TRIGONOTARBID ARACHNIDS FROM THE PENNSYLVANIAN OF KANSAS

Trigonotarbids form a diverse order of extinct terrestrial Paleozoic arachnids. Superficially resembling spiders, trigonotarbids lack spinnerets and other autapomorphies of Araneae. Although trigonotarbids are common arachnids in Carboniferous coal deposits throughout the world, arachnids are uncommon fossils, making any occurrence a notable contribution to their record and worthy of description. The family Anthracomartidae, Haase, 1890, is comprised of trigonotarbids having opisthosomal tergites divided into five plates, while all other trigonotarbids have three. Two trigonotarbid arachnids are described from the Upper Pennsylvanian (Virgilian) of Kansas. Both specimens are referred to Anthracomartus sp., Karsch, 1882, the type genus of Anthracomartidae. Hesitation in diagnosing to the species level is a result of recent work on the family suggesting a revision is necessary, with many genera synonymized. This marks the first occurrence of trigonotarbids in Kansas, increasing the number of fossil arachnid orders known from the state.