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Rare XL Amphiplaga Brachyptera Fossil Fish Green River Formation WY 4.8 Inches Long Oval - Fossil Age Minerals

Rare XL Amphiplaga Brachyptera Fossil Fish Green River Formation WY 4.8 Inches Long Oval


From: Kemmerer Wyoming

Weight: 8.3 Ounces

Dimensions: 6 Inches Long, 3.4 Inches Wide, 0.5 Inches Thick (Plate)

Fish is 4.8 Inches Long, 1.5 Inches Wide

The item pictured is the one you will receive.

This is a genuine fossil, not a replica.

56 million Years old Eocene age.

Amphiplaga brachyptera

50 million years old, Eocene-Era fossil fish comes from one of the world's famous Green River Formation in Wyoming. Amphiplaga is one of the rarer of the Green River fish fossils, making up some 1% of the total from Fossil Lake, its only known location. Named by the famous 19th Century paleontologist E.D. Cope, the name Amphiplaga is thought to mean "amiguous wound", pointing to the fact that the holotype specimen was headless. Shaped rather like a cross between a trout and a perch, the Percopsidae have colloquially termed “trout perches”. Fossil percopsids are only known from North America, the current home of the extant genus Percopsis. With a maximum total length of 150 mm and an average of 100 mm, this is an average-sized adult specimen of this rarely offered taxon.

Fifty million years ago ancient Fossil Lake existed in what is now southwest Wyoming. Of its estimated maximum extent of 930 square miles, approximately 500 square miles of sediment remains. The 230 square miles across the center of the ancient lake-bed contain exceptionally fossiliferous sediments and associated geologic features including deltas, beaches, springs, and rocks from the center and nearshore environments.

The unusual chemistry of fossil lake prevented decay and scavenging of dead organisms while millimeter-thick layers of alternating limestone matter slowly accumulated. The result is laminated limestones that contained the highest concentration of fossil fish in the world. These fish, other aquatic organisms, and associated geologic features make Fossil Lake the world's best Paleogene record of the freshwater lake ecosystem.

Since the discovery in the 1870's, many perfectly preserved fossil fish have been recovered. Preserved with the fish in the laminated limestone is a complete aquatic ecosystem: cyanobacteria, plants, insects, crustaceans (shrimp, crawfish, and ostracods), amphibians (frog and primitive salamander), alligators, turtles, birds, and mammals, including the oldest pantolestid (otter-like animal). The subtropical terrestrial ecosystem surrounding the lake is also represented by rare fossils, including a horse, two snakes, lizards, two bat species, birds, apatemyid (an arboreal insectivore), miacad (primitive carnivore), insects, and more than 325 types of leaves, seeds, and flowers.

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