Cinachyrella solis Sim-Smith & Hickman & Kelly 2021, sp. nov.

Cinachyrella solis sp. nov.

(Fig. 17)

Material examined. Holotype — MCCDRS9476, Darwin’s Arch, 1.672° N, 91.991° W, 20.4 m, 14 Nov 2003.

Type locality. Darwin’s Arch, Darwin Island.

Habitat and distribution. Only known from type locality. Found growing on rock; 20 m.

Description. Globular sponge, 30 mm in diameter, with a furry, hispid surface and numerous scattered, sometimes quite large porocalices. Much sandy debris and filamentous red algae are present on the surface. Colour in life is golden yellow, colour in ethanol is tan (Fig. 17A). Texture is very firm, not compressible.

Skeleton. Radial, dense bundles of oxeas radiate out from the centre of the sponge to protrude beyond the surface of the sponge. No ectosomal layer is present (Fig. 17B). Oxeas are the most common megasclere. Protriaenes are common, particularly protriaene/prodiaenes II, positioned with their cladomes just below the surface of the sponge. (Fig. 17C). Anatriaenes are rare. Sigmaspires are abundantly scattered throughout the choanosome.

Spicules. Megascleres— oxeas, large and stout, 3165 (2113–4095) × 25 (17–33) µm (n = 20) (Fig. 17H). Protriaene I, 4208 (3056–4905) µm long (n = 6), with a variable shaped cladome; cladome width 40 (25–76) µm (n = 15) (Fig. 17E). Protriaene/prodiaenes II, with an extremely fine shaft, 1408 (1177–1970) µm long (n = 10), and a small, narrow U-shaped cladome with two or three clads; cladome width 12 (7–19) µm (n = 20) (Fig. 17F–G). Anatriaenes, very long with an extremely slender shaft making it extremely difficult to obtain whole spicules, up to 6700 µm long, with a narrow, flat cladome 53 (24–88) µm (n = 20) (Fig. 17D). Microscleres— sigmaspires, 10 (7–14) µm (n = 20) (Fig. 17I).

Etymology. Named for the sun-shaped golden orb of this species (Latin = ‘of the sun’).

Remarks. Only one species of Cinachyrella has been previously described from the Galápagos Islands — C. desqueyrouxae Van Soest & Hooper, 2020, which differs from C. solis sp. nov. in that the former possesses orthotriaenes, plagiotriaenes and microxeas, but no protriaenes.

Genus Craniella Schmidt, 1870

Diagnosis. Tetillidae without porocalices, with a distinct cortex strengthened by special cortical oxeas. Globular sponges with conulose but optically smooth surface over most of the upper body; at the base there are bundles of spicules acting as a root. Oscules few, usually on top. Megascleres, protriaenes, anatriaenes, choanosomal oxeas, shorter cortical oxeas. Microscleres, sigmaspires (may be lost not infrequently) (from Van Soest & Rützler 2002).