New shallow water species of Caribbean Ircinia Nardo, 1833 (Porifera: Irciniidae) Author Kelly, Joseph B. Stony Brook University, Department of Ecology and Evolution, Stony Brook, NY, USA. & Limnological Institute University Konstanz, Aquatic Ecology and Evolution, Konstanz, Germany. Author Thacker, Robert W. Stony Brook University, Department of Ecology and Evolution, Stony Brook, NY, USA. & Smithsonian Tropical Research Institute, PO Box 0843 - 03092, Balboa, Republic of Panama. text Zootaxa 2021 2021-12-01 5072 4 301 323 journal article 3155 10.11646/zootaxa.5072.4.1 b715a8f1-cf4b-4f80-91bc-9019eb8a3409 1175-5326 5748820 1D561060-A3A6-4F21-80B5-C393744349DB Ircinia lowi sp. nov. Figures 2 , 3 ; Tables 1 , 2 . urn:lsid:zoobank.org:act: 78177724-A5A5-4396-B78D-F6A8181ACB82 Holotype : USNM 1582268 (P16x42; 9.37767 , -82.3032 ; appx. 0.5 m depth ; coll. J.B.K. ; 22 July 2016 ). Paratypes : USNM 1582267 (P16x41; 9.37767 , -82.3032 ; appx. 0.5 m depth ; coll. J.B.K. ; 22 July 2016 ) , USNM 1582269 (P16x43; 9.37767 , -82.3032 ; appx. 0.5 m depth ; coll. J.B.K. ; 22 July 2016 ) , USNM 1582270 (P16x44; 9.37767 , -82.3032 ; appx. 0.5 m depth ; coll. J.B.K. ; 22 July 2016 ) , USNM 1582278 (P16x52; 9.37767 , -82.3032 ; appx. 0.4 m depth ; coll. J.B.K. ; 23 July 2016 ) . Type locality: Bocas del Toro , Panama . FIGURE 2. Ircinia lowi sp. nov. A: USNM 1582268 (holotype), B: USNM 1582267 (paratype), C: USNM 1582269 (paratype), D: USNM 1582270 (paratype). Note the wide points of attachment to hard substrate and coral rubble. External morphology. Ircinia with a thickly encrusting growth habit and a forest green external surface color. Sometimes possesses lobate, short branches departing from base ( Figure 2 ). Conules small ( 1.5–2 mm in height), sometimes of lighter color than the rest of the body. The body is dotted with black oscula that are uniform in size ( 0.4–0.5 cm diameter) and are either slightly elevated or flushed to the surface. Interior morphology. Primary fascicular fibers 80–200 µm wide, cored. Interconnecting fibers 20–60 um wide, nearly uncored to completely uncored ( Figure 3 ). Irciniid filaments 1–4 µm wide, terminating in spherical knobs 6–10 µm in diameter. Ecology. All specimens were collected from shallow depths ( 0.4–0.5 m ) on patch reefs that occur in association with small seagrass beds. Etymology. This species is named for the immunologist Jun Siong Low for his methodological advances in identifying pan-coronavirus antibodies. Remarks. Tissue takes on a slightly crisper consistency when preserved in ethanol for several days. Referred to as the ‘Encrusting’ growth form in Kelly et al. (2021) .