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Ripiphorus vierecki vs rex

Some or all of the beetles currently identified as Ripiphorus vierecki may be R. rex. Vaurie(1) notes that the two species are very similar. To distinguish them, Evans and Hogue(2) state rex "is unique among the species of Ripiphorus in having a serrated outer edge of the middle tibiae". Three beetles formerly under vierecki were recently moved to rex on this basis:

I have posted images of a rex male's right middle leg showing the serrations in profile:

Note from the lateral full body view that if the serrations are not seen in perfect profile at high resolution, they appear as a series of dots due to their darker color. This appears to be the case for all three of the specimens remaining under vierecki:

This should be verified by an editor (who has access to the often higher resolution images as submitted). The first of these is a follow-up to photos of a different specimen on the same type of blossom and in the same location taken one week early and subsequently moved to rex for having more clear serrations. Evans and Hogue point out the Rhipiphorids are rare but may be locally abundant.

Before making any moves, though, note that Evans and Hogue is generally not a primary source, and the claim that only rex mesotibia are serrated in the genus is unreferenced. Does anyone know the source of this information? If it can be shown that vierecki too have serrations, a synonymy is suggested.

Finally, note my comment under Linsley and MacSwain(3), which may help explain the confusion.

Contributed by Edward L. Ruden on 18 May, 2012 - 11:03pm
Last updated 19 May, 2012 - 10:29am

serrations are non-diagnostic

In preparing a loan of Ripiphorus today, I came across this discussion thread, now a decade out of date. We have some 50 specimens IDed as "vierecki", ranging from CA to AZ to NV to NM to TX. They all have a hairy cone on the forecoxae, they all have serrated midtibiae. Every specimen, both sexes. We have specimens of another 9 Ripiphorus species, including numerous paratypes of Linsley & MacSwain species. Every one I've checked has serrations on the midtibiae, and a hairy projection on the forecoxa (though these projections vary somewhat in how elongated they are). I don't think these are viable characters for diagnosing taxa.

… Doug Yanega, 16 May, 2023 - 3:55pm

R. vierecki likely junior synonym

As stated above, "If it can be shown that vierecki too have serrations, a synonymy is suggested". I'm inclined to go with that.

… Edward L. Ruden, 16 May, 2023 - 4:30pm

Two additional distinguishing characters?

The 1955 reference by Vaurie(1) mentions two more traits for distinguishing R. rex from R. vierecki:
1) a median carination of the dorsal segments of the abdomen; and
2) a densely hairy, elongate, projection on the inner side of the front coxae at apex.

I think the 2) is visible in the thumbnail below:

The last sentence in Vaurie's discussion of R. rex mentions that the description of Fall's AZ and NM specimens of R. vierecki agree very well with R. rex, except that Fall made no mention of characters 1) and 2) above.

Vaurie makes no mention of the serrate outer edge of the mesotibiae for R. rex...I guess that's something noted after her work by Evans & Hogue (and/or others?).

I tried to check whether I could see if all these presumed characters of R. rex were indeed absent in the MCZ type images of R. vierecki...but those images weren't loading in my browser when I visited the MCZ web site. (I've noticed the MCZ web site sometimes has periods of non-functionality...hopefully the images will be accessible later.)

… Aaron Schusteff, 21 August, 2012 - 12:44am

Pictures added

I've added new views of my specimen, and describe them on my Main Page. They detail key features that may separate rex and vierecki in general (assuming they can be). It's clear though, that inspection of museum samples is needed. The published work is too ambiguous. If you succeed in locating some, I'd love to borrow a male and female of each if possible, and post a similar photo series for the set.

… Edward L. Ruden, 25 August, 2012 - 6:20pm

Coxal projection

The medial carination is ambiguous on my specimen since the dorsal abdomen is laterally compressed from dessication. It does not seem to have a coxal projection such as the one you show. I will add a ventral view in the next few days to my series. This may be a key feature to distinguish the two species. Hopefully MCZ images will confirm this when they return.

… Edward L. Ruden, 21 August, 2012 - 9:51pm

Zack Falin (pers. comm.) told me...

...that he used to treat the two as synonymous, but the issue deserves to be revisited: Bill Warner, for one, believes the two are separate species.

… v belov, 19 May, 2012 - 3:28pm

Synonyms vs. Distinct Species

The more I study the literature, specimens, images, collection data, etc....the more things seem to point to synonymy of R. rex and R. vierecki. Lots of details, including links to original descriptions of both taxa (and many other relevant references) can be found accompanying this post, which shows specimens from the CAS collection labeled as R. knaussi (= R. vierecki), and that seem to key and conform to description details of R. rex.

It would be very helpful to learn from Bill Warner, or others who consider the species distinct, what characters or criteria can be used to separate them. There are a number of BugGuide posts that will be difficult to place without resolving this.

There are other problematic species groups in the genus as well...where separating out species based on the available literature can be quite difficult or impossible (e.g the "R. fasciatus group"). Happily, BugGuide is accumulating images of a number of these entities...it sure would be nice to be able to place them to species.

This is a fascinating genus, eminently worthy of a thorough, well-researched and well-reasoned treatment. It's been wanting of a solid revision for many decades, and presumably a much larger pool of specimens are now available for study in collections, compared to when earlier references were written.

Hopefully one or more earnest and insightful coleopterists out there will produce such a work in the not too distant future.

… Aaron Schusteff, 23 January, 2013 - 1:21am

Synonyms vs. Distinct Species

As I was just slapping names on some of these things I thought I would chime in here directly...

In short, I still believe R. rex and R. vierecki are synonymous (though Bill has also mentioned to me in conversation that he believes there is a difference, though neither of us provided evidence to back up our assertions). Without re-hashing everything that's been written here, I'd like to point out just a few things.

First, R. rex was described from a single male, R. vierecki was described from only females- hence a lot of confusion (I'm not sure how Rivnay assigned R. rex to a species group according to female abdomen color [a horrific character to begin with] when the female of R. rex was unknown to him). The carination (or lack thereof) of the abdominal tergites is in my mind a bogus character and dependent on preservation. The odd little ventral projection of the procoxae is present in every male and female I've examined (more pronounced in males), and *every* male I've looked at appears to have some degree of serration (though it can be subtle).

I have dissected out the whackers for a number of Ripiphorus "species", but only enough to convince me that synonymy is rampant in the group; not enough to provide conclusive publishable evidence. And yes, this group and Macrosiagon cry out for modern comparative revision (including DNA evidence), though at my pace I kind of doubt I'll be the one to do it...

cheers,
zack

… Zack Falin, 8 March, 2013 - 2:00pm

Thanks for your comments Zack

To add some extra data points...I examined a number of specimens labelled as R. vierecki at the Essig Musuem (UC Berkeley) a few weeks ago. They all had serrate mid-tibiae and pronounced ventral projections of the procoxae, as in R. rex.

At the same time, while R. rex is said to occur in CA, it seems quite odd that there are no specimens labelled as R. rex at the Essig, CAS, or any other major other CA collections (as far as I can tell from online searching)...yet all those collections list lots of specimens labelled as R. vierecki. What might explain this?

Regarding a revision, I'm sorry to hear you doubt you'll be the one to do it. If it's any solace, if I were a rich philanthropist, I'd happily fund a vigorous collaborative effort, spreading the work over a larger group of workers, so no single one would be especially overloaded, and all could benefit from sharing and comparing their observations and insights. But alas, I'm not a rich philanthropist :-)

… Aaron Schusteff, 11 March, 2013 - 11:52pm

Revelant supporting posts of CAS specimens

Just made another post of a female Ripiphorus rex found recently in southern California...and that gave me occasion to revisit this page. It then occurred to me that it would be good to add thumbnail links here for two earlier posts of particular relevance to this forum topic:

The upshot of those posts is that, at this point (i.e. 4 years later, and still with no clear arguments to the contrary) I'm very much persuaded that R. vierecki = R. rex !!!

… Aaron Schusteff, 9 April, 2017 - 12:07pm

The id of my beetles

was done from the specimens at the UAIC and in addition by genetic analysis by Duane McKenna

… margarethe brummermann, 18 May, 2012 - 11:51pm

Excellent

Can you verify the outer mesotibae are serrated from additional or more detailed photos, or the specimen itself? To date, serrated Ripiphorus have been placed in rex based on Evans and Hogue. A positive result would challenge that criterion.

… Edward L. Ruden, 19 May, 2012 - 9:26am

Determination

Can you enter this info under the image?

… Beatriz Moisset, 19 May, 2012 - 9:15am

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