Dicyrtomina ornata

Dicyrtomina ornata

Dicyrtomina ornata is one of the small "globular" Springtails (Collembola) from the family Dicyrtomidae. Within its distribution range it is easily found in leaf litter from late fall to early spring. It can be confused with other species of Dicyrtomina, most notably with D. saundersi.
Dicyrtomina ornata - full subject (crop) https://www.jungledragon.com/image/104642/dicyrtomina_ornata_-_full_subject.html These images are taken on my second day of trying to capture this tiny springtail on camera. On day 1, I used a single shot approach using 5:1 macro: https://www.jungledragon.com/image/104612/dicyrtomina_ornata_heesch_netherlands.html https://www.jungledragon.com/image/104641/dicyrtomina_ornata_anatomy.html On this second day, I collected all my patience and courage to try and stack this subject, whilst alive. Given the odd angle into the water, I couldn't use my horizontal setup, instead had to put the entire macro rail and camera on a tripod, like so: https://scontent-amt2-1.xx.fbcdn.net/v/t1.0-9/126094164_10158741261882692_7246136820373851144_o.jpg?_nc_cat=107&ccb=2&_nc_sid=730e14&_nc_ohc=d5m19JERG6UAX99KeSb&_nc_ht=scontent-amt2-1.xx&oh=3e4926d9a6cd3c3fb581dec88150845b&oe=5FDF0481 The most difficult part is the positioning itself. The focus distance is so short that the lens almost touches the water or the edge of the petri dish, and I have to take into account the movement of the stacking process itself. Next, the stacking could begin. The first 3 attempts failed as the creature kept moving its antennae. A single movement ruins the stack. Furthermore, an annoying water flea kept bugging it. This is the only successful stack. Above all, it's a technical accomplishment, and not really an artistic one. The stacked image isn't really better, yet it does have the entire subject in focus. Unfortunately, just like the single shot results, fine details and sharpness are lacking due to optical limitations. And with that, I released them back into the pond. Dicyrtomina ornata,Extreme Macro

Appearance

Dicyrtomina ornata is very variable in the extent of the red/purple-ish colour markings, ranging from almost entirely yellow to almost entirely dark. On most specimen (except for the extremes of the colour range) the shape of the dorsal spot/bar at the end of the abdomen is quite diagnostic (without the clearly defined cross bars typical for D. saundersi) as well as the more uniformly toned antennae (on saundersi the colour changes clearly about half way). The eye-patches are all black on both species.
Dicyrtomina ornata, Heesch, Netherlands Our garden, little as it may be, has been a valuable source of extreme macro subjects thus far. Yet this being November, the insect world is bracing for winter. Except perhaps for...winter insects. If it wasn't for our new laser-pen-obsessed cat forcing me outside, I'd had no business there. For no particular reason I figured to do another gaze in the mini pond that I had been ignoring for weeks. These are just buckets of water dug into the ground. I pretty much let nature figure out what to do with this habitat. Eye ball almost meeting the water line, I normally look into the water. To see if anything moves down below. Being this very close to the water line, I noticed something tiny sitting on the surface itself. Arthropod-like but too small to the naked eye to decipher anything else. I carefully poured it into a petri dish and took it inside. I had a quick look in the viewfinder and rejoiced: a springtail! I know they exist. They are likely the most numerous of any insect species in our garden, yet thus far I've never consciously seen one, let alone capture one. Probably because I wasn't trying very hard, yet also because of their small size. They are easy to overlook and even if detected, standard macro photography (1:1) would struggle to capture them in detail, depending on which species it concerns: https://www.collembola.org/images/hopkin/2005/megmin01.jpg Both subjects are springtails. The small blob is a mere 0.25mm, the "giant" 6mm. The particular species on my photo has these dimensions: - body length (head to butt): 1.7mm - abdomen at widest point: 0.8mm - width of head, without antennae: 0.4mm As seen by the naked eye: https://www.jungledragon.com/image/104613/dicyrtomina_ornata_-_dimensions_heesch_netherlands.html Capturing this tiny subject is challenging in multiple ways: - As I needed a diagonal angle into the petri dish, I went without the macro rail. Handheld 5:1 macro photography is...interesting. - Despite the subject being so little, depth of field at 5:1 is still too tiny. It's about 0.25mm. So you can't get the entire subject in focus. Increasing aperture is no solution. This particular lens is useless beyond f/5.6, f/8 tops. - Resolving power. Whilst I'm generally very happy with this lens, clearly it's unable to resolve fine details at this magnification. The eye, as an example, would be about 0.08mm in size yet still make up hundreds of pixels on the D850's high resolution sensor. This glass, and probably most glass, can't resolve details that fine. It's not a problem for the typical subject (0.5 - 1cm), but this is another league. Luckily, the subject was strangely compliant. It's alive and unharmed. It didn't respond to my intense focus light and heavy flash. This is the best I was able to produce on day 1. I'll share a few more day 1 shots later. They are far worse, yet I'll use other angles to discuss characteristics of the species. On day 2, I actually tried to stack this subject. Results of that are also still to come. As for species ID, likely this is Dicyrtomina ornata. One of 3 winter species looking somewhat similar (the others are Dicyrtomina saundersi and Dicyrtomina minuta), based on this most excellent resource: http://www.janvanduinen.nl/collembola_a.html The decisive key in this case is the subject having a uniform antennae color, which sets it apart from Dicyrtomina saundersi. Update: anatomy discussion here: https://www.jungledragon.com/image/104641/dicyrtomina_ornata_anatomy.html Stacked image from day 2: https://www.jungledragon.com/image/104643/dicyrtomina_ornata_-_full_subject_crop.html Dicyrtomina ornata,Europe,Extreme Macro,Netherlands,Springtail,World

Naming

Higher level taxonomy of the Collembola has been shifting a lot over the past decades. Currently the most supported opinion would seem to have them as a class in its own right, placing the globular species in an order Symphypleona and Dicyrtomina spp. in the family Dicyrtomidae.

References:

Some text fragments are auto parsed from Wikipedia.

http://collembola.org/
http://urweb.roehampton.ac.uk/collembola/taxonomy/27641.html
http://www.janvanduinen.nl/collembola_a.html

Fanciulli, P.P. et al. (2001) Taxonomic diagnosis of Dicyrtomina ornata and D. saundersi (Collembola: Dicyrtomidae) and analysis of their population genetic structure. - Zootaxa, vol.10(1.1)
http://biotaxa.org/Zootaxa/article/view/zootaxa.10.1.1
Taxonomy
KingdomAnimalia
DivisionArthropoda
ClassEntognatha
OrderSymphypleona
FamilyDicyrtomidae
GenusDicyrtomina
SpeciesDicyrtomina ornata
Photographed in
Netherlands