Eulithidium pterocladicum (Robertson, 1958), Florida Pheasant Shells

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Eulithidium pterocladicum (Robertson, 1958)

Abbott includes several Eulithidium. However, the distribution data for several has become obsolete as well as Abbott’s commonality comments. I hope to eventually expand this topic to include images of all the Eulithidium presented by Abbott.

Abbott presents E. pterocladicum as a subspecies of Eulithidium affine (C. B. Adams, 1850). As Harry Lee has pointed out, this is consistent with Robertson's original name Tricolia affinis pterocladica [see Robertson, R., 1958. The family Phasianellidae in the Western Atlantic. Johnsonia 3: 245-283. May 8; specifically, 264-265; pl. 144, fig. 3, pl. 145, fig. 3]. Abbott indicates E. pterocladicum occurs in NW and SE Florida, and as “Uncommon.” I have found E. pterocladicum to be the most common Eulithidium along Florida’s eastern coast from Brevard County south to the Florida Keys and at Cape Romano in Collier County at the SW tip of Florida. Harry Lee reports that it is not found in Florida's three most NE counties. I have also found it at Tarpon Springs in Pinellas County on Florida’s west coast, but nowhere in between Cape Romano and Tarpon Springs.

Abbott distinguishes E. pterocladicum as being brown with white spiral lines descending from the suture at an angle of 45 degrees. The operculum is tinged with brown at the margin and the umbilicus is chinklike. The following specimens (3.3 mm and 2.8 mm) from Jupiter Sound, Palm beach County, exactly reflect this description. The spiral lines (often zigzagged) at an angle of 45 degrees and the absence of dots or dashes are a main distinguishing character.







I have found the coloration of E. pterocladicum to be quite variable, including reds, greens and often specimens with bright white splotches and lines. Here's a red color form from Jupiter Sound, Palm Beach County. 2.1 mm


Here's another red from Jupiter Sound, Palm Beach County, FL. 3 mm

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