Heliobatis radians (Stingray) | 100% Natural | Green River Formation | Wyoming
Heliobatis radians
Eocene (51.98 Million Years Ago)
Green River Formation, Wyoming, USA
In Stone Fossils Private Quarry
Specimen approx. size: 13.5" x 7"
Matrix approx. size: 20.5" x 20"
Stand not included.
**Due to the size of this specimen, it will be shipped in an internationally compliant wooden crate. The plate itself is backed with 3/4" plywood for durability and easy wall hanging. We recommend a french cleat system for hanging purposes.
This Heliobatis radians specimen is definitively male, as evidenced by the presence of well-preserved claspers - specialized reproductive structures unique to males.
Description
Heliobatis radians is an extinct species of freshwater stingray known from the Eocene Green River Formation of southwestern Wyoming, USA. It is among the earliest and best-preserved examples of Myliobatiformes in the fossil record and provides key insights into the early evolution and freshwater adaptation of stingrays.
Morphology
The body of Heliobatis radians is dorsoventrally flattened with a subcircular pectoral disc that typically measures between 15 and 60 cm in diameter. The disc is formed by the fusion of the enlarged pectoral fins to the sides of the head, creating the characteristic ray shape.
The tail is long, slender, and whip-like, often exceeding the disc length. Most specimens display one to three serrated venomous spines (caudal stings) located along the proximal part of the tail. These spines are occasionally found detached and preserved near the body.
The mouth, nostrils, and five pairs of gill openings are situated on the ventral surface, while the eyes and spiracles lie dorsally. The skeletal structure is cartilaginous, with preservation typically in the form of calcified cartilage impressions and phosphatic material.
Dentition
The teeth are small and pavement-like, adapted for crushing rather than cutting, consistent with a benthic diet of mollusks, crustaceans, and other invertebrates. Both jaws possess tightly packed rows of teeth forming a broad crushing plate.
Sexual Dimorphism and Reproduction
Evidence of sexual dimorphism is visible in the presence of claspers in males. The presence of these claspers in some specimens confirms that Heliobatis radians reproduced via internal fertilization, similar to modern stingrays.
Paleoecology
Heliobatis radians inhabited the calm, subtropical freshwater lake environment of Fossil Lake, part of the Green River Formation ecosystem. It coexisted with other freshwater fish such as Knightia eocaena, Diplomystus dentatus, Priscacara liops, and Amphiplaga brachyptera.