Q&A: Why do Octopi have warts?

Image courtesy of Janet Voight

When Janet Voight received deep-sea Graneledone pacifica specimens, she noticed that they looked different from their shallow water counterparts. “I received these really precious deep-sea octopi, and I was supposed to say whether or not they were the same as the species off of the coast of Oregon. They clearly belonged to the same genus, but they looked different,” Voight said. 

Voight’s research showed the differences were consistent with a pattern of clinal variation, where a trait varies with location within a single species, rather than species differentiation. That is, as the depth increased, thespecimens had more warts, fewer gill lamellae, and fewer suckers, alongside being smaller in size. Although Voight’s research highlighted these details, a big question remains: why do these differences occur? 

“Honestly I don’t know,” Voight responded. She plans to look more closely at the tissue samples under a microscope to answer this. “Right now, I’m having a colleague do some histological sectioning of some of these warts to figure out what they’re made of and why they’re there. I’m hoping we’ll stumble on something, but so far nothing.”

Despite this, Voight’s work promotes further research into understanding the creatures of the deep sea. She hopes to use what she has learned here to analyze other species in this globally-distributed genus and see just how different they are. “With this, we can change the focus of the characteristics we use to identity species and species boundaries,” she said.