An eye for the ladies

Copepods (“oar-footed”) are the most numerous of the metazoa and play an enormously important part in the food chain. In the colder waters closer the poles their biomass is so extraordinary that they sustain all manner of invertebrates and vertebrates from the lowly worms up to the baleen whales. Without these diminutive creatures our oceanic food chain would collapse, for these are primary consumers of microscopic bacteria and protists that are the base of the food pyramid. Copepods, members of the phylum Crustacea, are generally no larger than 1 mm long, but a few species may be somewhat larger. They can be found in all aquatic ecosystems throughout the world, including many cave systems or even leaf litter. Crustacea, like insects, are arthropods, but have more diversity of eye types than insects or, for that matter, any other invertebrate group. Within the Crustacea, there are single chambered eyes, all forms of compound eyes, and some forms of optical creativity seen in no other species. Certain species of pontellids, a family of copepods, have such extraordinary and unusual eyes that the optics remain a mystery to this day.

Pontella scutifer is a free living marine copepod found irregularly throughout the world’s …