Spondylus

''Spondylus'' is a genus of bivalve molluscs, the only genus in the family Spondylidae.MolluscaBase (2019). MolluscaBase. Spondylus Linnaeus, 1758. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=138518 on 2019-03-04 They are known in English as spiny oysters or thorny oysters (though they are not, in fact, true oysters).

Description

The many species of ''Spondylus'' vary considerably in appearance. They are grouped in the same superfamily as the scallops.

They are not closely related to true oysters (family Ostreidae); however, they do share some habits such as cementing themselves to rocks rather than attaching themselves by a byssus. The two halves of their shells are joined with a ball-and-socket type of hinge, rather than with a toothed hinge as is more common in other bivalves. They also still retain vestigial anterior and posterior ''auricles'' ("ears", triangular shell flaps) along the hinge line, a characteristic feature of scallops, though not of oysters.

As is the case in all scallops, ''Spondylus'' spp. have multiple eyes around the edges of their mantle, and they have relatively well-developed nervous systems. Their nervous ganglia are concentrated in the visceral region, with recognisable optic lobes connected to the eyes.

Evolutionary history

The genus ''Spondylus'' appeared in the Mesozoic era, and is known in the fossil records from the Triassic Cassian beds in Italy (235 to 232 million years ago) onwards. About 40 extinct species are known.

Fossils of these molluscs can be found in fossiliferous marine strata all over the world. For example, they are present in Cretaceaous rocks in the Fort Worth Formation of Texas, and in the Trent River Formation of Vancouver Island, as well as in other parts of North America.Finsley, Chalres. 1999. A Field Guide to the Fossils of Texas. Gulf Publishing. Lanham, Maryland. plate 55.Ludvigsen, Rolf & Beard, Graham. 1997. West Coast Fossils: A Guide to the Ancient Life of Vancouver Island. pg. 104

Distribution

Spiny oysters are found in all subtropical and (especially) tropical seas, usually close to the coasts.

Ecology

Spondylus are filter feeders. The adults live cemented to hard substrates, a characteristic they share, by convergent evolution, with true oysters and jewel boxes. Like the latter, they are protected by spines and a layer of epibionts and, like the former, they can produce pearls. The type of substrate they use depends on the species: many only attach to coral, and the largest diversity of species is found in tropical coral reefs; others, (particularly S. spinosus) however, easily adapt to man-made structures, and have become important invasive species. Others still are often found attached to other shells, perhaps the most common belonging to the genus Malleus.

Uses

Archaeological evidence indicates that people in Neolithic Europe were trading the shells of ''S. gaederopus'' to make bangles and other ornaments throughout much of the Neolithic period. The main use period appears to have been from around 5350 to 4200 BC. The shells were harvested from the Aegean Sea, but were transported far into the center of the continent. In the LBK and Lengyel cultures, ''Spondylus'' shells from the Aegean Sea were worked into bracelets and belt buckles. Over time styles changed with the middle neolithic favouring generally larger barrel-shaped beads and the late neolithic smaller flatter and disk shaped beads. Significant finds of jewelry made from Spondylus shells were made at the Varna Necropolis. During the late Neolithic the use of Spondylus in grave goods appears to have been limited to women and children.

''S. crassisquama'' is found off the coast of Colombia and Ecuador and has been important to Andean peoples since pre-Columbian times, serving as both an offering to the Pachamama and as currency. In fact, much like in Europe, the ''Spondylus'' shells also reached far and wide, as pre-Hispanic Ecuadorian peoples traded them with peoples as far north as present-day Mexico and as far south as the central Andes. The Moche people of ancient Peru regarded the sea and animals as sacred; they used ''Spondylus'' shells in their art and depicted ''Spondylus'' in effigy pots. Spondylus were also harvested from the Gulf of California and traded to tribes through Mexico and the American Southwest.

Spondylus shells were the driving factor of trade within the Central Andes and were used in a similar manner to gold nuggets, copper hatches, coca, salt, red pepper, and cotton cloth.

The use of Spondylus shells is what led to an economy of sorts in the Central Andes and led to the development of a merchant class, "mercardes", in different cultures within the Central Andes. This caused the development of different styles of trade that went through evolutionary changes throughout pre-Columbian times. These are reciprocity (home based), reciprocity (boundary), down-the-line trade, central place (redistribution), central place (market exchange), emissary trading, and port of trade. These modes of trade dictate the way that the Spondylus shells are traded, as well as who is benefiting the most from the trades. Modes such as central place (redistribution) require the entity that is the central place to be the one that gains the most benefit from the trade, and modes such as emissary trading and port of trade are the modes that started the "mercardes" class within the Central Andes.

The value of Spondylus shells in the Central Andes stems from supply and demand. There was a lot of demand for Spondylus shells due to the "fetishistic needs to the south."

Even today, there are collectors of ''Spondylus'' shells, and a commercial market exists for them. Additionally, some species (especially ''S. americanus'') are sometimes found in the saltwater aquariums.

''S. limbatus'' was commonly ground for mortar in Central America, giving raise to its junior synonym, "''S. calcifer"''.

Some Mediterranean species are edible and are commonly consumed, with ''S. gaederopus'' in particular being popular in Sardinia. Tropical species, however, tend to bioaccumulate saxitoxin.
The Romans ate them. Macrobius in Saturnalia III.13 describes a dinner party in 63 BCE in which there were two courses of spondylus.

Species

Spondylidae taxonomy has undergone many revisions, mostly due to the fact that identification is traditionally based on the shell only, and this is highly variable. To add to this, while some shallow-water species are extremely common, at least two deep-water ones are known from a single specimen, while a third (S. gravis) was only rediscovered after 77 years. At least another common species (S. regius) has a different shell when it grows in deep water.

*'' Spondylus americanus'' Hermann, 1781 - Atlantic thorny oyster
*'' Spondylus anacanthus'' Mawe, 1823 - nude thorny oyster
*'' Spondylus aonis'' d'Orbigny, 1850
*'' Spondylus asiaticus'' Chenu, 1844
*'' Spondylus asperrimus'' G. B. Sowerby II, 1847
*'' Spondylus aucklandicus'' P. Marshall, 1918
*'' Spondylus avramsingeri'' Kovalis, 2010
* † '' Spondylus bostrychites'' Guppy, 1867
*'' Spondylus butleri'' Reeve, 1856
*'' Spondylus candidus'' Lamarck, 1819
*'' Spondylus clarksoni'' Lamprell, 1992
*'' Spondylus concavus'' Deshayes in Maillard, 1863
*'' Spondylus crassisquama'' Lamarck, 1819
*'' Spondylus croceus'' Schreibers, 1793
*'' Spondylus darwini'' Jousseaume, 1882
*'' Spondylus deforgesi'' Lamprell & Healy, 2001
*'' Spondylus depressus'' Fulton, 1915
*'' Spondylus eastae'' Lamprell, 1992
*'' Spondylus echinatus'' Schreibers, 1793
*'' Spondylus erectospinosus'' Habe, 1973
*'' Spondylus exiguus'' Lamprell & Healy, 2001
*'' Spondylus exilis'' G. B. Sowerby III, 1895
*'' Spondylus fauroti'' Jousseaume, 1888
*'' Spondylus foliaceus'' Schreibers, 1793
*''Spondylus gaederopus'' Linnaeus, 1758 - European thorny oyster
*'' Spondylus gloriandus'' Melvill & Standen, 1907
*'' Spondylus gloriosus'' Dall, Bartsch & Rehder, 1938
* † '' Spondylus granulosus'' Deshayes, 1830
*'' Spondylus gravis'' Fulton, 1915
*'' Spondylus groschi'' Lamprell & Kilburn, 1995
*'' Spondylus gussonii'' O. G. Costa, 1830
*'' Spondylus heidkeae'' Lamprell & Healy, 2001
*'' Spondylus imperialis'' Chenu, 1844
* '' Spondylus jamarci'' Okutani, 1983
*'' Spondylus Lamarckii'' Chenu, 1845
*'' Spondylus layardi'' Reeve, 1856
*'' Spondylus leucacanthus'' Broderip, 1833
*'' Spondylus limbatus'' G. B. Sowerby II, 1847
*'' Spondylus linguafelis'' G. B. Sowerby II, 1847
*'' Spondylus maestratii'' Lamprell & Healy, 2001
*'' Spondylus marinensis'' Cossignani & Allary, 2018
*'' Spondylus mimus'' Dall, Bartsch & Rehder, 1938
*'' Spondylus morrisoni'' Damarco, 2015
*'' Spondylus multimuricatus'' Reeve, 1856
*'' Spondylus multisetosus'' Reeve, 1856
* † '' Spondylus multistriatus'' Deshayes, 1830
*'' Spondylus nicobaricus'' Schreibers, 1793
*'' Spondylus occidens'' G. B. Sowerby III, 1903
*'' Spondylus ocellatus'' Reeve, 1856
*'' Spondylus orstomi'' Lamprell & Healy, 2001
*'' Spondylus ostreoides'' E. A. Smith, 1885
*'' Spondylus pratii'' Parth, 1990
*'' Spondylus proneri'' Lamprell & Healy, 2001
* '' Spondylus pseudogaederopus'' T. Cossignani, 2022
* '' Spondylus purpurascens'' T. Cossignani, 2022
* † '' Spondylus radula'' Lamarck, 1806
*'' Spondylus raoulensis'' W. R. B. Oliver, 1915
* † '' Spondylus rarispina'' Deshayes, 1830
*'' Spondylus reesianus'' G. B. Sowerby III, 1903
*''Spondylus regius'' Linnaeus, 1758 - regal thorny oyster
*'' Spondylus rippingalei'' Lamprell & Healy, 2001
*'' Spondylus rubicundus'' Reeve, 1856
*'' Spondylus senegalensis'' Schreibers, 1793
*'' Spondylus sinensis'' Schreibers, 1793
*'' Spondylus spinosus'' Schreibers, 1793
*'' Spondylus squamosus'' Schreibers, 1793
*'' Spondylus tenellus'' Reeve, 1856
*'' Spondylus tenuis'' Schreibers, 1793
*'' Spondylus tenuispinosus'' G. B. Sowerby II, 1847
*'' Spondylus tenuitas'' Garrard, 1966
*'' Spondylus variegatus'' Schreibers, 1793
*''Spondylus varius'' G. B. Sowerby I, 1827
* † '' Spondylus vaudini'' Deshayes, 1858
*'' Spondylus versicolor'' Schreibers, 1793
*'' Spondylus victoriae'' G. B. Sowerby II, 1860
*'' Spondylus violacescens'' Lamarck, 1819
*'' Spondylus virgineus'' Reeve, 1856
*'' Spondylus visayensis'' Poppe & Tagaro, 2010
*'' Spondylus zonalis'' Lamarck, 1819

*'' Spondylus echinus'' Jousseaume in Lamy, 1927 ( taxon inquirendum)
*'' Spondylus imbricatus'' Perry, 1811 (nomen dubium)
*'' Spondylus microlepos'' Lamarck, 1819 (nomen dubium)
*'' Spondylus unicolor'' G. B. Sowerby II, 1847 (nomen dubium)
See also: Tikod amo, an undescribed species

References

External links

Spondylidae
pictures of the shells of most extant species.



Session Abstracts
on ''Spondylus'' research at the 13th Meeting of the European Association of Archaeologists at Zadar, Croatia, September 2007


from the website of the Gladys Archerd Shell Collection at Washington State University Tri-Cities Natural History Museum

Article on "notched" ''Spondylus''
Neolithic artifacts in Europe

Bibliography

A full and constantly updated bibliography
on ''Spondylus'' spp. in Aegean, Balkan, European and American contexts
* Lamprell, Kevin L.: ''Spondylus: Spiny Oyster Shells of the World'', E. J. Brill, Leiden, 1987

{{Commons category

Spondylidae
Bivalve genera
Extant Triassic first appearances