Scale bar = 10 µm
the headpole is rostrate, costae are prominent and irregular in partition, end blunt or narrowed to a smaller rostrate footpole
note: there are some discrepancies with authority nomenclature "Combination also introduced by Brun (1880). Priority remains to be established." - (30 Jun 2014) - M.D. Guiry
http://webcache.googleusercontent.com/search?q=cache:88lbV6aDOocJ:www.algaebase.org/search/species/detail/%3Fspecies_id%3D31490+&cd=3&hl=en&ct=clnk&gl=us
This size series is Stephanodiscus niagarae rather than Stephanodiscus reimeri because the areolae shape is circular and the density is 14, significantly higher than S. reimeri. Also, the diameter range in this series is more closely matched with previous observations of S. niagarae.
Diameter range: 45-67
Areolae are large and circular.
Spines are located by the perimeter.
Areolae become fasciculate at about the outer 2/3 of the valve face.
Fascicles at the margins of the valves are biseriate.
Spines are located at the ends of every two to three costae just inside the margin of the valve.
A fultoportula is found below each of the spines.