Paucijaculum

Paucijaculum
Temporal range: Moscovian,
~311–307 Ma
Paucijaculum samamithion specimen from Mazon Creek Pit 11
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chaetognatha
Genus: †Paucijaculum
Schram, 1973
Species:
†P. samamithion
Binomial name
†Paucijaculum samamithion
Schram, 1973

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. 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

Closeup of the rounded tail fin of Paucijaculum samamithion

Paucijaculum grew up to 3 centimetres (1.2 in) long and had incipiently developed fins alongside a circular tail fin.

Most specimens are poorly preserved and lack detail.

References

  1. ↑ P. A. Allison (1987). "A new cephalopod with soft parts from the Upper Carboniferous Francis Creek Shale of Illinois, USA". Lethaia. 20 (78): 117–121. doi:10.1111/j.1502-3931.1987.tb02028.x.
  2. ↑ "Paucijaculum Schram, 1973". GBIF. Retrieved 9 February 2026.
  3. 1 2 3 4 F. R. Schram. (1973). Pseudocoelomates and a nemertine from the Illinois Pennsylvanian. Journal of Paleontology 47:985-989
  4. ↑ Chen, Jun-Yuan; Huang, Di-Ying (2002-10-04). "A Possible Lower Cambrian Chaetognath (Arrow Worm)". Science. 298 (5591): 187–187. doi:10.1126/science.1075059. ISSN 0036-8075.
  5. ↑ "1" Fossil Arrow Worm (Paucijaculum) Pos/Neg- Illinois". FossilEra. Retrieved 11 February 2026.