PHORONIDA: Collection, Preservation and Examination


The easiest sampling is by Scuba-diving, in soft and on hard substrates. On soft substrates the best apparatus is a suction sampler (Emig, 1977). To prevent lophophore autotomy the phoronids must be fixed quickly after collecting.


Identification of the adult species needs histological slides. Consequently the best fixative is a histological one, i.e. Bouin. Nevertheless formalin or alcohol may also be used but the specimens should be studied rapidly, although specimens stored for more than 8-10 years are usually impossible to identify because tissue deterioration.



Transversal slides at about 5-7 mµ at level A, B, C. Make continuous slides at level A. Some slides at B and C are enough.
See disposition in the paraffin block [in front].

The characters for genus and species are listed below in relation with the three levels for identification.
See also Taxonomic characters.


For accurate identification on histological slides the best staining routine is Azan according to the Heidenhain’s method (see Emig, 1971, 1979).

Emig C. C., 1971. Taxonomie et systématique des Phoronidiens. Bull. Mus. Nat. Hist. nat. Paris, (Zool.) 8, 469-568.

Emig C. C., 1977. Un nouvel aspirateur sous-marin à air comprimé. Mar. Biol., 43, 379-380.

Emig C. C., 1979. British and other Phoronids. In : Synopses of the British fauna, Eds Kermack D. M. & R. S. K. Barnes, Acad. Press, London, 13, 57 pp.

Diagnostic features of the adult genera Section level
  • Phoronis: without epidermal invagination at the base of the lophophore.
  • Phoronopsis: with an epidermal invagination at the base of the lophophore.
Diagnostic features of the adult species Section level
  • Habits
  • Shape of longitudinal muscle bundles (fathery of bushy)
A & B
  • Number of giant nerve fibres (one or two)
  • Coelomic funnels of nephridia (one or two)
  • Nephridia branches (ascending or ascending & descending)
  • Development of nephridial epithelium (absent-present: restricted to reproductive period)
  • Lophophoral organs (small or large)
  • Gonads (dioecious or hemaphroditic)
  • Developmental patterns, (direct release or brooding patterns: a, b, or c)
  • Larva (actinotroch or creeping)
  • Additional non-phylogenetic characters are also used as:
    • Mean and general formulae of the longitudinal muscles bundles
A & B & C
    • Shape of the lophophore (oval, horshoe-shaped, spiral with x coils on each side, helicoidal)
    • Morphology of the nephridia as opening of the nephridiopore, size of the coelomic funnels
    • Absence of lateral mesentery (Phoronis muelleri)
A & B & C
    • Circulatory system (Phoronis ovalis)
A & B