Tethya annona, Sim-Smith & Hickman & Kelly, 2021

Sim-Smith, Carina, Hickman, Cleveland & Kelly, Michelle, 2021, New shallow-water sponges (Porifera) from the Galápagos Islands, Zootaxa 5012 (1), pp. 1-71 : 55

Tethya annona sp. nov.

( Fig. 26 , Table 10)

Material examined. Holotype —MCCDRS9479, Punta Vicente Roca , Isabela Island, 0.0489° S, 91.558° W, depth unknown, 15 Nov 2003 . Paratype —MCCDRS9478, Punta Vicente Roca , Isabela Island, 0.0489° S, 91.558° W, 11 m, 16 Jan 2003 .

Type locality. Isabela Island .

Habitat and distribution. Only found from type locality. Found growing on rock; 11 m.

Description. Globose sponge, 20 mm in diameter, covered in flattened, rounded tubercles that are around 1 mm high. No oscules are visible. Colour in life is pale peach yellow, colour in ethanol is tan ( Fig. 26A–B ). Texture is firm.

Section. Cortex is well-developed, densely packed with tylasters and spherasters. Bundles of strongyloxeas radiate out from the centre of the sponge, spreading out into terminal fans at the surface ( Fig. 26C ). A palisade of smaller auxillary strongyloxeas is present in the periphery of the choanosome, aligned perpendicular to the surface ( Fig. 26D ). Spherasters and tylasters are scattered throughout choanosome.

Spicules. Megascleres —Strongyloxeas, 878 (332–1402) × 15 (6–33) µm (n=80), no clear size separation between auxiliary strongyloxeas and main strongyloxeas ( Fig. 26E ; Table 10). Microscleres (megasters) —Spherasters, 52 (15–106) µm in diameter (n=80); ray:centrum ratio is 0.96 ( Fig. 26F ). Microscleres (micrasters) —Tylasters with spined tips, 10 (6–15) µm in diameter (n = 40) ( Fig. 26G ; Table 10).

Etymology. Named for the shape and surface of this sponge, which resembles a custard apple, the fruit of Annona squamosa (Latin nominative singular in apposition).

Remarks. This species is very similar in appearance and spicule complement to T. sorbetus sp. nov. The main differences are that T. annona sp. nov.: lacks apical oscules; lacks the surface crust of tylasters; has only one size class of spherasters; and, has, on average, longer strongyloxeas than T. sorbetus sp. nov. Tethya annona sp. nov. differs from all other eastern Pacific species as per T. sorbetus sp. nov.

Order Suberitida Chombard & Boury-Esnault

Figures

FIGURE 26. Tethya annona sp. nov. A. Holotype, MCCDRS9479, in situ. B. Paratype, MCCDRS9478, deck photo. C. Cross section through the ectosome. Position of auxiliary strongyloxeas is shown by the arrow. D. Cross section showing the palisades of auxiliary strongyloxeas below the ectosome (arrow). E. Strongyloxea. F. Spherasters. G. Tylasters (all SEM photos from the holotype).