An annotated and illustrated identification guide to common mesophotic reef sponges (Porifera, Demospongiae, Hexactinellida, and Homoscleromorpha) inhabiting Flower Garden Banks National Marine Sanctuary and vicinities Author Diaz, Maria Cristina https://orcid.org/0000-0001-9485-0011 Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL, USA taxochica@gmail.com Author Nuttall, Marissa https://orcid.org/0000-0003-1384-8978 Flower Garden Banks National Marine Sanctuary, Galveston, TX, USA & CPC Inc, Galveston, TX, USA Author Pomponi, Shirley A. https://orcid.org/0000-0003-4982-1515 Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, FL, USA Author Ruetzler, Klaus National Museum of Natural History, Smithsonian Institution, Washington D. C., USA Author Klontz, Sarah Genetic Disease Research Branch, NHGRI, NIH, Bethesda, MD, USA Author Adams, Christi https://orcid.org/0000-0002-8411-4595 Flower Garden Banks National Marine Sanctuary, Galveston, TX, USA Author Hickerson, Emma L. https://orcid.org/0000-0002-2595-8878 Flower Garden Banks National Marine Sanctuary, Galveston, TX, USA Author Schmahl, G. P. https://orcid.org/0000-0002-5657-5204 Flower Garden Banks National Marine Sanctuary, Galveston, TX, USA text ZooKeys 2023 2023-05-11 1161 1 68 http://dx.doi.org/10.3897/zookeys.1161.93754 journal article http://dx.doi.org/10.3897/zookeys.1161.93754 1313-2970-1161-1 4CE0D6C5C3044F748387FCC71F8F8AC0 97BBCF0865EA537F8147171EA5BBA1B5 Ircinia sp. 1 Fig. 60 Diagnostic features. Single, two, or three tubes connected at the base. Tubes taper towards the tip. Pink to white in life. The tubes in Fig. 60 are 13 cm high. The surface has minute conules homogeneously spaced. One large oscule per tube (~ 2 cm in diameter) with a thin paler membrane. Figure 60. Ircinia sp. 1, 54-60 m deep. Samples DFH9-8B, DFH9-7F. Similar species. This is a very unique Ircinia species, probably undescribed. Distribution and abundance. This is an undescribed species of Ircinia . At FGBNMS the species was seen once at two localities. MCD has seen this species once in the Bahamas. Ecology. Silted coralline algae reefs, silted lower mesophotic reefs. Identification. CA, KR, SK, MCD. Reference. van Soest 1978 .