#trigonotarbida

[sinasinasinas]

Ukrainian trigonotarbid from Upper Carboniferous of Horlivka.

[ostracartderms]

Wow palaeocharinus where did you find that great icosidodecahedron

[extinctanimals]

Trigonotarbida, an order of spider-like arachnids that lived from the late Silurian through the early Permian.

[astronomy-to-zoology]

Order: Trigonotarbida

...an extinct group of arachnids that lived from the late Silurian to early Permian period. Trigonotarbids superficially resembled spiders but unlike spiders they have tergites on the dorsal side of their abdomen that are divided into median and lateral plates, they also lacked silk-spinning spinnerets. Trigonotarbids were a very diverse group of animals with most species found in the Carboniferous, although some were found in the late Silurian (415 mya), making them some of the first terrestrial animals. And as such they were very important in early ecosystems.

Phylogeny

Animalia-Arthropoda-Chelicerata-Arachnida-Trigonotarbida

Images: Dunlop,1996 and Tommy