File:Paleolimulus signatus (fossil horseshoe crab) (Wood Siding Formation, Upper Pennsylvanian; southwest of Maple Hill, Wabaunsee County, Kansas, USA) 1.jpg

English: Paleolimulus signatus (Beecher, 1904) - fossil horseshoe crab from the Pennsylvanian of Kansas, USA. (USNM 484410, United States National Museum - National Museum of Natural History, Smithsonian Institution, Washington D.C., USA) (= specimen in figure 4F of Babcock et al., 2000) (centimeter scale in the background)

Horseshoe crab fossils are relatively uncommon in the rock record. The fossil seen here, from the Pony Creek Shale Lagerstätte of eastern Kansas, is the prosoma, or cephalothorax, which is the "head" of the horseshoe crab. The abdomen and telson are absent - they became disarticulated by decay of soft connective tissues. The paleoenvironment of this fossil is an inferred tidal flat facies (see Babcock et al., 2000).

Classification: Animalia, Arthropoda, Chelicerata, Xiphosurida, Limulina, Paleolimulidae

Stratigraphy: Pony Creek Shale Lagerstätte, Pony Creek Shale Member, Wood Siding Formation, upper Wabaunsee Group, Virgilian Stage, Upper Pennsylvanian

Locality: ~2 miles southwest of Maple Hill, northeastern Wabaunsee County, northeastern Kansas, USA (along north section line, section 35, T11S, R12E, Maple Hill, Kansas 7.5' topographic quadrangle)

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Reference cited:

Babcock et al. (2000) - Paleolimulus, an early limuline (Xiphosurida), from the Pennsylvanian-Permian Lagerstätten of Kansas and taphonomic comparison with modern Limulus. Lethaia 33: 129-141.