Our today parasite has, as indicated by the species name, a quite circular appearance. Unfortunatly, I cannot show you a global view of this species. I am really sorry but it was to big for my lowest magnification objective !
Zonurobia circularis Lawrence 1935 belongs to the family of Pterygosomatidae and has been found on Platysaurus guttatus, the dwarf flat lizard. It can be found in Nord Transvaal in South Africa.
This is probable that the author of the prepared slide is Frank J. Radowsky (1929-2010), but I am not sure. Anyway this specimen and slide is now part of the French collection MNHN, Paris.
This prepared slide is really good and we can observe many details. I particularly appreciate the scale-like setae, which reminds me the scales of a butterfly. Have you ever observed butterfly scales in a microscope ?
Gnathosoma reminds me a tick, with hypostome and chelicerae, but it is far from an Ixodida !
I draw your attention on peritremal tubes araising on each side of the gnathosoma. I made specially two photographies of the gnathosoma, with two different focusses.
By the way, I recommend you the following publication which shows some very good drawings of this species :
If you observe carefully the description and drawings which are made of Zonurobia circularis, you may notice that my photos are showing exactly the same configuration of articles and setae…
This publication, here above in reference, mentions that Lawrence has described 5 different types of Zonurobia circularis, and this species would probably require some deaper analysis linked with the type of hosts… Zonurobia is considered by Jack (1964) as near to Pterygosoma genera. One may wonder if some described species of Pterygosoma could not be in reality Zonurobia !
I propose you to compare both genera with the following post showing Pterygosoma transvaalense.
We are at you disposal to make such analysis if you can provide us some specimens of these nice parasites !