Common prawn

P. serratus may be distinguished from other species of shrimp by the rostrum, which curves upwards, is bifurcated at the tip and has 6–7 along its upper edge, and 4–5 teeth on the lower edge. Other speciesmay have a slightly curved rostrum, but then the teeth on its dorsal surface continue into the distal third, which is untoothed in P. serratus. P. serratus is pinkish brown, with reddish patterns, and is typically 100 millimetres (3.9 in) long, making it the largest of the native shrimp and prawns around the British Isles. P. serratus is one of the few invertebrates to have its hearing studied in detail; it is sensitive to frequencies between 100 Hz and 3 kHz, with an acuity similar to that of generalist fish. While the hearing range of a P. serratus individual changes as it grows, all are capable of hearing tones at 500 Hz.