Giant Copepods

The short period of time between the Hunger and the late Archeacene proved to be a golden age for copepods. Capable of living in deep waters away from the continental shelf (and the global megashoal of herring), they had boundless space, no predators, and a massive influx of food courtesy of the marine snow blizzard. Until the herring began to colonise the deeper waters the copepods had their own Garden of Eden, where diversity peaked for the tiny zooplankton.

One of the most charismatic species of this time was the simply named giant copepod. In terms of body shape it was not revolutionary; like the majority of copepods it has two long antennae, a single large eye, and a myriad of little legs used for swimming. However, what sets them apart from their kin is their unusual size- a whopping 5cm from head to tail! This does not sound impressive, but when compared to the 1.5mm that is the average size for copepods, they are absolute kaiju.

As copepods do not have gills they must absorb oxygen through their bodies, which due to the mass/surface area ratio puts a limit of how large they can grow- as mass grows exponentially larger than the surface area when the organism increases in size it will eventually outstrip the amount of oxygen the surface area can absorb, thus their mass can only reach a certain point. To help mitigate this restriction giant copepods have evolved elaborate antennae, which branch out into great swaying fronds. These thin fronds greatly increase the available surface area whilst not contributing much to mass, allowing more oxygen to be absorbed into the body.

The reign of these mini giants will sadly be short lived, as once the herring evolve to hunt in open waters the giant copepods with their elaborate antennae will be unable to swim quick enough to escape. But- for a short period of geological time- they rule as kings in their finery amongst the bounties of paradise.