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 Aplysilla aff. sulfurea Schulze, 1878 Fig. 53 Diagnostic features. Thin encrusting sponge, 1-2 mm when preserved in alcohol. Pale yellow/orange in color alive. In alcohol it turns dark purple. In life the surface bears low conules, and oscula a few mm wide. Similar species. The overall growth form, color, and color change in alcohol is similar to those in Aplysilla sulfurea . Distribution and abundance. Aplysilla sulfurea is the type species for the genus and was described from the Adriatic and Mediterranean seas and eastern Atlantic. The reports from Bermuda, Florida, and southern Africa probably represent different species of similar habit and color. At FGBNMS the species is widely distributed at 14 sites with a range of abundance from rare to medium (2-100). Figure 53. Aplysilla aff. Aplysilla sulfurea , 78 m deep. Samples DFH9-14B. Ecology. Coralline algae reefs, lower mesophotic reefs, algal nodules. Identification. CA, MCD. References. de Laubenfels 1950 , 1953 .