A unique example of the Late Cretaceous horseshoe crab Tachypleus syriacus preserves transitional bromalites

Figures & data

Fig. 1. Examined Tachypleus syriacus with a cololite transitioning to a coprolite and modern xiphosurid scat. A, Complete specimen, AMNH-IF 141422. B, Close up of cololite transitioning to coprolite. C, Close up of prosomal border showing nodules (white arrows). D, Example of modern xiphosurid scat, morphologically comparable to observed coprolite.

Table 1. Summary of previously documented xiphosuran cololites. Ordered by time period and higher taxonomic assignment following Bicknell & Pates (2020) and Lamsdell (2020).

Taxon	Family	Formation	Age	Reference
Pickettia carteri (Eller, 1940)	Kasibelinuridae	Cattaraugus Formation, Pennsylvania, USA	Late Devonian (Fammenian)	Bicknell et al. (2019b, fig. 1A, E)
Paleolimulus mazonensis Bicknell, Naugolnykh & McKenzie, 2022b	Paleolimulidae	Mazon Creek Konservat Lagerstätte, Carbondale Formation, Illinois, USA	Pennsylvanian (Moscovian)	Bicknell et al. (2022b, fig. 3C, D, 5C0
Tachypleus syriacus	Limulidae	Sannine Formation, Lebanon	Late Cretaceous (Cenomanian)	Bicknell et al. (2019a, fig. 2, 3d)
Tachypleus syriacus	Limulidae	Sannine Formation, Lebanon	Late Cretaceous (Cenomanian)	This work

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