The Find-a-Spider Guide

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Spider Identification Guide

The majority of spider species are not easily identified by the non-expert. This is partly because individuals of two different species sometimes look very similar to one another or, conversely, two individuals of the same species show enough variability in physical appearance to be perceived as being different species. Visitors to this website who do not have an extensive knowledge of spider classification may even be confused or overwhelmed by the terminology associated with spider recognition. If you are such a person you might like to visit the identification conventions page that has now been added to the Find-a-spider website.

If your ambitions are more modest but you do have a spider you would like to identify, a good way to start might be to seek answers to at least some of the following questions:

1. What does your spider look like?
The physical characteristics of a spider are of great importance when its identity is being established. Each individual spider page included in this guide contains at least one image of the spider as well as some significant facts about it. If some of the terminology used is unfamiliar to you, visit the glossary page for a set of illustrated definitions.

2. What sex is your spider?
Males and females of the same spider species are sometimes very different in size, markings and general appearance. This is known as sexual dimorphism. All mature male spiders have the terminal segments of their palps modified for mating whereas the palps of females are like short legs. Conversely, on the underside of the abdomen of araneomorph females is a species-specific epigynum which the male lacks.

3. Is your spider an adult or is it an immature spiderling?
Most spiders pass through about five immature stages called instars before reaching adulthood although in rare instances maturity may be reached in fewer steps. These young instars (with the possible exception of the penultimate one) will normally be smaller than an adult of the same species. They can also be expected to have immature or non-existent mating apparatus and differences in marking patterns. Sometimes the sex of a living spider cannot be determined until it becomes an adult. For these reasons you may find some spider specimens impossible to identify with certainty.

Most species have a particular mating season, usually spring, summer or autumn, and for many species no mature males can be found except during this season. Egg sacs will often be found near the end of the mating season and immature spiders will generally be most common shortly after mating or in spring.

4. Did you find a web or egg sac as well as the spider?
The shape and general appearance of any web or burrow a particular spider has produced can often be used to verify its identity. Some species create net-like webs for trapping flying insects and the shapes and detailed construction of these are reproduced very faithfully by each species. Unfortunately, many webs are quite fragile and damage inflicted by a struggling insect or by a large animal could change the appearance of a spider's web to the point where it is no longer useful for classification purposes.

Spiders that burrow or build leafy retreats also tend to be remarkably consistent in the architecture of the home they have constructed for themselves. It is for this reason that some images of burrows, retreats and egg sacs are presented in this web site. It is usual for female spiders to enclose their eggs in an egg sac until the spiderlings hatch out, and once again the shape of this varies greatly from species to species. In some cases a semi-rigid sphere is produced but many spiders prefer to make a fluffy mass of silk or a flattened pillow. Occasionally, the shape and colour of the egg sac seem to involve deliberate camouflage.

5. Where did you find your spider?
Most spider species have habitats and geographic locations in which they are most common and this can sometimes be very useful for verifying the identity of a particular spider. On the other hand, individual spiders will occasionally be found in unexpected places, perhaps because of human intervention, so no identification should be made purely on the basis of the place where the spider was found.

SOME OTHER THINGS TO REMEMBER

You may now feel ready to commence comparing your spider with photos of named species but it might still be a good idea to first note the following additional details about the identification of spiders and the contents of this website:

  • Because this website was developed to identify spiders found in South-east Queensland its focus is on spider species found in this region. However, not all of the species featured are unique to Southern Queensland and may be found across Australia. Also, it is likely that spiders that are very similar to, but not exactly the same as, spiders featured in this guide at least belong to the same spider family and have similar functional characteristics. It should also be noted that the list of spiders featured in the guide is incomplete since many Australian spiders have yet to be described and assigned a scientific name and for some that are known to exist as distinct species no photographs were available for use on this website.

  • Correct identification of a spider may require some knowledge of spider anatomy. For this reason it might be beneficial for you to first examine the glossary page where you will find illustrated descriptions of spider surface anatomy as well as some other useful facts such as the differences in appearance caused by immaturity or sexual dimorphism.

  • As far as possible, the images displayed in this website are of living spiders shown as they normally appear in nature. On the other hand, a few spiders have been deliberately "posed" so that their distinguishing characteristics are easier to view. In order to see all of the distinguishing characteristics of a spider it is often necessary to disturb the spider, which many people are frightened to do. Please note that it is perfectly safe to view a spider through the sides of a glass bottle provided the lid is securely in place. Note also that many spider species are not equipped to climb glass surfaces and have a very limited ability to jump, although many tree-dwelling species may seem to have jumped as they drop to the ground when approached by a potential predator. In addition, many members of the (Salticidae and Oxyopidae) families have a noteworthy ability to spring horizonatlly or even upwards.

  • In a number of instances where no live specimen was available to photograph, spiders that have been kept in a preservative fluid have been used instead. This fact is marked on the individual images as appropriate. Preserved spiders typically exhibit some distortion of legs and other body parts and suffer significant colour changes when compared to the original living specimens.

  • Body size is an important consideration in establishing the identity of a particular spider. This generally will not be obvious in the images presented in this guide but the information supplied for each species will give approximate adult body lengths of both male and female specimens. Note that the body length data used here will include the abdomen, cephalothorax and retracted chelicerae but not the legs, fangs or spinnerets. Other authors may only provide measurements of the abdomen and carapace but this requires a closer inspection of the spider.

  • The classification of Australian spiders is far from complete. Many species names were first assigned more than 150 years ago and are currently being revised. Other species have yet to be formally described and thus do not have a scientific name at the present time. The name of the family to which a particular spider belongs has also been changed in many instances. Often a large family has been broken up into several smaller families, perhaps based on a generic or former sub-family name. Conversely, in a few cases groups of spiders have lost their family status and have instead have been added to other existing families. A good example of this is the Family Zoridae, which in 2014 was incorporated into the Family Miturgidae.

  • PLEASE NOTE: While some of the species names employed in this guide were supplied personally by arachnologists at Australian museums, notably the Queensland Museum (QM), many have instead been derived from the information in published research papers. Other identifications are based on photos and descriptions in comparatively recent monographs/websites written by authors with recognised expertise in spider taxonomy, including Ramon Mascord (RM) and Volker Framenau (VF) from the Western Australian Museum. Thus, where you find "(QM)" after the scientific name stated for a particular species this is intended to show that the name has been derived from information supplied by the Queensland Museum, although the spider itself usually will NOT have been examined by Museum staff so any errors of identification should not be attributed to them. The same will be true for all other sources of scientific names used here and for most species the actual source of the information can be accessed by clicking on the linked name or initials that follow the species name.

  • It must be understood that some of the scientific names used in this guide may no longer be accepted by most expert arachnologists or may change in the near future as individual spider families or genera are revised. Fortunately, it is usual for taxonomists to record all synonyms when renaming individual species. In the material presented in this guide scientific names that have become superseded will be stated only when they are ones that have been widely used in recently published books and articles intended for use by the general public.


Email Ron Atkinson for more information.    Last updated 1 April 2018.