Posted: Dec 22 2006
Chione elevata (Say, 1822), Cross-barred Venus
(Florida specimens previously C. cancellata)
Chione cancellata (Linnaeus, 1767) has been described as widely distributed from North Carolina throughout 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 (Say, 1822).
Two prominent characters differentiate the two. Sorry, I have no samples of C. cancellata to present for comparison. I would be happy to hear from anyone who has specimens of C. cancellata available displaying the recurved ridges. Contact me at firstname.lastname@example.org.
1. 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.
2. 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.