{{Short description|Species of gastropod}} {{Speciesbox | taxon = Diloma subrostratum | image = Diloma subrostrata subrostrata 01.JPG | image_caption = | authority = (Gray, 1835) | synonyms = * ''Chlorostoma undulosum'' <small>A. Adams, 1853</small> * ''Diloma (Fractarmilla) subrostrata subrostrata'' <small>(Gray, J.E. in Yate, 1835)</small> * ''Diloma plumbera'' <small>Hutton, 1882</small> * ''Diloma subrostratum novaezelandiae'' <small>(Anton, 1838)</small> * ''Diloma subrostratum subrostratum'' <small>(J. E. Gray, 1835)</small> * ''Labio corrosa'' <small>A. Adams, 1853</small> * ''Labio hectori'' <small>Hutton, 1873</small> * ''Labio pica'' <small>A. Adams, 1853</small> * ''Monodonta subrostrata'' <small>Gray, 1835</small> * ''Trochus attritus'' <small>Hombron, and Jacquinot, 1854</small> * ''Trochus novaezelandiae'' <small>Anton, 1838</small> * ''Zediloma (Fractarmilla) corrosa'' <small>(A. Adams, 1853)</small> * ''Zediloma (Fractarmilla) corrosa zebrina'' <small>A. W. B. Powell, 1946</small><ref>{{cite Q|Q58676636}}</ref> | display_parents = 3 }}
'''''Diloma subrostratum''''', common name the '''mudflat top shell''', is a species of small sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.<ref name="WoRMS">{{WRMS species|546863|''Diloma subrostratum'' (J. E. Gray, 1835)|18 November 2025}}</ref>
==Description== The length of the adult shell of this species varies between 11 mm and 32 mm. The solid, conical shell is suborbicular. It is often more or less black, with close wavy longitudinal yellow lines. The spire is short with five whorls. The last whorl is large, rounded, with its hinder part with three to six spiral keels. The axis is imperforated. The inside of the aperture is smooth and silvery.<ref>[https://archive.org/details/manualofconcholo111tryo Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia] (described as ''Monodonta subrostrata'')</ref>
==Distribution== This common estuarine species is endemic to New Zealand, occurring in the North and South Islands, and in Stewart Island.<ref>Cook, Steve De C., “New Zealand Coastal Marine Invertebrates Vol 1”, Canterbury University Press, NZ 2010, ISBN 978-1877257-60-5</ref>
==References== {{Reflist}} * Miller M & Batt G, ''Reef and Beach Life of New Zealand'', William Collins (New Zealand) Ltd, Auckland, New Zealand 1973 * Powell A. W. B., ''New Zealand Mollusca'', William Collins Publishers Ltd, Auckland, New Zealand 1979 {{ISBN|0-00-216906-1}} * Donald K.M., Kennedy M. & Spencer H.G. (2005) ''The phylogeny and taxonomy of austral monodontine topshells (Mollusca: Gastropoda: Trochidae), inferred from DNA sequences.'' Molecular Phylogenetics and Evolution 37: 474-483. * [http://www.tandfonline.com/doi/abs/10.1080/03014223.1995.9517499 Bruce A. Marshall, ''Molluscan and brachiopod taxa introduced by F. W. Hutton in The New Zealand journal of science''; Journal of the Royal Society of New Zealand, Volume 25, Issue 4, 1995]
==External links== * {{Gastropods.com|key=5|id=20995|title=''Diloma (Fractarmilla) subrostrata subrostrata''|access-date=16 January 2019}} * [http://www.mollusca.co.nz/speciesdetail.php?speciesid=219&species=Diloma%20subrostrata New Zealand Mollusca: ''Diloma subrostrata'']
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subrostratum Category:Gastropods of New Zealand Category:Gastropods described in 1835 Category:Taxa named by John Edward Gray