Female L. fabalis.
Goodwin & Fish (1977) wrote that the colour of the female’s ovipositor is “to varying degrees black pigmented” on L. obtusata, while that on L. fabalis “lacks pigmentation” in 99% of cases in Wales. Reid (1996) stated that it is not so in all areas.
This specimen has a pigmentless ovipositor (1) that matches the description for L. fabalis except for a small patch of yellow at the anterior (2). The shell size, form and colour match those of males of that species (penes checked) found with it on Fucus serratus, and no male L. obtusata were found on the shore, so there is no doubt that this female is L. fabalis.
Shell height 14 mm. Llŷn, North Wales. September 2015.
Full account at: 02 Differentiation L. obtusata/L. fabalis

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