Chione elevata (Say, 1822), Florida specimens previously cancellata

[Marlo]

Chione elevata (Say, 1822)

Chione cancellata (Linnaeus, 1767) has been described as widely distributed from North Carolina throughtout the Caribbean. However, authors began noticing differences and in One species becomes two: The case of Chione Cancellata, the resurrected C. Elevata, and a phylogenetic analysis of Chione, Peter D. Roopnarine and Geerat J. Vermeij, J. Moll. Stud. (2000), 66 517-534, (see Abstract) it was demonstrated that two species had been lumped together and that the one found in Florida is Chione elevata.

Two prominent characters differentiate the two.

Both have concentric ridges. The ridges on C. elevata curve upward and are oriented perpendicular to the shell surface and with sharp edges. The ridges on C. cancellata curve upward and recurve back toward the shell surface.

Both have radial ribs. The early ribs of C. elevata are single, undivided and cord-like and bifurcate at later stages. The early ribs of C. cancellata are bifurcate frequently from the earliest stages of the adult shell.

Sorry, I have no samples of C. cancellata. So my images are all of C. elevata. The main reason I did this exercise was to present images of micro-size specimens to aid in identifications. So, here they are:

This specimen is from Raccoon Key, Florida Keys:

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This specimen is from Mosquito Lagoon, Brevard County, Florida:

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C. elevata is most commonly dull white on the outside and inside, but often has brown rays or zigzags on the outside and with the inside flushed with purple, yellow or a tanish-brown. Here are some samples (all approx. 29mm X 35mm):



See another image at Jaxshells.

[Marlo]

As noted above, one of the distinguishing characters of C. elevata is that the concentric ridges curve upward and are oriented perpendicular to the shell surface and have sharp edges. Unfortunately, the ridges become worn on older shells and this character becomes less apparent. Here's an image of a juvenile (6mm X 7.5mm) to illustrate the orientation of the ridges. This specimen is from Mosquito Laggoon, Brevard County, FL.


Here's a very large typical white (36mm X 42mm) specimen from just south of Sebastian Inlet, Indian River County, FL, and another from Mosquito Lagoon showing the often displayed brown rays (21mm X 26mm). Both have beautiful purple interiors.
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[Marlo]

The following specimen is from Jupiter Sound, Palm Beach County, FL. 9 mm x 12 mm

This specimen is an uncommon predominately brown with images to illustrate the

1. undivided and cord-like, early ribs



2. perpendicularly oriented concentric ridges


3. heart-shaped lunule with minute vertical threads mmmmmmmmm4. long, smooth and V-shaped escutcheon with 6 or 7 brown zebra-stripes