Axinyssa ambrosia

Axinyssa ambrosia (de Laubenfels, 1936)

Figs. 1, 3 A–C

Rhaphisia ambrosia de Laubenfels, 1936: 135.

Axinyssa ambrosia; van Soest et al., 1990: 27, fig. 21 (in part, holotype and material from Curaçao); Diaz et al., 1991: 146 (in part, holotype and material from Curaçao); Diaz et al., 1993: 289, fig. 10 (in part, holotype and ZMA Por. 6895 from Curaçao); Zea, 1993: 87 (ecology); Lehnert and van Soest, 1999: 149; Rützler et al., 2009: 302.

? Axinyssa sp; Moraes, 2011: 159.

[Non: Dictyonella yumae Pulitzer-Finali, 1986 (a valid species of Axinyssa; synonymy suggested by van Soest et al. 1990: 27 and Diaz et al. 1993: 289)].

[Non: Leucophloeus lewisi van Soest and Stentoft, 1988 (= Axinyssa yumae Pulitzer-Finali, 1986; synonymy suggested by van Soest et al. 1990: 27 and Diaz et al. 1993: 289)].

Material examined. Holotype USNM 22452, SE of Loggerhead Key, Dry Tortugas, Florida, USA, 70 m, dredged, 26 June 1932 (spicule and skeleton slides). ZMA Por. 6895 (fragment INV–POR 0519), in front of Carmabi, Curaçao, 18– 20 m, coll. excursion Curaçao 1975, id. R.W.M. van Soest. Material from Santa Marta, Colombia, coll. by S. Zea: INV– POR 0522 (11 Febr. 1997), ICN –MHN(Po) 0173 (20 Sept. 1997), INV–POR 0523 (31 March 1999), Punta de Betín, Bahía de Santa Marta, reef-sand slope edge, 20–25 m; INV–POR 0520 (10–12 Febr. 1988), El Morro, Bahía de Santa Marta, reef base, 35 m; INV–POR 0521 (2 April 1982), Bahía de Nenguange, reef edge, 20 m.

Description. Irregular masses, 2–3 cm thick, up to 10–15 cm wide or more, with lobate to digitiform, sometimes stalked, cylindrical projections, up to 1–2 cm in height-width; sometimes as repent to partly projecting branches, ca. 10 cm long, 1–3 cm wide. Surface organic, rugose, with microconulose to microhispid areas; some areas honeycombed; loosely to strongly fouled. Oscules scarce, scattered, up to 3 mm in diameter. Consistency compressible but not resilient, slightly difficult to tear, spiculose; dried specimens are hard. Tissue color bright yellow to orange-yellow, with vinaceous shades on the exterior; specimens fixed directly in ethanol turn black, yielding a dark brown ink; other fixed specimens creamy; dried specimens creamy. Ectosome organic; pinacoderm supported by projecting spicules or spicule tracts. Choanosome non-cavernous; skeleton as a confused arrangement of spicules in between ascending, radiating and anastomosing spicule tracts, 2–10 spicules across, 30–50 µm wide. Spicules slightly curved oxeas, with symmetrical, rather long, hastate, mucronate and stepped ends; axial canal often visible; a few fusiform oxea as developmental stages; a few strongyloxeas and anysostrongyles; length 490–941 µm (specimen means 653–803 µm); width 4.8–23.8 µm (means 10.9–17.0 µm).

Distribution and ecology. Florida (Dry Tortugas: de Laubenfels 1936, Rützler et al. 2009), Jamaica (Lehnert & van Soest 1999), Curaçao (van Soest et al. 1990), Colombia (Santa Marta). At Santa Marta, occasional in deep reef areas, usually growing on dead sides or on undersides of corals, 18–35 m in depth. Material from Curaçao collected in reefs at 18–20 m in depth. Holotype dredged at 70 m in depth, encrusting a rock. Jamaican material found in the deep fore-reef, 85 m in depth.

Remarks. Axinyssa ambrosia is distinguished from A. yumae by its irregular shape and smaller oscules in the former, vs. clusters of volcano-shaped lobes to tubes in the latter. Spicules are predominantly oxeas in A. ambrosia and always anysostrongyloxeas (fusifom styles) in A. yumae. The Jamaican material described by Lehnert and van Soest (1999) can be ascribed to A. ambrosia by its slightly larger (720–1160 µm x 6–16 µm) oxea with telescoped ends. The material from the Bahamas described by Diaz et al. (1993) was not studied here and may deserve further analysis. Axinyssa sp. described by Moraes (2011) from the Archipelago of São Pedro e São Paulo, off Brazil, may belong to this species. This species yielded nitrogenous eudesmane-type compounds with strong cytotoxic activity (Petrichtcheva et al., 2002).