Ircinia vansoesti, Kelly & Thacker, 2021

Kelly, Joseph B. & Thacker, Robert W., 2021, New shallow water species of Caribbean Ircinia Nardo, 1833 (Porifera: Irciniidae), Zootaxa 5072 (4), pp. 301-323 : 312-313

Ircinia vansoesti sp. nov.

Figures 10 , 11 ; Tables 1 , 2 .

urn:lsid:zoobank.org:act:D3C1295B-95FC-4DDB-A3EF-35B0C2EAF3A8

Holotype: USNM 1641998 (JK18x20; 16.8285, -88.1044; appx. 0.6 m depth; coll. J.B.K.; 16 August 2018).

Paratypes: USNM 1641996 (JK18x18; 16.8285, -88.1044; appx. 0.6 m depth; coll. J.B.K.; 16 August 2018) , USNM 1642006 (JK18x28; 16.8083, -88.1496; appx. 0.5 m depth; coll. J.B.K.; 18 August 2018) , USNM 1642012 (JK18x34; 16.8083, -88.1496; appx. 0.5 m depth; coll. J.B.K.; 18 August 2018), USNM 1642013 (JK18x35; 16.8083, -88.1496; appx. 0.5 m depth; coll. J.B.K.; 18 August 2018).

Type locality: Mesoamerican Barrier Reef, Belize.

External morphology. Ircinia with a ramose growth form, although can be occasionally massive lobate in smaller individuals ( Figure 10 ). This species is polymorphic with regard to pinacoderm coloration, and multiple color morphs (gray, dark red, dark green) can be found within a population. Possesses smaller conules (1–1.5 mm). Oscula typically 0.5–1.2 cm in diameter.

Interior morphology. Massive fascicular fibers 90–300 µm wide, sometimes cored, and always more heavily than interconnecting fibers. Interconnecting fibers 25–60 um wide, usually uncored ( Figure 11 ). Irciniid filaments 2–6 µm wide terminating in spherical to tear-drop knobs measuring 4–11 µm in diameter. Foreign spicules and sediment are occasionally included in the cortex and are seldom found in the in mesohyl. Fascicles can be rare and difficult to discern from interconnecting secondary fibers ( Figure 11 ).

Ecology. This species is found growing on Rhizophora prop roots.

Etymology. This species is named for the sponge researcher Rob van Soest.

Remarks. Interior morphology can vary somewhat depending on population, as the Twin Cays specimens contained less foreign inclusions relative to the Blue Ground specimens. Referred to as the ‘Sp. 1’ growth form in Kelly et al. (2021).

Figures

FIGURE 10. Ircinia vansoesti sp. nov. A: USNM 1641998 (holotype), B: USNM 1641996 (paratype), C: USNM 1642006 (paratype), D: USNM 1642013 (paratype).

FIGURE 11. Histological sections of Ircinia vansoesti sp. nov. USNM 1641998 (holotype). Abbreviations follow Figure 3. A: Histological section demonstrating low degree of coring in secondary fibers. B: Section showing the higher degree of coring in primary fibers, most notably in the lower of the two primary fibers that runs horizontally across the image.