Thin shell with tall spire. On this one the spire eroded, and thin outer calcite layer lost from penultimate whorl exposing black-brown aragonite layer. Rounded unconstricted aperture. No sculpture apart from fine growth lines. Colour of this ecotype is most often uniform-brown, or pale-brown with darker bands or tesselation.

From salting pool. Image of site by D.Tipping at flic.kr/p/poka2G

Det. criteria: habitat (L. arcana and L.compressa do not live on saltings; may be because they need hard substrate to attach spawn) and distinctly mucronate penis (see L. saxatilis s.s. B90 03 Littorina saxatilis s.s. B90. Shell height 6 mm. Mature male removed from shell. Inland Sea, Anglesey. March 2014. )

No full account yet of this species.
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