Lithothamnion purpureum P. Crouan & H. Crouan, 1867: 150, pl. 20: fig. 133 bis:1–5 (lectotype locality: Mingant, near Brest, Finistère, France fide Woelkerling & L. Irvine, 1986: 69, 71).
Phymatolithon purpureum (P. Crouan & H. Crouan) Woelkerling & L. Irvine, 1986: 71.
Misapplied names:
Melobesia polymorpha.—Harvey, 1849 [1847–1849]: 110.
Lithothamnion polymorphum.—Areschoug, 1852: 524.— Prain, 1892: 341.— Barton, 1893: 202.— Delf & Michell, 1921: 119.
INDIAN OCEAN DISTRIBUTION: Burma (Coco Group), South Africa.
Note: Millepora polymorpha Linnaeus (1767a: 1285) is a superfluous and hence illegitimate substitute name for M. calcarea Pallas (1766: 265; syntype localities: Atlantic Ocean near America; Mediterranean Sea). Nonetheless, the two names have traditionally been applied to separate species. According to Woelkerling and L. Irvine (l.c.), the species traditionally but incorrectly known as Melobesia polymorpha Linnaeus, Lithothamnion polymorphum (Linnaeus) Areschoug (1852: 524), or Phymatolithon polymorphum (Linnaeus) Foslie (1898a: 4) is conspecific with L. purpureum.