Description

Despite the similar common name, the thorny oyster molllusc is more closely related to the scallop. Like scallops and file clams, they have a well developed middle mantle that carries sensory tentacles with multiple eyes around the shell edges. Reflecting this rich endowment of sensory receptors, their cerebral and visceral ganglia become much more concentrated, in the visceral region, and show distinct optic lobes with nerve trunks to the mantle edges (Morton, 1960). 

 

However, in common with the true oysters, thorny oysters live cemented to shells or other substrates as epifaunal species, rather than living attached by a byssus. Their  key shell characteristic is a ball & socket type hinge, rather than the more common toothed hinge of bivalves.

Classification  

Class: Bivalvia

Subclass: Pteriomorpha

Order: Pterioida

Suborder: Ostreina

Family: Spondylidae

 

Single Genus: Spondylus

 

Spondylus japonica
Japanese Spiny Oyster

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