Observations of the mating behavior and dentition of the round stingray,Urolophus halleri

Abundance and distribution of the round stingray, Urobatis halleri, near a heated effluent outfall

“…Although several species of nearshore elasmobranchs have been observed to aggregate in shallow habitats close to the shoreline, few species have been shown to aggregate in such high densities as U. halleri. Russel (1955) and Babel (1967) both reported catching large numbers of U. halleri at Seal Beach and similar observations have been made of large aggregations of U. halleri close to shore in shallow bays during March in the Gulf of California (Nordell, 1994). Other species of stingrays, such as the Atlantic stingray (Dasyatis sabina), have also been reported to be abundant close to the shore of estuaries (Snelson & Williams, 1981;Snelson et al, 1988), although their abundances are substantially lower than U. halleri aggregations.…”

Functional implications of ontogenetic and sexual dimorphic dentition in the eastern shovelnose ray Aptychotrema rostrata (Shaw & Nodder, 1794)

“…This synchrony of development implies that the dentition may have a role in reproductive behaviour. Although the mating behaviour of A. rostrata has not been documented, it is likely to involve a pre-(and probably mid-) copulatory biting phase similar to that reported in many other elasmobranch species (Carrier et al, 1994;Johnson and Nelson, 1978;Kajiura et al, 2000;Klimley, 1980;McCourt and Kerstitch, 1980;Nordell, 1994;Tricas, 1980;Tricas and Lefeuvre, 1985;Young, 1993). Evidence for mating behaviour was witnessed during the study, as mature females both in the laboratory and during field collections had visible mating scars on the pectoral fins and cranial areas (A.N.G., personal observation).…”

Morphological abnormalities of round rays of the genus Urotrygon in the Gulf of Tehuantepec

“…The absence of a clasper found in a male of U. chilensis is a rare abnormality that would probably place this organism at a competitive disadvantage with respect to other males during reproduction. This is because in elasmobranchs, the male inserts only one of the two claspers (left or right) during reproduction (Carrier et al 1994;Chapmana et al 2003;Nordell 1994;Pratt and Carrier 2001;Whitney et al 2004), and in batoids, the male inserts the clasper opposite the pectoral fin of the female (left or right) that the male holds during copulation (Chapmana et al 2003). Therefore, a male with the left clasper absent would be limited during reproduction to holding the female on the left side.…”