Myliobatiformes Rhinopteridae (the cownose rays ) Jeff Guertin 12/04/07

Taxonomy One genera, 8-11? species Rhinoptera adspersa (1841) - Rough cownose ray Rhinoptera bonasus (1815) - Atlantic cownose ray Rhinoptera brasiliensis (1836) - Ticon cownose ray Rhinoptera javanica (1841) - Javanese cownose ray Rhinoptera jayakari (1895) - Oman cownose ray Rhinoptera marginata (1817) - Lusitanian cownose ray Rhinoptera neglecta (1912) - Australian cownose ray Rhinoptera steindachneri (1891) - Pacific cownose ray

Distinctive Features Much wider than long Much wider than long Eyes lateral Eyes lateral Subterminal mouth Subterminal mouth 5 pairs of gills 5 pairs of gills Large, flat crushing teeth Spiracles close to eyes Elongated tail No caudal fin

Atlantic cownose ray Javanese cownose ray Pacific cownose ray pup

General Characteristics Generally mid to dark brown dorsally, pale ventrally Generally mid to dark brown dorsally, pale ventrally Can migrate in large schools Can migrate in large schools May be triggered by water temperature May be triggered by water temperature Move through the water by oscillating the pecs in broad up and downstrokes which provide vertical lift similar to birds Move through the water by oscillating the pecs in broad up and downstrokes which provide vertical lift similar to birds Often confused as sharks when pectoral fins breach surface Often confused as sharks when pectoral fins breach surface

Habitat Benthopelagic (Marine and brackish), depths to 20m Rhinoptera bonasus - Eastern Atlantic, Western Atlantic, Gulf of Mexico Rhinoptera neglecta - Queensland to NSW Australia Rhinoptera javanica - S. Africa to Southern China

Food Habits Mostly benthic invertebrates Mostly benthic invertebrates Mostly thin-shelled bivalves Mostly thin-shelled bivalves Crustaceans Crustaceans Stirs up sediment by flapping pectoral fins to find prey Stirs up sediment by flapping pectoral fins to find prey Dental plate of Rhinoptera bonasus

Size, Age, & Growth Max length = 85cm (Australian cownose) - 216cm (Atlantic cownose ray) WD Max length = 85cm (Australian cownose) - 216cm (Atlantic cownose ray) WD Atlantic cownose ray Atlantic cownose ray DW = 36cm at birth; considerable variation of size at maturity depending on geography DW = 36cm at birth; considerable variation of size at maturity depending on geography Live to 16+ years (males) and 18+ years (females) Live to 16+ years (males) and 18+ years (females)

Reproduction Ovoviviparous Generally one young/litter (but up to 6 embryos have been found) Atlantic cownose ray Breeding period June - October Gestation believed to be months (maybe two 5- 6 month periods?) Females keep pecs out of water to avoid males

Conservation 4 Listed Atlantic Cownose Ray - Near Threatened Pacific Cownose Ray - Near Threatened Brazilian/Ticon Cownose Ray - Endangered Javanese Cownose Ray - Vulnerable Low fecundity, harvesting (esp. in Asia) and by-catch (gillnets, shrimp trawlers, beach seine)

Bibliography Carrier, J,, Musick, J., and Heithaus, M Biology of Sharks and Their Relatives. CRC Press, Boca Raton. Collins A.B., Heupel M.R., Motta P.J Residence and movement patterns of cownose rays Rhinoptera bonasus within a south-west Florida estuary. Journal of Fish Biology 71 (4): 1159–1178. Collins A.B., Heupel M.R., Motta P.J Residence and movement patterns of cownose rays Rhinoptera bonasus within a south-west Florida estuary. Journal of Fish Biology 71 (4): 1159–1178. Florida Museum of National History.. Downloaded on 01 December IUCN IUCN Red List of Threatened Species.. Downloaded on 01 December Life history of the cownose ray, Rhinoptera bonasus, in the northern Gulf of Mexico, with comments on geographic variability in life history traits. Environmental Biology of Fishes 73: Neer J. and Thompson B Life history of the cownose ray, Rhinoptera bonasus, in the northern Gulf of Mexico, with comments on geographic variability in life history traits. Environmental Biology of Fishes 73: