This specimen displays the Pantoneura morphology of Membranoptera (Image A; see Wynne & Saunders 2012) and was incorrectly identified in the field being confused with its congenor Membranoptera fabriciana (Lyngbye) M.J.Wynne & G.W.Saunders. Although based on this single specimen, in our flora this species has a thick cortex masking the central axial filament (Image B) in contrast to thin cortex in M. fabriciana.
Reported in the Canadian Arctic by Lee (1980) as Membranoptera angustissima (Turner) Kuntze, our single genetically verified collection from northern Labrador (Torngat region), NL, collected subtidally at 6 m growing on rock, is a good morphological match (Wynne 1997) to this species. It clearly allies to the genus Membranoptera in preliminary phylogenetic analyses.
Taxonomic Note: Maggs & Hommersand (1993; as M. angustissima) considered this species a morph of M. alata (Hudson) Stachhouse, which would mirror the situation in the NW Atlantic (see Wynne & Saunders 2012), but COI-5P data indicate that the Canadian specimen is a distinct species (Saunders unpublished). Material from the type locality in Scotland is needed to asses conspecificity of M. alata and M. angustissima (= M. carpophylla (Kützing) Athanasiadis) and thus confirm assignment of Canadian populations to the latter species.
Image A. Pressed voucher of our single Arctic collection (GWS039353).
Image B. Surface view 1 cm down from tip; cortication obscures central axial filament (GWS039353).