Australian Biological Resources Study

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Family PUNCTIDAE Morse, 1864

Pinhead Snails


Compiler and date details

September 2013 - Dr John Stanisic

Introduction

Australian punctids live in a wide variety of habitats from rainforests and vine thickets to sub-alpine tussock grassland, coastal dunes, strand lines and semi-arid environments. A few species are widely dispersed while others have small discrete distributions. Punctids occur in the Northern Hemisphere, Africa, Australia, New Zealand, Subantarctic islands and some Pacific islands. The greatest species diversity occurs in cool, moist uplands such as in montane rainforests and sub-alpine woodland and eucalypt forest. Lord Howe Island in particular has a diverse punctid fauna most of which is endemic and lives in the southern mountains.
Punctids typically have a shell with a glassy to somewhat frosted, translucent appearance and rounded to angulate whorls. The protoconch sculpture is spiral in the form of low cords and the teleoconch sculpture generally consists of major radial ribs and a microsculpture of radial threads and crowded spiral cords. Colour patterns are uncommon.
Punctids are thought to be herbivores and detrital feeders. Most are leaf litter dwellers however some, notably Lord Howe Island taxa, are arboreal and may possibly feed on micro-algae growing on leaf surfaces. Life history and reproduction of Australian species remain virtually unknown.

 

Diagnosis

Australian punctids are minute to small-sized (1.2mm-8mm shell diameter) snails with a great diversity of shell shape with species having trochoidal, turbinate, sub-globose or discoidal shaped shells. Whorls may be rounded, shouldered, angular or keeled and sutures are generally moderately to strongly impressed. The umbilicus varies from wide to narrow and is reduced to a chink in some taxa. There is generally no lip development in Australian mainland species and the apertural edge and columella are entire. The protoconch is large and usually sculptured with spiral lirae or cords which may or may not be beaded or pustulated. There is always strong sculptural differentiation between the protoconch and the post-nuclear whorls. Post-nuclear or teleoconch sculpture consists of radial periostracal ribs and incised spiral striae. In some species there is a row of periostracal spines or triangular wings at the shell periphery. Shells generally are translucent and of a waxy or resinous lustre. Colours comprise various shades of brown to cream and most Australian species lack well defined colour patterns. Shells are usually dextral but a small number of species in southern Australia are sinistral.

 

History of changes

Note that this list may be incomplete for dates prior to September 2013.
Published As part of group Action Date Action Type Compiler(s)
06-Feb-2014 PUNCTOIDEA 03-Sep-2013 MODIFIED Dr John Stanisic
12-Feb-2010 (import)