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Cicindela sp. - Cicindelidia punctulata

Cicindela sp. - Cicindelidia punctulata
Wilcox, Cochise County, Arizona, USA
July 17, 2007
Size: 1 cm
Drawn to blacklight


Sorry, one last comment!
I'm really trying to avoid using subspecies names in the guide since they're especially dubious in most tiger beetle species (with a few rare exceptions). Because they don't form "clean" groups anyway (they often blend over large geographic areas) it becomes very difficult to place many populations into one or another... not to mention the fact that there is often as much intrapopulational variation as there is variation between subspecies.

C. punctulata 'chihuahuae' blends very gradually with the nominate subspecies over a large area and like many tiger beetle subspecies it's more of a clinal variation than anything else (and evidence suggests it's not genetic but just environmentally induced color changes).

In order to avoid oversplitting and confusion I'm going to just place this under C. punctulata. Hope that doesn't offend anyone.


Daniel, although my expertise lies more with buprestids and cerambycids, I would like to lend support to your statement that many 'subspecies' actually represent extremes of clinal variation.

Another example is with Cicindela formosa - here in Missouri most populations are assignable to subspecies generosa; however, in eastern and southeastern Missouri (along the Current River and in the Lead Mines area) exist populations assignable to the nominate form. The differences between these populations and those in other parts of the state cannot be a result of genetic divergence caused by exogenous restriction of gene flow, but instead must represent phenotypic expressions of soil type or some other environmental agent.

The same problem exists in buprestid and cerambycid taxonomy, though not nearly to the same degree as with cicindelids. The concept of subspecies as allopatric populations where gene flow is prevented by geographical barriers has been completely abandoned by many, otherwise very knowledgeable taxonomists. I agree it is useful to have 'names' to which geographical variation can be attached, but hijacking the subspecies concept for this reduces its utility for denoting true subspeciation events.

Excuse the rant, but I just wanted to lend support to your comments and highlight the issue.

Good example!
C. formosa is an excellent example. You are also right that virtually no professional evolutionary biologists/ systematists use subspecies anymore, but of course there can be 'evolutionarily significant units' - major genetic subdivisions within species, although these necessarily need to be identified using molecular tools. Still, it is possible that potential ESUs could be first discovered by finding population(s) that appear to be distinct based on some morphological characteristics, and then these can be tested for distinctiveness using molecular markers. But my biggest problem is the giant assumption that populations that differ in color, size, etc are the result of restricted gene flow. The null hypothesis (if taxonomy is to be a science) is that they are not different and that we need to test to see if they really are.

However all of that said, it is good to be understanding that taxonomy was done this way for centuries and even if we now know that it wouldn't fly today in a more rigorous scientific environment, remember that most people doing taxonomy are not trained as modern professional biologists. So I understand and sympathize with the desire to name all different populations... part of my job is to try to make sure everyone is informed as much as possible.

C. punctulata
Just a quick note that C. punctulata is very difficult to separate from C. nigrocoerulea in that geographic area (**both** species have punctures along the suture and both are typically green with reduced markings in southern AZ). The only characteristics that cleanly separate the two are the presence/absence of very fine microserrations at the tip of the elytra (present in punctulata, not in nigrocoerulea), and the number of hairs on the first antennal segment, neither of which are visible without a lens or microscope.

Otherwise you can separate them by the general body shape which is subtley different. C. punctulata is more "atheletic" looking typically with a narrower neck, but it's still pretty subtle unless you're used to looking at them a lot!

- Dan

accidentally posted twice.... deleted
- D

Cicindela punctulata chihuahuae
Note the row of punctures on either side of the elytral suture. This subspecies is described as bright metallic green to green-blue, with maculations absent or reduced to small spots.