Primnoeides, STUDER & WRIGHT

Taylor, M. L. & Rogers, A. D., 2017, Primnoidae (Cnidaria: Octocorallia) of the SW Indian Ocean: new species, genus revisions and systematics, Zoological Journal of the Linnean Society 181, pp. 70-97 : 90-91

PRIMNOEIDES STUDER & WRIGHT

IN STUDER, 1887

Primnoeides Studer & Wright in Studer, 1887: 52. – Bayer, 1956: F220; 1961: 292 [illustrated key to genus]; – 1981: 934 [key to genus]. – Bayer & Stefani, 1989: 455 [key to genus]. – Williams, 1992: 276. – Cairns & Bayer, 2009: 23, fig. 3A–F.

Primnoides Wright & Studer, 1889: 90 [incorrect subsequent spelling]. – Versluys, 1906: 9. – Kükenthal, 1915: 142, 144 [key to genus]; 1919: 339; 1924: 253.

Digitogorgia Zapata-Guardiola & López-González, 2010 a: 317–320 , figs. 2c, d, 7–10). – Zapata-Guardiola & López-González, 2010b: 56–63 (figs. 8–12). – Taylor & Rogers, 2015: 189 (listed).

Diagnosis (from Cairns & Bayer, 2009, changes in bold): Colonies uniplanar, branching in an opposite pinnate manner, flagelliform or bottlebrush. Calyces arranged in pairs or whorls of three, calyces inclined upwards. Rudimentary operculum composed of small round, tongue-shaped or elongate triangular scales that bear no keel on the inner surface. Body-wall and marginal scales similar in shape, becoming progressively smaller distally. Small calyces completely covered with eight longitudinal rows of body-wall scales, with larger calyces sometimes having additional basal scales placed in an irregular manner, resulting in non-linear arrangement of body-wall scales. Broadly, outer surface of scales smooth, inner surface with only sparse tubercles. Coenenchymal scales in two layers: outer layer consists of smooth, flat, circular to elliptical scales; inner layer of small tuberculate spheroids.

Type species: P. sertularoides Wright & Studer, 1889 , by subsequent monotypy.

Known distribution: Southern tip of South America, Southern Africa to the SW Indian Ocean, 111.5–2468 m.

Remarks: With the addition of a species to the genus Primnoeides that has a layer of inner coenenchymal tuberculate scales, and regularly has whorls of three polyps (see P. flagellum sp. nov.), there is need to reassess the taxonomic classification of Digitogorgia , which also has these morphological characters and was placed in a well-supported clade alongside Primnoeides in phylogenetic analysis ( Fig. 3). These genera share many common characters: cylindrical polyp shape, flat, round scales, a rudimentary operculum and similar scale orientation (both have eight regular rows at the polyp base, which becomes more haphazard towards the polyp anterior in Primnoeides ). Digitogorgia is seemingly only differentiated from Primnoeides by having species with a bottlebrush colony shape. And, with the expansion of Primnoeides to include a second colony shape (fan and now flagelliform as well), colony shape seems a weak reason for their continued separation. We hereby propose Digitogorgia as a junior synonym of Primnoeides , with the latter taking precedence according to the Principle of Priority, article 23.1 of the ICZN.