Scratched Littoraria, Scabby Littoraria
This species has a wide-ranging Indo-West Pacific distribution. It ranges from South Africa to eastern Polynesia. In Australia it ranges from Shark Bay in WA, across the NT and Qld shores, to southern NSW (WA, NT, QLD, NSW).Features:
This large, well camouflaged, high-spired (pointy), turban-shaped mollusc is commonly found on mangroves. It can grow to be the largest of the Littorinids, growing to 30-43 mm. in length. The shell is often thin. It has six to nine well-rounded whorls and the sculpture is of 10-12 weak to strong spiral chords with shallow spiral striations between. The axial sculpture is of fine growth lines. The aperture is large and rounded, with a thin outer lip that curves out widely. Its operculum is large and thin.
The species colour pattern is very variable, usually a mosaic of zigzag or axial brown blotches or no pattern. The animal is large and darkly pigmented on the foot, snout and tentacles.Ecology/Way of Life:
The Scratched Littoraria is found on the trunks and roots of mangroves, on the ground and on man-made structures. In some locations it is common to abundant. Because of its colour pattern it is excellently camouflaged. It is not common on shore rocks, except in areas without mangroves. It is ovoviviparous, hatching live young within its body and producing related, inbred populations. It shows great variability, both in colour and sculptural forms. Because of its ability to produce inbred populations, where variations and mutations are perpetuated, forms of this Littoraria appear to be able to rapidly acclimatise to varying habitats. This "species" may therefore be a species group, consisting of a cline, or clines of closely related forms. It may be consist of more than 20+ species. Rosewater comments that its variations occur "more or less randomly" throughout its geographic range. It is a surface browser and feeds by rasping microscopic algae from the bark and surfaces on which they live.Interaction with Humans/Threats:
Because of the wide-ranging nature and the apparent rapid evolution of this species, it appears to be under no threat from human interference.Other Comments:
Littoraria scabra , Linnaeus, 1758. Littoraria comes from two Latin words; littoralis means belonging to the seashore, and aria means air. The name describes this groups preference for living above high-tide levels. Scabra also comes from the Latin word scabrosus or scabridus that means rough, and describes its form of being rough with projecting points.Further Reading:
Davey, K. (1998) A Photographic Guide to Seashore Life of Australia p.103. New Holland Press, Sydney.
Rosewater, J. (1970). The Family Littorinidae in the Indo-Pacific. Pt. 1: The Sub-family Littorinidae. Indo-Pacific Mollusca, V.2(11), pp.5-261.
Short, J.W. & Potter, D.G. (1987). Shells of Queensland and the Great Barrier Reef: Marine Gastropods. p.20, Golden Press, Drummoyne.
Wells, F.E. & Bryce, C.W. (1988) Seashells of Western Australia. p.52, Western Australian Museum.
Wilson, B.R. & Gillett, K. (1979). A Field Guide to Australian Shells: Prosobranch Gastropods. p. 38, Reed.
Text, map & photograph by Keith Davey.Sponsorship welcomed:
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