 "Cartorhynchus" appears to have had 5 neck vertebrae and 26 back vertebrae, for a total of 31 pre-sacral vertebrae (vertebrae in front of its sacrum, or hip).Along with "Sclerocormus" (with 34 pre-sacrals) and "Chaohusaurus" (with 36 pre-sacrals), "Cartorhynchus" falls within the typical range for terrestrial animals, unlike the 40 to 80 pre-sacrals common among the more derived (specialized) ichthyopterygians.Unlike "Sclerocormus", the neural spines projecting from the top of the vertebrae in "Cartorhynchus" were relatively narrow and inclined instead of broad and flanged.