Phylum BRACHIOPODA

Brachiopoda

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Phylum BRACHIOPODA

Compiler and date details

31 December 2001 - Peter Middelfart and Shannon Reid, Australian Museum, Sydney NSW Australia

Introduction

Brachiopoda, commonly known as lamp shells, are solitary, benthic marine invertebrates closely related to the other lophophorate phylum the Phoronida. Brachiopods resemble the bivalve molluscs in having a mantle and two calcareous shell halves. However, the basic bauplan of the brachiopods is quite different from molluscs: the most obvious character is that the two valves are dorsal and ventral, whereas in the bivalves they are lateral. This partly accounts for the late segregation of the Brachiopoda from the phylum Mollusca in the middle of the nineteenth century.

Most brachiopods are attached to the substrate by means of a pedicle, while others are cemented. Some species that have long pedicles do not attach to a hard substrate but anchor the pedicle deep in the sand or lie freely. Some species have attached and unattached populations. Pedicles may be deeply anchored in the sand or mud, or used as temporal anchorage of the animal. The substrate relationships of brachiopods are varied and differ from those of other phyla because the majority of living species retain the substrate used for larval settlement as one component of the behavioural system.

The brachiopods range in size from one millimetre to over nine centimetres and may be found from the intertidal zone through to the abyssal depths.

The phylum dates back to at least 600 million years. It was particularly abundant in the Palaeozoic but has progressively decreased in diversity toward the Recent. Worldwide, there is an estimated 12,000 described fossil species but only 335 described Recent species. In Australia only 46 species have been recorded.

Acknowledgements

We would like to thank J. Richardson for reviewing the present catalogue, work done to the collection at the Australian Museum and the notes left behind which facilitated this compilation. We express appreciation for the help received from the staff at the museum library; Winston Ponder for providing comment on the draft; Keith Houston and Kathy Tsang, ABRS, for editorial help and database management, and ABRS for funding for this project.

ABRS thanks Dr Christian Emig for his advice on the appropriate classification to use for this group.

Database Notes

The classification adopted here follows that provide by Dr Christian Emig, pers. comm. (2004).

Etymology

Greek: brachium = arm, poda = feet.

Limiltal Area

Distribution data in the Directory is by political and geographic region descriptors and serves as a guide to the distribution of a taxon. For details of a taxon's distribution, the reader should consult the cited references (if any) at genus and species levels.

Australia is defined as including Lord Howe Is., Norfolk Is., Cocos (Keeling) Ils, Christmas Is., Ashmore and Cartier Ils, Macquarie Is., Australian Antarctic Territory, Heard and McDonald Ils, and the waters associated with these land areas of Australian political responsibility. Political areas include the adjacent waters.

Terrestrial geographical terms are based on the drainage systems of continental Australia, while marine terms are self explanatory except as follows: the boundary between the coastal and oceanic zones is the 200 m contour; the Arafura Sea extends from Cape York to 124 DEG E; and the boundary between the Tasman and Coral Seas is considered to be the latitude of Fraser Island, also regarded as the southern terminus of the Great Barrier Reef.

Distribution records, if any, outside of these areas are listed as extralimital. The distribution descriptors for each species are collated to genus level. Users are advised that extralimital distribution for some taxa may not be complete.