° References of the most recent published diagnoses

Diagnosis

Last update: July 22, 2006   Extended specimens up to 190 mm long, diameter 0.5-2 mm. Colour in life: body pink, lophophore transparent with white (occasionally yellow, green or red) pigment spots. Lophophore horseshoe-shaped with ends turned medially. Up to 190 tentacles, length 1.5-2.5 mm. Nephridia with a single funnel, with descending and ascending branches; nephridiopore on anal papilla opening below anus. Single giant nerve fibre on left side, 7-27 µm in diameter; very thin nerve fibre rarely present on right side. Longitudinal muscle bundles of feathery type; the mean formula and general formula are respectively: 12 | 11  6 |  6 =35  and  7-19 | 7-18 4-11 | 4-11 [24-53]   (n= 3244 individuals) Sexual reproduction dioecious; females brooding embryos in a single mass in lophophoral cavity through nidamental glands of type C (i.e. formed by fusion of inner row of lophophore tentacles); males with large, glandular lophophoral organs. Asexual reproduction by transverse fission. Phoronis psammophila lives in the soft substratum at depths ranging from the intertidal zone to 69 m, commonly between 0 and 10 m. Densities may reach 18,000 to 20,000 ind.m-2. This species particularly prefers a sediment structure mainly composed of fine and very fine sand fractions (58 to 93%), with a moderate muddy fraction (8 to 41%). Phoronis psammophila is a cosmopolitan species: the distribution is represented below on the map. Type-locality: Messina (Italia) © Christian C. Emig Last update: July 25, 2007