Silk and the earliest spiders
Selden, Paul A. Paleontological Institute, University of Kansas, Lawrence, Kansas.
- Origin and evolution of silk
- Early fossil arachnids
- Links to Primary Literature
- Additional Readings
Spiders are familiar animals whose intricate webs have been marveled at by humans for thousands of years. Silk production is not unique to spiders; indeed, silk is made by arthropods as diverse as silkworms, the spectacular glowworms of New Zealand, and other arachnids including pseudoscorpions. All spiders produce silk, and the possession of silk glands in the abdomen (opisthosoma) is a characteristic feature of the arachnid order Araneae. Other characters of spiders include venom glands in the forepart of the body (prosoma), which emerge from a pore in the cheliceral fang, and the presence of hairless fangs separates spiders from closely related arachnids such as Amblypygi (tailless whip scorpions). During spider evolution, not all of these characters appeared at the same time. For example, the most primitive living spiders, members of the suborder Mesothelae, lack venom glands and hence have no pore in the fang. All other spiders (the suborder Opisthothelae) possess venom glands, except rarely when they have been secondarily lost. New evidence from 380-million-year-old fossil spiderlike animals shows that they lacked venom glands. However, like true spiders, they had silk glands and spigots. The weaving apparatus was different, though, and thus we can speculate on how the silk was used. Arachnologists can now see more clearly the evolutionary pathway of silk production and silk use in early arachnids.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information