TABLE 1. Comparison of known fossil species of Ricciaceae.

Taxon Rosette-forming Thallus
size
Branch base Number of dichotomies Segment shape Segment surface Segment width Ventral scale Rhizoid Age References
Ricciopsis sandaolingensis sp. nov yes 26-37 mm in diameter not fused 4 linear narrow ridge 1.9-3.7 mm semi-circular 13-19μm wide, unicellular Middle Jurassic this paper
Ricciopsis florinii yes 25 mm in diameter fused 3 longth almost equal to width median furrow 1-3 mm - 23μm wide, unicellular or multicellular Early Jurassic Lundblad (1954)
Ricciopsis scanica yes 10 mm in diameter fused 2 linear to wedge-shaped ribs or striae 1-1.5 mm - - Early Jurassic Lundblad (1954)
Ricciopsis grandensis yes 15 mm in diameter fused up to 3 linear to wedge-shaped strongly marked midrib 1-2 mm - - Early Cretaceous Cladera et al. (2007)
Ricciopsis algoaensis yes 9 mm in diameter fused 6 linear median ridge ca. 0.5 mm - - Early Cretaceous Anderson and Anderson (1985)
Riccia chitaleyii yes 6.5 mm in diameter fused 2 linear to wedge-shaped air spaces - - - Late Cretaceous Sheikh and Kapgate (1982)
Riccia thongjaorokensis yes 75 mm in diameter fused up to 2 linear wide groove 10 mm - - Oligocene Hemanta Singh and Kishor (2009)
Ricciopsis ferganica no up to 15 mm long, 7-13 mm wide - 3 linear median furrow 0.9-2.2 mm - - Middle-Late Triassic Moisan et al. (2012)
Ricciopsis speirsae no up to 25 mm long - 7 linear narrow furrow or sulcus 1.5-2 mm - - middle Paleocene Hoffman and Stockey (1997)