Eratigena

Picture ID 76745

Picture of Eratigena - Dorsal
  • Submitted by: 
    Eightleg
  • Submitted: Aug 9, 2019
  • Photographed: Aug 9, 2019
  • Spider: Eratigena
  • Location: Oregon, United States
  • Spotted Outdoors: Man-made structure (building wall, fences, etc.)
  • Found in web?: No
  • Attributes: Dorsal
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ItsyBitsy

Giant House Spider, Eratigena duellica or saeva.

j_staff99

Is saeva still in use?

ItsyBitsy

Yes, what happened is duellica, saeva, and atrica were synonimized in 2013 … then DNA analysis was done showing them to be three distinct species after all (see “Oxford & Bolzern, 2018). It was also shown that in some places there is potential for hybridization between saeva and duellica, sometimes I leave them at genus for this reason.
https://wsc.nmbe.ch/species/46142/Eratigena_saeva

j_staff99

Oh that’s interesting! So is genetics the only known way to distinguish them?

ItsyBitsy

There are morphological differences. I can make an educated guess based on location and subtle differences in the patterns. I have an idea how to distinguish saeva from duellica but it’s based on only one I saw IDed as saeva on the British Arachnological Society site, I don’t know if it’s reliable… so if I see that variation in areas where the species might overlap I’m inclined to file those to genus rather than to species … atrica is a little easier to distinguish … close examination of the genitalia can differentiate them with more certainty.

j_staff99

Very interesting! Thank you!

Additional Pictures

Picture of Eratigena spp. - Dorsal Enlarge Picture
Picture of Eratigena spp. - Dorsal Enlarge Picture
Picture of Eratigena spp. - Dorsal Enlarge Picture
Picture of Eratigena spp. - Dorsal Enlarge Picture