Description: Very small. Thallus uniseriate, erect and finely branched to 5 - 13 mm long.

Habitat: Epiphytic and epizoic in the sublittoral.

Distribution: West coasts of Scotland and Ireland. Europe: Portugal, Spain, France and the west Baltic.

Similar Species: All species of Aglaothamnion and Callithamnion are similar and not easy to identify.

Distribution Map from NBN: Aglaothamnion bipinnatum at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Aglaothamnion bipinnatum at iNaturalist World Species Observations database.

WoRMS: Aglaothamnion bipinnatum at World Register of Marine Species. Accepted name: Aglaothamnion bipinnatum (P.Crouan & H.Crouan) Feldmann & G.Feldmann, 1948. AphiaID: 144489.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Ceramiales; Callithamniaceae; Callithamnioideae; Callithamnieae; Aglaothamnion