The Squamate Clitoris: A Review and Directions for Future Research

Area of Science:

• Comparative anatomy
• Evolutionary biology
• Herpetology

Background:

• The clitoris in female amniotes functions in sensory arousal and is homologous to the penis.
• In squamates (lizards and snakes), the homologous structure is the paired hemiclitores, while males possess hemipenes.
• Hemipenis evolution in squamates is well-researched, but hemiclitores anatomy remains poorly understood and inconsistently described.

Purpose of the Study:

• To clarify the current state of knowledge regarding squamate hemiclitores anatomy.
• To provide a foundation for future research on hemiclitores morphology and function.
• To address inconsistencies and erroneous reports in existing literature on snake hemiclitores.

Main Methods:

• Literature review and analysis of existing studies on squamate genitalia.
• Examination of anatomical descriptions and historical reports of hemiclitores in lizards and snakes.
• Identification and analysis of potential sources of confusion, such as intersex individuals in snake populations.

Main Results:

• While lizard hemiclitores gross anatomy is described in several studies, comparative data for snakes is absent.
• Previous reports of hemiclitores in snakes (vipers, colubrids) were found to be erroneous, stemming from misinterpretations of anatomy or species.
• Intersex individuals in some snakes, possessing ovaries and a single hemipenis, have been mistakenly identified as hemiclitores.

Conclusions:

• There is a significant lack of comparative anatomical information on snake hemiclitores.
• Misidentification of intersex hemipenes has contributed to erroneous reports of hemiclitores in snakes.
• Further research is crucial to define the anatomical features of squamate hemiclitores for future comparative studies of female genitalia.