Shell fragile, medium to large sized, equivalve slightly inequilateral. Outline almost circular, a little longer than high; anterior margin rounded, posterior part more or less transversally or obliquely expanded, often slightly truncated. Sculpture of 41 ribs (34-52) as wide as the interstices; ribs generally rounded in the anterior part; flatly rounded to asymmetrically triangular in the median third of the shell; more rounded with calcareous spines or tubercles in posterior part. No granulation in the adults except sometimes on the lunule. Internal margin crenulate.
externally whitish, beige, to yellow with a purple stain only on the umbo. Internally white with purple at the posterior third and sometimes at the umbonal cavity.
common size :
to 75 mm in height.
It can be confused with F. australis especially in juvenile shells (< than 3-4 mm). However, the presence of "spines" in the posterior part and sometimes a periostracal insertion on the last fold are diagnostic for F. australis. Fulvia fragilis can be distinguished from by its less oblique shape, by its rounded and large instead of triangular and smaller last fold, by its fewer ribs and by the presence of well rounded ribs, never observed in F. australis (Vidal, 1994).
BIOLOGY / ECOLOGY
See remarks under Fulvia australis. The thin shell is typical of species living in protected muddy biotopes. Usually sympatric with F. australis.
littoral to shallow waters; dredged from 9-37 m sandy, sandy muddy and muddy bottoms; also on sandy bottoms with Zostera sp.