TABLE 1. Summary of documented Recent xiphosurids with abnormalities.

Reference and figure number (where given) Abnormality Species Possible Cause
Packard (1870, figure 36). Refigured in Bateson (1894, figure 143), and Gudger (1935, no figure number) Forked telson bifurcating at the last third of the sagittal length Limulus polyphemus Not stated
Osburn (1911, no figure number). Refigured in Gudger (1935, no figure number) Double telson bifurcating at opisthosomal joint Limulus polyphemus Moulting
Gravier (1930, figure 1) Forked telson bifurcating halfway sagittal length Tachypleus sp. Mechanical damaged during early development
Gudger (1935, no figure number) Forked telson bifurcating in the last fifth of the sagittal length Limulus polyphemus Moulting
van der Meer Mohr (1935, figures 2–4) Shortened processes, pretarsus and apotele of pushing legs Tachypleus gigas (Müller, 1785) Not stated
van der Meer Mohr (1935, figure 1) Slit-like injury to posterior cephalothorax Tachypleus gigas Not stated
van der Meer Mohr (1941) (not figured) Shortened processes, pretarsus and apotele of pushing legs Tachypleus gigas Predation or mating
van der Meer Mohr (1941) (not figured) Curved telson Tachypleus gigas Predation or mating
van der Meer Mohr (1941) (not figured) Removal and recovery of moveable spines Tachypleus gigas Predation or mating
Bursey (1977) (not figured) Amputated legs (specific leg not stated) with thickened endocuticle Limulus polyphemus Not stated
Shuster Jr (1982, figure 14. A) Double telson bifurcating at the opisthosomal joint Limulus polyphemus Mechanical injury
Shuster Jr (1982, figure 14. B–D) Forked telsons. B and C bifurcate halfway along the sagittal length. D bifurcates at the distal section Limulus polyphemus Mechanical injury
Shuster Jr (1982, figure 14. E) Enlarged axial spine Limulus polyphemus Mechanical injury
Shuster Jr (1982, figure 14. F) Kink halfway along the telson with enlarged axial spine Limulus polyphemus Mechanical injury
Botton and Loveland (1989) (not figured) Injured book gills, missing or short telsons Limulus polyphemus Predation by gulls, mechanical injury
Jell (1989, figure 1) Left anterior cephalothoracic margin buckled. Left opisthosomal section with two fewer moveable spines than the right Limulus polyphemus Mechanical deformation post-moult. Rocks or waves
Brockmann (1990, figure 3) Injured female posterior opisthosoma Limulus polyphemus Injuries from mating
Schaller et al. (2004) and Schaller et al. (2005) (not figured) Loss of male pedipalp Limulus polyphemus Injuries from mating
Schaller et al. (2004) (not figured) Hole through the dorsal cephalothoracic section Limulus polyphemus Predation by gulls
Duffy et al. (2006) (not figured) Decayed lateral eyes, missing or damaged prosomal appendages Limulus polyphemus Disease, ageing, mechanical injury
Shuster Jr (2009, figure 1) Butterfly spawning scars on female opisthosoma Limulus polyphemus Injuries from mating