Australian Orthopteroids's Journal

Alright alright alright, let's make some more use of this journal! It's a good place for me to go through how to ID some groups both for your benefit and for my own, when I inevitably forget everything in a few months :P

So, Austrophlugis! A uniquely Australian genus with quite a number of species that can really only be differentiated by the end of the abdomen. Sounds difficult, right? You'd think so, and yet some of them are really easy to distinguish.

The further north you go, the more species there are, so for now I'm just gonna focus in on the area with the most sightings - southeastern Queensland and northern NSW. There are only two species in this region - A. debaari, which is the most common and widespread species, and A. orumbera which is still fairly common but has a much more restricted range.
Based on iNat records, A. orumbera ranges from about Noosa in the north down to Lismore in the south, buuuut it's always good to be safe and cast a wide net when using distribution to narrow down species. So for the purposes of iNat I'm gonna say that everything between about Bundaberg and Port Macquarie could be either species. Further south is only the introduced Sydney population (which I believe is A. debaari) and further north you get a mix of species including A. debaari, A. malidupa, A. manya, etc.

Adult males of the two species are the easiest to distinguish, and provided that the end of the abdomen isn't completely obscured, you should be able to tell the difference from pretty much any angle. In A. debaari the abdomen is 'normal', so to speak, and the external genitalia don't really protrude or anything:

By contrast, in A. orumbera the external genitalia are greatly produced into these huge lobate structures that extend beyond the wings and out to the sides as well:

These structures really are quite extraordinary, and they're visible even in blurry photos or photos from strange angles. They're also quite obvious on subadult and sub-subadult males, and if the photos are good they can probably be seen in even younger nymphs as well. Here is a subadult male A. orumbera:

And here is a sub-subadult male A. orumbera:

Compare that with the much more normal abdomen of the subadult male A. debaari, which only has two small flanges near the base of the cerci:

Okay, what about females then? They are a little more difficult in that you need to see them from a specific angle, but the difference is still quite large and obvious. The key is the shape of the subgenital plate, so you will generally need a lateral or ventral view. Dorsal only unfortunately won't cut it unless you're looking at a male. Here's the female A. debaari:

The subgenital plate is quite small and difficult to see - i.e. it's 'normal'. If you're struggling to work out where the subgenital plate even is, it's this little flap-like structure at the very base of the ovipositor:

In the female A. orumbera, the subgenital plate is greatly elongated into a strange pointed structure that extends almost to the end of the ovipositor. Unfortunately we don't have any super clear photos here on iNat so here are two different angles that should show you the structure pretty well:

It's that odd pointy thing underneath the ovipositor - from some angles it could quite easily be mistaken for one of the cerci, but it has a rounded rather than pointed tip, and it's usually rather brown towards the end as well.
The beginnings of this structure can also be seen in subadult female A. orumbera:

Aaaaand I reckon you could see it in a sub-subadult as well if you had good photos, but any younger than that and I think you'd just be guessing. The subadult female A. debaari have a subgenital plate which is very similar to that of the adult female.

So that about wraps it up for these two species. They're otherwise very similar, and have the same behaviour, diet, and habitat. Both species can and have been found at the same locality, as shown by @natashataylor's excellent observations, so just because you've seen one species before doesn't mean you don't have both! I may do an explanatory post about the other species in the genus at some point, but we just don't really have enough iNat sightings of them to do a good comparison with photos. The differences are very similar to those between A. debaari and A. orumbera but more subtle - A. orumbera is by far the most extreme species of the genus, which is helpful considering it is one of the most common!