It is a monotypic genus, containing the single marine species Aquamarina speciosa, originally found in North Carolina, and distributed in the Atlantic Coast of the United States.
The hamathecium (tissues surrounding the asci within the central part of the ascoma) is made of paraphyses covered with gelatinous material.
The asci (spore-bearing cells) are 130–180 by 6.5–9.5 μm, eight-spored, cylindrical, short-stalked, thin-walled, unitunicate (made of a single functional layer), and have an apical non-amyloid ring near the top.
[1] Aquamarina speciosa grows on the culms (stems) of the saltmarsh Juncus roemerianus, typically in an area between 2 and 13 cm (0.8 and 5.1 in) above the rhizome.
The lower part of the culm is covered with sediment, algae, and fungi which are exposed to salt-water twice in a 24-hour period owing to the action of tides; any species growing on this area are considered obligate marine.