Sensory systems in sawfishes. 2. The lateral line

Area of Science:

• Ichthyology
• Sensory Biology
• Comparative Anatomy

Background:

• The lateral line system is crucial for elasmobranchs to detect hydrodynamic stimuli.
• Sawfish (Pristidae) exhibit specialized rostrum morphology, prompting investigation into their sensory capabilities.

Purpose of the Study:

• To investigate the distribution and morphology of pit organs and lateral line canals in four sawfish species.
• To infer the functional roles of different lateral line canal systems in prey detection based on morphology.

Main Methods:

• Morphological examination of pit organs and lateral line canals across four sawfish species: *Anoxypristis cuspidata*, *Pristis microdon*, *P. clavata*, and *P. zijsron*.
• Analysis of canal structure (pored vs. non-pored) and tubule network development.

Main Results:

• Pit organs were exclusively found in *A. cuspidata*.
• All four species displayed well-developed lateral line canals, differentiated into pored and non-pored regions.
• *A. cuspidata*, *P. microdon*, and *P. clavata* possess extensive, pored tubules on their rostra, contrasting with the non-pored canals found between the mouth and nostrils.

Conclusions:

• The extensive pored tubules on the rostra of three sawfish species suggest they may not primarily use this structure for substrate searching.
• Non-pored canals anterior to the mouth likely detect stimuli from direct prey contact.
• Further behavioral studies are needed to confirm these functional hypotheses.