Mipus nodosus (A. Adams, 1854)
Description: Adult shells of 4 whorls with an angled periphery. Axial ribs form nodules on the periphery of the spire whorls, becoming obsolete on the body whorl. Whole shell ornamented with densely scabrous spiral ribs; one large rib at the periphery, with about 4 ribs above. Below the periphery there are about 10 ribs on the body whorl, sometimes with smaller ribs between. Columella smooth, outer lip crenulated by the external sculpture. Umbilicus almost or completely closed. Interior white or pink, exterior fawn.
Size: Length up to 20 mm.
Distribution: Indo-West Pacific; eastern and south-eastern Australia.
Habitat: Taken as a beach shell and trawled down to 200 m. Specimens have been taken off Sydney by scuba diver in 8-30 m, living on gorgonian and soft coral.
Remarks: A number of names have been assigned that may be synonyms of this species, or additional closely related species. Purpura sertata Hedley, 1903 was described from juvenile shells from southern NSW. Liniaxis elongata Laseron, 1955 was named from southern NSW and is described as being more slender than P. sertata. Liniaxis wilsoni (Pritchard and Gatliff, 1898) has been named from Victoria. Laseron (1955) gives differences between the species, but these characters do not adequately differentiate species in the large quantity of specimens collected since 1955. Further work is required to clarify the taxonomy of this group.
Comparison: With the exception of possible additional species within the Mipus nodosus complex, the smaller species of Coralliophilinae found in NSW are quite readily separated:
Mipus nodosus: densely scabrous spiral ribs; lives subtidally.
Mipus arbutum: similar in size to M. nodosus but has a strongly angled body whorl. Occurs intertidally.
Emozamia licinus: thin, fluted varices; occurs subtidally.
Coralliophila squamosissima: stronger axial sculpture than M. nodosus, more rounded whorls than M. arbutum. Spiral sculpture not densely scabrous.
Fig. 1,2: Long Reef, Collaroy,. NSW (C.348788)
Copyright Des Beechey 2000