Tardigrades aka water bears or moss piglets were first described at the end of the 18th century by the German pastor J.A.E. Goeze. The name Tardigrada, meaning "slow stepper," was coined by the by the Italian biologist Lazzaro Spallanzani.
Tardigrades can be found in almost every habitat on earth! Water bears have been sighted from mountaintops to the deep sea, from tropical rain forests to the Antarctic. Most species live in freshwater or semiaquatic terrestrial environments, some marine species have been identified as well.
Tardigrades are short (0.05mm - 1.2mm in body length), plump, bilaterally symmetrical, segmented organisms. They have four pairs of legs, each of which ends in four to eight claws. They feed on the fluids of plant cells, animal cells, and bacteria.
Johann August Ephraim Goeze (28 May 1731—27 June 1793) was a German zoologist from Aschersleben. He studied theology at University of Halle. In 1751 he became a pastor in Aschersleben and later (1762) of St. Blasius' Church in Quedlinburg. He focused his work on aquatic invertebrates, particularly insects and worms. In 1773, he was the first to describe tardigrades.
The original text in German language is: "Seltsam ist dieses Thierchen, weil der ganze Bau seines Körpers ausserordentlich und seltsam ist, und weil es in seiner äusserlichen Gestalt, dem ersten Anblicke nach, die grösste Ähnlichkeit mit einem Bäre im Kleinen hat". page 367-375
Lazzaro Spallanzani (10 January 1729 – 12 February 1799) was an Italian Catholic priest, biologist and physiologist who made important contributions to the experimental study of bodily functions, animal reproduction, and essentially animal echolocation. He provided the scientific name Tardigrada (meaning "slow stepper") to water bears.
In the 19th century water bears were alternatively grouped with Rotifera or Pycnogonida or even Arthropods. In the first half of the 20th century their grouping remained controversial. Finally the Italian biologist Giuseppe Ramazzotti promoted water bears into their own phylum. Further classification of their taxonomy was undertaken by the German biologist Ernst Marcus.
In the year 1927 Benedictine friar Gilbert (Franz) Rahm (* 9/21/1885 in Bonn; † 4/14/1954, Abtei Newark, New Jersey, USA; renamed himself Gilbert Rahm) published his research in volume 22 of the scientific series "Biologie der Tiere Deutschlands" with the title "Tardigrada". He had compiled 56 densely filled pages offering a full review of the contemporary knowledge about water bears.
In 1928 Ernst Marcus published, as part of the series "Die Tierwelt Deutschlands", 230 pages about tardigrades. It contains beautiful tardigrade drawings, most of which had been prepared by Ernst Marcus' wife Eveline. In 1929 the next tardigrade book by Ernst Marcus appeared. A true tardigrade bible, made up of 608 pages.