Hemiclitoris discovered: a fully differentiated erectile structure in female monitor lizards (Varanus spp.) (Reptilia: Varanidae)

In female monitor lizards (Varanus spp.), the ubiquitous presence of paired evertible and erectile structures in the ventral portion of the tail root, which are miniaturized mirror images of the hemipenes of the males, was discovered. These organs contain all the structural elements (including a forked retractor muscle, supporting ossifications, epidermal flounces etc.) that are also characteristic for the hemipenes of the respective conspecific males. Consequently, it is proposed that the term hemiclitoris be used for this organ. A preliminary survey showed this organ to be present in several other squamate families, suggesting that it is ubiquitous in all female Squamata.