Calthalotia fragum (Philippi, 1848)
Description: Whorls straight sided, sharply angled at the base. Spiral sculpture of about 5 beaded ribs on each whorl and about 8 on the base, with finer ribs between on larger specimens; Ribs immediately above and below the suture frequently larger than the rest. Outer lip and columella smooth, umbilicus closed. Colour mottled brown and white, sometimes as axial white streaks on a brown background. Interior white, nacreous. Normally eroded.
Size: Up to 25 mm high.
Distribution: Endemic to Australia; Southport, Qld, to Mallacoota, Vic.
Habitat: Abundant in estuarine seagrass beds.
Comparison: Odontotrochus marginata (Tenison-Woods, 1880) is a very similar species which occurs in southern Queensland and northwards.
Synonym: Prothalotia comtessei Iredale, 1931; Odontotrochus indistinctus (Wood, 1828)
Figs. 1,2: Kurnell, Botany Bay, NSW (C.326563)
Page change record: Illustrated specimen changed 25 Apr 2007.