Appearance
''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 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.
Habitat
Individuals live for 3–5 years in groups in rocky crevices at depths of up to 40 metres . Females grow faster than males, and the population is highly seasonal, with a pronounced peak in the autumn. They are preyed upon by a variety of fish, including species of Mullidae, Moronidae, Sparidae and Batrachoididae.References:
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