Checkered Nerite, Black Nerite
Phylum: Mollusca, Class: Gastropoda, Order: Cycloneritida, Family: Neritidae, Genus: Nerita, Species: Nerita atramentosa · Neritidae (Nerite family) · Gastropod (snail); whole shell; globular/neritiform shape
Species
Nerita atramentosa (Confidence 95%)
Shell Type
Gastropod (snail); whole shell; globular/neritiform shape
Family
Neritidae (Nerite family)
Size
Approximately 12-18mm in diameter; this is a small-to-medium specimen within the typical range of 10-30mm.
Color & Pattern
Dull greyish-green to charcoal exterior, likely slightly weathered or sun-bleached. The surface shows fine concentric or spiral ribs. The aperture (interior) is off-white to yellowish-cream with a smooth finish.
Rarity
Very Common; these are ubiquitous on the rocky coastlines and mudflats of Southeast Queensland.
Habitat
Found in the intertidal zone, specifically on rocky shores and mudflats. They are highly adapted to the 'splash zone' where they are exposed to air between tides. This is a marine species.
Geographic Range
Eastern and Southern Australia, ranging from Queensland (including Brisbane/Sandgate) down to Tasmania and across to Western Australia.
Description
A robust, thick-walled globose shell with a low spire. The exterior is characterized by numerous fine, crowded spiral threads or grooves. The aperture is large and semi-circular with a thickened outer lip and a smooth, flat columellar area (the deck). This specific specimen appears to be an older shell found on the beach, showing some rounding from sand abrasion.
Key Features
Semi-circular aperture; smooth, flat columellar deck; globose shape with very low spire; fine spiral ribbing; thick, heavy shell for its small size.
Collector Value
Low; due to being very common, it has little market value, but it is a classic representational shell for the Moreton Bay region. It is most valued by local hobbyists for educational collections.
Condition Notes
Good condition for a beach-find. There is some minor erosion of the fine ribbing and slight discoloration from the typical deep black of live specimens, indicating it has been empty and exposed on the beach for some time. Grade: Good.
Interesting Facts
Nerites are incredibly hardy; they can survive long periods of exposure to heat and air by sealing their trapdoor (operculum) tightly to retain moisture. They are herbivores that graze on algae at night and huddle together for protection during the day.
Ecological Role
Important algae grazers that keep rocky surfaces clean. They serve as a food source for shorebirds and larger crabs. They are not currently considered at risk or protected, but local collection limits for live mollusks may apply.
Similar Species
Nerita plicata (which has much stronger, deeper ribs and is usually whiter) and Nerita albicilla (which has a pimpled/granulated columellar deck).
Beach Finding Tips
Look around the rocky outcrops at Sandgate or near the pylons of the Shorncliffe Pier. They are best found at low tide clinging to stones or washed up in the high-tide debris lines near the mudflats.
Notes
Sandgate beach Brisbane