Another Tibicen cicada from Dardenne Prairie, MO

Posted By: Bill Meyers | On: 2011-07-28 | Website:

Okay, I'm really curious, what distinguish this as a T. pruinosus and not something else? I have collected T. pruinosus almost every other night and I've never seen one like this before.

Cheers

Posted By: Massachusetts Cicadas | On: 2011-07-28 | Website:

Hi Bill,

Please clarify. What is different about it?

After studying this specimen very closely there are several morphological keys that would rule out T. canicularis as the identification of this species.

Typically, T. canicularis females either lack those large pruinose spots at the abdomen base or what they do possess is very minuscule.

You indicate this specimen was close to 5 cm (Approximately 2 inches). T. canicularis generally are not that large the maximum length on T. canicularis is roughly 1.5 to 1.75. This one is just larger than that.

The next species I thought was T. robinsonianus but according to a colleague of mine, the eyes of T. robinsonianus are extremely dark. This one has a purplish blue tinge to them. It does seem to have some black occlusions in the pronotal collar that bisects it but I think in T. robinsonianus black bisection would be a bit more pronounced. Also T. robinsonianus has an extremely smooth edged rather darkly pronounced ventral stripe, the one on this specimen seems a bit jagged and not as glossy.

I definitely agree that this is probably T. pruinosus with 99% surety, my colleague will probably post a follow-up comment. Do you not think it looks very similar to the T. pruinosus you reported a few weeks back?

Posted By: Jake Readnour | On: 2011-07-28 | Website:

i have collected over 40 robinsoniaus and pruinosus. This is very dark for a pruinosus and it has a very shiny ventrel stripe. the eyes are not always black! infact most of them are dark brown/black/purple from western IL.however it could be a very dark pruinosus as the pruinos spots are indeed this shape in pruinosus. just putting my thoughts on here

Posted By: Massachusetts Cicadas | On: 2011-07-28 | Website:

I'm pretty confident this is T. pruinosus. You will see a slight variance in morphological attributes among species like we see in other cicadas, especially Northeastern T. lyricens. Among the same populations the you get light and dark forms. This specimen looks extremely similar to me as the specimen previously reported from the same location here:

http://www.masscic.org/sightings/cicadas/cicada-sightings.php?sid=201

Posted By: Bill Meyers | On: 2011-07-29 | Website:

There are a couple of unusual things about it that had me scratching my head trying to figure out what it was:

1) On all of the T. pruinosus I have come across around here, the submedian sigilla make a distinctive "W" shape. The submedian sigilla on this one are VERY close together, almost completely closed (just short of forming a "U" shape), and actually merging with, what I call, the "spade" marking on the mesonotum. I've never seen the spade and the submedian sigilla actually touching on a T. pruinosus. So, that was the first thing that had me scratching my head.

2) The lateral sigilla on the T. pruinosus around here are usually large, brown spots with a thin black outline; the black outline being wider at the base than the top (That is, at least, if the black outline is able to completely encircle the brown spot as, sometimes, the brown spot "splotches" over the top of the black outline, completely covering it). This one had what looked more like a thick, black splotch with a brown "feather" running through it.

Anyway, those were the two main items that have me wondering what it was. I knew it couldn't be a T. robinsonianus variant because the eyes were not swept back as far as the T. robinsonianus we have around here (that's how, at a considered glance, I can tell the T. pruinosus apart from the T. robinsonianus I have collected: The T. robinsonianus has more of an "arrow-head" shape than does the T. pruinosus).

Of course, this specimen has the head of a T. pruinosus, along with the spots of a T. pruinosus as well as the "not as well-defined as a T. robinsonianus" black stripe running along the sternites.

Ergo, I guess the lesson for the day is; if it kinda' looks like an odd duck, but walks like a duck, swims like a duck, and quacks like a duck, it must be a duck...

:)

Cheers

P.S. - This specimen is currently running/flying loose somewhere in the house as "someone"---naming no names (my *cough* daughter *cough*)---left the top open on the butterfly cage. Hopefully, I can find it before it dies and gets brittle and is difficult to mount.

Any tips for re-hydrating a cicada?

Posted By: Massachusetts Cicadas | On: 2011-07-29 | Website:

Well, this is why we need series of cicadas in multiple geographic locations. While I noticed the lateral markings were unusual for T. pruinosus there were other keys that just didn't jive with other species.

Another consideration was perhaps T. linnei because the markings are similar but again, T. linnei females are not known to have those large pruinose spots at the base of the abdomen.

Mesonotal patterns I guess is something that while considered, there are other more stronger keys to think about.