Maritime tardigrades (VII) - anatomical detail of Batillipes
We do receive many e-mails my microscope amateurs, some of them asking
for a detailed printed tardigrade species determination algorithm. Of course, this algorithm
should reach down until well below species level, if possible even into all species variations.
It should be fairly easy to use and to understand and it should be valid for all tardigrade
individuals worldwide - at low cost, in English, not in one of those
old-fashioned European languages. But we are terribly sorry to state that this
determination key doesn't exist at the moment.
Apparently the grandseigneur of tardigrade species determination, Italian scientist Giuseppe Ramazzotti,
in co-operation with Walter Maucci, was the last to try. His impressive monograph entitled
"Il Phylum Tardigrada" (3rd edition, 1983), is written in Italian
language and comprises more than 1,000 pages. Unfortunately it is out of print
and it is expensive when bought from an antiquarian. Some of the more lucky
people own an authorized English translation CD by Clark Beasley.
On the other hand the Ramazzotti bible is > 25 years old. As a consequence
you will not find newly detected species therein, like e.g.
a bizarre tardigrade marvel called Tanarctus bubulubus with "buoyant" bodies
as Prof. Kristensen from Denmark describes it. And you will not
find the funny Milnesium tardigradum-relative Milnesioides exsertum
with its extra-long nose, as discovered by tardiologist Sandra K. Claxton
in remote Tasman regions.
Though a new, universal tardigrade species identification textbook is missing,
there are many exquisite "genus reviews" (i.e. partial tardigrade taxonomy chapters)
to be found in the more recent literature, in particular within the various tardigrade symposium proceedings.
But be warned: some of those more special publications are terribly expensive.
Moreover, even with most of the modern literature at hand, some species determinations,
in particular those of exotic tardigrades from remote, touristic locations
might still remain doubtful.
In contrast to the scientific world the amateur can escape to a less serious
style of investigations, simply concentrating on deliberately chosen details.
As an example we would like to mention a study of the Batillipes median cirrus.
This median cirrus has been interpreted by Ernst Marcus as a kind of water level
sensor, with the tardigrades escaping downwards when sensing low tide. Besides,
we have no idea about the exact function of the "worm" which sometimes
can be found on the tip of the median cirrus: