Pholas dactylus

Summary

Pholas dactylus, or common piddock, is a bioluminescent clam-like species of marine mollusc in the family Pholadidae.

Pholas dactylus
Shell of Pholas dactylus from Sicily on display at the Museo Civico di Storia Naturale di Milano
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Myida
Family: Pholadidae
Genus: Pholas
Species:
P. dactylus
Binomial name
Pholas dactylus
Synonyms[1]
  • Pholas callosa Cuvier, 1817
  • Pholas callosa Lamarck, 1818
  • Pholas dactylina Locard, 1886
  • Pholas dactylus var. decurtata Jeffreys, 1865
  • Pholas dactylus var. gracilis Jeffreys, 1865
  • Pholas edwardsi Monterosato, 1878
  • Pholas hians Lightfoot, 1786
  • Pholas jordani van Hoepen, 1941
  • Pholas marmoratus Perry, 1811
  • Pholas muricatus da Costa, 1778
  • Pholas mytiloides Bory de Saint-Vincent, 1827
  • Zirphaea julan H. Adams & A. Adams, 1856

The piddock bores into the substrate for shelter, and lives in a tubular burrow formed by grinding the material away with hard parts of the shell by rotating on the longitudinal axis. It has been known to bore into the hard metamorphic rock gneiss, though it more often lives in softer rock. It is a filter feeder, using its siphons to reach the water outside the burrow. It was once a highly esteemed food in Europe.[2][1]

Pholas dactylus: 1. Animal in the shell a) foot b) siphons c) inhalant orifice d) exhalant orifice. 2. shell e) accessory valves or plates

It is sensitive to light, retracting into its shell when exposed to it.[3]

Distribution edit

The coasts of the North Atlantic and the Mediterranean Sea.

Ancient history edit

Pliny spoke of luminescence in the mouths of people who ate Pholas, the rock-boring shell-fish, and of such importance is this phenomenon that it is even said to have gained the first king of Scotland his throne.[4] Hippolytus of Rome tells us that it was a common pagan trick to use the luminescent property of this clam to create the illusion of burning, "And they accomplish the burning of a house, by daubing it over with the juice of a certain fish called dactylus."[5]

References edit

  1. ^ a b Gofas, S. (2012). Pholas dactylus Linnaeus, 1758. Accessed through: World Register of Marine Species on 2012-02-23
  2. ^ "Pholas dactylus (clam) - Britannica Online Encyclopedia". Britannica.com. Retrieved 2011-09-24.
  3. ^ Selig Hecht (1927). "The kinetics of dark adaptation". The Journal of General Physiology. 10 (5): 781–809. doi:10.1085/jgp.10.5.781. PMC 2140923. PMID 19872361.
  4. ^ [1] Author: Field Naturalists' Club of Victoria, Volume: v.21, 1904-1905, Subject: Natural history; Natural history, Publisher: [Melbourne] Field Naturalists Club of Victoria, Year: 1884, Possible copyright status: NOT_IN_COPYRIGHT, page 93
  5. ^ [2] Author: Hippolytus of Rome, Refutation of All Heresies Book IV, Chapter XXXI.