Skate and Ray Morphology

One of the most frequently asked questions about skates and rays, especially those found in UK waters, is what is the difference between them? The problem is made more difficult by the fact that many of the species around the UK coastline are historically misnamed. This has resulted in Blonde, Small-eyed, Thornback, Undulate, Spotted and Cuckoo skates being known as rays. The Shark Trust refers to the commonly known UK names throughout the website to minimise confusion but the scientific classifications for skates and rays are detailed below.

Skates and rays belong to the Superorder Batoidea, although they look very similar in appearance and tend to live in the same coastal habitats, there are a number of morphological differences, which determine a skate from a ray. 

Skate and Ray Morphology © Marc Dando.

 Skates (Order: Rajiformes):

  • Each pelvic fin is divided into two lobes.  
  • Tail is relatively stocky without a stinging spine. 
  • Tail usually has two small dorsal fins near its tip and a tiny caudal fin. Although some species lack dorsal and caudal fins.  
  • Bucklers (thorn-like scales) may be present along the midline of the back or tail. Enlarged scales along the side of the body (near the pectoral fin base) may also be present in some species.
  • Males have rows of enlarged scales near the eyes and wingtips (termed 'malar' and 'alar' spines, respectively).
  • Skates lay eggcases (via oviparity). 

Rays (Order: Torpediniformes, Pristiformes, Rhinobatiformes, Myliobatiformes):

Electric Rays (Torpediniformes), Sawfish (Pristiformes) and Guitarfish (Rhinobatiformes) tend to be distinctive in appearance and so are less often confused for skates, however rays belonging to the Order Myliobatiformes (that includes stingrays, Eargle Rays, butterfly rays, devil rays and cownose rays), can be more difficult to tell apart.

  • Each pelvic fin has one lobe. 
  • Tail is slender/whip-like, usually with a stinging spine midway along its length.  
  • Tail usually without a dorsal fin (although some species have a single dorsal fin that occurs near the tail base), caudal fin is reduced and continuous, or absent completely.  
  • No bucklers along the back, tail or side of the body. Although Hypolophus sephen, sometimes called the 'Pearl Ray', has three rounded scales in the midline of its back.
  • Males lack malar or alar spines.
  • Rays give birth to live young (via ovoviviparity).

Related Links:

Skate and Ray Taxonomy

Download Skate and Ray ID Guides and Factsheets

Related Projects:

The Great Eggcase Hunt

Angler Recording Project