Key to Families of Australian Aquatic Molluscs


This large phylum is divided into several classes of which only the Bivalvia (bivalved molluscs) and Gastropoda (snails and slugs) are found in inland waters.


Bivalved molluscs occur commonly in marine and estuarine environments.  Four families are known from Australian inland waters.  Identification to Bivalvia is relatively easy based on the bi-valved shell which covers the whole body, but care should be taken, especially with small specimens, to check the animal is not a crustacean of class Conchostraca (clam shrimp) Ostracoda (mussel-shrimp or seed-shrimp), or Cladocera (water flea).  These animals have a bi-valved carapace and may superficially resemble bivalved molluscs, but within the carapace is a shrimp-like body with several pairs of jointed legs.

The four freshwater bivalve families are:

1 Hyriidae (Freshwater mussels)

A family restricted to South America and Australasia.  Found throughout mainland Australia and central-north Tasmania, absent from southern Tasmania.  Some species are endemic to particular catchments whilst others are cosmopolitan.  The first larval stage is the minute, bivalved glochidium, ectoparasitic on the gills, fins, or general body surface of various fish.

2 Corbiculidae (Orb-shell mussels)

Found in Asia, Australia and Oceania, with isolated introductions in other parts of the world.  A tropical to subtropical group.  There are two distinct species groups in Australia.  The first (genera Batissa and Polymesoda) inhabit fresh and estuarine coastal streams of northern Australia, and are closely related to forms found in south-east Asia.  The second (genus Corbicula, endemic subgenus Corbiculina) are found throughout Australia except for Tasmania and the southern part of Western Australia.

3 Sphaeriidae (Pea shell mussels, pea shells, fingernail clams)

A little studied but cosmopolitan family of small bivalves.  Previously, many names were based on minute differences in the shell and on geographic distribution.  Some species are widespread throughout Australia but others are confined to small regions or in some cases to a single body of water.

4 Mytilidae (Mussels)

The cosmopolitan family which includes the marine mussels.  Several species are estuarine and some may be found in near-fresh water, but never entirely away from marine influence.

Identification to family can be based on the shell.  The Hydriidae and Mytilidae are elongate mussels with the beak of the shell at one end.  Corbiculidae and Sphaeriidae are sub-circular.  Hydriid larvae (glochidium larvae), parasitic on freshwater fish, are keyed separately in this key.


The aquatic gastropod families divide into two subclasses, the gill-breathing Prosobranchia are related to marine snails, the lung-breathing (or secondarily gilled) Pulmonata are related to land snails.  Eleven prosobranch families and nine pulmonate families are recorded from Australian inland waters.

Almost all species are shelled and recognisably snail-like, but one family (Onchidiidae) of marine, air-breathing slugs extends into estuaries and damp terrestrial situations near the sea.

Identification to class Gastropoda is relatively easy based on the snail-like shell and/or the presence of a pulmonate lung in the mantle cavity.  Larvae of Helicopsychidae, a family of caddis-fly (Insecta: Trichoptera) construct a helical case which resembles a snail shell, and could be mistaken for molluscs.  The trichopteran case is composed of sand grains and the animal inside is a typical insect larva with segmented body and three pairs of legs.

The identification of gastropods to family level can be difficult because the families are defined on internal anatomical structures.  There are few readily observable characters, other than those of the shell, but shells vary as much within as between families.  Adult whole animals can be identified using a combination of shell (and operculum) plus external body characters, but juveniles and shells alone are not always identifiable to the family level.

Character systems useful for identifying gastropod families include:

1   Shell coiling (dextral, sinistral, flat, or not-coiled)

2   Operculum presence/absence

3   Shell shape (spired, globose, turbinate, etc.) and spire height

4   Shell patterning (ridges, striations, colour patterns, etc.)

5   Tentacle and eye position

Some species will key easily to family level, but others may be difficult.

Posted By: Site Admin Last Updated: Aug 8, 2012 Views: 7455
Key Author(s): CSIRO Entomology Key Version: 1.1
Key to the Goodeniaceae of Western Australia

This key allows identification of all species of the fanflower family (Goodeniaceae) in Western Australia.


We are grateful to many friends and colleagues working at the WA Herbarium for supplying diverse data, images, maps, ideas, and taxonomic and computing expertise that have made the development of this data set possible. In particular we wish to thank Rob Davis and Mike Hislop, Steve Dillon, for their help with taxonomic queries. John Huisman for the use of his camera, microscope. Thanks also go to Kelly Shepherd for her help and advice.  Karina Knight for her help and encouragement throughout the project. Images available here come from the WA Herbarium’s online plant information system, FloraBase, and represent the work of a team of dedicated volunteers. The maps, also part of FloraBase, represent specimens held at the WA Herbarium. 

Posted By: Site Admin Last Updated: Apr 20, 2016 Views: 7444
Key Author(s): Chris Hollister and Kevin Thiele Key Publisher: Department of Environment and Conservation WA Key Version: 1.0
Key to Families of Australian Aquatic Odonate Larvae

Odonata (dragonflies and damselflies) occur in all types of inland water except saline lakes.  The adults are winged and can be found near their breeding sites or else (in some species) far from water.  The larvae, with one or two exceptions, are fully aquatic.  The larval stage lasts from a few weeks to several years, depending on species.  All Odonata are predatory in all life stages.

Species numbers usually are greatest where there is a variety of larval habitat.  A mosaic of stones, mud, and sand with a complex emergent vegetation yields the greatest range.  Some families occur across a wide range of larval habitat but others are restricted, eg to streams and torrents, to still or gently flowing water or to bogs, swamps and seepages.  Seventeen families are recorded from Australia.  One family, several subfamilies, about 60% of genera and 80% of species are endemic.

Posted By: Site Admin Last Updated: Aug 9, 2012 Views: 7415
Key Author(s): CSIRO Entomology Key Version: 1.1
Key to Families of Australian Aquatic Neuroptera & Megaloptera Larvae

These two closely related orders are sometimes placed as one.  We follow The Insects of Australia by keeping the orders separate but for convenience present them in a single key.

Neuroptera comprises about 18 families worldwide (14 in Australia) but the aquatic component is restricted to three families within the superfamily Osmyloidea.  Osmylidae is a diverse group of medium to large lacewings.  Aquatic or semiaquatic species predominate in several subfamilies.  The other two families, Sisyridae (spongeflies) and Neurorthidae, are of smaller insects and always associated with water.

Megaloptera comprises just two families worldwide.  All larvae are aquatic, pupation takes place in the soil beside streams, and the adult insects are rarely found far from their breeding sites.  Both of the megalopteran families, Sialidae and Corydalidae, are recorded from eastern Australia and one species of Corydalidae from the south-west.

The remaining taxon in this key is that of the beetle family Gyrinidae (order Coleoptera).  It is included here because it is rather easy to confuse gyrinid larvae for megalopteran Corydalidae.

Posted By: Site Admin Last Updated: Aug 9, 2012 Views: 7409
Key Author(s): CSIRO Entomology Key Version: 1.1
Chrysophyte Key

Chrysophyte Key

Posted By: Site Admin Last Updated: Aug 24, 2016 Views: 7398
Key Author(s): Australian Antarctic Division Key Version: 1.0
Key to Families of Australian Aquatic Plecoptera Larvae

This is a small order of aquatic insects comprising about 2000 species worldwide.  There are 15 recognised families but only four occur in Australia.  Of the 26 Australian genera 24 are endemic and 2 are shared with New Zealand, but at species level all 196 Australian species are endemic.  Stoneflies occur in eastern Australia from Tasmania to Cape York, and in South Australia and southern Western Australia, but not in central or north-western parts of the country.

Adult stoneflies are soft-bodied insects with long antennae, a moderately wide head, three free thoracic segments, and a cylindrical, parallel-sided abdomen terminating in two prominent cerci (and, in males, varied copulatory apparatus).  Typical adult stoneflies have two pairs of membranous wings each with numerous crossveins, the hindwing broader than the fore, but in some species the wings are reduced and in others they are altogether absent.

This key deals only with the larvae, and of all the keys in this series, is the simplest and least demanding.  Identification of larval stoneflies to family level can be based entirely on the configuration of the abdominal gills.  Eustheniidae carry lateral gills on abdominal segments 1-5 or 1-6.  Gripopterygidae carry a tuft of fine gill filaments on the terminal segment.  Austroperlidae carry 3-5 fingerlike gills on the terminal segment, with further fingerlike gills on the cerci or anal plate in some species.  Notonemouridae have no external gills at all.  Additional characters assist in identifying specimens to family when the gills are small and hidden under sternite 10.

Posted By: Site Admin Last Updated: Aug 9, 2012 Views: 7396
Key Author(s): CSIRO Entomology Key Version: 1.1
Western Australia Pasture selection tool

Pasture selection tool for Western Australia

Posted By: Site Admin Last Updated: Oct 22, 2008 Views: 7396
Lasiocnemus key Dikow 2007

Key to species of Lasiocnemus (Insecta: Diptera: Asilidae) based on the taxonomic revision by Dikow 2007 (doi:

Posted By: Site Admin Last Updated: Apr 22, 2015 Views: 7390
Key Author(s): Torsten Dikow
Key to Orders of Trichomycetes

Trichomycetes are a cosmopolitan group of fungi and protists that grow obligately in the guts of insects, crustaceans, and millipedes that live in freshwater, marine, or terrestrial habitats. The taxonomy of these organisms is based primarily on morphology of the vegetative thallus; spore type and dimensions; host; and habitat.

Posted By: Site Admin Last Updated: Jul 27, 2016 Views: 7367
Key Author(s): R.W. Lichtwardt, University of Kansas, Lawrence KS USA and D.B. Strongman, Saint Mary’s University, Halifax NS Canada Key Version: 1.0
The moss genus Orthotrichum in Switzerland

Taxonomic scope: Bryophytes

Description: The moss genus Orthotrichum is of particular interest in monitoring air pollution. This key contains 31 species known from Switzerland and adjacent countries. Nearly all characters are illustrated with microscopical photographs.

For more information:

Posted By: Site Admin Last Updated: Mar 8, 2016 Views: 7362
Key Author(s): H. Hofmann, M. Lüth & A. Büschlen Key Version: 1.0
© 2021
Terms of Use Privacy Policy