Sharks and Rays
Comparison: Catshark and Freshwater Ray - Form and Function
The catshark and the freshwater stingray, shown below, illustrate two typical but very different body plans present in elasmobranch fishes.

Although there is diversity among the sharks and rays, these two specimens represent typical body plans. Use the following images and interactive specimens to compare the relationship between form and function. Look closely at these representatives of the two groups to explore their similarities and differences.

Potamotrygon orbignyi
Reticulated freshwater stingray

This stingray specimen measures approximately 24 cm (9.4 in) in total length (including tail) and about 15 cm (5.9 in) disc length (see course notes for explanation of measurements). It is adapted for living on the river bottom and hides by covering itself with sand. The curled edges on the pectoral disc are a result of storage in a jar in a museum collection.

Scyliorhinus stellaris
Nursehound catshark

This catshark specimen measures approximately 20 cm (7.8 in) in total length. Nursehound catsharks spend most of their time near the ocean floor. The curl of the shark's body is the result of storage in a jar in a museum collection.

Interactive Specimens
Use the links on this page to view each specimen individually or to manipulate the shark and the ray image together in the same plane at the same time.

Hypothesize how the form and function of the body is affected by where the animal lives. For example, think about how each animal moves, feeds, and breathes. For a diagram of the anatomy of each specimen, look at the last image below.

For a 360-degree view of each specimen, click on one of the links below. When the image opens in a new window, drag your cursor in either a horizontal or vertical direction to change your view of the specimen.



Potamotrygon orbignyi Specimen collected in the early 1970s from Rio Tapajós, Brazil. Preserved in the Museu de Zoologia de Universidade de São Paulo, Brazil. Scyliorhinus stellaris Specimen collected in 1966 from Ligurian Sea, 51 km East of Genoa, Italy. Preserved in the American Museum of Natural History.

Specimens shown in hands for scale.