Early Spider-like Arachnids
Among the oldest known land arthropods are Trigonotarbids, members of an extinct order of spider-like arachnids.
Sharing many superficial characteristics with spiders, Trigonotarbida were terrestrial, respired through book lungs, and walked on eight legs with two additional legs adapted to use around their mouth. Arguments still remain open as to whether they possessed the ability to create silk. This had been popular thought for quite some time, until an unpublished fossil was described with distinct microtubercles on its hind legs, akin to those used by spiders to direct and manipulate their silk.
Regardless, Trigonotarbida are not considered true-spiders. They are generally accepted as an independent early offshoot within the Arachnida clade, and not directly ancestral to modern spiders.
Read more about this topic: Evolution Of Spiders
Famous quotes containing the word early:
“I doubt that I would have taken so many leaps in my own writing or been as clear about my feminist and political commitments if I had not been anointed as early as I was. Some major form of recognition seems to have to mark a woman’s career for her to be able to go out on a limb without having her credentials questioned.”
—Ruth Behar (b. 1956)