• Category
  • Length Range
    27-54 µm
  • Width Range
    7-9 µm
  • Striae in 10 µm
  • Reported As
    Mastogloia smithii Morphotype I (Slate and Stevenson 2007)
    Mastogloia smithii var. lacustris (Gaiser et al. 2010)



Valves are linear-lanceolate (post-initial and small valves are elliptical-lanceolate) with rostrate ends (post-initial valves have round ends, small valves have subrostrate ends). Striae are punctate, radiate, weakly curved at the central area, and become parallel at the apices. The striation pattern on the valve face continues unchanged onto the mantle. The central area is elliptical to polygonal and is often asymmetric. Areolae are round and internally occluded by a cribrum, 16–20 areolae per 10 µm. The raphe is straight to weakly undulate with a kink near the central area. The proximal raphe ends are slightly expanded and deflect in the same direction. The distal raphe ends are slightly expanded, extend centrally over the mantle and hook to the same side. There is a small hyaline area where the curve of the distal raphe ends occurs.

Internally, the raphe is straight and encased in a thickened sternum. The internal proximal raphe ends are straight and the sternum fuses into the thickened central nodule. The internal distal raphe ends are occluded by pseudosepta. The partectal ring is closed, forming a complete band, and lacks a flange separating the ring from the valve margins. A pseudopartectum is present between the apex and each terminal partectum. There is a furrow opening into a pore-like cavity by each pseudopartectum. The apices of the partectal ring have a narrow cleft that expands into a pyriform lacuna. One pore is present between the center most pair of partecta on each side of the partectal ring. The partecta are distributed along both sides of the partectal ring, except near the apices. Partecta are clearly distinguishable and evenly sized, but they are slightly larger closest to the apices, 5-6 partecta in 10 µm. Thickened virgae are present throughout the valve interior. Cribral pores become highly irregular near the sternum and central nodule. There are five partectal pores located near both sides of the apices. Live specimens produce mucilage strands from the partectal pores. Live cells contain 2 H-shaped plastids at each pole.


Lives embedded within microbial communities dominated by filamentous and coccoid cyanobacterial species that form extensive mats upon the sediment or bedrock surface and around the submersed stems of aquatic plants in shallow-water, limestone-based environments with seasonal desiccation. Weighted-averaging optima: water depth 52 cm, salinity 0.1, total phosphorus 225 μg/g, and pH 7.6.

Confirmed distribution records outside of the Florida Everglades include similar karstic wetlands in Jamaica, Belize, and Mexico.

M Calcarea Live 4
Credit: Florida International University Periphyton Lab
Floating and epiphytic periphyton in the Everglades, Florida
M Calcarea Live 1
Credit: Sylvia Lee and Franco Tobias
Mastogloia calcarea within periphyton mat
M Calcarea Live 2
Credit: Sylvia Lee and Franco Tobias
Recently divided frustules of Mastogloia calcarea within periphyton mat
M Calcarea Live 3
Credit: Sylvia Lee and Franco Tobias
Mastogloia calcarea with mucilage strands

Original Description

  • Author
    Sylvia S.Lee, E.E.Gaiser, Van de Vijver, Edlund, and S.A.Spauld. 2014
  • Length Range
    27-54 µm
  • Width
    7-9 µm
  • Striae in 10µm

Original Images

M Calcarea Orig Desc Plate1
M Calcarea Orig Desc Plate2
M Calcarea Orig Desc Text

Cite This Page

Lee, S. (2014). Mastogloia calcarea. In Diatoms of North America. Retrieved May 30, 2024, from https://diatoms.org/species/mastogloia_calcarea


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Mastogloia calcarea 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.