Valves are arcuate, symmetric about the trans-apical axis and asymmetric about the apical axis. Apices are capitate and deflexed to the ventral side. The capitate ends are recurved slightly toward the dorsal side. The dorsal margin is tumid at the valve center and the ventral margin has a distinct central inflation. Striae are alternate and parallel, occurring 16-18 in 10 µm throughout the valve. In some specimens, a hyaline area is present in the central inflation on the ventral side. A rimoportula is present at one of the valve apices, a feature visible only in SEM.
Author: Bixby, Edlund, & Stoermer 2005
Length Range: 111.8-170.2 µm
Width Range: 4.9-7.8 µm
Striae in 10 µm: 10-15
Cells attached at the end forming rosette colonies (Fig. 4). Chloroplast central, plate-like, along the dorsal side of frustule (Fig. 3). Nucleus central, ventrally located (Fig. 3). Lipid droplets one or more, positioned at distal ends of the chloroplast. Cingula open with valvocopula crenate on advalvar margin, with single row of punctae abvalvar to crenate margin. Valves arcuate with secondary reflexion towards dorsal margin, capitate ends, central unilateral inflation (Figs 3-9). Valves 111.8-170.2 µm length, 4.9- 7.8 µm breadth (at inflation), length/breadth ratio approximately 22:1, degree of curvature 0.0033-0.0065 µm-1. Raphe absent. Axial area narrow. Central inflation with occluded striae. Striae punctate and parallel, uniseriate on valve face and mantle, 10.3-15.1 in 10 µm (Figs 10-11). Spines between striae, occasional (Fig. 11). Valve apices with a single polar, sessile rimoportula per valve (Figs 9-10), with modified ocellulimbi on mantle of both valve apices (Fig. 10)
Cite This Page:
Burge, D., and Edlund, M. (2017). Hannaea superiorensis. In Diatoms of the United States. Retrieved March 25, 2017, from http://westerndiatoms.colorado.edu/taxa/species/hannaea_superiorensis
Species: Hannaea superiorensis
Reviewer: Sarah Spaulding
Antoniades, D., Hamilton, P.B., Douglas, M.S.V. and Smol, J.P. (2008). Diatoms of North America: The freshwater floras of Prince Petrcik, Ellef Ringnes and northern Ellesmere Islands from the Canadian Arctic Archipelago. Iconographia Diatomologica 17.
Bixby, R.J., Edlund, M.B., and Stoermer, E.F. (2005). Hannaea superiorensis sp. nov., an endemic diatom from the Laurentian Great Lakes. Diatom Research 20: 227–240.
Hannaea superiorensis forms rosette colonies and grows in planktonic, epilithic and periphytic habitats throughout the upper Laurentian Great Lakes. It was described from Lake Superior, but occurs more rarely in northern Lake Michigan and Lake Huron (Bixby et al. 2005). This diatom is especially common in the wave zone along the Minnesota North Shore of Lake Superior. Although this species was originally thought to be endemic to the upper Laurentian Great Lakes, it has been reported from lakes of northern Ellesmere Island and Ellef Ringnes Island, Canada (Antoniades et al. 2008).
Size range of Hannaea superiorensis
Credit/Source: Specimens found by: Tobie, Megan, Giovanna, Like, Caroline, Maxine, Nicholas, Hannah, and Bridget, all young citizen scientists at the Science Museum of Minnesota Members Behind the Scenes event on January 16, 2017.
Live cell of Hannaea superiorensis shows a single chloroplast appressed to the dorsal margin in the center of the valve. An oil droplet, or libroplast, is present at each end of the chloroplast.
Credit/Source: Mark Edlund