Halysis

Halysis is a genus of red alga thought to fall in the coralline stem group. It has only been recovered in thin sections, and thus is only known in two dimensions; however, an interpretation as a sheet of cells rather than a sheet of tubes or a single row of cells is the most plausible.^[1]

Halysis Temporal range: Mid Ordovician PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Clade:	Archaeplastida
Division:	Rhodophyta
Class:	Florideophyceae
Stem group:	Corallinales
Genus:	†Halysis HØeg, 1932
Species
H. moniliformis HØeg, 1932 (type) H. yui (Bian and Liu, 1999) Riding & BRaga, 2005

See also

• Coralline algae#Evolution
• Other stem-group corallines:
  • Arenigiphyllum (Ordovician)
  • Petrophyton (Ordovician : Caradoc)
  • Graticula (Silurian : Wenlock)
  • Halysis (Ordovician)
  • Archaeolithophyllum (Pennsylvanian)
  •  ?Maimonachaetetes (Mississippian)
  •  ?Palaeoaplysina (Pennsylvanian – Permian; possibly an animal)
  •  ? Solenoporaceae (Ordovician)