definebeakandsculpture


    New York Metropolitan Region and New Jersey
Freshwater Mussel Identification Handbook

Mussel Features
Beak and Beak Sculpture

    
Beak, top view
Alasmidonta heterodon

    Beak size, prominence 
and structure vary among
species and may aid in 
identification. The shape 
and arrangement of the 
contours of the beak are 
known as the beak sculpture, 
and if present can be seen 
clearly with a hand lens.  
Examples of the beak and its
sculpture are depicted below, 
and others may be seen in  
the species accounts.

    The beak, the oldest
part of the animal's shell,
may best be seen in a
posterior view.

Beak, left valve
Anodonta implicata

       
       
     

    
 
    

    It is not necessary to remove
the thick outer covering, or
periostracum, of the shell in
order to reveal the lines
and contours of the beak
sculpture.


    Alasmidonta undulata
triangle floater

    Ligumia nasuta
eastern pondmussel

     

      
      
     

    
 
    
 
    A specimen of S. undulatus 
shows the distinct rings of
the beak sculpture; 
although prominent, the
double-looped beak sculpture
of L. radiata is no longer
apparent in this older
specimen. Shell wear in
older specimens and those
from acidic waters may 
cause the beak sculpture to
appear absent or indistinct.

    Lampsilis radiata
eastern lampmussel 

     Strophitus undulatus
creeper

     
 


    View other features
Anterior and Posterior
Beak and Beak Sculpture   Color Ray
Growth Lines  Hinge Teeth 
Length, Width, Height, Profile, Silhouette 
 Posterior Ridge and Slope  
Shell Shape

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Beak, top view Alasmidonta heterodon	Beak size, prominence and structure vary among species and may aid in identification. The shape and arrangement of the contours of the beak are known as the beak sculpture, and if present can be seen clearly with a hand lens. Examples of the beak and its sculpture are depicted below, and others may be seen in the species accounts.	The beak, the oldest part of the animal's shell, may best be seen in a posterior view. Beak, left valve Anodonta implicata

		It is not necessary to remove the thick outer covering, or periostracum, of the shell in order to reveal the lines and contours of the beak sculpture.
Alasmidonta undulata triangle floater	Ligumia nasuta eastern pondmussel

		A specimen of S. undulatus shows the distinct rings of the beak sculpture; although prominent, the double-looped beak sculpture of L. radiata is no longer apparent in this older specimen. Shell wear in older specimens and those from acidic waters may cause the beak sculpture to appear absent or indistinct.
Lampsilis radiata eastern lampmussel	Strophitus undulatus creeper