Caudal Spine Morphology and Puncture Performance of Two Coastal Stingrays

Abstract A diagnostic characteristic of stingrays in the family Dasyatidae is presence a defensive, partially serrated spine located on tail. We assessed contribution caudal morphology puncture and withdrawal performance from two congeneric, co-occurring stingrays, Atlantic stingray, Hypanus sabinus, bluntnose say. Spines exhibited high degree morphological variability. Stingray spines were along 50.8% (H. sabinus) or 62.3% say) their length. say had greater number serrations each side (30.4) compared with H. sabinus (20.7) but pitch did not differ between species. quantified forces using porcine skin as model for human skin. Puncture significantly species, within say, force was than sabinus. incorporated micro-computed tomography scanning to quantify tissue mineral density found that both shaft more heavily mineralized base, midway (50%) length tip. The mineralization variability may create stiff structure can fracture once embedded target act an effective predator deterrent.