Sequence of polyandrous mating events in southern stingrays. Arrows indicate clasper orientation. (a) ‘Close following’: The
posterior orientation of two males to the mature female. Male 1 (left) can be identified throughout the sequence by his shortened tail.
(b) ‘Pre-copulatory-biting’: Male 1 initiates copulation by grasping the margin of the female’s pectoral disc in his mouth and arching
his body so that his rotated claspers point towards the females urogential opening (cloaca). Male 2 remains on the female’s right side.
(c) ‘Insertion/copulation’: Male 1 inserts his right clasper into the females cloaca. Note that Male 2 is also attempting insertion with his
left clasper. (d) ‘Insertion/copulation’: Male 1 copulates in a ‘ventral to ventral’ (Yano et al. 1999) posture with the female. (e) ‘Resting’:
Male 1 finishes copulating, but his clasper remains inserted as he rapidly flutters his gills. Male 2 grasps the females disc, arches his
body and rotates his clasper into position (denoted by white arrow). (f ) Male 2 achieves insertion and copulates with the female. Male
1 maintains his oral grip and, possibly, the insertion of his clasper throughout (Male 1 is not visible because he is behind the female in
this frame). (g) Both males maintain an oral grip while rapidly fluttering their gills. Female swims slowly, towing both males. Soon after
(not shown), both males withdraw their claspers from the cloaca and move away from the female (male 1 departs and male 2 continues
to swim with the female slightly above the middle of her disc).