A pholcid gynander
 

Recently I came across a rare example of a spider gynander which seems to be only the second case in this family. Interestingly, it is in the same species as the first record (Blackwall 1867), and the specimen is not purely male on one side and purely female on the other side but one female character is expressed on both sides. The species is Crossopriza lyoni, a widespread synanthropic species that shows several differences between males and females, apart from palp and epigynum: Males have modified chelicerae and spines on the frontal femora Females have a stridulatory apparatus consisting of a pair of cone-shaped elevations posteriorly on the prosoma and a pair of sclerotized plates frontally on the abdomen. The gynander has on its left side a relatively normal epigynum as can be seen on this photo.

On the right side, the specimen seems to be male, but the only character that supports this view (externally) is the enlarged right palp that reminds of the palp of a penultimate male. Since chelicerae and leg femora of penultimate males are unmodified too, these sexually dimorphic traits may not yet be expressed in this specimen. Blackwall's (1867) specimen apparently had a fully developed male palp and modified male chelicerae on the left side and an epigynum on the right side. The left (male) legs were missing so he could make no statement about spines. He also failed to note the presence or absence of the female stridulatory apparatus (see below).

Most surprising is the female stridulatory apparatus: both plates are developed on the abdomen (arrows) but none of the two cones on the prosoma are developed. In the meantime, this has been published in a revision of the genus (Huber 2022).