I have about 100 taken from a 3 minute kick sample from a chalk stream in Hampshire, UK in Oct 2016. They all measure c. 4 mm
Included in the images is a photo of the hind leg, and photos of them dry and wet (where they have a reddish brown colour).
I'm thinking it may be Dysticidae, but I've a feeling all the legs are a bit too long.
Thanks in advance for any help!
Hi
It could most probably be. Checking the male genitalia can affirm it.
To be 100% sure you can check " Predaceous Diving Beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska" by D.J. Larson, Y. Alarie, and R.E. Roughley, 2000.
http://www.nrcresearchpress.com/doi/book/10.1139/9780660179674#.WYMiXYjyuM8
This is description of the key:
Metatrochanter with hind margin relatively densely punctate and
setose; body more elongate, length: width = 1.60 to 1.83; ratio
metafemur length: metatrochanter length = 2.39 to 2.71 mm; arctic and
northern boreal
It is widespread in Canadian Arctic and in alpine and arctic regions of the Palaearctic.
Cheers
Armin
Armin
Can confirm Michal's identification that it is Oreodytes sanmarkii. The genus has lateral furrows on the pronotum and the elytra are usually striped. O. sanmarkii can be separated from the three other UK Oreodytes speciesby its small size c.3.0-3.3mm and its round oval body shape. They are common in shallow flowing streams and sometimes wave-washed shores of lakes.
- Badges
- Science method
- Similar topics
- Mathematics
- Statistics
- Statistical Techniques
- Meta-Analysis