L. fabalis dwarf form; heights 4 mm to 5.5 mm.
Other views of same shells at 51Dof 51 Differentiation L. obtusata/L. fabalis & 43Dof 43 Differentiation L. obtusata/L. fabalis
Dwarf form from exposed shore (Ballantine scale 3). IFS was uncertain of identity as penes not examined and shell form unfamiliar, but wide experience of Dr Reid enabled him to confirm the identification..
Fusca colour is described for L. fabalis as dark chestnut brown (Reid, 1996). 1 & 8 best represent the colour of these specimens; exaggerated orange tint of the others arises from strong flash on thin, translucent, empty shells. But the images are of 45year old specimens, so the colour has probably changed; they may have been reticulata form.
For L. obtusata, “fusca” is described as dark brown to black (Reid,1996), so there seems some flexibility of definition.
Fusca form is rare, less than 1% of large, pan British collection of both species (Smith, 1976, in Reid, 1996) but 100% of sample of 14 L. obtusata s.l. from one site on brackish Isefjord, Denmark (Rasmussen, 1973).
Cliffs near Aberdeen, Scotland. 1971.
Full account at: 02 Differentiation L. obtusata/L. fabalis

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