|
|
PSAMMOBIIDAE |
|
|
Click on an image to enlarge
|
Gari
crassula (Deshayes,
1855) Description:
Shell
usually eroded. Shape ovate to elongate-ovate. Umbo on midline;
anterior end evenly rounded, ventral margin evenly rounded or sinuous
with a shallow concavity posteriorly, posterior end rounded or
subtruncate. Exterior surface smooth, covered with greenish brown
periostracum. Interior violet or violet splashed with white;
muscle scars and pallial line deeply impressed; pallial sinus deep,
extending in front of hinge plate. Hinge with right valve with 2
cardinal teeth, left valve with 2 cardinal teeth, 1 massive and bifid,
the other a minute lamina. Ligament external, attached to nymphs
that extend beyond shell margin. Shell colour purple. Periostracum
thick, dark brown, usually eroded on dorsal area. Size:
Up to 40 mm in length. Distribution:
Tropical
western Pacific: in eastern Australia, as far south as Clarence River. Habitat:
Lives in the estuarine sections of large tropical and warm
subtropical rivers, sometimes at extraordinary high densities. Comparison:
This species is distinctive among Gari species in having a
thick periostracum, a relatively solid shell and in inhabiting river
estuaries. Synonymy:
Several synonyms are listed by WoRMS, none of which has been used
in recent Australian literature. Fig.
1:
Fitzroy River, Qld (C.070390) |
|
