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Donax fossor Say, 1822 Fossor Coquina |
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Some time after this essay was
penned, a molecular genetic study by Adamkewicz and Harasewych demonstrated
Donax fossor and D. parvulus to be conspecific, to wit: <https://www. |
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In sand, Little Talbot Island, Duval County, Florida December, 2002 (about 4 mm.) |
| Donax fossor With Hydroid |
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During the summer and fall months a significant portion of the Donax found on northeast Florida beaches have a hydroid "plume" attached to the posterior aspect of the shell (the short end; the upper end when burrowing; the end with the siphons). Over the years this phenomenon has been a continuing source of amazement to those observing it for the first time and has generated many questions. A study of Donax fossor indicates predation by Neverita duplicata (Shark Eye; Moon Snail) was affected by the presence of a hydroid colony. Donax without a hydroid colony were drilled more frequently than those possessing it, which suggests that the Donax benefits from the hydroid by way of predator deterrence. The reduced predation supports the case that this symbiosis is an instance of mutualism. Also see Donax variabilis Say, 1822 with hydroid Dougherty, J.R. and M. P. Russell, 2005. The association between the coquina clam Donax fossor Say and its epibiotic hydroid Lovenella gracilis Clarke. Journal of Shellfisheries Research. 24: 35-46. |
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| Minus tide, Little Talbot Island, Duval County, Florida 4/17/2012 |
| Donax fossor And Donax variabilis Comparison |
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| Donax fossor - In muddy sand, Big Talbot Island, Duval County, Florida (about 10 mm.) |
| Donax variabilis - In sand, Little Talbot Island, Duval County, Florida (15 mm.) |
