Phoronis pallida (Schneider, 1862) Silén, 1952.

Larva: Actinotrocha pallida Schneider, 1862

° References of the most recent publications

Diagnosis

Last update: February 9, 2003  

Extended specimens up to about 140 mm, diameter 0.3 to 1 mm.
Colour in life: pink-yellowish.
Lophophore horseshoe-shaped, ends sometimes turned medially. Up to 140 tentacles, length 2-2.5 mm .
Nephridia with two pseudo-funnels, the anal slightly larger than oral, a descending and ascending branch; nephridiopore opens on anal papilla at anus level.
A single giant nerve fibre, on the left side at the level of the attachment of the left lateral mesentery to the body wall, 10-20 µm in diameter.
Longitudinal muscle bundles of feathery type, developed into six longitudinal zones and circular musculature with three sphincters (see Silén, 1952); the mean formula and general formula are respectively:

5 | 5
4 | 4
= 18  and  4-5 | 5 
4-5 | 3-4
[17-19]   (n= 144 individuals)

Sexual reproduction: hermaphroditic, ova freely discharged in the sea-water; males with large, glandular lophophoral organs.

Phoronis pallida is embedded vertically in soft sediments, generally sand to muddy sand. Santagata (2002) cites a commensalim within the burrow of the thalassinid shrimp Upogebia pugettensis in False Bay (Washington, USA).
Bathymetric range from the upper subtidal to 25 m. Densities up to 74 000 individuals/ m-2.

The distribution of Phoronis pallida is represented below on the map.
Type-locality: Gullmar Fiord (Sweden)

© Christian C. Emig

Last update: November 28, 2006

Distribution of P. pallida

  •  Most recent published diagnoses
  • Emig C. C., Roldán C. & J. M. Viéitez, 2005. Filo Phoronida. In: Fauna Ibérica, vol. 27. Museo de Ciencias Naturales, CSIC Madrid, p. 19-54 & 180-186 & 223-224.
  • Santagata S., 2004. A waterborne behavioral cue for the actinotroch larva of Phoronis pallida (Phoronida) produced by Upogebia pugettensis (Decapoda: Thalassinidea). Biol. Bull., 207, 103-115.

    Santagata S., 2002. Structure and metamorphic remodeling of the larval nervous system and musculature of Phoronis pallida (Phoronida). Evolution and Development, 4 (1), 28-42.

  • Bailey-Brock J. H. & C. C. Emig, 2000. Hawaiian Phoronida (Lophophorata) and their distribution in the Pacific region. Pacific Science, 54 (2), 119-126.

  • Viétiez J. M., Emig C. C., Rodriguez-Babío C. & A. M. García Carrascosa, 1987. Foronídeos de las costas de la Península Ibérica e Islas Baleares: sistemática, ecología, distribución y estados larvarios. Boletin del Instituto Español de Oceanografia,, 40, 129-133.

  • References on Phoronis pallida