Knightia: This is undoubtedly among the most common of the fish fossils found at GRF in Wyoming. It is similar to today’s herrings, about 10 to 25 cm long, and is now naturally extinct. It mainly fed on plankton, algae and insects, and lived in large schools. Large numbers of Knightia specimens can be found in all areas of the lakes. Below is a simulation from the “Fossil Butte Museum” of what the Knightia looked like alive.
Diplomystus: This is the second most common species among the fossils
in the GRF. It was a fish measuring up to 65 cm, that most likely did
not live in large schools. The morphology of its body and the structure
of its mouth are peculiar features of predators. In fact, finding of Dipos
with a prey in its stomach or even in its mouth, are not rare. Diplos
are difficult to prepare for their thin delicate scales are hardly ever
preserved, even in ideal conditions. Pictured below.
Here’s a beauty of a Prisky [Priscacara] specimen. It is in our private collection! Dug last summer.
These Priskys are one of the most beautiful fishes found in the GRF, in my opinion!
Priscacara: It’s disk-like shape, similar to that of the perch, makes it look different from the other species found in the lakes. Perhaps Priscacara lived only during the Eocene period; in fact, similar specimens are not present in deposits of more recent geological periods. Most likely it lived in schools, fed on gastropods and crustaceans and was an easy prey to the voracious Diplomystus and Phareodus. It’s peculiar morphologic features are long, thick dorsal and anal spines. They were a self defense weapon against predators. It was a medium-small Size fish [10-15 centimeters long] and could reach at the most, 40 centimeters in length. They are fairly common in all areas of the lakes. But still hard to find for the weekend digger.
Ok…….here we have several pictures of Mioplosus fossils. The one in the center is in our personal collection. See how the Knightia below on the plate is almost centered and both fish are heading in the same direction! This was a definite candidate for our collection, The ones on either side are other specimens collected last year. You can see the one on the right is what they call disarticulated. This means the head is disfigured or was crushed before fossilizing. It could have be deviled by other fish before it fossilized. But it is a fish of some size. This particular specimen is still for sale asking price is $125.00. You can see my thumb in the pictures, use it for a size reference.
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Mioplosus: This fish is easy to distinguish because of its distinctive double dorsal fin. It’s jaws were equipped with many sharp small teeth and its diet included small size fishes such as the Knightia. It was 20-30 centimeters long but it could reach a maximum length of 51 centimeters. Like the modern day perch, Mioplosus lived close to the shores of the lakes. Similar fossils species, belonging to the same family, come from Asia, Europe and New Zealand. It is quite common in Fossil Lake, but not so common in Lake Gosiute and Lake Uinta deposits.
(Bottom right) This is a sting-ray Art found. It is in need of repair but all the pieces are there. Due to it’s rarity Stingrays generally stay in the hands of the paleontologist or the private quarry owners. They are rare and are their meal ticket for the long hard winter’s in Wyoming. Art has dug 3 stingrays to date……..he will be allowed to keep his 9th one he finds, if the rules at the quarry do not change before it happens. No hard feelings on the issue. It’s just the way things are and understandable with respect to the quarry owner.
Helobatis radians; Also called Stingray. The fishes belonging to this family have cartilage bones and more similar to those of their close relatives the sharks than to those of the boney fishes. It reach 90 centimeters in length and fed on crustaceans, mollusks and small fishes. On its tail is had a spine that it could move in all directions and use it as a self defense weapon. Today freshwater stingrays live in South America.