ID Keys

Key to Abra species

Beaks at midpoint, trigonal, H=L
Abra tenuis
Beaks towards posterior H<L
Go to #2
Posterior distinctly acute compared to anterior
Go to #4
Posterior rounded but not acutely, similar to anterior
Go to #3
Commarginal growth lines and faint radial striations, found on continental margin and upper slope
Abra longicallus
Commarginal growth lines, no radial striations, found on continental shells only
Abra alba
Elongate ovate, beaks a third from posterior of shell
Abra prismatica
Subovate, beaks just after midline
Go to #5
Depression behind umbo, no deeper than 200m
Abra nitida
No depression behind umbo but several tiny ridges present, found below 2000m
Abra profundorum