Classifying spiders

By studying and classifying spiders, scientists learn about their diversity, biology, distribution and evolutionary relationships.

Australia's described spider fauna consists of about 2000 species, perhaps as little as half of the total spider fauna. Most of these species come from the eastern and southern regions of Australia. Numbers of species are are continually changing due to constant research and new species discoveries.

World-wide, more than 40,000 species of spiders have been described. To make sense of this diversity scientists recognise taxonomic groups, of which the most natural is the species. Species are separated from each other by differences in the structure of their mating organs (genitalia). Related species share similar genitalic structural patterns.

Related species are classified into groups called genera and related genera into larger groups called families.

• Phylum - Arthropoda
• Class - Arachnida
• Order - Araenae
• Suborder Mesothelae - segmented spiders
• Suborder Opisthothelae - includes all other spiders
  • Infraorder Mygalomorphae - 'ancient' spiders such as tarantulas, trapdoor and funnel web spiders). Mygalomorph spiders have reduced spinnerets, dagger-like fangs and two pairs of book lungs similar to ancestral ground-living spiders.
  • Infraorder Araneomorphae - 'modern' spiders include the vast majority of spiders such as orb weavers, redbacks and huntsman spiders. Araneomorph spiders have pincer-like fangs, most have 6 spinnerets, and one pair of book lungs plus a pair of air tubes (tracheae)

At each of these taxonomic level a unique set of structural identifying features (morphological characters) identifies the particular taxonomic group. Characters may be derived from examination of chromosomal, protein and genomic (DNA, RNA) data. Relationships between groups of species, genera, families, etc. can be studied by examining the distribution of derived characters within the group using cladistic techniques.

Taxonomic keys are used to seperate spiders into different families, genera and species. Keys are constructed using key structural features of the spiders. Taxonomic descriptions and revisions, with keys and data on distribution patterns, relationships and biology, are published in scientific journals.

Australian mygalomorph familes inlcude:

• Family Actinopidae: Mouse spiders
• Family Hexathelidae: Funnel-web spiders
• Family Idiopidae: Trapdoor spiders
• Family Theraphosidae: Australian tarantulas

Australian araneomorph familes inlcude:

• Family Araneidae: including Orb weaving, bird-dropping and bolas spiders
• Family Austrochilidae: Tasmanian cave spiders
• Family Clubionidae: Sac spiders
• Family Deinopidae: Net-casting spiders
• Family Desidae: Lace web or house spiders
• Family Gnaphosidae: Ground spiders
• Family Hersiliidae: Two-tailed spiders
• Family Lamponidae: White tailed spiders
• Family Lycosidae: Wolf spiders
• Family Nephilidae: Golden orb spiders
• Family Nicodamidae: Red and black spiders
• Family Pisauridae: Water or nursery web spiders
• Family Salticidae: Jumping spiders
• Family Scytodidae: Spiting spiders
• Family Sparassidae: Huntsman spiders
• Family Tetragnathidae: Long jawed spiders
• Family Theridiidae: Comb-footed spiders
• Family Thomisidae: Flower or crab spiders

Find out more information on many of these spider families using the Spider Finder

There is much more collecting, observational and descriptive work to be done on Australia's spider fauna. We need to gather more information about how Australian spiders live - their behaviour, ecology and life histories. With so much to find out, the study of spiders is a rewarding field for both professional and amateur researchers.