''Lithophaga'', the date mussels, are a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of medium-sized marine

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Mytilidae The Mytilidae are a family (biology), family of small to large Marine life, marine and Brackish water, brackish-water bivalve molluscs in the order (biology), order Mytilida. One of the genera, ''Limnoperna fortunei, Limnoperna'', even inhabits f ...

. Some of the earliest

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

''Lithophaga'' shells have been found in

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

rocks from the

Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...

and from

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest ...

.Ludvigsen, Rolf & Beard, Graham. 1997. West Coast Fossils: A Guide to the Ancient Life of Vancouver Island. pg. 102Kleemann, K.H., 1994. Mytilid bivalve ''Lithophaga'' in Upper Triassic coral ''Pamiroseris'' from Zlambach Beds compared with Cretaceous ''Lithophaga alpina''. Facies 30, 151–154. The shells of species in this genus are long and narrow with parallel sides. The animals bore into stone or coral rock with the help of pallial gland secretions,"integument (mollusks)."Encyclopædia Britannica. 2009.

Encyclopædia Britannica 2006 Ultimate Reference Suite DVD An encyclopedia is a reference work or compendium providing summaries of knowledge, either general or special, in a particular field or discipline. Encyclopedias are divided into articles or entries that are arranged alphabetically by artic ...

hence the systematic name ''Lithophaga'', which means "stone-eater". Their club-shaped borings are given the

trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...

name ''

Gastrochaenolites ''Gastrochaenolites'' is a trace fossil formed as a clavate (club-shaped) boring in a hard substrate such as a shell, rock or carbonate hardground. The aperture of the boring is narrower than the main chamber and may be circular, oval, or dumb-be ...

''.

Species

Species within the genus ''Lithophaga'' include: * '' Lithophaga antillarum'' (

d'Orbigny Alcide Charles Victor Marie Dessalines d'Orbigny (6 September 1802 – 30 June 1857) was a French naturalist who made major contributions in many areas, including zoology (including malacology), palaeontology, geology, archaeology and anthropol ...

, 1842) - giant date mussel * '' Lithophaga aristata'' ( Dillwyn, 1817) - scissor date mussel * '' Lithophaga attenuata'' ( Deshayes, 1836) - attenuated date mussel * '' Lithophaga balanas'' Dall * '' Lithophaga balanus'' Dall * '' Lithophaga bisulcata'' (

, 1842) - mahogany date mussel * '' Lithophaga cardigera'' * '' Lithophaga cavernosa'' * '' Lithophaga cinnamomeus'' * '' Lithophaga dactylus'' * '' Lithophaga fasciola'' Dall, Bartsch, & Rehder * '' Lithophaga gracilis''

Philippi Philippi (; , ''Phílippoi'') was a major Greek city northwest of the nearby island, Thasos. Its original name was Crenides (, ''Krēnĩdes'' "Fountains") after its establishment by Thasian colonists in 360/359 BC. The city was renamed by Phili ...

* '' Lithophaga hawaia'' Dall, Bartsch, & Rehder * '' Lithophaga ilabis'' ( Deshayes) * '' Lithophaga lithophaga'' ( Linne) * '' Lithophaga nigra'' (

, 1842) - black date mussel * '' Lithophaga plumula'' (Hanley, 1844) - feather date mussel * '' Lithophaga punctata'' (Kleemann & Hoeksema, 2002) * '' Lithophaga rogersi'' S. S. Berry, 1957 - Roger's date mussel * '' Lithophaga truncata'' (Gray, 1843) * '' Lithophaga simplex''

References

*
Stephen D. A. Smith, Densities of the endolithic bivalve Lithophaga lessepsiana (Vaillant, 1865) in Pocillopora damicornis, Solitary Islands Marine Park, northern NSW, Australia; Molluscan Research 31(1): 42–46; ISSN 1323-5818
Bivalve genera Extant Triassic first appearances Taxa named by Peter Friedrich Röding {{Mytilidae-stub