Note the anterior abdominal segments:

Specimen on RIGHT (male):
The first abdominal segment is nearly invisible and greatly reduced/compressed, but present posterior to the "elevated cruciform structure" ("Green X" on the back) of the thorax.
The second abdominal segment, the most apparent anterior segment of the abdomen (along an anterior-posterior axis), is nearly twice the width of the abdominal segments seen on the specimen to the left - these observed differences in shape and size of the abdominal segments on the specimen to the right are indicative of a male. The 2nd segment, largest visible segment, would incorporate the tymbal covers on the sides which are, as Gerry said, NOT clearly visible in this image (to this observation I do agree). The terminal segment of the abdomen is slight conical/tubular with a more blunt tail (male charater).
Compare notes here to a known MALE (& comments): http://bugguide.net/node/view/263001/bgimage

Specimen on Left (female):
In strong contrast, the abdominal segments on the specimen to the left are nearly equal in width (ant-post axis) all the way down - indicative of a female. The terminal segment of the abdomen is very conical, elongated and sharp, houses the ovipositor (female charater).

For reasons stated above, I am certain we have a pair....whether they are the same taxon...I only suspect it to be likely based available distribution information for all members of this complex. To date, T. davisi is only known as a Southeastern species and T. auriferus is considered to be the "western" counterpart. Based on the lit I have reviewed, distributions west of the Mississippi River and up into the Great Plains, addresses these members as T. auriferus. Should T. auriferus populations be like those of T. davisi, then we can expect tremedous individual variability and possible geographic tendencies in characters as well.

While I do agree with Gerry regarding the ambiguities, I cannot agree in the interpretations.

Tibicen davisi usually has much more infuscation along the veins towards the tips of the wings (however not always!!!!). This gives the veins a heavy appearance.

Thanks for the image upgrade! - I still stick to my belief we have a PAIR.

Subcategories explaining the relationship(s) held by davisi & auriferus might be helpful.

Those of question originating from the Southeast (mid-South) could be placed in one & those from the Plains region in another.

Any images that seem to defy either taxon clearly could be put in these subgroups instead of floating in Tibicen "never land". It is important, though there is debate, these images stay close to the core of the taxonomic issue being addressed.

Thanks,
bill

I studied these images closely and I can honestly say that I cannot detect tymbal covers on the top specimen underneath the wings. The image is clear and close enough that one should be able to see them pretty easily.

I have also read David Marshall's email and he also states:

Note that this is mtdna only (one marker), and it is always possible that another gene could tell a different story.

Finding one marker in mtDNA does not make the same species. From what I remember from biology class to determine species one has to look at allele values and look for similar haplotypes. You can't get similar haplotypes from only one genetic marker but rather multiple markers along the same dna strand.

I would agree that the top one is T. auriferus and the bottom one may be a form of T. davis proper or harnedi.

One marker may be enough to determine that these are the same genera. (You don't need a dna marker to determine that) but the physical attributes between these two specimens are different enough to be suspect.

I would advise caution in determining these to be the same species until a paper is published and agreed upon by the consensus.

I think I might also have to re-evaluate my T. auriferus specimens from Kansas.

AGREED: Very good case!
As stated: "Note that this is mtdna only (one marker), and it is always possible that another gene could tell a different story."

Hence I quote:
"Regarding Tibicen davisi harnedi (populations that occupy the western part of the T. davisi range): Preliminary analysis (based on mtDNA, K.H.) suggest these to be more closely related to "T. auriferus" than to "T. davisi"!....more work & data is needed before conclusive."

"Preliminary" & "Suggest"
"...more work & data is needed before conclusive."

Gerry makes an Excellent case! Perhaps I did "jump the gun". Much more work is to be done and huge series from across the range(s) are needed! We need to compare the morphology, ecology and genetics across the board!

----------------------------

Pic's: The last segments are pretty clear - shorter, cone-tubular and blunt at the end (i.e. claspers) on the specimen at RIGHT and more elongated, conical and sharp on the specimen at LEFT (i.e. segment housing ovipositor) - suggestive of a pair (?).

I don't know how cicadas compare in N.E., but in most places I have collected and among most Tibicen species I have pinned and reviewed, the females seem to have longer sharper wings to body ratio. While the males appear to have more body mass, i.e. bigger abdomens, the abdomens are mostly empty air chambers and probably light weight - this overall makes the wings seem shorter by comparison (body length to wing length ratio). In contrast the abdomens of females contain denser tissues (ovaries, eggs, etc.) - perhaps explaining the tendencies in sexual dimorphism regarding wing alometrics.

On a final note, I cannot comfortably place material under T. davisi that was collected in Kansas (provided the collection data given is correct). Nor would it be a good notion to loose these images under "Tibicen spp." since they are playing a pivotal role in discussion (comparisons & contrasts regarding this complex).

Hey Bill,

Have you looked closely at these specimens? I know you and I have had conversations with regards to T. davisi and T. auriferus from Kansas. I even have many T. auriferus from Kansas in my collection but man these two just look totally different. Taking the keys to these species as you and I have discussed in the past,

The top specimen seems to have really "stubby" and rounder forewings which I am coming to agree may in fact be a great key in differentiating T. auriferus from T. davisi and that the one on the bottom has longer and narrower forewings.

I'd also like to add that the heads differ in the way the compound eyes lay against the pronotums. The one on the bottom is more prominent (sp?) than the one on the top.

Was wondering if these two might be T. auriferus and T. davis respectively. Your thoughts?

Gerry

First let's address the issue of sexual dimorphism - the top specimen is a male and the lower a female, hence body shape and wing reference to body length will be different ... Now, to address the question more directly - we have had a similar conversation about that Tibicen davisi harnedi or T. auriferus pair from Colbert Co., Alabama form my collection. Seems we have the same issue!

My brother will actively seek more of this typology in nw. Alabama and I have requested every individual he can obtain ... regardless of condition. We need to scrutinize this typology, and we need a good series in which to do that. Counting chickens before they hatch, it is my plan to forward some to you once I have more in hand so that you will have more than images to mull over.

For certainty, these are not T. walkeri (syn. T. pronotalis), so in part, there has been a better move.

In conversation with Dave Marshall, there is ambiguity in the davisi/auriferus complex.

Scenario #1: What if they (davisi & auriferus) are conspecific and represent races?
Scenario #2: What if they are distinct species but have a blend zone (Introgression)?
Scenario #3: What if we have more than the above situations &/or combo. + there is a third member?....lots of questions and not enough resources in hand to answer them adequately.

I agree these may represent some spectrum of variability. Kathy Hill is doing genetic work with this complex, so for now, until we have definite evidence that davisi does in fact range into that region, T. auriferus represents the best "Pigeon Hole" we have to place these images.

Hope that addresses the question.

On another note, T. davisi in Alabama and Mississippi seems to have 2 forms (?) 1) a longer narrower winged type and 2) a shorter rounded winged form - but what if this observed difference represents 2 species and not forms???

bill

Better here or up at genus? I think either is fine. Especially with these comments people can see there are "issues" and exactly what they are. So even if there is some discussion anyone who does more than "just look at the picture" may benefit more from this placement, rather than lost at genus. (just my $0.02)
Let me know if anyone wants a move.

I recommend keeping it here for now.

As you mentioned, taxonomy is an ongoing issue in many groups.

thanks,
bill

These specimens are T. auriferus. I have both specimens in my collection from Kansas. T. pronotalis is significantly larger than 24mm, has a brighter green pronotum and collar with brighter maculations on the mesonotum. In addition to having grey eyes similar to T. auletes. See the below image of a true T. pronotalis

T. chloromera is really dark, with the contrasting silver spots visible in these two images. The specimens on this post lack those markings.

You are right - T. chloromerus has a black band ("collar") across the back of the pronotum, whereas these specimens have green collars. You need measurements to be sure of the species, but I expect that they are T. pronotalis.

I missed that.