Sharp teeth, bizarre shapes, gargantuan sizes, and a family tree that dates back over 100 million years…I’m not talking about dinosaurs, but ancient freshwater fishes!
Twenty-five years ago today (June 11, 1993), Jurassic Park debuted in theaters. That date is fossilized in my mind because I recorded the trailer on VHS (wow, talk about ancient) and watched it over and over. Paleontological inaccuracies aside, that movie brought to life many of the creatures that inspired my interest in biology; that interest, and the relatives of those Jurassic fishes are still alive and well today.
When describing these groups as “Jurassic World Fishes”, I’m referring to the classification order (e.g. Amiiformes, the bowfins) that has been around since the Jurassic Period, the time between approximately 200 million to 145 million years ago. I’m also looking at just a few groups; several other orders have been around since the Jurassic Period. For example, did you know that Cypriniformes (minnows and carps) and Siluriformes (catfishes) also lived during the Jurassic? Imagine Spinosaurus (fast forward to the Cretaceous Period) getting hit in the face by a jumping Asian carp ancestor while “noodling” for a prehistoric catfish.
Hold on to your caudal fins, here are five groups of North American fishes that, as Jeff Goldblum’s Dr. Ian Malcolm might say, “uh, found a way” to outlast Tyrannosaurus rex.
Shark-like in appearance, sturgeons have elongate bodies and primarily cartilaginous skeletons. Sturgeons use barbels (similar in appearance to catfish “whiskers”) to find food, and a vacuum-like mouth to siphon bottom substrates of lakes and rivers for invertebrates and other small prey. Sturgeons primarily lack scales, but do have large, bony scutes that armor their sides. Once considered nuisance fishes that tore apart commercial fishing nets, Lake Sturgeon in the Great Lakes were caught by the thousands, piled up, and burned en masse. Several sturgeon species were also overfished for their eggs (caviar). Perceptions and harvest rates have since changed, and most species are now protected in the United States. The White Sturgeon is the largest freshwater fish in North America, reaching 20 feet long and over 1,700 pounds!
Freshwater fishes don’t get much more bizarre-looking than paddlefishes. Sharing the same order as sturgeons, the paddlefish family (Polyodontidae) contains only two modern species, the American Paddlefish and the [likely] now-extinct Chinese Paddlefish. As you might guess from their common names, paddlefishes have an elongate, paddle-shaped snout, or rostrum. This “paddle” is lined with numerous electroreceptors that help the fish detect tiny zooplankton in the water column. Once prey has been located, the paddlefish opens its huge (but toothless) mouth, creating a vortex that funnels and filters planktonic prey using its fine gill rakers as a sieve. Harvest of American Paddlefish is regulated through most of their range; they’re also farmed for their eggs (roe) as an alternative to sturgeon caviar.
Known as the “bony tongue” fishes, members usually have teeth or bony patches on their tongues. This group includes arowanas (popular tropical aquarium fishes), and arapaimas (giant South American air-breathing fishes), but did you know that we have bony tongue fishes in North America? The Mooneyes and Goldeyes (family Hiodontidae) are medium-sized (up to 20 inches), white-silvery fish that somewhat resemble shad or herring. But open up their mouths and you’ll find a row of distinct teeth on their tongues, giving their jaws an almost xenomorph appearance. Named for the pigmentation around their large eyes, Mooneyes and Goldeyes primarily feed on aquatic invertebrates and small fishes, and are valued as sport fishes.
The Bowfin is the last remaining species of a once-diverse group that spanned all continents except Australia and Antarctica. Today, “America’s underdogfish” lives in slower-moving waters of lakes and rivers from southern Canada to the southeastern United States. Bowfins certainly have a prehistoric appearance, with a cylindrical body covered in tough scales, large mouth, and lots of sharp teeth. They are identified by a long, undulating dorsal fin, which propels the fish through vegetated waters. Bowfins are also air-breathers; they have a highly-vascularized gas bladder that acts like a lung, allowing them to survive in low-oxygen environments. Today, Bowfins are gaining popularity as hard-fighting sport fish, even on the fly! As an alternative to sturgeon caviar, Bowfin eggs (like American Paddlefish) are harvested as more sustainable “Cajun caviar.”
If there’s a group of modern-day fishes that look like dinosaurs, it’s got to be the gars. With armored scales and the general appearance of an alligator with fins instead of legs, gars are the epitome of a “dinosaur fish”. Like the bowfins, gars are air-breathers, and can persist where more conventionally respiring fishes cannot. Gars are also gaining popularity as sport fish, with anglers traveling from all over the world to Texas and Louisiana to fish for giant Alligator Gars that can reach over 8 feet long and weigh over 300 pounds. Additionally, scientists recently found the Spotted Gar to be a valuable model organism in biomedical research, informing us about evolutionary development. This week is officially #GARWEEK via Texas Parks & Wildlife Department, so be sure to follow the hashtag for video, ganoid factoids, and the opportunity to voice your opinion through an Alligator Gar fishery management survey. For more information on recent efforts in conservation and management of gars and bowfins, check out “Angling for Dinosaurs,” a special issue of Transactions of the American Fisheries Society, coming soon this summer!