Caponea guide
  1. Valves elliptic-lanceolate
  2. Conopeum large
  3. Striae unresolvable under LM
  4. Central area with H-shaped spines
  5. Central area with 4 punctate stigmata

Valves are lightly silicified and elliptic-lanceolate with broadly rounded ends. The raphe is straight with simple proximal and distal ends. Punctate stigmata are positioned near the central area. H-shaped spines are also present. The outline of the oval-shaped conopeum is visible only in the apical region. Transmission electron microscopy showed evidence of a second silica membrane between the valve and the conopeum that is attached by the spines on the valve face and supported by the spines arising from the sides of the valve (Podzorski 1984). The marginal spines make the appearance of depressions on each of the four-quadrants of the valve face.

Caponea is monotypic and includes the sole species Caponea caribbea, described in 1984 by Podzorski. Caponea caribbea was first found in Jamaica, St. Elizabeth, Broad River (Podzorski 1984). The altitude of the Broad River was close to sea level. The taxon was found in algal mats recovered at this location from the surface of a peat swamp was sparsely covered with Rhynchospora spp., Cladium jamaicense, and Crinum americanum. The swamp had caught fire some months previously.

In North America, Caponea has been found in the Water Conservation areas of Everglades National Park, Florida as well as other areas in southeast Florida’s coastal mangroves and the Biscayne Bay Coastal Wetlands (BBCW) where mesohaline to euhaline conditions prevail. These areas have brackish-saline waters that are very shallow and are productive habitats that habituate short red mangroves (Rhizophora mangle) and white mangrove (Laguncularia racemose). In the areas where specimens of Caponea were found in BBCW, conditions range from pH of 7.1 -7.3, conductivity of 19.6 mS -26.6 mS, and salinity ranges from 9.8 ppt – 13.3 ppt.