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: 4564
Key Author(s): CSIRO Entomology Key Version: 1.1
Key to Families of Australian Aquatic Crustacea

This key attempts to cover all families of Crustacea known to occur in Australian inland waters, fresh or salt, permanent or temporary, running or still.

The first two characters enable a quick assignment to subclass or order. Use these when the higher-level taxon is determinable at a glance.

The next 13 characters together have much the same effect as character 1 or character  2 although the division of the taxa may not exactly follow conventional subclass/order boundaries. Use these characters to narrow the possibilities by summarising the individual features of a specimen when the higher-level taxon is not clear.

The remaining characters (37 in all) in effect form eight separate "sub-keys", one to each subclass or order for which more than one family is present in Australian inland waters. These sub-keys are listed in conventional museum-drawer order from Anostraca to Decapoda, except that for convenience the two classes with bivalved carapace (Conchostraca, Ostracoda) are dealt with together. The selection of any character-state from a sub-key will cause all other subclasses/orders to be eliminated. Hence this action, too, is like making a selection from character 1.

Throughout the key we have tried to avoid using characters which are difficult to see, which require dissection, or which depend on the specimen being fully adult or of one particular sex. Dichotomous, printed keys often offer a hierarchic identification process in which successive steps represent identification to class, order, suborder, and superfamily level. A difficulty with such keys is that the characters which indicate a higher-taxon may be less immediately obvious than those which indicate a lower ranking. For example, some superfamily may be recognised by a character of the mandibular palp but the local genus may have unique, bright green antennae.Faced with situations of that sort, we have opted to mention the antennae and ignore the palps. The result is a key which should work rather readily for the known fauna, but undescribed and unrecorded species may or may not key out as well as they would in a conventional key. Further, the information content of the key in some instances will not suffice for a family or superfamily synopsis.

In other words, this key is designed for putting a name on a specimen. We have been less concerned with describing (or redescribing) higher taxa, with summarising the hierarchy of names, or with providing taxonomists with clues to where a new species might be put.

Without a thorough first-hand knowledge of every species in every sub-group of the Crustacea (an impossible requirement even for the specialist), a key such as this must rely largely on published descriptions, revisions, and previous keys. Very often,  important data which would allow the easy identification of specimens are missing from such sources (taxonomists tend to write in terms of the taxonomic hierarchy). Thus, there are some places at which unnecessarily obscure characters had to been used, simply for lack of knowledge. Hopefully, the number of these instances will be reduced in later editions.

We thank the compilers of earlier keys, describers and revisors of taxon groups, for the provision of information on which this key has been based. Acknowledgement for the use of images is shown o the face of the relevant image.

Please note:

1. Many juveniles of aquatic Crustacea simply cannot be identified to family. For those the key should produce a correct but incomplete result.

2. New species may key correctly, incorrectly, partially, or not at all. That is in the nature of being new.

Posted By: Site Admin Last Updated: Aug 8, 2012 Views: 4664
Key Author(s): CSIRO Entomology Key Version: 1.1
Key to Orders of Australian Aquatic Arthropoda

This intermediate-level key covers the huge and diverse phylum Arthropoda.

The major classes of arthropod found in inland waters are Crustacea (all life stages) and Insecta (adults and/or larvae and/or pupae).  Lesser components of the fauna include Arachnida (mites, spiders), Myriapoda (millipedes) and Collembola (springtails).

Arthropods have in common a segmented body which is differentiated into regions, an external chitinous cuticle, and paired jointed appendages (as gills, swimming organs, walking legs, antennae, chelicera, etc.).  Appendages may be absent in some juvenile forms.  The mouth is more or less anterior, the gut usually straight and the anus sub-terminal.  The nervous system is patterned on a dorsal brain with paired ventral nerve cords and paired ganglia in each body segment.  An open, dorsal heart circulates haemolymph around the body cavity.

Some arthropods appear worm-like, notably apodous (maggot-like) insect larvae although the body always is clearly segmented and there almost always is a well-developed head with biting, jointed mouthparts.  In some families of Diptera (true flies) the larvae are legless, eyeless, and apparently headless (the head is small and retractile).  Paired unjointed prolegs, hooks, gills or other appendages often are present in these species.

This Key to Arthropoda takes (1) minor groups directly to family level, (2) others to ordinal level or else to artificial but readily recognisable groupings, within which each component is then identified to family level in a separate key, (3) some Crustacean taxa to intermediate levels, in which families are recognised but not keyed.

Posted By: Site Admin Last Updated: Aug 8, 2012 Views: 4219
Key Author(s): CSIRO Entomology Key Version: 1.1
Key to Phylum and Class of Australian Aquatic Invertebrates

This is the central key in this series of linked Keys to Australian Aquatic Macro-Invertebrates.  The key is designed to identify any specimen to a level corresponding approximately to Phylum or Class.

For most major invertebrate groups this key points directly to a family-level subkey.  For arthropod taxa, it points to a Key to Arthropoda as an intermediate-level key.  Groups for which no subkey is provided can be identified further using the notes and illustrations given against the relevant terminating taxon in this key.  In most cases, these notes allow identification to family level, but a few taxa, namely rotifers, gastrotrichs and nematodes, are taken only to ordinal level.


This set of keys was prepared mainly from the primary and secondary taxonomic literature and from existing dichotomous keys.  Expert advice and assistance was sought in some cases.  References and acknowledgments with respect to each key are given in the text which accompanies that key.

Taxon coverage

These keys cover the free-living macroscopic invertebrate taxa known to occur in Australian inland waters, including introduced taxa.  Taxa represented in fresh or saline, running or still, permanent or ephemeral inland waters are included, but wholly marine taxa which may extend into upper estuarine habitats, and wholly terrestrial taxa some species of which extend into intermittently wet habitats, have generally been omitted from the keys.

The aim has been to key free-living organisms to family level.  Only higher-level identification is provided for (i) taxa in which all species are obligate parasites, (ii) taxa mainly comprised of organisms too small to be retained by a 250mm mesh sorting sieve, and (iii) semi-aquatic, damp-soil and semi-marine (upper estuarine) taxa.

Some taxa are not taken to family level because the taxa are poorly known.  For these the key runs to whatever level can be achieved on current knowledge.  For example, phylum Nematoda is taken only to order (and then only by way of taxon notes) and part of Platyhelminthes is taken only to superfamily level.

Geographic coverage

Our aim has been to cover the whole of Australia, but not all source documents specify whether offshore territories, etc, are included.  Thus, coverage of tropical/subtropical island territories, and Antarctic/sub-antarctic territories may not be complete for some taxonomic groups.

Ecological coverage

Our aim has been to cover all inland waters: fresh or salt, flowing or still, including marshlands and temporary waters.  The dividing line between riverine and estuarine habitats is hazy, as are also the line between marine littoral and coastal saltmarsh and that between wetlands generally and damp terrestrial environments.

At genus or species level the decision what to include or exclude could be problematic, but at family level it is less so.  For the most part, families which are strongly represented in marginally-aquatic environments also include one or more truly aquatic species, and thus are included in the keys.  Where this is not the case we err on the side of including taxa which might be found in aquatic samples.  Where sources differ as to whether a family has aquatic members we treat it as if it has.

Posted By: Site Admin Last Updated: Aug 8, 2012 Views: 4801
Key Author(s): CSIRO Entomology Key Version: 1.1
Key to Families and Subfamiles of Water Mites (Hydracarina) in Australia
The Hydracarina, commonly called 'water mites', includes more than 5000 named species worldwide.  In Australia there are 413 described species in 89 genera, representing 22 families (Harvey 1998).  Larval water mites are 6-legged and are extremely heteromorphic relative to nymphal and adult mites.  This key is designed for identification of adults (which can be recognised by the presence of a genital opening); however, nymphs may be identifiable for some taxa.  Males can be differentiated from females by the presence of a complicated group of internal sclerites, the 'ejaculatory apparatus', associated with the genital opening. 

Water mites are parasitic on insects as larvae and are predatory as deutonymphs and adults.  A few taxa are parasitic on bivalves or crayfish in their postlarval stages (Walter & Proctor 1999). 

Posted By: Site Admin Last Updated: Aug 6, 2012 Views: 4774
Key Author(s): CSIRO Entomology Key Version: 1.1
Key to Class and Order of Australian Aquatic Flatworms

The phylum Platyhelminthes (flatworms) is divided into three classes and a large number of orders and families.  The class Turbellaria contains free-living and commensal species, and the majority of aquatic flatworms are members of this class.  Classes Trematoda (= flukes) and Cestoda (= tapeworms), contain parasitic worms, but some Trematoda go through one or more free-living dispersive stages.  This key covers aquatic free-living turbellarians at family-group level, ectoparasitic trematodes (fish flukes, etc.) at order-level, and the final aquatic stage (cercaria) of the endoparasitic trematodes of some terrestrial vertebrates (family Fasciolidae: sheep liver fluke, etc.).  Other animals which could readily be mistaken for flatworms and are included in this key include Nemertea (ribbon worms), Hydridae (some Hydra-like Cnidaria), Tardigrada (tardigrades), and some families of segmented worms (Annelida).

Posted By: Site Admin Last Updated: Aug 6, 2012 Views: 4710
Key Author(s): CSIRO Entomology Key Version: 1.1
Relhania and Macowania groups

Key to the southern African genera in the Relhania and Macowania groups in the tribe Gnaphalieae (Antithrixia, Arrowsmithia, Comborhiza, Leysera, Macowania, Nestlera, Oedera, Relhania, Rhynchopsidium and Rosenia)

Posted By: Site Admin Last Updated: Feb 22, 2012 Views: 5430
Key Author(s): M. Koekemoer Key Version: 1.0
Key to Reticulitermes spp. of Georgia

 Identify the all endemic species of Reticulitermes spp. found in Georgia, USA

Posted By: Site Admin Last Updated: Jan 10, 2012 Views: 4423
Key Author(s): Su Yee Key Version: 1.0

Current version. The current version of the Key was developed as a special joint project between Emma McLarnon (BSc Biology, Leeds University, 2008 – 2012; work placement at Kew 2010 - 2011) and the Malpighiales Team at Kew (Gill Challen, Sue Zmarzty).

Taxonomic Scope: all genera of Achariaceae, Centroplacaceae Euphorbiaceae, (Flacourtiaceae), Gerrardinaceae, Pandaceae, Peraceae, Phyllanthaceae, Picrodendraceae, Putranjivaceae, Salicaceae, (Samydaceae). Gerrardinaceae (Huerteales) is also included because its single genus, Gerrardina, has only recently been excluded from Salicaceae. Flacourtiaceae is not recognised, its genera now belong to Achariaceae and Salicaceae. Samydaceae is not recognised.
Neotropical and subtropical Euphorbiaceae s.l. Parts of the Key treating neotropical (and subtropical) Euphorbiaceae s.l. have been upgraded and link to the Malpighiales Scratchpad, which provides genus descriptions and image galleries. 
Taxonomic standards: Angiosperm Phylogeny Group 3 (APG 3;; World Checklist of Selected Families (; for Centroplacaceae, Euphorbiaceae, Pandaceae, Peraceae, Phyllanthaceae, Picrodendraceae and Putranjivaceae).
Geographic standard: Brummitt, R.K. 2001 onwards. World Geographical Scheme for Recording Plant Distributions edn 2. International Working Group on Taxonomic Databases For Plant Sciences (TDWG). Hunt Institute for Botanical Documentation
Carnegie Mellon University, Pittsburgh.  (

Software: Lucid3, version 3.5; Lucid Translator.
Posted By: Site Admin Last Updated: Nov 11, 2011 Views: 5674
Key Author(s): Emma McLarnon and the Malpighiales Team at Kew (Gill Challen, Sue Zmarzty) Key Version: 1.0
Identifly 2: The South African Sarcophaginae

About the key: The flesh flies (Family Sarcophagidae) are comprised of three subfamilies Sarcophaginae, Miltograminae and Paramacronychiinae. This project proposes to focus on members of the subfamily Sarcophaginae found within South Africa. Identifying flesh flies is generally recognized as a difficult challenge because the group is rather uniform in its external morphology. The identification of species within this subfamily is most reliably based on examination of the characters of the male genitalia. The only comprehensive key to the African flesh flies is an out of date, ordinary dichotomous text key by Zumpt (1975), but it is difficult to use because of its terminology, and the constraints imposed by having to start at the beginning of the couplets. No other comprehensive keys are available for Africa. For the mentioned reasons, a clearly illustrated, modern key would be invaluable. This has been provided by creating online resources (a scratchpad: SARCBYTES) and a digital key for 2 genera (comprising 96 species) for the South African region.

Current version: The current version of the key was developed as an honours project by C-L. Clitheroe (BSc(Hons) Zoology, Rhodes University) under the Supervision of Professor Martin H. Villet, Prof. of Entomology, Rhodes University. It is probably the first of many versions. It is heavily reliant on images, (microphotographs) taken by the author and many diagrams; copyrighted, provided with permission, from Lehrer, A.Z and Pape, T.

Taxonomic Scope: All described species of Sarcophaginae (Diptera: Sarcophagidae) of South Africa.

Taxonomic standards: PAPE, T. (1996) Catalogue of the Sarcophagidae of the world (Insecta: Diptera). Memoirs of Entomology, International, 8, 1–558.

Software: Lucid3.3.

Author: Crystal-Leigh Clitheroe

Posted By: Site Admin Last Updated: Nov 8, 2011 Views: 4880
Key Author(s): Crystal-Leigh Clitheroe Key Version: 1.0
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