Larva: not an Actinotrocha Silén, 1954



About the species name ovalis:
    Wright (1856) wrote: "I noticed a great number of animals which I for some time mistook for Lepralia, until my attention was arrested by a slight want of symmetry in the circle of the tentacles. It was not a circle, but rather an oval very slightly flattened on one side."

° References of the most recent publications

Pictures of Phoronsis ovalis

Last update: October 9, 1982

Extended specimens up to 15 mm, diameter 0,15-0,35 mm.
Colour in life transparent, sometimes lophophore brownish or whole body.
Lophophore oval-shaped. 11 to 28 tentacles, length 0.3-1.2 mm .
Nephridia with a small funnel, a single straight ascending branch, nephridiopore on the anal papilla at the level of the anus.
Giant nerve fibre absent, sometimes a left and right one (diameter: 2.5 µm).
Absence of lateral mesenteries, consequently the muscular formulae are unusual (see below).
Presence of an "accessory" blood vessel and two lateral longitudinal blood vessels.
Longitudinal muscle bundles rather of bushy type; the mean formula and general formula are respectively:

= 29  and  7-21
[14-39]   (n= 67 individuals)

Sexual reproduction: hermaphroditic (or dioicious?); embryos brooded in the parental tube. Absence of nidamental glands and lophophoral organs.

Asexual reproduction by transversal fission, by autotomised lophophores, by budding.

Phoronis pallida burrows into empty and decayed mollusk and barnacle shells and carbonate rocks. Bathymetric range from 0 - 55 m, commonly between 20 and 50 m.

The distribution of Phoronis ovalis is represented below on the map.

Type-locality: Inchkeith, Firth of Forth (UK)

© Christian C. Emig

Last update: January 9, 2013>

Distribution of P. ovalis

  •  Most recent published diagnoses

  • Mamkaev Y. V., 2011. Phylum Phoronida. In: Illustrated Keys to Free-Living Invertebrates of Eurasian Arctic Seas and Adjacent Deep Waters, Buzhinskaja G. N. ed., Alaska Sea Grant College Program (Publisher), Vol . 2 [168 p.].

    Ruesink J. L. & Trimble A. C., 2010. First report of Phoronis ovalis from Africa and its effect on mussel hosts. African Journal of Marine Science, 32 (1), 109-114.

    Grobe P. & T. Bartolomaeus, 2007. The coelomic origin and phylogenetic affinities of the Phoronida. 100. Jahresversammlung der Deutschen Zoologischen Gesellschaft (Köln, 2007), Abstract, p, 38.

  • 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.
  • Gruhl A., Grobe P. & T. Bartolomaeus, 2005. Fine structure of the epistome in Phoronis ovalis: significance for the coelomic organization in Phoronida. Invertebr. Biol., 124 (4), 332-343.

  • Zezina O. N. & S. N. Temereva, 2005. Brachiopoda and Phoronida. In: Biota of the Russian waters of the Sea of Japan, Ed. A. V. Adrianov, vol. 3, 138 p. Dalnauka, Vladivostock.

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

  • References on Phoronis ovalis

    Sampled subtidally below a beach of Swakopmund (Namibia) in a mollusk shell of Perna perna
    © 2009 Dr. Alan Trimble , Department of Biology, University of Washington, Seattle (USA)