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 Aplysina sp. 1 Fig. 48 Diagnostic features. A single white tube (7 cm high, 3-4 cm wide); the sponge turns to medium brown color in alcohol. The surface is verrucose to finely conulose, and firm in consistency. One apical oscule (6 mm wide) with a thin membrane. Figure 48. Aplysina sp. 1 at 88 m deep. Sample DFH9-2B. Similar species. The overall growth form of this species is similar to that of Aplysina archeri . However, Aplysina archeri tubes are usually much larger, and invariably a pink to violet color at all its depth range of distribution. A similar whitish Aplysina with larger dimensions was observed in Cuba at 58 and 81 m deep. Distribution and abundance. This is a unique and rare species of Aplysina , found in mesophotic reefs at FGBNMS and Pulley Ridge. At FGBNMS it was found once at the east Flower Gardens bank. Ecology. Found at coralline algal reef, algal nodule, lower mesophotic reef. Identification. KR, CA, SWK, MCD. References. van Soest 1978 ; Pinheiro et al. 2007 .