Amblychilepas javanicensis (Lamarck, 1822)
Description: Shell subquadrate in outline, widest at posterior; ends raised. Apical opening elongate, sloping, almost central. Sculptured with concentric growth lines or ridges, and usually numerous weak axial ribs. Margin smooth and thickened internally, apical opening bordered internally with strong callus. Exterior colour fawn with brown rays. Interior white in large specimens, fawn in smaller shells.
Size: Up to 31 mm in length.
Distribution: Endemic to Australia: Broken Bay, NSW, to Houtman Abrolhos, WA, including Tasmania.
Habitat: Under rocks on rocky shores, low intertidal down to 10 m. Uncommon in NSW, more common in southern Australia.
Comparison: This species is much broader than A. nigrita, with the widest point at the posterior quarter. It is fairly consistent in colouration, while A. nigrita is extremely variable. A. nigrita is common throughout NSW while A. javanicensis is uncommon and occurs only from Broken Bay southwards. Cosmetalepas concatenatus is easily distinguished by its pitted surface and lack of concentric and radial sculpture.
Fig. 1 Port Hacking, NSW (C.370612)
Copyright Des Beechey 2005