Common name(s)
Sun Ray, Sun Stingray.
Identification
H.radians has a roughly circular disc that is slightly longer than wide. Snout obtusely angular. Tail (when intact) is roughly the same length as the body. Tail has up to three barbs (modified denticles). Teeth triangular and tightly spaced for crushing crustaceans.
Colour
Unknown
Size
Max length 90cm. Most collected fossils are between 30-40cm. The smallest fossil recorded was 8cm in length from nose to tail.
Habitat
A freshwater, demersal (bottom dwelling) ray confined to river and lake beds.
Distribution
Heliobatis radians was discovered in the Green River Formation in southwest Wyoming. Fossils are particularly common at a spot called Fossil Lake.
Conservation Status
EXTINCT
Heliobatis radians flourished during the Wasatchian stage in the early Eocene 50-55 million years ago.
Citation
N/A
Reproduction
Probably ovoviviparous. Unborn fetuses have been identified within the fossils of adult animals.
Diet
The abundance of H.radians fossils at Fossil Lake (the only place where the crayfish Procambarus primaevus and the prawn Bechleja rostrata are found) suggest that small crustaceans were an important part of this ray’s diet.
Behavior
Unknown.
Reaction to divers
N/A
Diving logistics
N/A
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Similar species
Asterotrygon maloneyi Mahoney’s Speartail Stingray is a second species of ray to have been found in the Green River formation. It is closely allied to the urobatid rays.