Figure 61 (p. 9) does not suggest range over lap of the two species, however the text (p. 19, 22) and this observation suggests otherwise.

Using the key provided on p. 6-7:

17(b) Anterior edge of atrial opening is concave at center (Figs. 36, 37, 38)...20

20(a) Epigynal bridge short and thick (Figs. 36, 37)...21

21(a) Sclerotized edges of epigynum broaden anteriorly (Fig. 36, arrow)...utahana

21(b) Sclerotized edges of epigynum taper anteriorly (Fig. 37, arrow)...oregonensis

I believe BugGuide has some observations for further comparison: https://bugguide.net/node/view/300034.

Further Reading

Whitman-Zai, Julie, Maren Francis, Margaret Geick, and Paula E. Cushing. “Revision and morphological phylogenetic analysis of the funnel web spider genus Agelenopsis (Araneae: Agelenidae).” Journal of Arachnology 43, no. 1 (March 3, 2015): 1–25. https://doi.org/10.1636/k14-35.1. https://www.researchgate.net/publication/276833638_Revision_and_morphological_phylogenetic_analysis_of_the_funnel_web_spider_genus_Agelenopsis_Araneae_Agelenidae.

Moved from Spiders.