defineanteriorandposterior


    New York Metropolitan Region and New Jersey
Freshwater Mussel Identification Handbook


Mussel Features
Anterior and Posterior  

    posterior

anterior

    posterior
 
anterior

    The anterior is the 
shorter end of the shell
as measured from beak.

In species with a long,
elliptical or "narrow"
shape the anterior end
should always be 
evident.  
 Mussel Shell Shapes

    Anodonta implicata
alewife floater 

    Alasmidonta heterodon
dwarf wedgemussel

      

       
       
     

    posterior

anterior

    posterior

anterior

    In those species that
are rhomboidal or
"rounder" in shape, 
such as Leptodea 
ochracea, the shorter 
end may not be apparent
at first.  Typically, the
end where the growth
lines are farthest from
the beak is the posterior
(see image left).


    Alasmidonta undulata
triangle floater 

    Leptodea ochracea
tidewater mucket 

     
 

    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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posterior anterior	posterior anterior	The anterior is the shorter end of the shell as measured from beak. In species with a long, elliptical or "narrow" shape the anterior end should always be evident. Mussel Shell Shapes
Anodonta implicata alewife floater	Alasmidonta heterodon dwarf wedgemussel

posterior anterior	posterior anterior	In those species that are rhomboidal or "rounder" in shape, such as Leptodea ochracea, the shorter end may not be apparent at first. Typically, the end where the growth lines are farthest from the beak is the posterior (see image left).
Alasmidonta undulata triangle floater	Leptodea ochracea tidewater mucket