Ircinia radix sp. nov.

Figures 6, 7; Tables 1, 2.

urn:lsid:zoobank.org:act: 5E1E2B6C-0345-4449-B185-5E27D58DE4E2

Holotype: USNM 1582258 (P16x32; 9.30583, -82.1732; appx. 0.5 m depth; coll. J.B.K. and R.W. T.; 21 July 2016).

Paratypes: USNM 1582257 (P16x31; 9.30583, -82.1732; appx. 0.5 m depth; coll. J.B.K. and R.W. T.; 21 July 2016), USNM 1582259 (P16x33; 9.30583, -82.1732; appx. 0.5 m depth; coll. J.B.K. and R.W. T.; 21 July 2016), USNM 1582260 (P16x34; 9.30583, -82.1732; appx. 0.5 m depth; coll. J.B.K. and R.W. T.; 21 July 2016) .

Type locality: Bocas del Toro, Panama.

External morphology. Ircinia with a massive growth form and light to bright pink pinacoderm (Figure 6). Growth morphology can range from a round ball (Figure 6A–C) to massive form with variously shaped upright elongations (Figure 6D). Surface with low, rounded conules (1.5–2 mm). Oscula, 0.2–1.2 cm in diameter, flushed to the surface or slightly recessed, with a lighter-colored oscular membrane, usually white. Secondary smaller apertures may be sparsely distributed, made by animals inhabiting the sponge interior.

Interior morphology. Fascicular fibers 110–250 µm wide, heavily cored. Interconnecting fibers 10–50 um wide, lightly cored with elongate foreign spicules oriented in parallel to the axis of the fiber and occasional sediment grains (Figure 7). Irciniid filaments 1–4 µm wide, terminating in knobs with highly variable shapes, ranging from spherical to oval to tear-drop, and measuring 4–12 µm in diameter.

Ecology. This species inhabits shaded entanglements of mangrove roots.

Etymology. The name refers to the mangrove roots that this species lives on.

Remarks. Referred to as the ‘Massive A pink’ growth form in Kelly et al. (2021).