Cypraea staphylaea Linnaeus, 1758 (shell ca. 20mm)
ANIMAL OF THE WEEK
Opisthobranch-like animal of the Week Data
Frequency on Okinawa:
- Class: Gastropoda
- Subclass: Prosobranchia
- Order: Sorbeoconcha (Neotaenioglossa)
- Family: Cypraeidae
[brackets indicate range for all Okinawa-collected specimens of the species]
- Individual Collection No: RFB #2487-D [many individuals seen but only a single collected living animal]
- Location: Tengan Pier, Okinawa (26o 24.0'N, 127o 51.1'E)
- Date: 8 March, 1991 [adults are commonly found during all times of the year]
- Depth: 20ft (6m)
- Water temperature at collection depth: Not recorded
- Size: TL (shell), not recorded but ca. 20mm [numerous shells on hand, ranging in size from 12mm ~ 22mm.
- Specimen deposited: Photo only, without specimen
- Photo Data: Original Kodachrome shot at 1:1.5
Note: The above animal was originally referenced on this page (29 Dec. '03) as Erosaria poraria. A recent message from Gustav Pauley (pers. comm), in re a note from Chris Meyer, mentions that he is pretty sure this is not E. poraria, as that species has dendritic tentacles all over (as an Erosaria) . . . it is probably C. staphylaea, although there is a possibility it is C. limacina. In either case, this animal at least superficially resembles what some might confuse with an opisthobranch. I've now changed the original page to Cypraea staphylaea.
As I've done several times in the past I've departed from the usual opisthobranch presentation with the above featured animal. Although it superficially resembles an opisthobranch, it's classified into an entirely different group of molluscs, the Prosobranchia. The conventional schema of mollusc classification is to divide the Class Gastropoda into the following three Subclasses:
- The opisthobranchs include the sea slugs and their relatives the sea hares, sea butterflies, and others. The bodies of most member of this group show evidence of detorsion. Shells may or may not be present; if present they may be reduced and/or internally located. Opisthobranchs usually lack a mantle cavity and operculum. Many species lack gills and respiration takes place through the skin, which may bear numerous projections and folds that increase the area for gas exchange. The head bears 1-2 pairs of tentacles. This diverse group of organisms is divided into around nine Orders. There is some disagreement about whether these form a monophyletic group.
- Prosobranchs are the largest subclass of gastropods. Most species are marine, but many freshwater species and a few terrestrial forms are also known. Prosobranchs have an operculum (lacking in pulmonates), and most have a spirally coiled shell. The head includes eyes that are located on tentacles. The mantle cavity is anteriorly directed and near the head. They are divided into three Orders.
- Pulmonates are the land snails and slugs (a few species are marine). A coiled shell is usually present, but it is lost in some groups. Some detorsion has occurred in many species. The Subclass derives its name from the fact that the mantle cavity forms lungs; these are filled with air as a result of contractions of the mantle floor. One or two pairs of tentacles are found on the head, depending on whether the snail or slug is terrestrial (two pairs) or aquatic (one). The nervous system is highly concentrated. Pulmonates are dioecious and hermaphroditic as are prosobranchs, but pulmonates develop directly (there is no larval form).
Cypraea staphylaea, the above featured animal, is in fact a juvenile cowry (a neogastropod of the Subclass Prosobranchia). Cypraea staphylaea is an uncommon cowry of Okinawan waters, primarily in the upper ten meters of water in numerous habitats. The mantle covering the entire dorsum of this young cowry loosely resembles the
appearance of some opisthobranchs.
I've added two additional pages, one with a series of Cypraea staphylaea shells and another with a "group photo" of
a series of miscellaneous Okinawan cowry shells.
In addition to the above prosobranch, I also have links to a series of non-opisthobranch molluscs which are similar in appearance to opisthobranchs:
Page Date: 29 Dec '03
Page Modification Date: 01 Feb '04
Digitally manipulated photo
Copyright © 2004 Robert F. Bolland