Spondylus

Thorny oysters Temporal range: Triassic - Recent PreЄ Є O S D C P T J K Pg N
A shell of S. regius
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Subclass:	Pteriomorphia
Order:	Pectinoida
Suborder:	Pectinina
Superfamily:	Pectinoidea
Family:	Spondylidae Gray, 1826
Genus:	Spondylus Linnaeus, 1758
Species
See text

Spondylus is a genus of bivalve molluscs, the only genus in the family Spondylidae. As well as being the systematic or scientific name, Spondylus is the most often used common name for these animals, though they are also known as spondylids, thorny oysters, and spiny oysters (though they are not, in fact, oysters) . The meat of these bivalves is edible.

Description

The many species of Spondylus vary considerably in appearance and range. 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 attach themselves by a byssus. Their key characteristic is that 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 common feature of scallops though not of oysters.

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

Spondylus shells are much sought after by collectors, and a lively commercial market exists for them.

History

The genus Spondylus originated in the Mesozoic era and it is known in the fossil records from the Triassic to the Quaternary (age range: from 235.0 to 0.0 million years ago). There are about 40 extinct species.^[1]

Fossil valve of Spondylus crassicosta from the Pliocene of Italy

These molluscs can be found in fossil shells all over the world. They are present in cretaceaous rocks in the Fort Worth Formation of Texas and in the Trent River Formation of Vancouver as well as in other parts of North America.^[2][3]

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.^[4] The main use period appears to have been from around 5350 to 4200 BC.^[4] 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.^[4] 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.^[4]

S. princeps 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.^[5] 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.^[6] 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.^[7] Spondylus were also harvested from the Gulf of California and traded to tribes through Mexico and the American Southwest.

Species

Pacific thorny oyster, S. crassisquama Lamark, 1819, from the Gulf of California, Mexico

The interior of two fossil valves of Spondylus from the Pliocene of Cyprus

Cat's tongue oyster, Spondylus linguaefelis Sowerby, 1847, from Hawaii

A view of the colorful mantle edges of a live thorny oyster from East Timor: The eyes can be seen on the fringe between the mantle and the shell.

A fossil Spondylus gaederopus from the Pliocene of Cyprus

References

1. ↑ Fossilworks
2. ↑ Finsley, Chalres. 1999. A Field Guide to the Fossils of Texas. Gulf Publishing. Lanham, Maryland. plate 55.
3. ↑ Ludvigsen, Rolf & Beard, Graham. 1997. West Coast Fossils: A Guide to the Ancient Life of Vancouver Island. pg. 104
4. 1 2 3 4 Gardelková-Vrtelová, Anna; Golej, Marián (2013). "The necklace from the Strážnice site in the Hodonín district (Czech Republic). A contribution on the subject of Spondylus jewelry in the Neolithic". Documenta Praehistorica. Znanstvena založba Filozofske fakultete Univerze v Ljubljani. 40: 265–277. doi:10.4312/dp.40.21. Retrieved 2 December 2015. 
5. ↑ Carter, Benjamin. "Spondylus in South American Prehistory" in Spondylus in Prehistory: New Data and Approaches. Ed. Fotis Ifantidis and Marianna Nikolaidou. BAR International Series 2216. Oxford: Archaeopress, 2011: 63-89.
6. ↑ Shimada, Izumi. “Evolution of Andean Diversity: Regional Formations (500 B.C.E-C.E. 600). The Cambridge History of the Native People of the Americas. Vol. III, pt. 1. Ed. Frank Salomon & Stuart B. Schwartz. Cambridge: Cambridge University Press, 1999: 350-517, esp. "Mesoamerican-Northwest South American Connections", pp. 430-436.
7. ↑ Katherine Berrin and Larco Museum. The Spirit of Ancient Peru: Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.

External links

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