Arachnida
Spiders, mites, scorpions, whipscorpions, pseudoscorpions
This tree diagram shows the relationships between several groups of organisms.
The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.
You can click on the root to travel down the Tree of Life all the way to the root of all Life, and you can click on the names of descendent subgroups to travel up the Tree of Life all the way to individual species.
For more information on ToL tree formatting, please see Interpreting the Tree or Classification. To learn more about phylogenetic trees, please visit our Phylogenetic Biology pages.
close boxReferences
Braddy, S. J., R. J. Aldridge, S. E. Gabbott, and J. N. Theron. 1999. Lamellate book-gills in a late Ordovician eurypterid from the Soom Shale, South Africa: support for a eurypterid-scorpion clade. Lethaia 32:72-74.
Coddington, J. A. and R. K. Colwell. 2001. Arachnids. Pages 199-218 in Encyclopedia of Biodiversity. Volume 1. S. A. Levin, ed. Academic Press, San Diego, California.
Dunlop, J. A. and M. Webster. 1999. Fossil evidence, terrestrialization and arachnid phylogeny. Journal of Arachnology 27:86-93.
Giribet, G., G. D. Edgecombe, W. C. Wheeler, C. Babbitt. 2002. Phylogeny and systematic position of Opiliones: a combined analysis of chelicerate relationships using morphological and molecular data. Cladistics 18:5-70.
Harvey, M. S. 2002. The neglected cousins: What do we know about the smaller Arachnid orders? Journal of Arachnology 30(2):357-372.
Harvey, M. S. 2007. The smaller arachnid orders: diversity, descriptions and distributions from Linnaeus to the present (1758 to 2007). Pages 363-380 in: Zhang, Z.-Q. & Shear, W.A., eds. Linnaeus Tercentenary: Progress in Invertebrate Taxonomy. Zootaxa 1668:1–766.
Shultz, J. W. 1989. Morphology of locomotor appendages in Arachnida - evolutionary trends and phylogenetic implications. Zoological Journal of the Linnean Society 97:1-56.
Shultz, J. W. 1990. Evolutionary morphology and phylogeny of Arachnida. Cladistics 6:1-38.
Shultz, J. W. 1994. The limits of stratigraphic evidence in assessing phylogenetic hypotheses of recent arachnids. Journal of Arachnology 22:169-172.
Shultz, J. W. 2007. A phylogenetic analysis of the arachnid orders based on morphological characters. Zoological Journal of the Linnean Society 150(2):221–265.
Starobogatov, Y. I. 1990. System and phylogeny of Arachnida (analysis of morphology of paleozoic groups) [Russian]. Paleontologicheskii Zhurnal 24:4-17.
Weygoldt, P. 1998. Evolution and systematics of the Chelicerata. Experimental & Applied Acarology 22:63-79.
Weygoldt, P. and H. F. Paulus. 1979. Untersuchungen zur Morphologie, Taxonomie und Phylogenie der Chelicerata. 1. Morphologische Untersuchungen.. Zeitschrift für Zoologische Systematik und Evolutionsforschung 17:85-116.
Weygoldt, P. and H. F. Paulus. 1979. Untersuchungen zur Morphologie, Taxonomie und Phylogenie der Chelicerata. 2. Cladogramme und die Entfaltung der Chelicerata. Zeitschrift für Zoologische Systematik und Evolutionsforschung 17:177-200.
Wheeler, W. C. and C. Y. Hayashi. 1998. The phylogeny of the extant chelicerate orders. Cladistics 14:173-192.
Information on the Internet
- International Society of Arachnology
- American Arachnological Society.
- British Arachnological Society.
- The Arachnology Home Page.
- Introduction to the Cheliceramorpha. UCMP Berkeley.
- Arachnodata. The Arachnological Information and Coordination Agency.
- Arachnida Catalog. Department of Entomology, Texas A&M University.
- Arachnid Origins and Evolution. Jason Dunlop's home page. Museum für Naturkunde Berlin.
- Spiders on the Web. Peter Bryant's photos of spiders and other arachnids.
- The World of Spiders and Scorpions. Images from Thais in 2000.
Title Illustrations
| Scientific Name | Dermacentor occidentalis |
|---|---|
| Location | Olympia, Thurston County (Washington, US) |
| Comments | Pacific coast tick |
| Specimen Condition | Live Specimen |
| Source | Dermacentor occidentalis |
| Source Collection | CalPhotos |
| Copyright | © 2002 |
| Scientific Name | Smeringurus mesaensis |
|---|---|
| Location | Palm Desert (California, US) |
| Comments | California gold scorpion |
| Specimen Condition | Live Specimen |
| Source | Smeringurus mesaensis |
| Source Collection | CalPhotos |
| Copyright | © 2002 |
| Scientific Name | Argiope bruennichi |
|---|---|
| Location | Coastal grassland, Viareggio (Italy) |
| Specimen Condition | Live Specimen |
| Source | Argiope bruennichi |
| Source Collection | CalPhotos |
| Copyright | © 2001 |
About This Page
Page copyright © 1995
Page: Tree of Life
Arachnida. Spiders, mites, scorpions, whipscorpions, pseudoscorpions.
The TEXT of this page is licensed under the
Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media
featured on this page are each governed by their own license, and they may or may not be available
for reuse. Click on an image or a media link to access the media data window, which provides the
relevant licensing information. For the general terms and conditions of ToL material reuse and
redistribution, please see the Tree of Life Copyright
Policies.
Citing this page:
Tree of Life Web Project. 1995. Arachnida. Spiders, mites, scorpions, whipscorpions, pseudoscorpions. Version 01 January 1995 (temporary). http://tolweb.org/Arachnida/2536/1995.01.01 in The Tree of Life Web Project, http://tolweb.org/
