Valves are lightly silicified and elliptic-lanceolate in shape with broadly rounded apices. The central area is widened transapically but unevenly, forming an H-shaped outline. The raphe is straight. Depressions run from the valve apices to the central area on either side of the raphe. There are small groups of 3 short spines clustered at each of the four corners of the H-shaped central area. There are also 4 larger groups of 4-7 spines located halfway between the valve middle on each side of the valve and the apices, that project from the valve face edge and arch toward the raphe.

An oval conopeum is present and is supported by the spines around the central area and at the valve face edges. There is a narrow second silica membrane located between the valve face and the conopeum that runs adjacent to the valve margin and widens where each of the 4 marginal spine groups project from the valve face.

The distinctive combination of the large H-shaped central area, the 4 large groups of marginal spines, and the second silica membrane adjacent to the valve margin, all of which are evident using LM, makes this diatom recognizable, despite its small size.


Caponea caribbea has been found in Southeast Florida’s 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 caribbea were found in BBCW, conditions range from pH of 7.06-7.33, conductivity of 19.62 mS -26.6 mS, and salinity ranges from 9.829 ppt – 13.27 ppt. Caponea caribbea was first found in Jamaica, St. Elizabeth, Broad River. The altitude of the Broad River was close to sea level. Algal mats recovered at this location from the surface of a peat swamp sparsely covered with Rhynchospora spp., Cladium jamaicense and Crinum Americanum contained the specimen. The swamp had caught fire some months previously. It has also been found in the Water Conservation areas of Everglades National Park, FL as well as other areas in southeast Florida’s coastal mangroves.

Caponea inat
Dona caponea02
IMG 6039
IMG 6038 1

Original Description

Caponea caribbea Podzorski, sp. nov.

Frustulum oblongum copulis destitutum. Valvae leniter siliceae, oblongae,apicibus,obtuse rotundatis; 15.9-27.2 µm longae, 6.5-8.3 µm latae. In quoque quadrante valvae cavitas ab apice ad aream centralem in alteroutro latere raphidis currens. 4-7 spinae aggregatae e mediano margenis externi cabitatis omnis exorientes, ex parte interiore cavitatis raphem versus recurvatae et in segment brevi supra fontem erigentes. Area centralis incrassate, litterae ‘H’ ad instar, 3 spinae aggregatae ad quemque quatuor anguli praesentes. Margo valvae areae centrali oppositus in 4-5 transtra transapicalia prolongatus, ‘’puncto’’ ad basim cujusque transtri. Striae transapicales omino radiatae circa 50 in 10 µm, punctis circa 7 in 1 µm, cribris punctorum perforationibus pro parte maxima circum marginem dispositis. Raphe simplex, terminationibus proximalibus rectis, terminationibus distalibus non observatis; nodulus centralis manifestus, angustus; area axialis linearis. Membrana silicea angusta annularis in planitie frontis et cavites perducens, ad marginem frontis parallela et contigua currens, valvae ad transtra transapicalia areae centrali opposite, extension transapicalis membranae spinas aggregatas ad bases segmentorum verticalium suorum contigens; membrana apices valvae versus in filum attenuate. Canopeum octo catervis spinarum suffultum, ambitu ovali, apicibus late attenuates; foramina rimis similia in ordinatione semiregulari in utroque latere areae axialis lineari-lanceolatae disposita.

Caponea caribbea Podzorski, sp. nov.

Holotypus: Jamaica, St. Elizabeth, Broad River, c. 11.3 km upstream; altitude, near sea level. Algal mat from the surface of a peat swamp sparsely covered with Rhynchospora spp., Cladium jamaicense and Crinum americanum. The swamp had caught fire some months previously. 1977. June. 21. No. JAF 48, slide no . I. Collector: A.C. Podzorski. British Museum Slide No. B.M. 78493, Diatom Section, British Museum (Natural History), Cromwell Road, London, England.

  • Author
    Podzorski, A.C. 1984
  • Length Range
    15.9-27.2 µm
  • Width
    6.5-8.3 µm
  • Striae in 10µm

Original Images

Picture1 caponea origimage
Picture3 origimage2 Caponea
Picture2 original Caponea desc

Cite This Page

Hormiga, S. (2022). Caponea caribbea. In Diatoms of North America. Retrieved June 08, 2023, from


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Caponea caribbea from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.