Higginsia johannae, 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 : 32-34

Higginsia johannae sp. nov.

( Fig. 14 , Table 5)

Material examined. Holotype — MCCDRS9415, Tagus Cove , Isabela Island, 0.265 ° S, 91.373° W, depth unknown, 17 Jan 2003 . Paratypes — MCCDRS9416, Tagus Cove , Isabela Island, 0.265 °S, 91.373° W, 13 m, 16 Nov 2003; MC- CDRS9414 , Las Marielas , Isabela Island, 0.597° S, 91.092° W, 5 m, 2 Dec 2004 . Other material— MCCDRS9413, Las Marielas , Isabela Island, 3 m, 2 Dec 2004 .

Type locality. Tagus Cove , Isabela Island .

Habitat and distribution. Only collected from type locality; 3–13 m, but commonly observed around Isabela Island. Grows on rock substrate and often encrusted by zoanthids ( Parazoanthus sp. ).

Description. Thickly encrusting sponge, with a rugose to deeply dissected surface ( Fig. 14A–C ). Holotype is 50 mm wide × 25 mm thick. Texture is firm, slightly compressible. Colour in life is deep orange, colour in ethanol is tan.

Skeleton. The choanosomal skeleton is formed by bundles of styles I, pointed end uppermost, which form plumose tracts ascending through the centre of the sponge, and protruding slightly beyond the surface of the sponge. Bundles of thinner styles II and very thin oxeas line the periphery of the extra-axial skeleton, orientated tangential to the surface. Acanthose microxeas form a dense, paratangential band, around the periphery of the lower portion of the sponge and lining the spaces in the basal region of the choanosome. Microxeas are also sparsely scattered throughout the choanosome ( Fig. 14D ).

Spicules. Megascleres— Styles I (choanosomal, Fig. 14E ), short and stout, usually with a pronounced curve; 561 (401–715) × 26 (12–45) µm (n = 90). Styles II (extra-axial, Fig. 14G ), long and thin, often curved or slightly sinuous; 1164 (810–1702) × 15 (4–27) µm (n = 76). Oxeas (extra-axial, Fig. 3I ), very thin and hair-like; 775 (438– 1377) × 7 (2–13) µm (n = 90). Microscleres— microxeas ( Fig. 14F ), spined and angulate; 101 (55–161) × 5 (2–10) µm (n = 90).

Etymology. Named for Johannah E. Barry, founder and first president of the Galápagos Conservancy, a USbased non-profit organisation created in 1991 to support Galápagos conservation, research, and education. Johannah was also instrumental in encouraging the creation of similar organisations in Canada, Europe, and Japan dedicated to conservation in the islands.

Remarks. This is the first record of the genus Higginsia from the Galápagos Islands. MCCDRS9413 has slightly longer spicules than the other three specimens ( Table 5), but this difference is likely to be due to natural variability.

Only one other species of Higginsia is recorded from the eastern Pacific— Higginsia higginissima Dickinson, 1945 from California and west Mexico, which has oxeas (600 × 12 µm) as the main choanosomal megasclere.

Higginsia is closely related to the genus Halicnema , with one species, Halicnemia diazae Desqueyroux-Faúndez & Van Soest, 1997 , described from the Galápagos Islands. Higginsia johannae sp. nov. has a similar suite of spicules to H. diazae with both species possessing, two sizes of styles, oxeas and angulate acanthoxeas. However, H. diazae possesses a distinct ectosome that consists of a felted mass of tangential acanthoxeas and bouquets of oxeas, whereas H. johannae sp. nov. lacks a distinct ectosome. Furthermore, H. diazae has shorter styles II (800 (720–1300 µm), oxeas (375–520 µm), and acanthoxeas (65–115 µm) than H. johannae sp. nov.

Order Bubarida Morrow & Cárdenas

Figures

FIGURE 3. Chelonaplysilla violacea (Von Lendenfeld, 1883). A. MCCDRS9432, in situ; B. MCCDRS9431, deck photo. C. Cross section of MCCDRS9432 showing the surface sand grains reticulation. D. Spongin fibre from MCCDRS9432 showing the distinct concentric laminations and diffuse pith.

FIGURE 14. Higginsia johannae sp. nov. A. Holotype, MCCDRS9415, in situ. B. MCCDRS9413, in situ. C. Holotype, deck photo. D. Vertical cross section of the holotype showing the plumose axial skeleton of styles I (black arrows), the extra-axial skeleton of styles II and oxeas (white arrows), and the crust of microxeas along the periphery of the inner sponge (grey arrow). E. Style I (axial). F. Acanthose microxeas. G. Style II (extra-axial). H. Oxea (extra-axial) (all spicule images from the holotype).