A guide to Australian Terpandrini

Some of you may have noticed that I've been going back through all of Australia's katydid observations recently, fixing up errors and making identifications for things that we all put in the 'too hard' basket. It's been fantastic to finally sort out some of these trickier groups, especially when some of the species involved have never been photographed alive before. I've just finished up going through the wealth of Terpandrus sightings we have, and it turns out we really do have a number of different species here that aren't too difficult to separate. But even though I know how to separate them at the moment, I am liable to forget all of that important information in future. So here's a perfect spot to write it all down! And of course, that also means that everyone else can get a good guide to the identification of these katydids. There are a couple of similar genera as well, so here is a guide to all of Australia's species of Terpandrini (plus one unplaced genus). Big thanks to @manassas for helping out with these, and I'm sure I'll get some comments from them below about important things I missed!

The most distinctive of our Terpandrini is of course Chlorobalius leucoviridis, the Spotted Predatory Katydid. It cannot be confused with any other species:

Both sexes are similar, with the only real differences being the ovipositor and the stridulatory region:

Larger nymphs are also distinctive and unique, and although I'm not exactly sure what smaller nymphs look like I imagine they are similar:

There is some variation in colour, with individuals ranging from bright green to dull olive green/brown, but the pattern is consistent and really there is nothing similar:

Other important features to note are the large forefemoral spines, the deep transverse groove on the pronotum, and the small white tubercles all over the femora.

C. leucoviridis is known from arid and semi-arid habitats across a very broad range, and has been recorded in every state except Tasmania and the ACT. The seem to be more common in the south and southwest and most records are from SA and southern WA, but in the east they extend into western Victoria and all the way out to southeast Queensland, and they have been recorded as far north as the Gulf of Carpentaria and just west of the Wet Tropics in FNQ.

Our second-most distinctive Terpandrini, in my opinion at least, is Burnuia mirru. This odd species has very short, broad wings that are unlike any other species. In the males this is particularly exaggerated:

The female's wings are not quite so broad, but the triangle where the forewings overlap each other is greatly elongated and has very noticeably convex sides:

Other than the wings, the rest of the body is fairly standard, and I would expect that nymphs would be fairly nondescript. This katydid is rarely seen though and I don't know whether a nymph has ever been seen before, let alone photographed!

B. mirru is known from a small number of sites in southwester WA, from Frank Hann National Park in the west to near Caiguna in the east.

Next up is a genus that is not actually assigned to the Terpandrini at present, and is currently unplaced within Listroscelidinae - Alinjarria. It is quite similar to several of our Terpandrini though so I am including it here for completeness.

Alinjarria contains two fairly similar species, A. elongata from the NT and A. jadoni from Queensland. Both are very slender katydids with short wings and long cerci. Here is the male A. jadoni:

And here is the female A. jadoni:

Here is the male A. elongata:

And here is the female A. elongata:

The easiest differences between males of the two species is the length of the cerci, and the easiest difference between females of the two species is the length of the wings. The two are currently only known from widely separate locations though, so there's no real danger of confusing them.

A. jadoni is currently known from a few localities in north Queensland in the vicinity of Mt Molloy and Dimbulah, and A. elongata is currently known from a few localities in northern NT in the vicinity of Darwin and Mataranka. They're known from drier savannah and woodland habitats which are widespread in those areas, so both are probably more widespread than this but they're just uncommon.

Nothing really is known about the nymphs of this genus as far as I can tell.

Next we have two genera that are quite similar to each other, Yutjuwalia and Yullandria. They contain two species each, three of which are very similar to each other (and have similar ranges), so we will look at those three together and then the fourth one by itself.

Yutjuwalia nyalma, Yutjuwalia sallyae, and Yullandria kakadu are all slender green katydids with a few white stripes and black stripes. They are overall very similar in form and colour to Alinjarria but are fully-winged, so adults at least cannot be confused! Nymphs are probably very similar but I do not know what the nymphs of any of these are like.

Yutjuwalia sallyae is by far the most well-known of the three species, and it's the only one for which live photos exist. Here's the female:

And here's the male:

For the other two we are stuck with specimens photos unfortunately, but specimen photos are far better than no photos. Here's the male Yutjuwalia nyalma:

And here is the male Yullandria kakadu:

So, how do we differentiate these three species? The best and most reliable character is the male cerci. Yutjuwalia sallyae has a short cercus with a long internal spine and a broad, almost square-shaped flange near the base on the inner dorsal surface:

Yutjuwalia nyalma has a cercus with a similar overall shape, but it is a bit longer, the internal spines is a bit shorter, and the basal flange is much longer and does not project very far:

Yullandria kakadu has a very different cercus to both of these, it being very elongate with two very small internal spines:

So in short: if you see one of these, get a photo of the cerci!

Okay, but the majority of photos of these species will probably not be that clear, at least not clear enough to distinguish the two Yutjuwalia species. And of course, we cannot differentiate females using this method. So are there other differences? The short answer is probably, but I'm not 100% confident in them. They seem to be consistent but we don't know enough about these katydids to tell what the variation between and within species is like.

The key lies with the shape and pattern of the pronotum and the top of the head. I'll show you the species first and then we'll discuss the differences.
Yutjuwalia sallyae:

Yutjuwalia nyalma:

Yullandria kakadu:

The first thing to notice is that the pronotum of Yullandria kakadu is noticeably broader towards the rear, and has broad white stripes dorsolaterally along its whole length. That is a very conspicuous difference that I am very certain will be consistent between the two genera, so we will not have any problems there.
The two Yutjuwalia species are much more similar to each other though. The key feature, I think (and thanks to @manassas for pointing it out), is that in Yutjuwalia nyalma the black stripes extend onto the head and reach the eyes, whereas in Yutjuwalia sallyae the black stripes stop at the anterior end of the pronotum. Is this difference actually consistent? I have no idea. I have only seen the holotype of Yutjuwalia nyalma so I don't know how variable they are, but I have seen four different individuals of Yutjuwalia sallyae now (not including the male above, where the ID is based solely on the length of the stripe) and all lack black striping on the head. So I think for now it is our best option in differentiating the two species.

In terms of range, all species are very similar, being found in the northern portion of NT. Yullandria kakadu, as its name suggests, is known from a number of records around the vicinity of Kakadu. Yutjuwalia nyalma has been recorded from similar localities, but is also known from further southeast near Borroloola. Yutjuwalia sallyae has records primarily from a tad further inland, from Katherine down to near Newcastle Waters, although the single iNat record is from up closer to Darwin. It's quite likely that all three of these species are a bit more widespread than what is currently known about them.

Yullandria lawagimana is a much more distinctive species than the three others above. In terms of shape it is very similar to Y. kakadu, but it has a very different colour and pattern:

And here is the female:

The pale greenish ground colour with some darker markings, the white stripes on top of the wings, and the very slender body are good features to look for. Additionally, to distinguish it from similar Terpandrus spp., look for the very elongate cerci and the saddle-shaped pronotum.

Y. lawagimana is widely distributed through central Australia, with records extending from far western WA through to inland Queensland. I wouldn't be surprised if they showed up in far inland NSW as well, but they probably do not extend much further than that. If iNat records are anything to go by then it is much more common that Y. kakadu, and indeed much more common than all of the other species we have looked at so far other than C. leucoviridis.

Aaaand that's it then, all done with the Terpandrini! Right?

What's that, you actually want to know about Terpandrus itself? Surely not.

Alright, fiiiiiiiine. I guess we'll talk about Terpandrus then.

Terpandrus is by far our most diverse and most common genus of Terpandrini, and it contains some of Australia's very largest katydids. T. cabon is either our second or our third last species, about on par with Segestidea queenslandica and smaller than Siliquofera grandis. Species of Terpandrus are found across Australia in a wide range of habitats, although they are absent from Tasmania and they have not been recorded within tropical rainforests as far as I'm aware. They're often quite common but they tend to live high up in the tops of trees, so although they are easy to hear they are not so easy to see!

The 19 species of Terpandrus have been divided up into five species groups, which are represented as species complexes here on iNat because iNat does not have a 'species group' rank. The Endota Group contains five species (T. borral, T. calperum, T. endota, T. paruna, and T. splendida), the Horridus Group contains three species (T. burragah, T. eucla, and T horridus), the Itye Group contains one species (Terpandrus itye), the Jumbunna Group contains five species (Terpandrus cabon, Terpandrus jimiramira, Terpandrus jumbunna, Terpandrus moonga, and Terpandrus norabeetya), and the Tauwa Group contains five species (Terpandrus bundawoodgera, Terpandrus illamurta, Terpandrus tauwa, Terpandrus weema, and Terpandrus woodgeri). These species groups are primarily delineated based on the structure of the cerci, but as we will see they are also very helpful in splitting the species up into broad categories.

I'll go through these roughly by species group with some exceptions, starting with the easiest-to-ID species and moving on to the more difficult ones later.

Three of the species of Terpandrus are very distinctive and cannot be confused with any other species. Funnily enough though, they are all from different species groups!

In my eye the single most distinctive species is Terpandrus itye. It seems Rentz (2001) felt the same way when he described it, as it is in a species group all of its own. Why is it so distinctive? Well it just looks... odd. Odd at least compared to all the other Terpandrus species. Here is the female:

And here is the male:

Do you see what I mean about it being odd, or is that just me? It almost looks like a cross between a regular Terpandrus and Burnuia. It's quite small too I think, on the lower end for Terpandrus. Now the most important feature to look at to distinguish this species is the heavily granulate pronotum. Only two species of Terpandrus have this feature, and we'll get to the other one in a moment.

T. itye is found only in the southwestern corner of WA, where it is known from a few records from Geraldton to Kalgoorlie and down south to near Northam.

The second distinctive species is Terpandrus eucla. Like T. itye, T. eucla has a densely tuberculate pronotum, but in terms of overall morphology and 'feel' it is much more normal. Here's the male:

The female I have no images of but it is similar.

The pronotum is really quite different to that of T. itye, being a bit more saddle-shaped and obviously with a different pattern. In fact, the broad black band towards the rear of the pronotum is also a good diagnostic feature. Some other species can have a black stripe but it is never this thick, and it isn't followed by a reddish band either. So even as a nymph this species is very distinctive and cannot be confused with any other.

T. eucla is a bit more widespread than T. itye, and is known from a few scattered localities in southern WA and SA, from the Nullarbor Plain westwards.

The third and final distinctive species is one of the most familiar, Terpandrus splendidus. T. splendidus is one of the largest species, and has a very distinctive pattern of white stripes on its wings and body:

Both sexes are similar:

As you might expect, nymphs also are similar and are very easy to ID:

They are the only species with such thick white lines on the pronotum as adults (some other can have very thin white lines, and some nymphs can have rather thick lines, but these species are generally found along the east coast), and as such it should be quite easy to identify them.

T. splendidus has one of the broadest ranges of our Terpandrus species, being found in arid areas across central and western Australia from the west coast all the way across the middle and just reaching far inland NSW. They have not been recorded in Queensland or Victoria but they do come close and I would not be surprised if they were found there; their range also extends north just past Alice Springs in the NT.

Next we'll look at some not-as-distinctive-but-still-pretty-distinctive species, starting with the two other species in the Horridus group.

Terpandrus burragah is superficially similar to T. splendidus but upon closer inspection it is really quite different. Some specimens do have a number of white stripes on them but overall the proportions and 'feel' are quite different:

Of note though is that the species really is quite variable; e.g. the holotype is quite a bit plainer:

The one consistent part is those large black patches at the posterior corners of the pronotum though, and as far as I know no other species has them. So adults certainly should be quite easy to ID.

Nymphs are a little different, and are much more similar to those of T. splendidus:

You can see that the black pronotal patches are starting to form, but they are interrupted by a white band. There are also a number of other white stripes elsewhere on the body.

T. burragah is known from a number of localities in northeastern NSW and SEQ, from about Bundaberg in the north and inland to near Dubbo. There are only a few records from coastal NSW in the far northeast, and it is apparently absent from most of the coast there.

You are very unlikely to ever confuse T. burragah and T splendidus simply because there ranges are so different, but it's not impossible that you might find one in an area in between the known ranges of the two species. So if it's a nymph, how would you tell? The best difference is to look at the leg spines (you will see this feature pop up a few times because it is quite useful for IDing nymphs).

In T. splendidus, there are several small spines on the dorsal surface of the foretibia, near the apex, and in T. burragah there are no such spines. Have a look at this zoomed in version of the T. splendidus nymph above and you will see what I mean:

There is a very obvious anterodorsal spine poking out in the distal half of the tibia. There are also two posterodorsal spines but they are a bit harder to see because they are pointing towards us - one is at the same level as the anterodorsal spine, and the other is lower down near the apex of the tibia. The exact number of spines on the dorsal surface of the foretibia is a bit variable, but in T. splendidus there are always at least two, and in T. burragah there are always none.

The caveat of course is that these spines can be very hard to see and you should be very certain that they are absent before concluding that you are looking at T burragah. To complicate matters further, tiny nymphs have only tiny spines or might lack them completely, so under a certain age an ID may just not be possible. And be sure you are looking at the right pair of legs! In both species there are dorsal spines on the middle tibia.

Next up is the first Terpandrus to be described and the type of the genus, T. horridus. When I first saw this species I thought it looked quite distinctive, and then I looked a bit closer and I couldn't see much to distinguish it from other species other than 'feel', but now that I've looked at it more closely it is indeed obviously quite distinctive:

The easiest feature for me is the texture of the tegmina. Rentz (2001) described them as 'coriaceous' which I think is a good word - in my eye the veins seem very coarse and raised above the surface, and on the whole there are a lot more very obvious small closed cells near the base of the wing. This is quite obvious when you compare with some of the species we have not discussed yet, which tend to have distinct veins in parallel to each other but with quite indistinct crossveins, at least compared to T. horridus. If you look carefully at T. burragah you'll notice that it also has very similar tegmen texture, albeit with the veins a bit more sparse.

The colour is also quite distinctive but you need to see a couple of individuals to get a hang of the variation. Here is a female that is a bit less vibrant in colour:

The purplish underside to the fore and mid femora, and the rather red subcosta and radius (the two main veins on the tegmina, very close to each other and running down the middle) both seem to be good features to look for. And you know what else is a good feature to look for? You guessed it, leg spines! Like T. burragah, T. horridus has no spines at all on the dorsal surface of the fore tibia. All other species in the area (except of course T. burragah) have at least one spine on the dorsal surface. As before it can be a bit hard to see sometimes, and you should be confident that it really is absent before concluding that it's not there.

T. horridus has a surprisingly small distribution considering that it was the first described species. It's known only from a small area around Sydney where it seems to be fairly common. It hasn't been recorded much further afield but I would still keep a lookout in adjacent areas of NSW.

Next up is one of the most vibrant species, Terpandrus jimiramira. With the bright red legs, ovipositor, and stripes on the tegmina and pronotum, it is quite a distinctive one:

There do not seem to be any live photographs of males but here is the holotype:

Of particularly important note here is that I don't know how variable the colour is. Certainly all of the ones that I have seen images of have very vibrant red patterning, but I can easily imagine some would be more subdued, so care should be taken to make sure T. jimiramira isn't ruled out based solely on the brightness of the red.

The bright colouring on this one seems to be a direct result of the trees it lives in - have a look how well they blend in:

T. jimiramira is known from mallee and other semi-arid habitats in a broad area around the corner between NSW, Victoria, and SA. It's most widespread in SA where it is known as far west as Port Lincoln, and although it is only recorded near the border in Victoria and NSW, it's probably a bit more widespread in NSW at least.

Now we are starting to head into the territory of less-distinctive-but-still-kind-of-okay species (or species pairs in fact), but soon enough we will find ourselves in the more difficult regions of the genus, alas!

Let's look at Terpandrus cabon and Terpandrus moonga, two rather uncommon species about which not all that much is known. Both are very large species - T. cabon is our largest listroscelidine and one of our largest katydids, and T. moonga is only marginally smaller. They are somewhat similar so we will deal with them together. Unfortunately only one live individual of either species has ever been photographed as far as I am aware, a male T. cabon:

Note the relatively uniform colour of the pronotum and most of the wings (including the radius and subcosta), the white stripes bordering the stridulatory region, and the very short, compact cerci.

For comparison, here is the holotype of T. moonga:

Overall it is very similar, but note especially the rather different pronotal pattern, with black stripes and a reddish posterior region. In life T. moonga is probably similar to T. cabon but a bit more colourful.

The white stripes bordering the stridulatory region seem to be a good feature to distinguish these two species from the others in the genus, but they are not really present on the type of T. cabon. I suspect that's because it has faded a bit, but really I just don't know. There certainly appears to at least be a hint of them so I reckon that is a good feature to look for, but it always pays to be cautious. And of course, we don't have any images of females from these two species, so who knows whether they share a similar pair of stripes. Hopefully the combination of location, size, cerci, and overall 'feel' will be enough to distinguish T. cabon and T. moonga from the others.

So how do we distinguish T. cabon and T. moonga from each other then? Well there is the pronotal pattern to go off, which I suspect is a good feature, but I am only working with one T. moonga and two T. cabon specimens so it is good to be a bit cautious. How on earth can we distinguish these two? If only there was an easy feature that we have used on other species before.... Yep, you guessed it, the spines on the foretibia are very useful. T. cabon has two rows of spines on the dorsal surface of the foretibia, an anterior row and a posterior row (each with 2-3 spines), whereas T. moonga has only the posterior row (usually with two spines). Our live T. cabon specimen has a very obvious row of three spines on the anterodorsal foretibia, quite a bit longer than the other species we have looked at so far. So hopefully they will be quite easy to distinguish!

Both T. cabon and T. moonga are known from southwestern WA. T. moonga occurs in the south, with records from Lake Grace in the west to Newman Rock in the east. T. cabon is known only from two localities I think, both further north - the type is from Leonora, and the photographed specimen is from Lake Austin.

Next we have two interesting eastern species, Terpandrus jumbunna and Terpandrus norabeetya. T. norabeetya seems reasonably common, and T. jumbunna is one of our most common species going by iNat sightings (or maybe that's just because they live near @reiner!). Both species are quite similar morphologically, so again we'll look at them in tandem.

Here is the male T. jumbunna:

And here is the female T. jumbunna:

Here is the male T. norabeetya:

Unfortunately I don't think we have a photo of the female T. norabeetya but you can imagine roughly what she looks like! Here's a different male for you, with a bit more vibrant patterning:

The most important thing to notice about these two species is the short, rather strongly tapering tegmina. That seems to be pretty unique to these two species, especially considering only east coast species, so it's a very good feature to look for. It can be a bit difficult to see unless you've got some side-by-side but once you get the hang of the difference it should be easy enough. Compare especially with some of the species below (e.g. T. endota) and you should be able to see the difference in proportions.

How do we separate these two species from each other though? The key feature listed by Rentz (2001) in his key is that in T. jumbunna the subcosta and radius are pretty much the same colour as the rest of the tegmen and do not contrast strongly with it, whereas in T. norabeetya the subcosta and/or radius are noticeably paler and do contrast with the rest of the tegmen.

I'm always kind of sceptical of subtle colour differences, so is that a real feature?
Well, yeah, it seems to be... but like...                    

In reality though that does seem like a pretty good difference. I have only found a single individual so far where I suspect that it is the other species, primarily based on range and the other nearby sightings. It's this female from Victoria which I am quite sure is T. jumbunna despite the colour of the veins:

So I think most of the time the vein colour is a good difference, but use a bit of common sense as well and see what has been recorded nearby and what the ranges are of the different species. If you want to be 100% certain of your ID, male cerci are the way to go.

Here is T. jumbunna:

And here is T. norabeetya:

They are definitely quite similar, but there are also some clear and obvious differences which is good. The internal spine of T. jumbunna is quite short and obtuse, whereas in T. norabeetya it is more elongate and much sharper. Similarly, the basal flange of T. jumbunna is rather short and evenly rounded, whereas in T. norabeetya it is larger and with rather straight, parallel sides. With luck these differences would probably be visible in a good photo even if you didn't know to photograph the cerci specifically. They don't help us with the females unfortunately, and we are reduced to having to associate them with a male, but it's better than we get for some other species later on so count yourselves lucky!

What about nymphs? They are quite easy to distinguish from other species if you know what you're looking for, but unfortunately they are not all that easy to distinguish from each other and you probably need an adult to be sure if you are in an area where both species have been recorded.

Here are some typical T. jumbunna nymphs:

And here is our only photographed T. norabeetya nymph:

In terms of colour, that black marking on the posterior of the pronotum in T. jumbunna seems to be a pretty good feature. Most nymphs seem to have it and no other species that I have seen has such a thing (but be careful, because T. norabeetya almost has that and I would not be surprised if other individuals can look exactly like that). T. norabeetya is a bit more indistinct, but compared to nymphs of other species it should still be diagnosable. The key feature to look for is.... drumroll.... of my god you guessed it, it's the spines on the dorsal surface of the foretibia! Of course.

We can't use the spines to distinguish between T. jumbunna and T. norabeetya, but we can use them to distinguish them from the other east coast species. In T. jumbunna and T. norabeetya, there are spines only in one row on the dorsal surface - the posterior row. There will only be 1-2 spines there, but that should be enough to see if the image is clear. If you look at our photos above, the spines should be clearly visible on all except the two adults where the forelegs are a bit out of focus (you can see them if you squint but I wouldn't trust that to ID them). All the other species in the area have either no dorsal spines on the foretibia, or they have both an anterior and a posterior row of spines. The only possible species that could cause confusion is T. jimiramira, which is only found near the extreme southwestern edge of the range of T. jumbunna, but it should otherwise be quite distinctive with its red legs.

Both species are found in the east of Australia, and there is a bit of overlap in the distribution. T. jumbunna is primarily known from the southeast, with the bulk of records coming from between Melbourne in the south and Sydney in the north. There are a couple of additonal scattered records in inland NSW though and a few in SEQ as well. T. norabeetya is a bit more restricted, with records in coastal NSW and SEQ, reaching from about Sydney in the south north to SEQ. I think for the most part it should be easy enough to decide on a species based purely on range, but in potential overlap areas around Sydney and SEQ we should be a little more tentative, especially if individuals seem a bit atypical.

Unfortunately that is where we end with the easy species, and now we come to the difficult and essentially identical groups of species. One group is still a bit easier than the other though, so we'll start with that one.

Excluding the distinctive T. splendidus, the Endota Group comprises four very similar species of Terpandrus that are really only distinguishable from call or with a specimen in hand: T. borral, T. calperum, T. endota, and T. paruna. It's probably just easiest to show you them and then do some explanation.

We have no live photos of T. borral but here is the holotype male:

Here is the male T. calperum:

And here is the female T. calperum:

Here is the male T. endota:

And here is the female T. endota:

Here is the holotype male of T. paruna:

And finally here is the female T. paruna:

As you can see they're all very similar, and although you may notice some differences in colour and pattern I assure you that they are just individual variation. The red posterior region of the pronotum is a good feature to look for here, although it varies from almost absent (as in the female T. calperum above) to very uniformly dark red (darker than any shown here). The tegmina are quite elongate and uniformly green, with a pale subcosta and/or radius. The broad pale posterior margin on the lateral pronotum is also a good feature (although it's present in other species too). These features in combination should be useful in separating them from the other species of Terpandrus that they are found with. If all else fails though, go for the leg spines! In these four species there is both an anterior and a posterior row of dorsal spines on the foretibia, whereas in all other species they could be found with there are either no spines or only a posterior row of spines (except T. cabon, but I don't think the ranges quite overlap, and that species is very different anyway).

So, how do you tell them apart then? Well, not very easily. If you don't have a specimen, you have three options: distribution, male cerci, and male call (and there is some overlap in all but call unfortunately!). That means that you generally can't tell females apart without associating them with a male, unless they are in an area where only one species occurs. I'll go through distribution first, and then we'll delve into how to split the species in areas of overlap.

T. paruna is the easiest species, because it has no recorded areas of overlap with the other three (although it comes close, so we will still go through differences later). It is found in southwestern WA, and has been recorded from near Stirling Range in the west to near Fraser Range in the east. So you should usually be able to distinguish T. paruna with some confidence.

T. borral is known from the far southern areas of SA and southeastern WA, from Caiguna in the west all to the Eyre Peninsula in the east. It has mostly been recorded very close to the coast but it could be present further inland as well.

T. calperum is known from SA and far western Victoria, and is probably present in southwestern NSW as well. It's known from near Nullarbor in the west and extends into Victoria at least as far as Hattah and Nhill.

T. endota has the broadest range of these four species and occurs along the east coast of the country, from Melbourne in the south to Bundaberg in the north along a broad coastal band.

So there are two, potentially three areas where there is some overlap. In these areas we need to look at the male cerci and the call.

In the easternmost overlap zone in Victoria, T. endota and T. calperum can be distinguished relatively easily if you have an image of the cerci. In T. endota, the serrations on the internal margin of each cercus extend right to the very end, and there is a large tooth at the tip of the cercus:

In T. calperum, the serrations on the internal margin of each cercus stop a bit short of the end, and there is a large tooth just before the tip of the cercus; the tip itself is rounded:

It's not the most clear thing to see in the photos but I assure you it is very easy to see in life; see also the live photograph below for a clearer view. So that is the easiest way to distinguish those two species. You can also distinguish them by call, but I must admit that I don't actually know what the call of T. endota sounds like! I'm sure it is written somewhere but I cannot find any diagram or recording of it.

T. borral, T. calperum, and T. paruna unfortunately all have rather similar cerci. There are certainly some minor differences but they are a bit more subjective and I don't know how much I trust them. For example, in T. borral the apical tooth is only a little larger than the other teeth, and it is basal to a small weakly concave area:

In T. calperum, on the other hand, the apical tooth is distinctly larger than the others and the region just apical to it is not concave:

The basal flange of the cerci of T. borral is also a little more prominent than that of T. calperum, but again these are not easy to see unless you compare the two side by side. A similar problem occurs when trying to distinguish T. borral and T. paruna in the west. T. paruna has cerci that are a little more similar to those of T. calperum but almost have between that and T. borral:

So in the regions where these three species could potentially overlap with each other (i.e. western Victoria and southeastern WA), the only reliable way to distinguish the species is by call. Luckily Terpandrus are generally quite noisy, although these species tend to usually call mostly at night. It's generally difficult to convey sound through a written description (especially considering that I haven't actually heard most of these myself), but luckily we have some wonderful diagrams from Rentz (2001) that show the difference:

So T. borral has a bit of a faster and shorter call than the other two, which is good to know because it's the one most that overlaps with both of the others. Even if you don't know how to interpret these call diagrams, if you're in the area for them you can make a recording and someone else will be able to help for sure!

Okay, what about nymphs? Well I'll just say upfront that there is no way to tell the nymphs of the four species apart aside from range and association with adults, but luckily they are quite easy to distinguish from other species in the genus. Here's a selection of medium-sized nymphs:

There's definitely some variation there but they all have the same general pattern - two pale stripes from the eyes to the cerci, with a darker brown region dorsally, with green elsewhere. They're small details but the darker patches near the wing buds and in the middle of the pronotum are also almost always present. As far as I can tell, this pattern isn't present in nymphs of any other species.

As the nymphs get older this pattern starts to fade a bit and reddish patches start to appear on the pronotum:

And finally subadults are really quite like the adults in terms of colouration:

So the nymphs should be easy enough to ID to species group at least.

We have one last group to go, and unfortunately they are the most difficult. The Tauwa Group contains five species, T. bundawoodgera, T. illamurta, T. tauwa, T. weema, and T. woodgeri. This is the only group that has managed to colonise the north of Australia, and they're the only species present through a lot of Australia. All five species look more or less like this:

The most distinctive feature is the green pronotum with a broad cream posterior section, with a thin black stripe separating the two regions on top. Of note though is that not all specimens have the black stripe (although most do). No other species is similar except T. eucla, which has a much thicker black stripe which fades into red, and has an obviously tuberculate pronotum.

How do we differentiate between these species? It's quite difficult unfortunately, and for the most part photographs will not show the differences unless you are specifically looking to photograph them. There is extensive range overlap as well, so location is not always all that useful.

The easiest of the five species to distinguish is T. bundawoodgera. Unlike the other four species, the top of the abdomen is very dark brown to black:

The other four species have the dorsal surface of the abdomen green, similar to the rest of the abdomen. This is the only species in which females can be readily distinguished unfortunately! And of course, the problem with it is that the dorsal abdomen is usually completely covered by the wings so in most photos you simply cannot tell. If you have an adult male and can see the cerci, they are also helpful. T. bundawoodgera cerci are strongly flattened and have two short teeth and one angulate bump; these three things are approximately evenly spaced:

Compare those with the images of the cerci of other species below as well to see the differences.

T. bundawoodgera is known from scattered localities in inland SEQ, from Goondiwindi north to Augathella and Rolleston in the north. It overlaps with T. woodgeri for the entirety of its range and also with T. tauwa in the north unfortunately, so we cannot use distribution to help us at all really!

There is one species that we can distinguish by range though - T. weema! As you can see, it's practically identical to the other species:

However, it's found in a completely different region, which is very helpful - it's the only species in this group known from the southern half of the continent. T. weema has been recorded from a few spots in southwestern WA, from Kalgoorlie to Lake Barlee. It's probably a bit more widespread than that but seems to be quite uncommon. It does not overlap in range with any of the other species in this group, but it comes a little close to the southwestern distribution of T. woodgeri. In this case, male cerci will be quite helpful. T. weema cerci have two large teeth, the more basal of which is strongly expanded, and the entire structure is bent upwards at the end:

Once again, compare with the cerci of the other species below to see the difference more clearly.

T. tauwa is - you guessed it - also pretty much identical:

Cerci are our best option to distinguish this species once again. The cerci of T. tauwa are fairly similar to those of T. weema, but the basalmost tooth is not strongly expanded and is only a little thicker than the apicalmost tooth:

T. tauwa is known from a broad range along the east coast of Queensland, from the tip of Cape York down to about Carnarvon Gorge. Unfortunately it overlaps with T. woodgeri over the entirety of its range, and also overlaps with T. bundawoodgera in the far south of its range.

Okay, we have mentioned T. woodgeri a couple of times, but what do we know of it? Well it's the only one that we have definitive iNat sightings of. Here's a male:

And here's a female:

The reason we have definitive iNat sightings is because T. woodgeri has the largest range of any species of Terpandrus, and there are many areas where it's the only species present (and quite often not just the only species in this group but the only Terpandrus or indeed Terpandrini of any kind). It's known from near Exmouth in the west all the way to about Goondiwindi in the east, and is known from pretty much everywhere north of this imaginary line as well, including all through the Kimberley, the NT, and Cape York. So if it's in an area where other species do not occur (e.g. Darwin) then you can be quite confident that you have T. woodgeri.

In most overlap areas though the same techniques are needed - i.e. we need to see the cerci. The cerci of T. woodgeri have the two teeth quite thin and very widely-spaced, which should be fairly easy to see in a clear photograph:

Can you believe we have only one last species to go?? Woohoo! I have bad news though. Here is the type of Terpandrus illamurta:

Doesn't look all that scary yet? Well, T. illamurta is identical to T. woodgeri, right down to the details of the cerci. Even the internal genitalia are remarkably similar. So even if you have a specimen in your hands, you can't tell whether it's T. illamurta or T. woodgeri. The only way to distinguish the two species is by the male call. I don't have a diagram unfortunately, but in T. illamurta the call has two pulses per chirp, whereas in T. woodgeri it has three pulses per chirp. T. illamurta also quite often has the black stripe on the pronotum missing, but this is not a reliable difference unfortunately.

Despite this difficulty, T. illamurta luckily has only a very small distribution. It has been recorded in a small region around Alice Springs, primarily Kings Canyon. So we only really need to hear recordings from a very small region to be sure of which species we have.

Surprisingly (given how widespread and common they are), we actually have no images of nymphs from this group at all. I imagine they are quite similar to the adults in terms of colour and pattern, but I guess we will have to wait for someone to find one and see for ourselves!

That's it for Terpandrus, but just as a summary here's the distribution of dorsal foretibial spines for all of the species groups (just because they are so useful!):

Itye Group - Posterior spine row only
Horridus Group - No dorsal spines
Jumbunna Group - Posterior spine row only, except T. cabon which has both anterior and posterior spine rows
Endota Group - Both anterior and posterior spine row
Tauwa Group - No dorsal spines

Just remember, this is only on the foretibia and it can be difficult to see, so make sure you're confident before deciding on a species!

Now you may also have been wondering, how are these species groups even defined? Some seem obvious, but others seem to have no meaning at all. E.g. why is T. eucla placed in the Horridus Group, and not with the Tauwa Group?? Well, it's based primarily on the shape of the cerci but there are other features that group them together as well. I'll show you all of the cerci below and give a brief description of each group so you can get an idea of the differences.

Itye Group - T. itye - cercus quite elongate and cylindrical with a single large internal tooth

Horridus Group - T. burragah (no image unfortunately - like T. eucla but broader), T. eucla, T. horridus (no image unfortunately - like T. eucla but a little narrower) - cercus elongate and rather flattened with a single internal tooth

Jumbunna Group - T. cabon, T. jimiramira, T. jumbunna, T. moonga, T. norabeetya - cercus moderately elongate to more compact, with a small internal subapical tooth and a broad internal basal flange, these variously fused

Endota Group - T. borral, T. calperum, T. endota, T. paruna, T. splendidus (no image unfortunately - like the others but much broader) - cercus flattened and serrated on internal margin

Tauwa Group - T. bundawoodgera, T. illamurta, T. tauwa, T. weema, T. woodgeri - cercus slightly flattened with two internal teeth

So then, that in fact wraps up all of the species of Terpandrini we have here in Australia! It's fantastic that live photos exist of most of our species, and photos of specimens exist for all of them. Far better than we can say for many groups!

But my friends, we are not done yet. Now comes the best part! We have all these species, and lots of images and explanatory notes, but it's rather a long document that I have produced. So to summarise all of the information and give you something nice and easy to work with here is a complete key to Australia Terpandrini based on the features most easily seen/heard in an iNat sighting!

Key to adult Australian Terpandrini

So, that just about sums up everything! One final question remains - how many of these species have we got on iNat, and how many do we still need to get sightings for?? Well, there are 27 species and we have iNat sightings for 16 of them (~60%), meaning we have 11 species still needed. What are they, and why have we not seen them yet??

Burnuia mirru - this species is apparently just quite uncommon. If anyone in southwest WA wants something to look for though, go ahead! There are a couple of others from the area too worth looking for (more on them below)

Alinjarria elongata - again, this species I think is just uncommon or at least quite localised. But in the right habitat it would surely be not too difficult to find. Anyone in the NT, please have a look and see what you can find!

Alinjarria jadoni - okay, I think I have to go looking for this one myself because it has been found in a few spots quite close by in north Queensland. Like its congener I think it's just uncommon

Yullandria kakadu - seems to have quite a restricted range centred on Kakadu NP, but I reckon it wouldn't be too uncommon in the right areas

Yutjuwalia nyalma - I think this species is probably a bit rarer, and its range is mostly within Arnhem Land so it's not the easiest spot to get to. There are records from a bit further east though so hopefully we will get lucky.

Terpandrus moonga - another which I think is probably just quite uncommon, but anyone in southwest WA please keep an eye out!

Terpandrus borral - we may have a sighting of this one in fact, but it's just too similar to T. calperum to accurately distinguish it from the photos. Anyone in southern SA, please record any Terpandrus you hear! (And get pictures please too)

Terpandrus bundawoodgera - this one is uncommon and difficult to distinguish from related species, but we have no potential sightings from within range yet. Anyone in the broad SEQ area who finds Tauwa Group Terpandrus, please check under the abdomen to see the colour!

Terpandrus illamurta - this one is definitely a combination of both rarity and difficulty. I think the best bet is to just make lots of recordings around Alice Springs (especially Kings Canyon) and hope that one of them is the right call.

Terpandrus tauwa - I have seen two potential T. tauwa myself now but they have both been females unfortunately! I'll keep my eye out and make recordings, but anyone else in Queensland please get some cerci pics :P

T. weema - finally, this one just seems to be uncommon because there are no sightings of anything similar in southwest WA. Another thing for people to look for!

So our hotspots for un-observed species are southwestern WA and northern NT, with three species each, and followed by north Queensland with two. So what are you all waiting for?? Go find some good katydids!!

Posted on March 27, 2023 02:33 AM by matthew_connors