Pholadoidea


Drawing of a shipworm Teredo without its burrow, from here.


Belongs within: Heterodonta.

The Pholadoidea is a clade of two families of bivalves, Pholadidae and Teredinidae, which are adapted for boring into hard substrates (rock or wood in the case of Pholadidae, wood for Teredinidae) using their shells to grind out a burrow. Teredinids, commonly known as shipworms, are particularly derived, with the shells reduced to cover only the tip of the long worm-like animal. The Pholadidae have a more complete shell which nevertheless bears a distinct pedal gape (though this may be secondarily closed by a callum) (Cox et al. 1969).

Characters (from Cox et al. 1969): Closed mantle and truncate, more or less circular foot developed as suction disc. Shells inequilateral, dorsal margin reflected anterior to beak, forming attachment area for anterior adductor muscle which works counter to posterior adductor when animal is boring. Hinge teeth lacking, but small chondrophore and internal ligament usually present. Ventral adductor muscle or at least thickening of muscles of ventral margin of mantle located at union of anterior slope and disc, forming pivotal point opposite umbones on which valves rock when boring. Gills usually elongate, with two demibranchs except in Xylophagainae and Teredinidae. Apophyses found in all Pholadoidea except in some Pholadidae.

<==Pholadoidea
    |--Teredinidae GW02
    |    |--Bankia Gray 1842 F27
    |    |    |--B. australis Calman 1920 F27
    |    |    |--B. carinata GW02
    |    |    |--B. gouldi (Bartsch 1908) FH89
    |    |    |--B. martensi (Stempell 1899) FH89
    |    |    `--B. setacea (Tryon 1863) FH89
    |    |--Teredo HJ08
    |    |    |--T. navalis Linnaeus 1758 HJ08
    |    |    |--T. norvegica Spengler 1792 [incl. T. bruguieri Delle Chiaje 1828] F27
    |    |    `--T. vastisas Etheridge 1902 F71
    |    |--Teredora malleolus (Turton 1822) [incl. Teredo thomsonii] FH89
    |    `--Lyrodus pedicellatus (Quatrefages 1849) FH89
    `--Pholas [Pholadidae] GW02
         |--P. australasiae Sowerby 1849 H09
         |--P. dactylus GW02
         |--P. latissima Sowerby 1849 H09
         |--P. multistriata Sowerby 1849 H09
         |--P. obturamentum Hedley 1893 H09
         |--P. orientalis Gmelin 1791 H09
         `--P. quadrizonata Spengler 1792 H09

*Type species of generic name indicated

REFERENCES

Cox, L. R., N. D. Newell et al. 1969. Treatise on Invertebrate Paleontology pt N. Bivalvia vol. 2. The Geological Society of America, Inc. and The University of Kansas.

[F27] Finlay, H. J. 1927. A further commentary on New Zealand molluscan systematics. Transactions and Proceedings of the New Zealand Institute 57: 320-485.

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1-167.

[FH89] Fuller, S. C., Y.-P. Hu, R. A. Lutz & M. Castagna. 1989. Shell and pallet morphology in early developmental stages of Teredo navalis Linné (Bivalvia: Teredinidae). Nautilus 103 (1): 24-35.

[GW02] Giribet, G., & W. Wheeler. 2002. On bivalve phylogeny: A high-level analysis of the Bivalvia (Mollusca) based on combined morphology and DNA sequence data. Invertebrate Biology 121 (4): 271-324.

[H09] Hedley, C. 1909. The Marine Fauna of Queensland: Address by the President of Section D. Australasian Association for the Advancement of Science: Brisbane.

[HJ08] Huisman, J. M., D. S. Jones, F. E. Wells & T. Burton. 2008. Introduced marine biota in Western Australian waters. Records of the Western Australian Museum 25 (1): 1-44.

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