Description

“21. Amphilaphis Studer and Wright

 

in Studer, 1887

 

FIGURE 10J–Q

 

Amphilaphis Studer and Wright in Studer, 1887:50–51.—Wright and Studer, 1889:xlix, 70–71.—Versluys, 1906:20–22.—Kinoshita, 1908e:49–50 [key to genus].—Thomson and Mackinnon, 1911:680.—Bayer, 1981b:936 [key to genus].

 

Thouarella.—Kükenthal, 1912:307 [in part: “regularis-Gruppe”].

 

Thouarella (Amphilaphis).—Kükenthal, 1915:149 [key to subgenus and species]; 1919:407–409 [key to subgenus and species]; 1924:288–289 [key to subgenus and species].

 

DIAGNOSIS. Colonies uniplanar, alternately pinnately branched. Calyces arranged in irregular spirals along branch (Figure 10j) or isolated; calyces inclined upward. Well-developed operculum present; inner face of operculars bears multiple ridges. Marginals arranged in two circles of four that alternate with one another, the circumference of distal polyp not being large enough to accommodate eight marginal scales; eight marginal scales fold over bases of operculars forming a circumoperculum; distal edges of marginals pointed (Figure 10m). Polyps protected by eight longitudinal rows of equal-sized body wall scales that completely cover polyp; body wall scales radially ridged on outer and inner surfaces (Figure 10n–o). Coenenchymal scales in two layers: outer layer composed of irregularly shaped scales with serrate edges, inner layer composed of small spheroids.

 

DISCUSSION. Originally described as a separate genus, Amphilaphis was later considered by Kükenthal (1915) to be a subgenus, but it was finally reestablished as a genus by Bayer (1981b) but curiously ignored by him in later general works (Bayer, 1956; Bayer and Stefani, 1989). Amphilaphis differs from Thouarella in having eight complete longitudinal rows of equal-sized body wall scales and pinnately branched colonies. The six species currently assigned to the genus are tentatively placed there at best, as the genus is badly in need of revision. The diagnosis above is based on the type species.

 

DISTRIBUTION. Tristan de Cunha, Bouvet I., Galápagos, Antarctic, Hawaii, 55–3,182 m.

 

TYPE SPECIES. A. regularis Wright and Studer, 1889, by subsequent monotypy (Wright and Studer, 1889). Syntypes are deposited at the BM (1889.5.27.60, 1889.7.5.1-15, 1894.11.20.1, 1932.12.8.7); a fragment of the type is also deposited at the ZMA (Coel. 3085) (van Soest, 1979) and as SEM stub B576 (USNM).”

 

Bayer & Cairns, 2009