Ircinia ruetzleri, 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 : 314-315

Ircinia ruetzleri sp. nov.

Figures 12 , 13 ; Tables 1 , 2 .

urn:lsid:zoobank.org:act:C789E5F2-0BAB-4D78-9EFB-FD01E5E57D87

Holotype: USNM 1642001 (JK18x23; 16.8010, -88.1461; appx. 0.8 m depth; coll. J.B.K.; 17 August 2018).

Paratypes: USNM 1641999 (JK18x21; 16.8010, -88.1461; appx. 0.8 m depth; coll. J.B.K.; 17 August 2018) , USNM 1642000 (JK18x22; 16.8010, -88.1461; appx. 0.8 m depth; coll. J.B.K.; 17 August 2018) , USNM 1642003 (JK18x25; 16.8010, -88.1461; appx. 0.8 m depth; coll. J.B.K.; 17 August 2018) , USNM 1642004 (JK18x26; 16.8010, -88.1461; appx. 0.8 m depth; coll. J.B.K.; 17 August 2018) .

Type locality: Mesoamerican Barrier Reef, Belize.

External morphology. Ircinia with an encrusting growth form, commonly with digitate projections, and dark gray pinacoderm ( Figure 12 ). Conules 1–1.3 mm in height. Oscula flush or slightly raised, always black, 0.2–1 cm in diameter.

Interior morphology. Massive fascicular fibers 120–240 µm wide, heavily cored and tightly bound. Interconnecting fibers 30–50 um wide, lightly cored ( Figure 13 ). Irciniid filaments 2–5 µm wide, terminating in spherical knobs, 5–10 µm in diameter. Cortex contains abundant inclusions of sand grains.

Ecology. This species is found on patch reefs co-inhabited by I. strobilina in shallow depths (0.5–1 m) adjacent to mangrove hammocks inhabited by I. vansoesti sp. nov. The surface is often covered with loose sand. The species commonly grows in close association with hydroids and multicellular algae.

Etymology. This species is named in honor of the sponge researcher Klaus Rützler.

Remarks. Referred to as the ‘Sp. 2’ growth form in Kelly et al. (2021).

Figures

FIGURE 12. Ircinia ruetzleri sp. nov. A: USNM 1642001 (holotype), B: USNM 1642004 (paratype), C: USNM 1642000 (paratype), D: USNM 1642003 (paratype).

FIGURE 13. Histological sections of Ircinia ruetzleri sp. nov. USNM 1642001 (holotype). Abbreviations follow Figure 3. Cn denotes conule. A: Image showing sediment and spicules included in the mesohyl. A representative band of irciniid filaments is highlighted. B: Examples of sediment coring in a delta-like formation of secondary fibers.At the left of the image, a primary fiber terminates at the tip of a conule.