Krapanj (V)

The is no doubt that even the bouys of the tiny western harbour of the Krapanj island alone are nice to look at:

No, there is no danger that we might switch over to the microscopy of buoys, instead we will stay in touch with the maritime tardigrades directly below the buoys. We had been showing a few total views in the previous issue of our e-zine. And we had pointed out by means of a video clip that there is some inner trouble within the Florarctus males: they appear to be steaming with sexual desire.

We have come across the following quotation from the internet which is able to point out that some biological questions remain to be solved in this area:

"The male reproductive system in all tardigrades seems to be relatively simple. The single testis is located dorsally and the two seminal vesicles open latero-ventrally via two seminal ducts in an oval gonopore papilla (in heterotardigrades) or in the cloaca (in eutardigrades). Penile structures have never been found in any male tardigrade, and it is still uncertain how the sperm transfer occurs. However, it seems that some females have structures that can be inserted into the male so that the female can actively grab the sperm. This method of sperm transfer is very unusual in the animal kingdom."

Source: www.what-when-how.com - sadly no more active

Scanning electron microscope images are razor sharp but when showing a tardigrade in total they will always be restricted to the utmost outer surface geometry of the water bears (the electrons are not able to penetrate more than one micron or so). In order to gain anatomical live insight the classical compound microscope is the superior instrument:

Florarctus sp. male. Detail view of the hind body. Image width ca. 0.05 mm.

This is a still image from a video depicting the ventral side of a tardigrade male. And we can zoom in a little bit to gain more detail:

Florarctus sp. male. Stronger magnification of the ventral part of the body.

Florarctus sp. male. Stronger magnification of the ventral part of the body. The numbers are marking sexual characteristics but we are not perfectly sure about the interpretration.

So, please, if you should be a professional, just tell us what we might have photographed here without a proper understanding.

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
The 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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