Lobariella angustata was
described in 2013 by the lichenologists Bibiana Moncada and
Robert Lücking as part of a revision of the family Lobariaceae (now equivalent to
Peltigeraceae subfamily Lobarioideae). Its
species epithet,
angustata, alludes to its narrow . It is most easily distinguished from the related
L. crenulata by its slender lobes (around 3–5 mm wide) and by its chemistry: while
L. crenulata produces the common lichen substance
gyrophoric acid,
L. angustata contains an unidentified compound (referred to as "
Lobariella unidentified 3") that gives a positive emerald‑green reaction with
potassium hydroxide solution. An expanded single-locus
ITS tree recovered
L. angustata inside the strongly supported
L. pseudocrenulata –
L. rugulosa clade, together with
L. auriculata, indicating a closer relationship to those taxa than to the
pallidocrenulata–
crenulata complex. While the
pallidocrenulata–
crenulata–
reticulata lineages formed a separate cluster,
L. angustata remained in the
pseudocrenulata group. ==Description==