Lepedella: Rotifera Monogonanta

Rotifers typically are found in many freshwater environments and in moist soil, including still water environments (lake bottoms) as well as flowing water environments (rivers or streams). Rotifers are also commonly found on mosses and lichens growing on tree trunks and rocks, in rain gutters and puddles, in soil or leaf litter, on mushrooms growing near dead trees, in tanks of sewage treatment plants, and even on freshwater crustaceans and aquatic insect larvae.
Since my collection area is fed by rainwater from roof gutters, that may be where these originated.
There are somewhere around 2,200 species of rotifers. One version of the current taxonomy has the phylum Rotifera, with three classes: Seisonidea, Bdelloidea and Monogononta.
The largest group is the Monogononta, with about 1,500 species, followed by the Bdelloidea, with about 350 species. There are only two known genera with three species of Seisonidea.
The star of this video is a member of Monogononta (meaning each individual has a single gonad). Males are smaller than the females, and are produced only during certain times of the year, with females otherwise reproducing through parthenogenesis (a form of asexual reproduction in which the embryo is produced directly from an egg, with no need for fertilization.)
Towards the end of the video, a giant Bdelloid Rotifer makes an appearance, giving a good representation of the size differences between these two species.
Video created using Hayear HY-500 camera, Amscope M620 microscope, 20X and 40X objectives, using Mac Photos for slight enhancement.
Original song/video "Wind 17.5 Knots" by My-Fi Saloon @my-fisaloon8370