Evolutionary morphology of the lizard chemosensory system

Area of Science:

• Evolutionary biology
• Comparative morphology
• Sensory ecology

Background:

• Foraging modes in squamates are traditionally linked to evolutionary changes in morphology, physiology, behavior, and life history.
• A dichotomy is proposed where sit-and-wait predators rely on vision, while active foragers use chemical cues, reflected in tongue and vomeronasal-organ morphology.
• Previous support for this idea is limited, based on distantly related taxa with confounding biological differences.

Purpose of the Study:

• To investigate the evolution of vomeronasal-lingual morphology in closely related lacertid lizards.
• To test the hypothesis of concerted evolution between foraging mode and sensory system morphology.
• To identify factors driving diversity in chemosensory system morphology within Lacertidae.

Main Methods:

• Comparative analysis of vomeronasal-organ and tongue morphology across various Lacertidae species.
• Assessment of interspecific variation within a single, closely related family.

Main Results:

• Significant interspecific variation in vomeronasal-lingual morphology was observed within Lacertidae.
• Evidence suggests independent evolution of tongue and vomeronasal-organ forms.
• Co-variation between tongue and vomeronasal-organ morphology indicates optimization for chemoreception.
• The degree of investment in chemical signaling, rather than foraging behavior, appears to be the primary driver of morphological diversity.

Conclusions:

• The chemosensory system in lacertid lizards has evolved substantially over a short evolutionary period.
• Foraging behavior is not the sole determinant of vomeronasal-lingual morphology.
• Investment in chemical signaling is a key factor shaping the diversity of lizard sensory systems.