When Jonas Quinn sits down to talk to Zenna Valk, you can see the "rock" compress under his foot.
Dollen states that a canopic jar was found, containing a "living female symbiote, perfectly preserved in stasis." The Goa'uld do not have genders, but are generally defined by their hosts; for example, Osiris is considered male based on previous hosts, but chose to take a female host in Sarah Carter because that was what was available. There is no way the Pangarans could have identified the gender of the symbiote, as it had none.