Dicyrtomina ornata - dimensions, Heesch, Netherlands
This is a support image for this main post:
This image shows the subject as seen by the naked eye. There's 2 springtails in the petri dish, the main photo concerns individual #1. With the petri dish having an exact diameter of 10cm, I was able to calculate the subject dimensions:
- body length (head to butt): 1.7mm
- abdomen at widest point: 0.8mm
- width of head, without antennae: 0.4mm
Although a simple process, I'll still explain this method of measuring. Using a measure tape, I measured the petri dish to be exactly 10cm in diameter. Next, I used the measurement tool in Photoshop, which allows you to draw a line between 2 points and see how many pixels it is. In this case, the 10cm diameter corresponds to 768 pixels.
Therefore, 1 single pixel corresponds to 100mm (10cm) / 768 = 0.13mm in the real world. With this in mind, one can zoom deeply into the image and keep using Photoshop's ruler tool to draw lines on the subject itself. This will give back the amount of pixels, which we then multiply with 0.13mm.
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.