Abbott includes several Eulithidium. However, the

distribution data for several has become obsolete as

well as Abbott’s commonality comments. 

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 adjacent

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.

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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

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