Paucijaculum is an extinct genus of chaetognath from the Carboniferous age Francis Creek Shale and Carbondale Group of Illinois, United States. It contains one species, Paucijaculum samamithion.
Discovery and naming The holotype is FMNH PE116 and it was discovered no later than 1972 inside an ironstone concretion at Pit 11 at Mazon Creek.F. R. Schram. (1973). Pseudocoelomates and a nemertine from the Illinois Pennsylvanian. Journal of Paleontology 47:985-989 Schram (1973) named and described Paucijaculum samamithion as the oldest known and first known fossil chaetognath; this was accepted until Eognathacantha was identified from the Cambrian Stage 3 in China.
Additional specimens have been found in the Carbondale Group near Essex, Illinois.
Description
Paucijaculum grew up to long and had incipiently developed fins alongside a circular tail fin.
Most specimens are poorly preserved and lack detail.
References