Type locality: New Holland.
Range: Central east coast of Australia and Norfolk Island, but seems to have a larger distribution. Its presence in Okinawa is pointed out by Kuroda & Habe but it has never been confirmed and confusion with blackish L. (L.) cassidula s.s. is possible. It appears however, that Norfolk Island is the sole locality where the presence of L. (L.) pattersonia has been regularly authenticated. Habitat: Shallow waters. Live specimens are found under stones on sandy bottom.

Description: In some respects this small Lyria is different and seems to be separated from the
deliciosa/cassidula-complex. Shell is small and light, of a fairly stocky form, measuring 20-25 mm long. Protoconch is smooth, brown coloured of one and a half whorls. Teleoconch is of five whorls, sculptured by 21-23 axial ribs, slightly attenuated on the last whorl, crossing dense minute spiral striae engraving the intercostal spaces of the first whorls. Remnants of these striae are also present on the summit of the ribs of the body whorl, hardly visible in some shells and on the older specimens. Aperture semi-oval measuring 0.75 of the total length. Outer lip is simple and thickened. Columella concave bearing three columellar plaits, followed adapically by fine lirae. Siphonal notch is narrow and shallow.
On a yellow background colour, pattern is formed by irregular thick brown axial zigzags and 12-15 poorly defined spiral rows of brown blotches, overlaid by thick spiral lines well marked on the ribs and condensed into three bands. Animal: Not available for study.

Comparison: This small Lyria is hard to find and often confused with worn specimens of Australian L. (L.) deliciosa s.s. The axial ribs with the spiral striae if any and the thick pattern should be sufficient to dif-ferenciate it.
Some dark small specimens of L. (L.) cassidula s.s. have a quite similar appearance. They differ only by their slighty more shouldered whorls with a glossy surface and by the different pattern. Remarks: Perry described this species in 1811 four months before Lamarck, giving the anteriority (fide Petit, 2003). Iredale renamed this species according to locality without clear justification: Lyria opposita Iredale, 1937: Master Head Reef, Queensland. Lyria peroniana Iredale, 1940: Newcastle, New South Wales.
Two colour morphs are found within the Norfolk Island-population: the one with a dominant spiral pat-tern named "nucleus-form", the other with the zigzag axial pattern being prominent, usually considered the "pattersonia-form" by many collectors .
Probably due to its cryptic habitat, this tiny species may be considered rare and live taken specimens are seldom found.

As Lyria nucleus:
TYPE LOCALITY: "La mer du Sud." For various synonyms of nucleus, Iredale (1937b, 1940) gave the following loca- tions: Mast Head Reef, Norfolk Island, Kermadec Islands, and Newcastle. RANGE: From New South Wales, Australia, eastward to Norfolk Island and New Zealand's northern Kermadec Islands. Kuroda and Habe (1950) report a range extension to Okinawa. HABITAT: Information not available. DIMENSIONS: Adult specimens are 19 to 31 mm in length. SHELL DESCRIPTION: Shell is variable in size and shape. Typically it is small, light in weight, and ovate; the spire is short and pointed. Protoconch is small and burgundy-wine colored, with one and a half smooth, globose whorls. Teleoconch has five and a half to six whorls, longitudinally ribbed throughout. There are about 20 such ribs on the adult body whorl of a shell 20 mm in length. There is no spiral sculp- ture. The suture is indented. Aperture is semiovate; outer lip is simple and somewhat thickened. Columella is slightly curved, with three anterior plaits (the first and second being strongest), sometimes followed by a few weak lirae. Base color is ivory to creamy-brown with scattered chestnut spots and blotches. Fine, broken chestnut lines encircle the adult body whorl; these lines intrude to the inner edge of the lip and there form dark spots. ANIMAL AND RADULA: Not available for study. REMARKS: Of the various populations of Lyria nucleus that have been formalized by Latin names, one may deserve subspecific recognition at some later date when more ma- terial becomes available for study: it is Lyria insignita Ire- dale, 1940 from the Kermadec Islands off northern New Zealand. This population appears to be larger than typical nucleus from Norfolk Island and has wide, flatter axial ribs. In all other respects it appears to be identical to nucleus. Although dead beach specimens of nucleus are not uncommon in collections, a live-collected specimen is rather rare. The species somewhat resembles Lyria cassidula (Reeve, 1849) from Japan, but differs in having a lower spire and more numerous axial ribs that terminate below the suture. Their color and color patterns also differ.