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Photo#903762
Rhadine  - Rhadine ozarkensis - female

Rhadine - Rhadine ozarkensis - Female
nr Ponca, Buffalo National River, Steel Creek, Newton County, Arkansas, USA
September 25, 2013
Size: 13 mm
Keys out to the larvalis group. I think it's R. larvalis, however R. ozarkensis, which is in the same species group, is known from a nearby cave, and I haven't ruled that out yet. Collected in a pitfall trap.

Rhadine ozarkensis (tentatively)
based on my microscopic examination of this female specimen which is deposited in the P.W.Messer collection as a photo-voucher. Thanks Michael for this specimen. The light coloration I presume is from lack of maturity. This one is so very important to my current work in describing the new species "R. barri" which is also in the larvalis group. I would really like to get a series from you if possible!

I (or my co-author Robert Davidson) still need to compare this specimen to the type specimens taken from a cave just one county removed from where this one was caught. For now this specimen appears to fit the original species account by Sanderson & Miller (1941). It appears quite different from examined specimens of R. caudata and R. larvalis. More to follow.

 
Exciting find
Wow, this is a really exciting find Michael! If it is in fact true R. ozarkensis Sanderson and Miller, this would be the 6th specimen known! I'm also interested in the group and am focusing on its phylogeny for my Master's and beyond. I haven't (yet) been able to examine many of the type specimens, but I concur with Peter, it is very different from R. caudata and R. larvalis. It'd be great if this could be included in my phylogeny...
The pronotum is very distinctive. My only concern is that the posterior angles of the pronotum do not appear particularly reflexed. However, the L/W agrees (1/4 longer than wide). Are the elytral setiferous punctures limited to the basal fourth?

 
Some microscopic findings in this female specimen
that support Rhadine ozarkensis are as follows: pronotal hind angles are distinctly reflexed but not so elevated as in R. caudatus; elytral luster is noticeably dull (vs shiny in caudatus) due to very finely granulate microsculpture; limited to the basal quarter of the elytra are 9 randomly positioned long erect setae (4R + 5L), each at least twice the length of a seriate seta in interval #3.

Antonio, good to hear from you again and to know that you are following BugGuide! How did you discover this newly posted species page so fast? This specimen has got to be Rhadine ozarkensis for so many reasons. Anything else would mean a new species. Forthcoming comparison to the type specimens is so important. I'll see what Robert Davidson has to say. In the meantime, it's a race to Steel Creek this summer for the hunt of the decade!

 
Peter has specimen
I sent the specimen to Peter Messer, so he'll have to answer you.

 
Steel Creek near Ponca AR in upper Buffalo National River area
likely provides cavernous & creviced limestone habitats for our "Rhadine ozarkensis" similar in nature to the cavernous type locality nearby that was originally reported for the species. A view above Steel Creek in Ponca is posted here which shows a formidable sedimentary stone cliff. It is reported that the upper Buffalo National River region is home to over 300 cave systems.

Michael, do you remember seeing similar rocky terrain very near the capture site?

 
Karst
That whole area of the Ozarks is karst habitat. I don't know of any caves in the immediate area, but it is quite rocky. Once you scrape the leaf litter away the rocks are piled atop each other and there are usually large open spaces between the rocks.

 
Karst habitat in northwestern Arkansas
with its typical crevices and likely cavernous spaces is an area to find additional Rhadine ozarkenesis. I expect they roam the surface at night. Currently the single ♀ specimen is with Robert Davidson for comparative study in preparation for our paper on the larvalis group. Thanks again!

 
only specimen
That's the only specimen I collected, unfortunately.

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