Instead of taking the shape of a scorpion-like stinger, the telson of Carcinosoma was slightly flattened and expanded anteriorly. The telsons of most eurypterids ends in a spike but the telson of Carcinosoma ended in a small and expanded structure with distinct segmentation, fossils preserving ten segments (though a small portion of the structure is not preserved, making more segments possible), otherwise not definitely reported from a eurypterid. The only other eurypterid from which a segmented structure occurring as part of the telson has been reported in is the slimonid Salteropterus abbreviatus. With such segmentation reported from two separate eurypterid genera, it is possible that the eurypterid telson is actually developed from a formerly normal abdominal segment and is thus not homologous to the telson of other arthropod groups. Further studies of Salteropterus has since revealed that the perceived "segmentation" of its "post-telson" was misinterpreted ornamentation of an elongated and unusually shaped telson and not actual segmentation, making the segmentation of Carcinosoma unique.
