Actinopharynx

A histological section of a coral. Photo by JK Da Anoy.

An email showed up in my inbox with the subject line "Data." This was the message I had been waiting for! I opened it immediately and followed the hyperlink. My screen lit up with an array of images - red and blue blobs on white backgrounds. They were histological sections from corals I had collected in Palau. In the center of each image, in bold black letters, was the word "Act." 

I responded to my colleagues' email almost immediately. "What does 'Act' mean?" I wrote.

JK answered me: "Actinopharynx." 

And just like that, the image I had open on my laptop screen went from being a series of pink-ish blobs to a high-precision anatomical depiction of a coral polyp. I knew exactly what I was looking at - I was staring down the polyp's throat! 

Invertebrates are such a fascinating group of animals to study because they have diverse, unexpected, sometimes wacky anatomies. All cnidarians - animals like anemones, jellyfish, and corals - have a blind-ended digestive system. Food goes in, gets digested, and then waste comes out the same opening. I once saw a cartoon that explained it as "pooping out the mouth or eating with the butt." Yep. Kind of gross, if you ask me. 

The actinopharynx is actually tangential to the story, but I had to share because corals are such cool animals. I am delighted to finally have the histology data. If you remember, I tagged a handful of corals at each of our study sites in Palau last November. I collected tissue samples from all the tagged colonies so we could gather information about them before the big experiment next spring - what genetic lineage they belong to and whether they're male or female. The histological sections help us determine the sex of each coral. 

Over the next few weeks, my collaborators and I will sit down together and choose which corals to use in our experiment. We want an equal number of males and females belonging to the same genetic lineage at each site. I'm looking forward to moving ahead with the project and (hopefully) a successful experiment!