Stephanodiscus yellowstonensis

E.C.Ther. and Stoermer 1984      Category: Centric

Stephanodiscus reimeri


Surirella amphioxys

LM scalebar = 10 µm = 40 pixels.


Contributor: Sarah Spaulding | Marina Potapova - March 2012
Diameter: 33-66 µm
Rows of areolae in 10 µm:


Valves are concentrically undulate with either concave or convex valve centers. Marginal spines are present, positioned at the end of every second to fifth hyaline costa (interfascicle). Areolae 12-18 in 10 µm and arranged in radiating striae separated by the interfascicles. Striae are uniseriate in the valve center, becoming multiseriate, up to 4 or 5 striae within a fascicle. Areolae appear round in high focus in LM. Internally, the areolae are closed by convex, domed cribra. Fascicles are closely spaced, separated by interfascicles. Central fultoportulae number 1-11, positioned in an irregular ring near the center of the valve; marginal fultoportulae are positioned between each marginal spine and the valve margin. Rimoportulae number 1-6, positioned near marginal spines, external expression a short tube that is shorter and thinner than a spine.

Original Description

Author: E.C.Ther. and Stoermer 1984
Diameter: 33-66 µm
Rows of areolae in 10 µm:

Original Description

Valves disc-shaped, with diameters 33-66 µm observed. Central area convex or concave. Areolae in fascicles between radiating costae, 12-18 in 10 µm parallel to a stria. Foramina external; cribra internal. Spines 11 to 23, in a ring 3 to 5 µm from the margin; diameter at the base usually 1 to 1.7 µm. Labiate processes 1 to 6, in an irregular ring located just outside the ring of spines; diameter at the base usually 0.8 to 1.5 µm. Strutted processes 1 to 11, in an irregular ring in central area, one between each spine and the margin.

Original Images

Cite This Page:
Spaulding, S., and Potapova, M. (2012). Stephanodiscus yellowstonensis. In Diatoms of the United States. Retrieved April 24, 2018, from

Species: Stephanodiscus yellowstonensis

Contributor: Sarah Spaulding | Marina Potapova

Reviewer: Mark Edlund


Theriot, E.C., Fritz, S.C., Whitlock, C. and Conley, D.J. (2006). Late Quaternary rapid morphological evolution of an endemic diatom in Yellowstone Lake, Wyoming. Paleobiology 32: 38-54.

Theriot, E. and Stoermer, E.F. (1984). Principal component analysis of Stephanodiscus: Observations on two new species from the Stephanodiscus niagarae complex. Bacillaria 7: 37-53.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Stephanodiscus yellowstonensis CAS

NCBI Genbank Taxonomy

Stephanodiscus yellowstonensis NCBI

North American Diatom Ecological Database (NADED)


Autecology Discussion

Stephanodiscus yellowstonensis evolved from S. niagarae in Yellowstone Lake, Wyoming (Theriot et al. 2006). It is endemic to the Yellowstone Lake basin, where it is dominant in the plankton community. Stephanodiscus yellowstonensis is considered to have evolved extremely rapidly, on the order of a few thousand years, as determined from examination of morphological features of Stephanodiscus niagarae and S. yellowstonensis in lake sediments.