Dataset: Byssal Thread Tests - All Proximal Breaks

For testing, an individual thread was excised from the byssus, with care taken to avoid loading the thread. The pebble to which the plaque was attached was epoxied to an aluminium bracket and the root of the thread was secured between cardboard with cyanoacrylate. The cardboard and aluminium bracket were secured in the clamps of an Instron 5565 materials testing frame. Byssal threads were tested while submerged in a 10 °C seawater bath by pulling normal to the substratum at 10 mm min⁻¹ until failure following ref. Thread strength, extensibility and failure location were recorded and unbroken thread portions were subsequently retested to measure distal yield and force to break plaque and proximal regions. Distal region failures were rare and excluded.