담수가오리화석(Rare freshwater stingray)우상귀

Heliobatis radians

Order Rajiformes, Family Dasyatidae (Common name; stingray or skate)

Geological Time: Eocene

Size : Matrix: 900 by 770 mm, Ray 480mm length

Fossil Site: Green River Formation, Fossil Lake, 18 inch layer, Kemmerer, Wyoming

경골어류화석 좌하측(7~8시 사이)

Diplomystus dentatus

Order Ellimmichyiformes, Family Ellimmichthyidae

Size : Diplomystus: 180~190mm

경골어류화석(5시,10시,2시)

Knightia alta

Order Clupeifomes, Family Clupeidae

Size : Diplomystus: 100~140mm

Description : 연골어류화석은 뼈가 없으므로 화석으로 발견되기가 매우어렵다. 표본은 멸종한 담수가오리화석으로 박물관급의 완벽한 표본이다. Rare Heliobatis radians Stingray Fossil from Green River.(freshwater stingray, Common name; stingray or skate)

This 50 million year old, Eocene-Era fossil fish comes from one of the world's famous Laggerstatten, the Green River Formation in Wyoming. A small portion of the fish fossils from Green River exhibit such fine preservation. The significant extent of soft-tissue preservation that makes the site famous is evident in this specimen. This is an exquisite, museum quality Stingray specimen from the Green River Formation of Wyoming. This is a male Heliobatis radians (Order: Rajiformes; Family: Dasyatidae), at once a rare and highly sought species, and the only species of ray from this formation. The preservation is superb and the preparation is the best there is. Note in the pictures the details in the ray tips and the barbs. Heliobatis is highly sought not only for the rarity, but because a specimen such as this makes for an awesome display.

Rays belong to the Chondrichtyes fish group, as do sharks that have an inner skeleton made of cartilage. Since cartilage comprises more organic material (collagen and elastic tissues) than bone, it decays more rapidly. Thus, fossils of cartilaginous fishes generally are rare. Cartilaginous fishes are also noted for well-developed, paired pectoral and pelvic fins, and powerful jaws with teeth.

The cartilaginous fishes appeared in Silurian time, and their ancestors remain one of the most successful groups of marine animals.