Passalidae: the mites of Pharochilus
Workbook
Shortly after hearing from Owen Seeman on iNaturalist, confirming the identity of several of my passalid sightings … and the mites they carried … I came upon this passalid apparently drowned in the pond.
Immobile beetle immediately after rescue from the frog pond (1st Dec, 2021)
I fished it out, took a few rough shots pond-side, and then put it in a container for closer viewing. A quick look confirmed it as a species we’d seen before … but it was the mites that now caught my attention. Would these be the same species as on the earlier sighting? And perhaps it was time to take a closer look at mites. So I popped a few off the immobile beetle, into a petri dish.
Regrettably, I didn’t take any decent close-up shots of the beetle so I can only hope that the pool-side shots are good enough for a positive ID. Based on the pattern of head tubercles, I’m calling it Pharochilus rugiceps.
The mites I chilled, imaged, and then stored in 100% ethanol. The beetle surprised me. It recovered overnight and so I released it the following day. But without taking any extra shots first … sigh!!
The larger ones (a & b) look similar in shape, size and colouration to the ones in my 2017 sighting of Pharochilus rugiceps …. Megisthanus, probably M. modestus).
And perhaps the small, shiny one (c) belongs to the family Fedrizziidae (again, based on info provided on iNaturalist).
This paper by Owen Seeman is obviously relevant, but at this stage I can’t easily access it
This is a workbook page … a part of our website where we record the observations and references used in making species identifications. The notes will not necessarily be complete. They are a record for our own use, but we are happy to share this information with others.