Picture ID 55369

Picture of unidentified spider

Comments & ID Thoughts

This is pic 1 of 2. While collecting fossils I first thought the black specs were 400M years old. To my surprise when I squeezed one out came yellow goo! They are kind of flattish. Could this be a spider egg or egg sac? Can anyone suggest a group of spiders that may be the source? These things are mostly on the underside of rocks, sometimes on shady sides. Found on shrubby/forested roadsides and waste areas. Pic 2 of 2 is through a microscope.

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  • Submitted: Mar 27, 2019
  • Photographed: Mar 22, 2019
  • Spider: Unidentified
  • Location: Altoona, Pennsylvania, United States
  • Spotted Outdoors: Under rock, log, or debris
  • Found in web?: No
  • Attributes:
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TangledWebItsyBitsy Recent comment authors
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Hi, yes … those *might* be spider egg sacs. Species in the genus Phruroptimpus make similar sacs but I’m used to seeing those reddish … there are other genera in the family though, I don’t know what all of their egg sacs look like. Maybe some of them make gray ones. Spiders in Corinnidae make some similar sacs too, again there are a lot of species in the family and I don’t know if any of them make something exactly like this … Gnaphosidae might be another… the best way to be sure is to hang on to some and… Read more »


That’s really interesting! Hope you find some protospider fossils while you’re working!