A rock wall (V)

The photomicrograph below - slightly nebulous - is shown here in order to point out once more that the precise species determination of a living tardigrade's species might be a tough job, even for the professionals.
At this point our photograph is merely documenting that we did actually find Echiniscus tardigrades on the Austrian rock wall, too.

One big advantage of the amateur status is that you are not forced to perform any species determination at all: as a consequence you do not need to kill tardigrades in order to count their filaments and spines.
But, as far as the photograph below is concerned we are able to tell on the basis of live view images that this Echiniscus tardigrade has filaments in positions A, B, C and D (with regard to the nomenclature please refor to the link above). In accordance with an earlier taxonomy approach by Prof. Ernst Marcus we might call this individuum therefore a member of the Echiniscus blumi-group. The bad news is that Ernst Marcus added a few more pages in order to cleanly discern even among the different members of this group.

Echiniscus tardigrade from the Austrian rock wall. Red eyes.
Body length ca. 0.3 mm.

Of course we could spend much more time on the study of the fine structure of the armour plates - as professional scientists did for more than a century, and with impressive diligence. One problem with those tiny cuticula details is that we are getting closer to the natural limits of light microscopy. E.g. in some cases we might be in doubt whether some given armour plate dots will be actually holes or protusions: the same kind of detail might look very different already at different focus positions. A much more famous example for this tiny detail resolution problem is known from the shell structure of the diatom Pleurosigma angulatum which looks clearly "hexagonal" under finest light microscopic optics but which turned out as a very different and much more complex combination of holes and slits under the modern scanning electron microscopes.

Echiniscus tardigrade. Top view of the armour at higher magnification (oil immersion objective).

We think that there are many interesting tardigrade properties to study and to talk about - also besides species determination. E.g. have a look at the photomicrograph below documenting a single double spine (the other spines of this individiuum were not double!). As with us humans life reality tends to destroy ideal symmetry, just think about the human faces, virtually all of which are far from ideal bilateral symmetry. Though e.g. the reknowned biologist Ernst Haeckel is very famous for his idealized engravings of ideally symmetrical microorganisms we might wonder whether the aim of nature is actually true symmetry and whether all our human symmetry "mistakes" might be a deviation from nature's more perfect symmetry masterplan? You know, it is widely accepted today that slight deviations from symmetry are to be considered as a clear criterion for outstanding human beauty.

Echiniscus tardigrade. Strange double spine on the dorsal armour.

Please do not hesitate to mail your findings to us in case you should have come across similar findings in your own microscopic work.

Furthermore we would like to recommend a quick glance at the web publication chapter "Tardigrade Survival" by Janice Glime now. It contains about 20 pages of dense tardigrade information (from a professional bryologist's perspective).

Literature

Ernst Marcus: Tardigrada. Jena 1928 [Key of species, starting from p. 42]

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

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