Branchurian or Pentastomida- microscope images

4fierygirls · Mar 20, 2023

I recently found several unusual organisms on our fish. I was able to get photos using a compound light microscope but as soon as water was added to the microscope slide, development began to occur so quickly it was hard to get the microscope focused. I believe it is a Branchurian or possibly Pentastomida, but I know next to nothing about families in this taxa, so I could be
way off. I uploaded the photos on onedrive (link below). Anyone that could offer any assistance or advice would be greatly appreciated. The link shared allows comments to be posted on each image so if you have any thoughts please share! The first three photos show what looks to be fertilization and development of primary larva. The second photo is an enlargement of the first, with arrows pointing toward what I believe are sperm. They moved rapidly so it was difficult to tell for sure, but it looked as though they were seeking out, and attaching to, this larger branching organism. The fourth and fifth images are what I believe to be larval stages. I believe the sixth may be an intermediate developmental stage and the seventh image depicts the adult. Eight and nine are enlargements of the 'adult' showing ejection of embryo and morphological detail of attachment organs. Images from microscope

Jay Hemdal · Mar 20, 2023

4fierygirls said:
I recently found several unusual organisms on our fish. I was able to get photos using a compound light microscope but as soon as water was added to the microscope slide, development began to occur so quickly it was hard to get the microscope focused. I believe it is a Branchurian or possibly Pentastomida, but I know next to nothing about families in this taxa, so I could be
way off. I uploaded the photos on onedrive (link below). Anyone that could offer any assistance or advice would be greatly appreciated. The link shared allows comments to be posted on each image so if you have any thoughts please share! The first three photos show what looks to be fertilization and development of primary larva. The second photo is an enlargement of the first, with arrows pointing toward what I believe are sperm. They moved rapidly so it was difficult to tell for sure, but it looked as though they were seeking out, and attaching to, this larger branching organism. The fourth and fifth images are what I believe to be larval stages. I believe the sixth may be an intermediate developmental stage and the seventh image depicts the adult. Eight and nine are enlargements of the 'adult' showing ejection of embryo and morphological detail of attachment organs. Images from microscope

Welcome to Reef2Reef!

I've never heard of Pentastomids, so I had to look them up. They are degenerate arthropod parasites that infect lungs of various animals, and only live in fish as secondary hosts. With the final hosts being freshwater or terrestrial species, I don't see it likely that a marine fish would harbor this species.

I have seen Branchurians infecting marine fish, usually stingrays. These crustaceans are relatively large and have very distinct body parts. Typically, you can see the eyes and the legs. I don't see any adults in your photos.

What is the history of the fish and the sample?

Jay