Lined Bubble Shell (also known as the Rose-Petal Bubble)
Phylum: Mollusca, Class: Gastropoda, Order: Cephalaspidea, Family: Bullinidae, Genus: Bullina, Species: Bullina lineata · Bullinidae (Bubble Shell family) · Gastropod (Univalve); specifically a Cephalaspidea or 'Headshield Slug' shell. Shape is ovate-globose (rounded/bubble-shaped).
Species
Bullina lineata
Shell Type
Gastropod (Univalve); specifically a Cephalaspidea or 'Headshield Slug' shell. Shape is ovate-globose (rounded/bubble-shaped).
Family
Bullinidae (Bubble Shell family)
Size
Approximately 12-15mm. Typical adult range for this species is 10mm to 25mm, making this a mid-sized specimen.
Color & Pattern
Milky white to cream base color with distinctive thin, spirit-red or reddish-brown horizontal spiral bands. It usually features two primary bands and vertical 'wavering' lines that create a grid-like or ladder effect. This specimen appears slightly weathered but retains its signature banding.
Rarity
Common (found regularly on beaches in the Brisbane/Sandgate area after high tides or storms).
Habitat
Found in intertidal and shallow subtidal zones, typically on sandy substrates or among seagrass beds. They are often found in tide pools during low tide.
Geographic Range
Indo-Pacific region, very common along the eastern coast of Australia, including Moreton Bay/Brighton Beach area, and extending to New Zealand and Japan.
Description
A delicate, thin-walled shell with a large, swollen body whorl and a short, sunken spire. The surface is relatively smooth with very fine growth lines. The aperture is large and ear-shaped, flaring at the base, which allowed the living colorful slug-like animal to partially retract.
Key Features
The most diagnostic feature is the 'crossed' pattern of red spiral bands intersected by fine vertical lines. The shell is fragile compared to heavy sea snails and has a deep, narrow umbilicus.
Collector Value
Low to Moderate. While beautiful, they are common in Queensland. Intact specimens with vibrant red lines are preferred. It is highly desirable for 'micro-shell' collectors due to its iconic aesthetic.
Condition Notes
Fair. The specimen shows significant beach wear at the apex/spire and the anterior canal (base), which is often the first part to break in bubble shells due to their thin structure. The color is still visible but slightly duller than a live-collected 'Gem' specimen.
Interesting Facts
The living animal is much larger than its shell and is strikingly beautiful, appearing translucent white with iridescent blue margins. Unlike many snails, they cannot fully retract into their shells. They are carnivorous, preying on small polychaete worms.
Ecological Role
Active predator in the sand-dwelling community. They help regulate the population of marine worms. They are not currently considered threatened, but like all mollusks, are sensitive to water pollution and habitat loss in bay areas.
Similar Species
Bullina roseana (usually smaller with more pinkish tones) and Hydatina physis (striped bubble shell), which is much larger and has black/brown stripes.
Beach Finding Tips
In the Brighton/Sandgate area, look in the 'drift line' (the line of debris left by high tide). They are light and often get trapped in seagrass clumps washed ashore. Best found after a storm or a strong easterly wind.
Notes
Brighton beach Sandgate Brisbane