Fig 4. Quantification of barb and serration shape.

(A) Rachis with a barb. The barb is divided into a base and a serrated tip. The base of the barb extends from the origin at the rachis to the point of separation. The positions of the bow and hook radiates are indicated as well. Two angles characterized the geometry. The inclination angle α is the angle between rachis and the base of the barb. The tip displacement angle β is the angle between the base of the barb and the tip of the serration measured from the point of separation. (B) Orientation and placement of a serration for the measurement of serration length.