Steiroxys Revision Beginnings

Steiroxys is a genus of shieldback katydids with currently four described species. Though we know there are many undescribed species (Caudell 1907) and though it's sister genus Idiostatus was revised (Rentz 1973) with many new species, now much work has been done on this genus. All we know is, there are many species and most probably have small ranges. I've decided to tackle this issue and use citizen science to view distinguishing features of potential species. The downside to this, I cannot be able to revise the genus with just photos naturalists posted because in order to describe a species, you must have a holotype specimen. Which means I have to go out into the field, capture and ultimately kill the insect. I can send the specimen to a museum with my description of species and only then will the science community accept my work. Right now, this is just a outline of eight potential species photographed on iNaturalist and I will tag the observers as I go.

We have additional problems with this. Out of the four described species as of now, S. trilieatus and S. pallidpalpus holotype specimens are lost so we have no clue what they look like. To add onto the problems, I cannot get a sufficient view of holotype of S. borealis to determine the distinguishing features. As mentioned by Caudell, potential species can be identified by the male's cerci, the sensory organs on the abdomen end and the shape or size of it can determine species. For females, subgenital plate shape seems to play a role in identification but since no iNaturalist observer has photographed the female underside, they are all genus level for me. So here's the list:

Steiroxys species-a

Observer: @jimmylegs
Individuals: 2 males
Range: South-central valleys of British Columbia; Kamloops Lake to Kettle River Recreation Area.
Cerci: Probably incorrect terminology but the cerci have two "prongs". The two prongs in this potential species are close to the tip of the cerci and they curve sharply inward in unison.
Notes: A lot of confusion here for this. The cerci of James's individuals are identical to Steiroxys trilieatus photographed by Dan Johnson in the website "Katydids North of Mexico". What I need to decide is whether these are a described species or Dan misidentified and his individual is a part of species-a.

Steiroxys species-b

Observer: @justine_dm
Individuals: 1 male
Range: White Lake Grasslands Protected Area, British Columbia.
Cerci: Compared to species-a, the inner prong is thicker, shorted and triangular-shaped. The outer prong is straight and long.
Notes: Might not be a potential species since it's a nymph.

Steiroxys species-c

Observer: @geographerdave
Individuals: 3 males
Range: Mount Saint Helens, Washington
Cerci: Short and stubby. Inner prong curves slightly and the outer prong may bend outward. The indentation between the two prongs is indistinct.
Notes: If I were to name this species... Steiroxys helenae

Steiroxys species-d

Observer: geographerdave
Individuals: 1 male
Range: Cascades near Panther Creek Falls, Washington
Cerci: Short and stubby. Almost identical to species-c but the inner prong is straight, not curved and is almost equal length of outer prong.

Steiroxys species-e

Observer: @axyaliendragon
Individuals: 1 male
Range: Willamette National Forest near Rainbow, Oregon
Cerci: Intermediate between species-a and species-c. The prongs angle inward at a slight curve but not as distinctive as species-a. Inner prong has a more definitive prong.
Notes: I admit the cerci in the photos are kind of blurry so its possible it's not species. Could be S. strepens.

Steiroxys species-f

Observer: jimmylegs
Individuals: 2 males
Range: North Shasta Mountains, California
Cerci: Cerci enormous with the two prongs exceptionally curved and they'll meet in the middle.
Notes: This could be a new species but this part of California is within the proposed range limits of S. borealis. Unfortunately the provided photo on Orthoptera Species Files (OSF) regarding the holotype does not clearly show the cerci.

Steiroxys species-g

Observer: birdwhisperer (myself), @coreyjlange and @birdernaturalist
Individuals: 3 males
Range: Eastern Oregon
Cerci: Identical to species-a but the inner prong is placed near the base of the cerci not near the tip. This type of cerci shape occurs in three in the same general vicinity leaving me to believe it is indeed different from species-a.

Stieroxys species-h

Observer: Heidi (BugGuide user)
Individuals: 1 male
Range: Lucky Peak near Boise, Idaho
Cerci:: Similar to species-i, long, mostly straight prongs though the outer prong has a slight arch to it.

Steiroxys species-i

Observer: @maybedre
Individuals: 1 male
Range: Atla, Utah
Cerci: Short and straight, very similar to species-d but the outer prong is significantly longer than the inner.
Notes: This sighting is well within the proposed range of S. pallidpalpus but since the holotype specimen has been lost, I cannot confirm if the cerci are correct.

Summary: So there you go, 8 potential species. I hope with help of James, we can collect a few specimens and clear up the waters of this genus. I'm expecting quite a few more species to show up since we do not know which species live in Montana, Colorado, Idaho, eastern Washington and species limits throughout the Cascades. I wouldn't be surprised if the number doubles. Through citizen science, we can make plans on where to go to find species and that's what makes iNaturalist such a great platform for a project like this.

Posted on August 11, 2020 11:08 PM by birdwhisperer birdwhisperer


@birdwhisperer Very cool! I'll be extremely interested to see what you turn up with this species complex!!!

Posted by coreyjlange almost 4 years ago

Very very cool!

Posted by sambiology almost 4 years ago

@birdwhisperer Wow, this is very cool. For those found on Loowit (i.e. Mt St Helens), why not loowitae?

Posted by geographerdave almost 4 years ago

Excellent summary and analysis! I'll try to take a specimen next time.

Posted by birdernaturalist almost 4 years ago

Additional details. I figured I'd just add new comments in this section instead of editing the journal entry. Two big things to mention in this edit; cerci of the described species and identification of females. It was stated in the revision of Idiostatus that females can be identified by the subgenital plate, the hard covering on the end of the abdomen, located below the ovipositor. Reason why I haven't brought this up is because there are no iNat observations of females showing the subgenital plate clearly, and I presume that's mostly because most don't know you have to catch the shieldback and observe the underside for a species' id. Outside of iNat, there are three female subgenital plate photos. Links and descriptions below.

Steiroxys strepens

Male Cerci: Holotype speciemen shows a straight prong with the inner prong curving sharply into claw. The cerci point towards each other. I'm figuring after closer examination that species-e that I suggested before is actually this species.
Female Subgenital Plate: Holding the shieldback with the ovipositor pointing up, subgenital plate is triangular, almost like a pyramid. The plate ends with two short points I'm calling "tooths". Triangular indentation between the tooths. Plat covers the basal region of the ovipositor well. Median ridge of the plate ill-defined.

Steiroxys borealis

Male Cerci: Doesn't really resemble any photographed male. Cerci are very broad basally and both prongs curve inward but because of the cerci being broad, the prongs are oddly disproportionate.

Steiroxys trilieatus

Male Cerci: Two prongs close together curving sharply inward. Almost identical to species-a that I proposed before. Upon more researching and examination, I forgot that there are illustrations of type specimens (Caudell 1907) and Dan Johnson's photos support that his Alberta individuals are indeed this species, which suggests that species-a too is this species. However, I believe James Miskelly, the observer for both photographed species would disagree especially when I read his reasonings (Miskelly 2012). So I need to figure out what's going on here.
Female Subgenital Plate: I am legit serious about this, subgenital plate is Batman's mask. Hexagon plate with two very well pronounced tooths that are close together, forming the Batman look. Moderately defined median ridge and ill-defined "sockets". Indentation between the tooths is squared-shaped.

Steiroxys pallidipalpus

Male Cerci: Cerci broad basally, much broader than S. trilieatus though the prongs curve in unison and are shorter. Outer prong, though curves, is mostly straight. Caudell describes a variation of this species' cerci and this illrustration is identical to species-g, the one lives throughout eastern Oregon. It will be a task to decide if this variation is a different species or that Steiroxys observed in eastern Oregon are of a described species.

Steiroxys species-g

Female Subgenital Plate: Short subgenital plate that does not cover the basal region of the ovipositor. Hexagon-shaped like S. trilieatus but the tooths are distant with a broad "U"-shaped indentation. Tooths are also shorter and almost indistinct. Median ridge of the plate is much broader than the other females.

Posted by birdwhisperer almost 4 years ago

Additional details for two more species and even though their alphabetically notation does not represent geographic distribution as I had previously done, I'm not "changing" the names of the others. These changes came about due to my recent camping trip and I'll do that information first.

From Tuesday-Sunday last week, I camped up along the Eagle Cap Wilderness in northeastern Oregon. I've caught a couple shieldbacks last year on lower elevations, before I realized all of this undescribed junk was happening. So easy to interpret, I took my time in the area and I was able to successfully capture (and release) 26 different individuals from two locations all within a 3-mile stretch of road. I only caught about a fourth of what I saw though, so these Wallowa populations seem quite large and stable. I caught 10 adult males, 13 adult females, 2 fourth-instar females and 1 second-instar nymph. They results quite surprised me.

The first female I caught had a subgenital plate that looked identical to the described species, S. trilieatus, the distinct "Batman"-shaped. Original hypothesis, this is first visit I've made in the Wallowas to observe male cerci, maybe undescribed species-g and abovementioned species are both present in Union County and are habitat differentiated. Scratch that, my ten male captures say otherwise and do not have cerci supporting trilieatus. Hypothesis two, maybe the male cerci are just a variation and the Steen Mountains individuals are the undescribed species.

Anyway, I scratched through like three more other possible solutions and I get my answer when I get home and I was able to look at photos again. The individuals photographed in Jordan Valley are a new undescribed species that I had unintentionally labelled as species-g. I also checked the Steen Mountain individuals again. I'm still certain they are species-g but another sighting was posted after I created this post. This individual was captured on the lower east slopes of the Steens, close to the Alvord Desert. I mentioned to the observer the cerci looked like species-g but now with new eyes, I can see quite significant differences and I think it is indeed a new species. Differences explained below.

Steiroxys species-j

Observer: @alexlamoreaux
Individuals: 1 male
Range: Lower east slopes of the Steen Mountains. Possibly present throughout the Alvord Desert.
Cerci: Like species-g but longer and skinner with the outer prong extending well past the inner tooth, to end in a short claw, while other species have the outer tooth curving almost immediately after the inner tooth diversion. Imagine S. strepens except with the outer tooth hooked at the end.

Steiroxys species-k

Observer: @brandonwoo
Individuals: 3 males and 2 females
Range: Probably the entire Owyhee Uplands and possibly the lava flats in southeastern Oregon.
Cerci: Like species-g with the inner tooth close to the abdomen, atypical of normal S. trilineatus which has it's inner tooth close to the end of the cerci. These cerci are also exceptionally long and thin, curving sharply. It appears in all the males, the cerci will cross, similar to that of species-f found by James Miskelly in northern California. Perhaps the same species but I doubt it.
Subgenital Plate: Short subgenital plate that does not cover the basal region of the ovipositor. Hexagon-shaped like S. trilieatus but the tooths are distant with a broad "U"-shaped indentation. Tooths are also shorter and almost indistinct. Median ridge of the plate is much broader than the other females. Note: Information copied from my last comment in which I thought these females were species-g.

Steiroxys species-g

Female Subgenital Plate: Identical to S. trilieatus, sporting the Batman look but shape of the plate matters. Hexagon vs square, five sides vs four sides. S. trilieatus have a distinct hexagon-shaped subgenital plate, with two points above halfway towards the tooths. Species-g has a completed square and does not have a indentation when the plate merges into the abdomen.

Third photo:
Comparison to S trilieatus:

Posted by birdwhisperer almost 4 years ago

Cool, hope you are able to see this project through! Unfortunately my specimens from Idaho were destroyed (at least I got some good shots!), but I do have the coordinates if you are ever in that area and want to collect some for yourself. I will probably not be back there any time soon.

Posted by brandonwoo almost 4 years ago

Hey Sean, would love to chat about your blog on subspecies ID. Can you contact my gmail, w.douglas.robinson? Cheers

Posted by wdouglas almost 4 years ago

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