Pelagic Predators of the Artechocene: Part 1
The Anthropic Extinction Event was massively damaging to the oceans, eliminating most surface dwelling pelagic fish, specially large pelagic predators. These were not only often heavily harvested themselves, but their main sources of food faced extinction too due to anoxic events and over harvesting, ultimately killing them off the face of the earth.
In the 39 million years since the extinction though, a myriad of groups have taken on these empty niches, adapting to rise to the top of the food chain, here are some notable examples of these "sea monsters":
Kobias (Basilothunnoididae): These carangiforms were one of the first groups of shallow water fish to venture into the open ocean, and have thus become one of the most successful. They have a range of sizes, but the largest of all are macroraptorial, feeding on large prey using their serrated, wedge shaped teeth, using their speed to catch them. The King Kobia (Basilothunnoides rex) is the largest of them, measuring up to more than 5 metres long, and is one of the few predators actually specialised for hunting adult tiamats.
Cuchonitos (Sardomimidae): These lizardfish descendants haven't achieved the grand sizes of the kobias, but they are still fairly successful across the world, using blade-like tooth rows scissor-like jaw arrangement to cut through unsuspecting prey into manageable pieces it can swallow.
Thick-Headed Hunters of the Deep:
Ramtunas (Bathoarietidae): These unique predatory sunfish evolved alongside squid and other pelagic cephalopods, which exploded in abundance and diversity after the extinction wiped out most surface pelagic fish. As their prey grew, so did they, and developed quite a unique way of bringing them down: their reinforced heads allowes them to cause massive damage to their internal skeleton, inhibiting movement or instantly killing the target. After that, the ramtuna starts quickly cutting and suctioning small chunks from the body to eat, while slowly drifting in the current to conserve energy. The Great Ramtuna (Bathoarietum crassus) is the largest of them all, with the largest individuals approaching 3 metres in length, being able to tackle even the largest cephalopods around.
Keelheads (Peroplouichthyidae): These fast swimmers are also descendants of small predators of soft bodied prey, typically inhabiting the deep sea. Now, they have become fast swimmers that use their reinforced nasal bones to ram into smaller prey items, typically smaller fish they can swallow whole after incapacitating them. The largest species however, like the Salamis' Keelhead (Peroplouichthys salamis), can tackle larger prey items, like small sharks, juvenile marine reptiles or even seabirds.
Pricklemouths (Letopecteninae): Bristlemouths, as one of the most abundant vertebrates on earth, survived the extinction relatively unscathed, but unlike other similar groups like lanternsfishes, they stayed relatively unchanged, with only a few clades adapting to surface waters, the pricklemouths being amongst them. They are not the largest, but definitely a very successful midwater mesopredators worldwide.
Cleaverfish (Guillotinognathidae): They are descendants of squaretails, starting as small predators of soft bodied prey like sea jellies. Like ramtunas, they were able to grow in size and diversity as their potential prey, cephalopods, exploded in abundance. Their mouth arrangement helped to hunt this type of prey, their lips creating a powerful suction force, coupled with a quick snap of a row of razor sharp teeth that act as a cleaver.
Cavallies (Hoplocarangidae): These descendants of deep sea barrelfish developed in their transition to shallower waters a set of modified dorsal scales and spines that form a spiky armor that protects them from predators. It's the most extended in the smaller, reef dwelling relatives of the group, but it is still kept by the larger, more pelagic members like the Bluespot Cavally (Hoplocaranx thalassinopunctatus).
Squalmons (Salmosqualus sp.): these are large predators that exclusively live in the open ocean, coming to nutrient-rich estuaries to undergo a drastic transformation in preparation for spawning and attracting mates. Unlike their ancestors, this transformation is reversible, and the structures and colours are shed or reabsorbed after spawning.
Old World Seachlids (Pontotilapiidae): the term refers to saltwater cichlids native to the waters around Afro-Eurasia and Australia belonging to different families, with Seachlids being a larger umbrella term that encompasses clades descendants of cichlids native to the Americas. While these mostly stay on continental shelves, hence their geographical distinction, some live in the open ocean, like the surfperches (Megastoma sp.), a genus of surface predators that cruise around the Indo-Pacific.
Wolfmollies (Lycopoeciliidae): one of the most unusual groups of saltwater fish that can be found in the shallow oceans of the Artechocene are the wolfmollies, aggressive hunters that stalk and hunt prey in large groups, chasing it down at high speeds. Although they are mostly native to coastal waters, barramollies (Ensiphallus sp.) are uncharacteristically pelagic, being found in a much wider range than their relatives.
Sharkcats (Selachariidae): descendants of ariids, they adapted to fill mostly benthic predatory niches, with some of them, like the deepwater sharkcat (Selacharius profundus) venturing into the open ocean, using their sensory capabilities to detect prey in the dark twilight zone.
Macanafish (Macuahuitlidae): gars are another one of the freshwater groups that quickly entered oceans and found great success, especially around the Americas. The Macanafish are one of these groups of gar descendants, that have spread across the world's oceans, adopting the ridged scales of sharks, with an extra added sharpness that can be used as defence, and a long, spear shaped snout that although it is used when hunting smaller prey, it is also very useful during intraspecific combat for territorial rights.
Sawlips (Prionolabiidae): this is a clade of lizardfish that had evolved their outer teeth rows to point outwards, forming a formidable weapon to incapacitate prey. It is an almost exclusively benthic clade, with members of this family staying close to the bottom, usually buried until the perfect moment to strike, except for one species, the Pelagic Sawlip (Volaticoserrae purpurascens). This species endemic to the Pacific Ocean swims up in the water column, quickly pursuing and swinging its snout across shoals of small fishes and squid.
Squid very favoured by the Anthropic Mass Extinction Event. With bony fish suffering much more losses in diversity during this event, squid and other mollusks managed to maintain a fair amount of their previous diversity, and quickly rebounded to become a major player in the ecosystems of the Artechocene oceans. Small predators, filter feeders, and a group that contains large macropredators that evolved the ability to do something extraordinary, co-operative hunting, the Army Squid (Strategoteuthidae):
These giant firefly squid initially evolved a series of photophore patterns for communication, with red photophores for communicating deep underwater without being noticed by predators. Later they evolved to use those communication abilities to hunt, coordinating attacks to prey much larger than themselves. They travel in the hundreds, their photophores appearing as a shoal of lanternsfish, luring prey to strike. They are menacing predators, as even the largest marine creatures struggle with an attack from a particularly large group of the largest species, the Admiral Squid (Strategoteuthis strategos), being quickly overwhelmed by the mass of strong beaks and tentacles.
Hope you enjoyed all these future pelagic hunters :>
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