Master of Defense: The Lumphead Grumpus

Not all swordwhales are impressive open-water creatures with bold and colorful markings. Some species have gone down a different route entirely.

Living in the deepest and coolest waters of Serina's northern polar waters 100 million years hence is one of the strangest of the large swordwhales, a creature so strange and divergent from its relatives that its ancestry is all but obscured entirely. Fourteen feet in length and 3,000 pounds, the strange - and very spiky - lumphead grumpus is certainly a sight to behold.

The lumphead grumpus is not especially closely related to the gigadon or other large pelagic swordwhales of the era; though it shares a smaller, coastal-dwelling ancestor from the end Cryocene, while its relatives moved out to the open sea and swiftly navigate surface waters, the grumpus remained better adapted to live along the sea floor and is a slow swimmer. Now a solitary, shellfish-eating specialist, it uses its extraordinarily strong smashing jaws and blunt teeth to pulverize bivalves and benthic snails. It swims slowly, always low in the water, often just above the sea floor where its own movements stir the sediment up and make visibility low. But this is not terribly important for the grumpus, which finds its food through touch. Its ancestors evolved elongated rays on its pectoral fins which they utilized to feel in the sand to uncover morsels of food. Over time two rays in each fin became hypertrophied into long and independently rotational rods just for this purpose, allowing the fish to forage for food throughout the night when there was no visibility at all. Its nocturnal nature and solitary habits meant its coloration became subdued and mottled for camouflage, avoiding trouble primarily through its large size, thick protective scales, and territorial nature.

These attributes ceased to be sufficient when other swordwhales grew into large and formidable predators, however, and the grumpus was caught slow and vulnerable to earlier ancestors of Gigadon, which quickly learned to overwhelm and flip the grumpus, targeting its underside where its scales were less defensive. The two species entered an evolutionary arms race, evolving better tactics to handle the other; the gigadon to kill the grumpus, the grumpus to survive. Today the grumpus has, rather uniquely in such competitive struggles, won this race. Over eons its elongated pectoral rays grew thick and sharply hooked, becoming defensive weapons with which it could thoroughly beat and stab its attackers eyes and sensitive gills, deterring even the most aggressive individuals. Able to move each ray independently in nearly 360 degrees of motion, even a group of predators could be kept at bay. The first ray of the dorsal fin gradually evolved into a fifth mobile weapon, adopting a similar shape to the pelvic spines through a replication mutation, while lastly along the tail thick keratinous growth developed into armor so that predators could find nowhere to grab hold and flip the ornery fish on its back to hit its underbelly. The ancestors of gigadon moved on to primarily specialize on easier prey, and today the adult grumpus is largely safe from predation. When threatened, this rhinoceros of the sea merely drops low onto the seabed and extends its large hooked spines, and very few creatures will attempt further harm upon it.

Because the young of the grumpus are still vulnerable to predation by gigadons and other large oceanic predators, even though they are born comparatively large like other swordwhales, the grumpus is a rare example that has re-developed significant parental care. A single young is usually born and stays very close to its mother for its first two years, relying on her to protect it from its threats in one of the longest and most complex parental interactions among fishes. Sexual maturity is extremely delayed in this species, with females not mating until almost thirty years old, but a slow and leisurely life allowed by their dramatic defenses can let these strangest of fish survive close to one hundred years.