Bembidion - Bembidion affine

Bembidion affine

The distinctive pronotum gives it away, and the doubled frontal furrows between the supraorbitals are clearly visible in the nice dorsal view of the head.

Moved from Bembidion versicolor.

… Curt Harden, 19 March, 2023 - 1:40pm

Moved

Moved from Subgenus Furcacampa.

… Tim Moyer, 15 November, 2011 - 9:46pm

Moved

Moved from Bembidion mimus.

… Tim Moyer, 3 November, 2011 - 8:48pm

Bembidion impotens-mimus-versicolor complex

is most reliably separated externally on the basis of surface microsculpture (m/s) on pronotum (P) & elytra (E). Need good stereo-microscope.

m/s absent on P (very shiny)--> B. impotens
m/s present as "mesh" on P (duller)--> two others.

male B. mimus: E m/s impressed throughout as isodiametric mesh.
male B. versicolor: E m/s weak/absent on medial intervals.

female B. mimus: E m/s very well impressed throughout.
female B. versicolor: E m/s absent/barely impressed on anterior half of the first interval (shiny).

Tim, the sinuation at pronotal base appears a bit too long to be B. mimus, so try studying the m/s. Expanded protarsi suggest that you have a male specimen.

… Peter W. Messer, 3 November, 2011 - 8:42am

m/s or no m/s, that is the question

I gave this and the "B. impotens" a look under the scope, and honestly I'm not sure if the pronotums have or do not have m/s. The scope view looks about the same as the enlargement of the left pronotum just posted. To me, there appears to be very faint m/s seen in the reflection areas just above the antenna and again down between the creases in the hind angle. But when that "m/s" is compared with what can be seen on the base of the head, it makes me wonder if I'm not just imagining m/s on the pronotum. Any comment or suggestion would be appreciated.

PS: I currently use a Meiji EMZ-5, .67-4.5x, with 10 or 20x eyepices - what I thought was a "good" lab scope. But if you want to tell me I just really need a Nikon SMZ1500 or Oly SZX-12, I'll be glad to take that running to the Budget Czar ;)

… Tim Moyer, 3 November, 2011 - 10:15pm

Thanks Peter

I think I see some evidence of m/s on the expended versions of these images, but I'll give a look under the scope.

Thanks for the key (it's certainly different than the one I was using from D&A). Even better, you've given me another reason to try some higher mag images (once I know what I'm going for from the scope :)

… Tim Moyer, 3 November, 2011 - 8:48pm