Trying to identify the genus
Since the last edition of Ramazzotti's giant tardigrade book (in 1983) apparently no one
has been able to provide a comprehensive tardigrade taxonomy book which might
serve as the ultimate reference in order to identify all those tardigrade species worldwide.
There exist many excellent professional reviews of single tardigrade genera in
the scientific literature. But they are spread among many publications and
congress papers, some of which might be really expensive and difficult to reach for the amateur.
As a small comfort for all of you we would like to add that also many of the professional
biologists appear to have trouble with the tardigrades. For example, Robert Hofrichter's
really splendid Mediterranean Sea Book estimates the number of marine tardigrades in
the Mediterranean Sea to be a modest "10 ?" (see vol. II/1, 2003, p. 50).
As there is a "?" after the number this statement is in perfect accordance with good scientific
practice. But it is wrong. The Italian tardiologist Susanna de Zio Grimaldi reported
in an earlier publication that she was aware of about 50 different marine tardigrades
within the range of the Italian coastline alone.
Clark Beasley's translation of Ramazzotti's tardigrade bible defines
a genus with the name Halechiniscus as follows:
"Halechiniscidae with legs with four
digits, terminating with a sickle-shaped claw, with or without distal spurs; head
flattened, with lateral expanded lobes".
Our tardigrade exhibits all the properties mentioned above. And the neighbouring
maritime genera obviously do not fit at all. For example, Batillipes and
Orzeliscus have round or oval adhesive plates at the ends of their toes.
Echiniscoides bears up to eleven claws at each leg, in any case always more than four.
Parastygarctus has claws of different length (the two in the middle being the longest ones).
Tanarctus shows cuticular protusions some of which occasionally are bearing "balloons",
overall resembling some floral artwork.
A serious tardiologist or professional biologist would probably ask the next question now:
and about which species exactly are you talking? Halechiniscus perfectus,
Halechiniscus greveni or something else? Our answer is simple: we do not know
and, furthermore, it might be not that much important to know.
But we feel that in Croatia the number of Halechiniscus tardigrades might
definitely be much higher than the number of tourists. And this information could serve as a
sort of mental food for the amateur philosophers among us!
By the way: a further tardigrade genus has been hiding in our miraculous "Rocharium".
Who else might be able to survive within a spoonful of sand and a cup of sea-water for
such a long time and remain undetected? Our tardigrades, yes. We will present this
tardigrade genus in one of our upcoming issues. See you.