Diagnose: shell transparent, colorless, yellow or brown, elongated oval with a truncate, more or less straight or slightly curved pseudostome; aperture nearly as broad as the shell; fundus broadly rounded or a little constricted; surface finely granulated; plasma usually partly filling the shell, with some epipodia; nucleus globular with a small nucleolus.
Dimensions: about 100-120 µm
Ecology: this species has been found in the ooze of a river near Oberndorf/Bremen in Germany. Food: mainly diatoms.
Remarks: this remarkable species was discovered by Steffen Clauss, Germany, who published some photomicrographs in a German Forum on the internet. According to his description he found about 50 specimens pro ml. ooze.
This species resembles H. penardi, but the latter is much larger (180 µm), has a nearly semi-circular aperture (“stark gewölbt”) and has no scale structure.