Stephanodiscus yellowstonensis
Theriot and Stoermer 1984 Category: Centric
BASIONYM: Stephanodiscus yellowstonensis Theriot and Stoermer 1984
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Sarah Spaulding | Marina Potapova - March 2012
Length Range: 33-66 µm
Striae in 10 µm:
Description
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
Basionym: Stephanodiscus yellowstonensis
Author: Theriot and Stoermer 1984
Length Range: 33-66 µm
Striae 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 May 25, 2013, from http://westerndiatoms.colorado.edu/taxa/species/stephanodiscus_yellowstonensis
Species: Stephanodiscus yellowstonensis
Contributor: Sarah Spaulding | Marina Potapova
Reviewer: Mark Edlund
Image Credit: Sarah Spaulding
- Valves concentrically undulate
- Areolae round
- Areolae 12-18 in 10 µm
- Marginal spines every 2-5 costae
Valves are concentrically undulate; only the valve margin or the valve center is in focus at one time. The areolae are round and arranged in fascicles of radial striae, separated by costae. Areolae are 12-18 in 10 µm. Striae are uniseriate in the center valve and multiseriate (2-5) near the margin. Marginal spines are present, positioned every 2-5 costae. Marginal fultoportulae are present, positioned below the spines. Central fultoportulae are also present in the valve center, singly or in a ring. One or more rimoportulae are present near a marginal spine, with a spine-like external extension.
Compare
Stephanodiscus yellowstonensis is distinguished from S. niagarae based on the number of spines / diameter (see Theriot and Stoermer 1984). Stephanodiscus niagarae has marginal spines positioned every 2-3 costae, while S. yellowstonensis tends tends to have marginal spines positioned every 2-5 costae. Stephanodiscus yellowstonensis also has thicker marginal spines and extensions of the rimoportulae (SEM features), as compared to S. niagarae. Stephanodiscus reimeri is smaller in size, with more regular placement of spines on every second to third costae and coarser polygonal areolae (8-12 in 10 µm).
Stephanodiscus niagarae
Stephanodiscus reimeri
Citations
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)
California Academy of Sciences (CAS)
Stephanodiscus yellowstonensis CAS
North American Diatom Ecological Database (NADED)
NADED ID:
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.