Valves are rhombic to broadly elliptic, scarcely heteropolar. Ends similar and protracted, rostrate-apiculate. The axial area is narrow and linear. Central area unilateral formed by a 1-4 shortened striae. Opposite the unilateral central area is a long stria that terminates in a single stigmoid positioned near the proximal raphe ends. The raphe is filiform, and slightly arched. The proximal ends are barely expanded, while the terminal ends are indistinct. Striae are widely spaced (more widely spaced in the valve center) and mostly radiate throughout, becoming nearly parallel near at the head and footpoles. Striae are punctate, and the areolae difficult to resolve, 25.0-28.8 in 10 µm. An apical pore field is present, but is indistinct.
Author: Czarnecki & Blinn 1979
Length Range: 12-23 µm
Width Range: 8-13 µm
Striae in 10 µm: 11-14
Valves elliptical to elliptical-lanceolate with irregular margins and protracted rostrate-capitate apices and bases. Axial area narrow, linear; central area small, unilateral, formed by a shortened median stria. The opposite median stria terminates in an isolated punctum. Striae punctate, radiate, 11-14 in 10 µm. Puncta 28 or more in 10 µm. Length 12-23 µm. Width 8-13 µm.
Cite This Page:
Edlund, M., and Burge, D. (2016). Gomphonema montezumense. In Diatoms of the United States. Retrieved April 24, 2017, from http://westerndiatoms.colorado.edu/taxa/species/gomphonema_montezumense
Species: Gomphonema montezumense
Reviewer: Loren Bahls
Czarnecki, D.B. and Blinn, D.W. (1979). Observations on Southwestern Diatoms. II. Caloneis latiuscula var. reimeri n. var., Cyclotella pseudostelligera f. parva nf, and Gomphonema montezumense n. sp., New Taxa from Montezuma Well National Monument. Transactions of the American Microscopical Society 98: 110-114.
Gomphoneme montezumense is apparently an endemic, known only from the Montezuma Well National Monument in Arizona. It lives in the epipelon or epilithon. Physical and chemical conditions suggest the well is a stable calcium-bicarbonate thermal spring with an elevated level of sodium chloride. The annual temperature range is 16-26°C. Water quality data are presented by Czarnecki & Blinn (1979): SiO2 = 22 mg/l; Ca = 106 mg/1; Mg = 43 mg/l; Na = 46 mg/l; K = 5.75 mg/l; Cl = 37 mg/l; HCO3 = 680 mg/l; pH = 6.6-6.8.
Montezuma Well National Monument. Only known locality for Gomphonema montezumense.
Credit/Source: D.B. Czarnecki