Palaeobiology of Silurian Leptaeninae (Brachiopoda) from Gotland, Sweden
Figure 4
Leptaena rhomboidalis. PMU G1054; Visby, Högklint Formation. Reconstruction of the function of the pedicle retractor muscle inferred from the specimen in Figures 3(b)–3(d). (a) Muscle is relaxed; commisure is oriented down towards the substrate and the current that hits the ventral valve tends to flow past the commisure in a smooth flow. (b) Muscle is contracted; commisure points more upwards and the current becomes disturbed with eddies forming outside the commisure, which makes particle fall out of suspension to be collected by the brachiopod.
