Errina Gray, 1835: 85.—Cairns, 1983 b: 459; 1986 a: 49; 1991: 49–50; 1992: 542, 545. Errina (Eu-Errina): Broch, 1942: 38.
Errina (Errina): Boschma, 1956 a: F 102.—Cairns, 1983 a: 85.
Type Species. Millepora aspera Linnaeus, 1767, by original designation.
Diagnosis. Colonies uniplanar or bushy. Coenosteal texture usually reticulate-granular, but may be linearimbricate, and occur in a variety of colours. Gastro- and dactylopores arranged uniformly on branches; gastropore abcauline lips may be present. Gastrostyles present. Dactylopore spines thick walled and horseshoe-shaped, the dactylotome facing downward (adcauline), sometimes clustered; dactylostyles absent. Ampullae usually superficial with lateral or apical efferent pores.
Discussion. There are 28 Recent and one fossil species known in the genus (Appeltans, et al. 2012), making it the third most species-rich in the family. Species are particularly common off New Zealand, Antarctica, Subantarctica, and in the Caribbean Sea.
In the course of this investigation it was noted that Errina hicksoni Cairns, 1991 is a junior primary homonym of E. hicksoni Boschma, 1963 a, and thus the replacement name of E. australis (Latin for southern) is proposed for Cairns’ name. Errina hicksoni Boschma, 1963 is a junior secondary synonym of Lepidopora eburnea (Calvet, 1903).
Holocene Distribution. New Zealand, Galápagos, N. Atlantic, Subantarctic, Antarctic, southwest Indian Ocean, 6–1772 m.