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Nerita melanotragus
A shell of Nerita melanotragus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Neritimorpha
Order:	Cycloneritida
Family:	Neritidae
Genus:	Nerita
Species:	N. melanotragus
Binomial name
Nerita melanotragus E. A. Smith, 1884

Nerita melanotragus, common name black nerite, is a medium-sized sea snail, a marine gastropod mollusc in the family Neritidae, the nerites.

There has been some confusion over the taxonomy of the genus Nerita in the Pacific region, however Nerita atramentosa and Nerita melanotragus are now recognised as separate species (the two have often been considered to be the same species).

Distribution

This nerite is endemic to the southern Pacific, including the south-eastern coast of Australia (Queensland, New South Wales, Victoria, Tasmania), Lord Howe Island, Norfolk Island, northern New Zealand and the Kermadec Islands.

Habitat

This species is commonly found on intertidal rocks, particularly in the mid to upper intertidal zone. It prefers to attach to sloped or vertical rock surfaces, or hang from the underside of rocks. This may be a method of thermoregulation, because if N. melanotragus is on a horizontal surface, it would absorb the maximum solar radiation, whereas on sloped or vertical surfaces it absorbs less energy (and thus heat).

Shell description

The shell is of moderate size, very solid, globose-oval, and smooth except for weak shallowly incised spiral lines. The external shell colour is black, but the aperture is white, except for a narrow black border. Once shells get over about 26mm they start to wear down and typically have knotched sides and a white wear on the right hand side of the shell.

The operculum is granular, pinkish-lilac, with two spiral bands of black.

The shell height is up to 30 mm, and width 32 mm.

Genetics

An almost complete sequence of the mitochondrial DNA of this species was analyzed by Castro & Colgan (2010).

References

1. Grove, S. (2007). Vicariance, dispersal, and the strange case of the Tasmanian Black Nerites. The Tasmanian Naturalist 129.
2. Spencer, H. G.; Waters, J. M.; Eichhorst, T. E. (2007). "Taxonomy and nomenclature of black nerites (Gastropoda, Neritimorpha, Nerita) from the South Pacific". Invertebrate Systematics. 21 (3): 229. doi:10.1071/IS06038..
3. CADDY-RETALIC, STEFAN; BENKENDORFF, KIRSTEN; FAIRWEATHER, PETER G. (2011). "Visualizing hotspots: Applying thermal imaging to monitor internal temperatures in intertidal gastropods" (PDF). Molluscan Research. 31 (2): 106–113.
4. Castro, L. R.; Colgan, D. J. (2010). "The phylogenetic position of Neritimorpha based on the mitochondrial genome of Nerita melanotragus (Mollusca: Gastropoda)". Molecular Phylogenetics and Evolution. 57 (2): 918–923. doi:10.1016/j.ympev.2010.08.030. PMID 20817109.

External links

• Waters, J. M.; King, T. M.; O'Loughlin, P. M.; Spencer, H. G. (2005). "Phylogeographical disjunction in abundant high-dispersal littoral gastropods". Molecular Ecology. 14 (9): 2789–2802. doi:10.1111/j.1365-294X.2005.02635.x. PMID 16029478. PDF.

• Neritidae
• Gastropods described in 1884