Arrow worms from the Devonian of the Holy Cross Mountains

Previously unidentified small phosphatic spines from the Devonian of the Holy Cross Mountains have been included into arrow worms (phylum Chaetognatha), which is a widespread group of marine invertebrates. The phosphatised grasping spines of chaetognaths are mostly known form the lowermost Paleozoic, therefore, the described fossils are unique remnants of such organic materials. Due to remarkable differences in the construction of the studied spines, compared to Lower Paleozoic forms, they have been included into a new genus and species, Phakeloides polonicus gen. et sp. nov.