I submitted my 18-month report a while ago, and the other day I had my 18-month review (although it has actually been 19 months). The review is there for a few reasons, but it particularly serves to identify major problems in time to solve them, and to scare the student into working if they haven't already started. You give a brief presentation, and then your supervisors and an assessor discuss your findings so far, and your assessor asks lots of questions, and they identify concerns. If you're in a really bad state in your project, they can supposedly kick you off it, but I think this is a story told by supervisors to young students to scare them into being good. I've only heard of people who have heard of people who have been kicked out. That said, as a graduate student you shouldn't need to rely on your supervisor to kick your arse into gear. You should be disciplining and organising yourself by now. That is what I tell myself all the time, anyway.
My report went OK, but the assessor had a lot of questions. That's fine really, because they don't know my project that well, but she raised some concerns that I thought were just interesting things. Like the fact that Cantuaria molecular data and morphological data say completely different things. I have the equivalent of two identical-looking lions, but their DNA says one is a tiger, and I also have a tiger and a lion that have DNA so similar that they might as well both be tigers. I thought that was quite interesting, and a nice illustration of how morphology and genetics don't always agree on how a phylogeny should look. It also means lots to work on with regards to taxonomy, which is great because I have special funding for taxonomy alone. But my assessor said it is a massive problem, and I need to find males to back it up (which I am looking for but cannot find!), and it is going to get in the way of landscape genetics. I'm not really sure that it is though, because I am not basing any of my inferences on morphology - just genetics - and I have always been working under the impression that the morphology will be misleading. I just hadn't reckoned with how misleading it would really be.
Overall though, my main supervisor says it went well. I need to get more sequences and more funding for tuition fees, but I have enough work for a PhD and it is meant to have challenges and be hard. I can keep going. They all gave me some useful pointers about landscape genetics to look into. More on that when I get to that part of my PhD. For now, I must continue to try and get rid of this inhibitor problem that I am having!