Anatomy
L
Lateral Line
/ /ˈlæt(ə)r(ə)l laɪn/ /
Etymology:
From Latin lateralis — "of the side"
Quick Definition
A sensory organ running along each side of the body that detects low-frequency vibrations and pressure changes in the water.
📖 Full Definition
The lateral line is a mechanosensory system comprising a series of pores and sub-epidermal canals containing neuromasts (hair-cell receptors). It runs from behind the operculum to the base of the caudal fin along each flank, and also across the head. It detects water displacements caused by nearby objects, prey, predators, and conspecifics. Together with the inner ear it forms the acoustico-lateralis system. Lateral line pore counts are important in species identification.
💡 Examples & Context
Blind cavefish retain a highly developed lateral line that allows them to detect obstacles and prey in total darkness.
🧪 Scientific Usage
Lateral line scale counts (e.g. LL = 47–52) are standard diagnostic characters in species descriptions.