Placotrochus Milne Edwards & Haime, 1848

Cairns, Stephen D., 2016, A key to the genera and species of the transversely-dividing Flabellidae (Anthozoa, Scleractinia, Flabellidae), with a guide to the literature, and the description of two new species, ZooKeys 562, pp. 1-48 : 24

Taxon classification Animalia Scleractinia Flabellidae

Genus Placotrochus Milne Edwards & Haime, 1848

Placotrochus Milne Edwards & Haime, 1848: 282.- Duncan 1884: 16 (in part: not fossil records).- Vaughan and Wells 1943 227 (in part: not fossil records).- Wells 1956: F432.- Zibrowius 1974: 21, 26.-Cairns 1989: 45, 75 (synonymy).- Cairns and Kitahara 2012: 13 (key to genus).

Diagnosis.

Asexual reproduction by apical transverse division of corallum, resulting in distal anthocyathus and basal anthocaulus. Corallum laterally compressed and fan shaped, having rounded thecal edges with one pair of basal thecal edge spines. Columella lamellar. Anthocaulus not stereome-reinforced.

Discussion.

Seven species of Placotrochus were described from the Australian Eocene-Miocene by Duncan (1864), Dennant (1899, 1903, 1904), and Tenison-Woods (1878a), but these species are not transversely dividing and thus should be assigned to a different genus (Cairns in prep.). Placotrochus is a monotypic genus.

Distribution.

Western Pacific, eastern Indian Ocean, 6-289 m.

Type species.

Placotrochus laevis Milne Edwards & Haime, 1848, by subsequent designation ( Milne Edwards and Haime 1850: xviii).